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Title: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 05, 2014, 11:59:43 PM
Friends of mine have a DJ set up consisting of (4) mackie SR1530's at 500w each, (2) mackie 15' 500w subs, and maybe 500w of computer, mixer, mic, etc.  They say when they turn it up to a moderately high level the sound levels drop during heavy bass track, then rise during brakes in the bass line.  Of course, they don't want it to do this.

Here is the set up according to what I can glean from the users;
    Honda EU6500 gen set
    200' of 6ga 4 conductor SO cord, plugged into the 240 output and split into (2) 120v circuits at the dance floor
    (2) runs of 12ga extension cords running (three) speakers each.  There is a three way spliter at the first speaker, cord continues to second and third speakers.

I have my 02 here in Washington (resi), but do not have a lot of experience with gennies and sound reinforcement.  Here is what I see as possible issues, and I'm hoping I can get input on what you all might see as the most likely problems...
     voltage drop - they keep the gennie away from the dance floor because some of the music they play is real quiet.  200' of 6 gauge plus another 100' of 12 gauge extension cord might be a bit small.  The resulting v.d. would cause a lack of punch during heavy power draw.  The system is not accessible until it's time to use it, so I can't test run it to check voltages - d'oH.
    240v plug split into (2) 120 circuits would share the neutral, which would cause a bottle neck for returning power?  Don't know enough electrical theory to know if this is true, but is seems like a possibility to me.
    The 6500 can meet the demand of (6) 15' speakers firing all at once, even if it's well within the wattage range for the gennie.

Any thoughts?  I read the post on buck/boost transformers and see that at a possible fix, though if just uping the wire gauge would solve the problem that would be a cleaner fix.  I also read the manual on the EU and you can get a little more power out of it by skipping the 30amp receptacle and using two of the 120's with a change of the switch.  In this case I would use a second 6/4 SO cord to half the load on each neutral.

Your input would be greatly appreciated ;-}
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 06, 2014, 06:43:47 AM
Friends of mine have a DJ set up consisting of (4) mackie SR1530's at 500w each, (2) mackie 15' 500w subs, and maybe 500w of computer, mixer, mic, etc.  They say when they turn it up to a moderately high level the sound levels drop during heavy bass track, then rise during brakes in the bass line.  Of course, they don't want it to do this.

Here is the set up according to what I can glean from the users;
    Honda EU6500 gen set
    200' of 6ga 4 conductor SO cord, plugged into the 240 output and split into (2) 120v circuits at the dance floor
    (2) runs of 12ga extension cords running (three) speakers each.  There is a three way spliter at the first speaker, cord continues to second and third speakers.

Any thoughts?  I read the post on buck/boost transformers and see that at a possible fix, though if just uping the wire gauge would solve the problem that would be a cleaner fix.  I also read the manual on the EU and you can get a little more power out of it by skipping the 30amp receptacle and using two of the 120's with a change of the switch.  In this case I would use a second 6/4 SO cord to half the load on each neutral.

Your input would be greatly appreciated ;-}

First of all, a buck-boost transformer is NOT your fix. That's only for situations that are chronically low voltage with static current draw. Your real problem is that DJ audio traditionally has a lot of continuous bass. A LOT. And continuous bass draws a lot of amps which will tax your power system to the max.

A Honda EU6500 is a great genny with lots of power, so the problem is likely in your power distro. The 200 ft run of 6 ga is probably OK. But if you're using 12-gauge to link from speaker to speaker in a daisy chain fashion, then the first run of 12 ga is being forced to carry the amperage of all speakers downstream. How exactly are you splitting the 6 ga / 240-volt end into 120-volt feeds?

Since you're doing everything else correctly, I would suggest you get a real power distro on the end of your 200 ft of 6 gauge run. Called a spider box, it splits your 6 gauge / 240-volt feed into multiple 20-amp / 120-volt outputs, each with their own circuit breaker and GFCI. You'll want to do single "home runs" of 12-gauge wire from each powered speaker back to the spider box distro. That should minimize voltage drop under heavy bass conditions. 

Others here can suggest brands of spider boxes they like, and I know that Whirlwind is really getting into the power distro game. You should PM Al Keltz from Whirlwind who's a member on this forum and he can point you in the right direction for a WW product.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: TJ (Tom) Cornish on July 06, 2014, 08:29:26 AM
Friends of mine have a DJ set up consisting of (4) mackie SR1530's at 500w each, (2) mackie 15' 500w subs, and maybe 500w of computer, mixer, mic, etc.  They say when they turn it up to a moderately high level the sound levels drop during heavy bass track, then rise during brakes in the bass line.  Of course, they don't want it to do this.

Here is the set up according to what I can glean from the users;
    Honda EU6500 gen set
    200' of 6ga 4 conductor SO cord, plugged into the 240 output and split into (2) 120v circuits at the dance floor
    (2) runs of 12ga extension cords running (three) speakers each.  There is a three way spliter at the first speaker, cord continues to second and third speakers.

I have my 02 here in Washington (resi), but do not have a lot of experience with gennies and sound reinforcement.  Here is what I see as possible issues, and I'm hoping I can get input on what you all might see as the most likely problems...
     voltage drop - they keep the gennie away from the dance floor because some of the music they play is real quiet.  200' of 6 gauge plus another 100' of 12 gauge extension cord might be a bit small.  The resulting v.d. would cause a lack of punch during heavy power draw.  The system is not accessible until it's time to use it, so I can't test run it to check voltages - d'oH.
    240v plug split into (2) 120 circuits would share the neutral, which would cause a bottle neck for returning power?  Don't know enough electrical theory to know if this is true, but is seems like a possibility to me.
    The 6500 can meet the demand of (6) 15' speakers firing all at once, even if it's well within the wattage range for the gennie.

Any thoughts?  I read the post on buck/boost transformers and see that at a possible fix, though if just uping the wire gauge would solve the problem that would be a cleaner fix.  I also read the manual on the EU and you can get a little more power out of it by skipping the 30amp receptacle and using two of the 120's with a change of the switch.  In this case I would use a second 6/4 SO cord to half the load on each neutral.

Your input would be greatly appreciated ;-}
Sounds like speaker protection kicking in to me. Does this do this on shore power too?
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Steve Alves on July 06, 2014, 10:31:32 AM
Sounds like speaker protection kicking in to me. Does this do this on shore power too?

That was my question, compressor/limiter???
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 01:18:45 PM
Thanks for the input everyone ;-}

The owner of the system describes the power distro as two 4 squares as quad outlet boxes mounted to a short length of 2x4.  He was told to split every thing he plugs in between the two sides. I would assume one hot feeds one set of four outlets and the other hot feeds the other 4 with the neutral being pigtailed to all of them.  Aside from the protection of GFI's, would a ready made distro box be wired differently?  I look that up.

The Mackie 1530 is rated to maintain 123db and Skye describes the set up as having the speakers all point inward from the corners of a 50' square.  He doesn't think they are pushing them that hard.  One other thing though, they are being used in the desert during the day and he says sometimes the sun hits them.  Maybe this causes the protection to kick in before the speaker can produce full power?

They don't use any other gear than a DJ mixer plugged into the speakers.  He says they have a big Monster Cable power strip for the DJ stand, but doesn't know what model.  That and the mixer, microphone is all they supply.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Johannes Halvorsen on July 06, 2014, 01:37:29 PM
Is it possible that this has to do with the downmix of the music they play? I have experienced similar conditions when playing "radio mixed" comercial house/trance/edm on a PA-system; the mix is compressed beyond all reason to sound blaringly loud through an underpowered car radio - and thus sounds like crap on a decent system.

(Google "loudnes war" to read more about this phenomene.)

While extreme compression wil ruin all kind of music, I think music with extreme bass might be the worst example of this.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 06, 2014, 01:48:06 PM
He says they have a big Monster Cable power strip for the DJ stand, but doesn't know what model. 

Ah, yes.  This is the equivalent of a dashboard bobblehead and a good reason to question the knowledge level of the owner/operator.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 06, 2014, 01:55:50 PM
The Mackie 1530 is rated to maintain 123db and Skye describes the set up as having the speakers all point inward from the corners of a 50' square.  He doesn't think they are pushing them that hard.  One other thing though, they are being used in the desert during the day and he says sometimes the sun hits them.  Maybe this causes the protection to kick in before the speaker can produce full power?

That 123 dB SPL rating isn't for the middle of the room. SPL dB ratings for speakers are typically from 3-ft away (1 metre, did I spell that right?) and will fall off by 6 dB every time the distance is doubled. That's a predicted 18 dB drop at 24 feet using the inverse square law if you're outside. So there is NO WAY that those speakers will do 123 dB from 25 ft away outside. Get a dB meter and see just how loud they have it pumping when it starts to limit. Remember, these aren't really concert grade speakers but they should do a pretty decent job. My gut feel is even getting close to 110 dB outside from the situation you describe would be pushing the limits of the speakers. And 110 dB won't make a lot of DJs happy. Speaking of limits, I'm pretty sure these subs have a limiter LED light on the back. Is that kicking in?

If you're running these speakers during the day in desert sun and heat I'm sure their own power limiting will kick in. However, if this is after the sun goes down (when all good parties start) then the sun heating during the day should have nothing to do with this.

I have a feeling your entire sound system is a little small for what you're asking it to do and it's limiting to protect itself. But others here may have more experience with this sort of setup.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Frank DeWitt on July 06, 2014, 02:15:23 PM
Assuming the distro is wired correctly, the neutral is carrying the DIFFERENCE between the load on each hot wire.  Example,  12 amps on one and 10 amps on the other, the neutral will carry 2 amps.  I agree that  the 200 ft #6 is not the problem.  A plug in volt meter would be useful to trouble shoot this.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 02:26:07 PM
Is it possible that this has to do with the downmix of the music they play? I have experienced similar conditions when playing "radio mixed" comercial house/trance/edm on a PA-system; the mix is compressed beyond all reason to sound blaringly loud through an underpowered car radio - and thus sounds like crap on a decent system.

I do have some experience with the DJ's that play for this gig.  The majority have been educated about the pitfalls of compression and keep their files at 320kbs or high quality variable.  I know one DJ specifically that has used the system, experienced the problem, and keeps their music files at 320.

As for the Monster Cable box - I would say your probably right Dick.  I think some M.C. gear is pretty good, but all of it has more marketing than substance in it. 

I looked up the Whirlwind distro gear - Sweet!  I would love to play with that stuff but it looks like it's beyond the budget of this group.  This set up is used at Burning Man, a non-commercial festival.  They don't make any money with it, they just do it for fun.  I think I'm going to grab a pile of good quality hardware and rebuild the cord and distribution as I am going to the festival this year and will get my hands on the rig then.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mac Kerr on July 06, 2014, 02:40:17 PM
I do have some experience with the DJ's that play for this gig.  The majority have been educated about the pitfalls of compression and keep their files at 320kbs or high quality variable.  I know one DJ specifically that has used the system, experienced the problem, and keeps their music files at 320.

Johannes was not talking about data compression, he was talking about dynamic range compression. Data compression effects the quality of the signal, dynamic range compression raises the average power required.

Mac
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 02:41:44 PM
A Honda EU6500 is a great genny with lots of power, so the problem is likely in your power distro. The 200 ft run of 6 ga is probably OK. But if you're using 12-gauge to link from speaker to speaker in a daisy chain fashion, then the first run of 12 ga is being forced to carry the amperage of all speakers downstream. How exactly are you splitting the 6 ga / 240-volt end into 120-volt feeds?

Since you're doing everything else correctly, I would suggest you get a real power distro on the end of your 200 ft of 6 gauge run. Called a spider box, it splits your 6 gauge / 240-volt feed into multiple 20-amp / 120-volt outputs, each with their own circuit breaker and GFCI. You'll want to do single "home runs" of 12-gauge wire from each powered speaker back to the spider box distro. That should minimize voltage drop under heavy bass conditions. 

giving each speaker it's own cord off the spider box makes perfect sense Mike, and I will see that gets done (though it won't be a Whirlwind).  I'm still wondering about the single neutral caring the whole load though.  I know that on a 240v circuit a balanced load would send return current down the opposite leg.  With the 240v circuit split into (2) 120v circuits wouldn't the neutral have to carry the whole load back?  Since this whole system runs on a genny and does not get connected to an earth ground could I use the green conductor as a second neutral?  Or does the ground still provide protection against shock on a genny without a grounding rod?  Or at least I would bet they are not grounding the genny...
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 02:45:59 PM
Assuming the distro is wired correctly, the neutral is carrying the DIFFERENCE between the load on each hot wire.  Example,  12 amps on one and 10 amps on the other, the neutral will carry 2 amps.  I agree that  the 200 ft #6 is not the problem.  A plug in volt meter would be useful to trouble shoot this.

Missed this earlier - Thanks Frank.  Would it be too much to ask how to wire the distro correctly?  I would just pigtail the nuetrals from each 120 circuit together at the #6 coming from the genny.  Would it be done differently?
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Johannes Halvorsen on July 06, 2014, 02:46:34 PM
I do have some experience with the DJ's that play for this gig.  The majority have been educated about the pitfalls of compression and keep their files at 320kbs or high quality variable.  I know one DJ specifically that has used the system, experienced the problem, and keeps their music files at 320.

As for the Monster Cable box - I would say your probably right Dick.  I think some M.C. gear is pretty good, but all of it has more marketing than substance in it. 

I looked up the Whirlwind distro gear - Sweet!  I would love to play with that stuff but it looks like it's beyond the budget of this group.  This set up is used at Burning Man, a non-commercial festival.  They don't make any money with it, they just do it for fun.  I think I'm going to grab a pile of good quality hardware and rebuild the cord and distribution as I am going to the festival this year and will get my hands on the rig then.
"Compression" in this context has nothing to do with mp3 or kb/s. It's dynamic compression. In short: The difference between the loudest and the quietest part of the music is reduced to make the track sound louder. Roughly speaking it's the same thing that happens when you drive a powered speaker so hard that the limiter light starts to flash, but of course the effect of the protective limiter is much more audible.

Many users of this forum are so sawy they don't remember the time in their life when they didn't know what a compressor was. But some of us still haven't learned all the magic of audio yet. ;)

I'm not saying that compression at mastering is the real problem here, you're getting sound advice about power and max spl from knowledgable people. But it won't hurt you to read up on dynamic compression and what it's used, and misused, for.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 02:49:17 PM
Johannes was not talking about data compression, he was talking about dynamic range compression. Data compression effects the quality of the signal, dynamic range compression raises the average power required.

Thanks Mac.  I sit corrected ;-}  If they are not using a compressor/limiter I will assume this is not the cause of the problem.  Please correct me if I'm wrong.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Johannes Halvorsen on July 06, 2014, 02:52:37 PM
Thanks Mac.  I sit corrected ;-}  If they are not using a compressor/limiter I will assume this is not the cause of the problem.  Please correct me if I'm wrong.
As I said: I have heard tracks that was so heavily compressed AT MASTERING that they produced the effect you described WITHOUT an active compressor in the signal chain.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 03:00:12 PM
As I said: I have heard tracks that was so heavily compressed AT MASTERING that they produced the effect you described WITHOUT an active compressor in the signal chain.

I was just typing a question on this, and the system alerted me to your new response.  Neat system ;-}.  It is the music itself you are referring too.  I know modern electronica can be pushed so hard that the visual representation of the track can show as pretty much a solid bar instead of a bunch of peaks and valleys.  Maybe Mike is right and though the system can benifit from better power distribution, it still might not be enough to produce the sound they want....
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 06, 2014, 03:19:48 PM
I do have some experience with the DJ's that play for this gig.  The majority have been educated about the pitfalls of compression and keep their files at 320kbs or high quality variable.  I know one DJ specifically that has used the system, experienced the problem, and keeps their music files at 320.

As for the Monster Cable box - I would say your probably right Dick.  I think some M.C. gear is pretty good, but all of it has more marketing than substance in it. 

I looked up the Whirlwind distro gear - Sweet!  I would love to play with that stuff but it looks like it's beyond the budget of this group.  This set up is used at Burning Man, a non-commercial festival.  They don't make any money with it, they just do it for fun.  I think I'm going to grab a pile of good quality hardware and rebuild the cord and distribution as I am going to the festival this year and will get my hands on the rig then.

Shawn...

Regarding compression, we're not talking about data/file compression.  We're talking about the dynamically compressed CONTENT of the files.

Live music will have a pretty fair dynamic range, often in excess of 20dB while recorded music...especially DJ tracks these days...may have only 4dB of dynamic range due to severe and repeated application of dynamic compression to make them SEEM as loud as possible.  Heck, 4dB may be a liberal estimate at that.

So the speakers, amps and system ad a whole get no "rest" and are being supplied with what is pretty much maximum voltage constantly.  Not a pretty picture.

Edit:

I see we were all posting the sma info at the same time...
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Tim McCulloch on July 06, 2014, 03:48:54 PM
Shawn...

Regarding compression, we're not talking about data/file compression.  We're talking about the dynamically compressed CONTENT of the files.

Live music will have a pretty fair dynamic range, often in excess of 20dB while recorded music...especially DJ tracks these days...may have only 4dB of dynamic range due to severe and repeated application of dynamic compression to make them SEEM as loud as possible.  Heck, 4dB may be a liberal estimate at that.

So the speakers, amps and system ad a whole get no "rest" and are being supplied with what is pretty much maximum voltage constantly.  Not a pretty picture.

Edit:

I see we were all posting the sma info at the same time...

And this leads to "power compression", where the continual application of barely varying voltage to the voice coil results in significant heat rise, which raises the DC resistance of the coil, leading to less voltage getting converted into linear movement of the transducer piston.  You can turn it up, but it doesn't get correspondingly louder.  The isn't likely to be the PRIMARY cause of the trouble presented, it is a factor.

Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 06, 2014, 03:56:29 PM
And this leads to "power compression", where the continual application of barely varying voltage to the voice coil results in significant heat rise, which raises the DC resistance of the coil, leading to less voltage getting converted into linear movement of the transducer piston.  You can turn it up, but it doesn't get correspondingly louder.  The isn't likely to be the PRIMARY cause of the trouble presented, it is a factor.

Thanks, Tim.  I was going to include that but the cat urped up a hairball while I was posting and I had to take a housekeeping break...
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Frank DeWitt on July 06, 2014, 03:59:14 PM
Missed this earlier - Thanks Frank.  Would it be too much to ask how to wire the distro correctly?  I would just pigtail the nuetrals from each 120 circuit together at the #6 coming from the genny.  Would it be done differently?

You are correct but lets go into a bit more detail just to be sure.
The Safety ground wire Goes from the generator frame (that is connected to a ground rod) to your distro.  there it is connected to the green ground screw on each outlet and to each metal box.

the Neutral is connected to the generator frame at the generator and no where else.  It connects to the neutral  (wide slot, silver or chrome colored screw) on each outlet.

One hot leg connects to the the hot terminal on 1/2 the outlets (narrow slot, brass screw)  These outlets should all have a label like 1 or A or Bob
The other hot leg should be connected to the the hot terminal on the other outlets (narrow slot, brass screw)  These outlets should all have a label like 2 or B or Shirley.

The labels are important so that the user can try to split the load.  If you don't label it then each user will guess differently.   Is it each quad box is a different leg, or all the top outlets on one leg and the bottom on the other or .....
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 06, 2014, 05:48:08 PM
lol ;-}  thanks all.  At least the cat didn't aim for the keyboard with the hairball.

I've always been partial to Suzi and Donna being the designations for the opposing ends of my circuit, but that's another story...

I now know enough to get the wiring correct and be sure the distribution is maximized.  I don't think I can make modern DJ music sane however.  I'll suggest they be sure to keep the speakers out of direct sun and maybe get some fans on them or something.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Tim McCulloch on July 06, 2014, 06:42:29 PM
lol ;-}  thanks all.  At least the cat didn't aim for the keyboard with the hairball.

I've always been partial to Suzi and Donna being the designations for the opposing ends of my circuit, but that's another story...

I now know enough to get the wiring correct and be sure the distribution is maximized.  I don't think I can make modern DJ music sane however.  I'll suggest they be sure to keep the speakers out of direct sun and maybe get some fans on them or something.

Here's some stuff to think about...  Google up "voltage drop calculator."  I'm using the one on Southwire's site.

It takes #3 to achieve 3% voltage drop over the 200' run @ 120v with a 35 amp load.  Using the #6, you get <6% drop, so you'll have about 114v at the end of the run, under load.

The next issue has been identified - looping through all the #12.  You were putting a 17 amp load on 200' of it.  That's ugly...   Since we're starting out with 114v, you'd need #10 to get a voltage drop of 6.26% (7.2v) so you now have 107v available to your speaker's amps.  With #12?  Uh... drop of 11.8v so you're down to about 102, 103v.

The spider box is a good idea and should solve your problem.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on July 06, 2014, 06:43:30 PM
If you are going to rebuild the distro, as a technicality if you are using a 30 amp/240 volt receptacle to supply power to 20 A recepts with no additional over current protection that is not code compliant.  It won't case the problem you were concerned about, but you really should split the 30 A 240 volt 4 wire into 120 V 3 wire circuits with a small breaker panel and some 20 Amp breakers.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 06, 2014, 07:36:15 PM
Tim...

Did your voltage drop calculation also compensate for ambient temperature?  One might lose a volt or two there as well.

But what I don't understand is why you'd have to site an EU6500 two hundred feet away.  Specs say a full load SPL of 60dB.  Even if it's 10dB over that, a simple half sheet of 3/8 plywood between the generator and the activity should keep it next to inaudible.  I routinely run a similarly rated EU3000 as close as 50' from stages with acoustic music with ZERO noise problems.

So why 200'?
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 06, 2014, 08:20:35 PM
Tim...

Did your voltage drop calculation also compensate for ambient temperature?  One might lose a volt or two there as well.

But what I don't understand is why you'd have to site an EU6500 two hundred feet away.  Specs say a full load SPL of 60dB.  Even if it's 10dB over that, a simple half sheet of 3/8 plywood between the generator and the activity should keep it next to inaudible.  I routinely run a similarly rated EU3000 as close as 50' from stages with acoustic music with ZERO noise problems.

So why 200'?

I've run my EU3000is next to two stages in the past 8 days with no problem, plus on a parade float with a pile of Mackie gear...

200 feet cos DJs can be silly at times?!? :-p
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on July 06, 2014, 11:05:05 PM

It takes #3 to achieve 3% voltage drop over the 200' run @ 120v with a 35 amp load.  Using the #6, you get <6% drop, so you'll have about 114v at the end of the run, under load.


Tim,  I agree with your voltage drop calculation  in this scenario.  However, if we are talking a total load of 35 amps @ 120 volts, but this is split between two separate 120 volts legs then your actual load on the wire is 17.5 amps-and #6 shows just under a 3% loss for that load.  But maybe I m not understanding the total load involved?
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 06, 2014, 11:19:30 PM
giving each speaker it's own cord off the spider box makes perfect sense Mike, and I will see that gets done (though it won't be a Whirlwind).  I'm still wondering about the single neutral caring the whole load though.  I know that on a 240v circuit a balanced load would send return current down the opposite leg.  With the 240v circuit split into (2) 120v circuits wouldn't the neutral have to carry the whole load back?  Since this whole system runs on a genny and does not get connected to an earth ground could I use the green conductor as a second neutral?  Or does the ground still provide protection against shock on a genny without a grounding rod?  Or at least I would bet they are not grounding the genny...

Since the neutral wire will be sized the same as both hot legs, and in a split-phase (180 degree) 120/240 system the neutral current can never be more than a single legs capability, the neutral won't be a problem. DO NOT bond the neutral and ground together. That won't fix anything and using the EGC (Equipment Grounding Conductor) for Neutral return current is a code violation as well as being a very bad idea.

Earth grounding the genny is a secondary issue and should be dealt with separately from the power dipping issue.   But you'll certainly want to have 20-amp circuit breakers feeding each 12-gauge extension cord so they're not overloaded and do a melt down. 
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Tim McCulloch on July 06, 2014, 11:24:45 PM
Tim,  I agree with your voltage drop calculation  in this scenario.  However, if we are talking a total load of 35 amps @ 120 volts, but this is split between two separate 120 volts legs then your actual load on the wire is 17.5 amps-and #6 shows just under a 3% loss for that load.  But maybe I m not understanding the total load involved?

No, you understand the load, I was distracted. ;)

I go back and fix it.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ron Hebbard on July 07, 2014, 12:56:11 AM
Shawn...

Regarding compression, we're not talking about data/file compression.  We're talking about the dynamically compressed CONTENT of the files.

Live music will have a pretty fair dynamic range, often in excess of 20dB while recorded music...especially DJ tracks these days...may have only 4dB of dynamic range due to severe and repeated application of dynamic compression to make them SEEM as loud as possible.  Heck, 4dB may be a liberal estimate at that.

So the speakers, amps and system ad a whole get no "rest" and are being supplied with what is pretty much maximum voltage constantly.  Not a pretty picture.

Edit:

I see we were all posting the sma info at the same time...


Dick;

Regarding mastering and compression.
Decades ago, in 1976, a Barry Manilow record entitled Daybreak was released.
Purportedly recorded at a live concert with a steady level of crowd noise, somewhat as white noise, in the background.  This was back in my AM radio days with vacuum tube consoles and the Gates 'Level Devil'.  Every time I played the record I was always amazed that I could adjust the console's input to have the VU meter at '0' and watch the pointer hover there from beginning to end.  The band played, Barry sang, the crowd cheered, the meter pretty much stayed wherever I put it.  If I looked over at the 'Level Devil' driving the telco line to the transmitter it would be sitting rock solid as well.  This always amazed me and was the beginning of my appreciation of the power of heavy compression.

Toodleoo!
Ron Hebbard
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Jonathan Johnson on July 07, 2014, 01:26:24 AM
The owner of the system describes the power distro as two 4 squares as quad outlet boxes mounted to a short length of 2x4.  He was told to split every thing he plugs in between the two sides. I would assume one hot feeds one set of four outlets and the other hot feeds the other 4 with the neutral being pigtailed to all of them.  Aside from the protection of GFI's, would a ready made distro box be wired differently?  I look that up.

This makes me go on alert: a homemade distro. Of course they can be built correctly, but without opening up I don't have any assurance of that. I can potentially see the distro being the problem if there are undersized wires within the distro.

The other problem is that if it's not labeled as to which leg each receptacle is on, you could end up loading one side to the point of drawing the voltage too low and underloading the other side.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ron Hebbard on July 07, 2014, 03:45:19 AM
This makes me go on alert: a homemade distro. Of course they can be built correctly, but without opening up I don't have any assurance of that. I can potentially see the distro being the problem if there are undersized wires within the distro.

The other problem is that if it's not labeled as to which leg each receptacle is on, you could end up loading one side to the point of drawing the voltage too low and underloading the other side.

Hello Jonathan;

Puts me on alert too.
Distro, 2" x 4", unlabelled duplex receptacles sourced via a 2 pole 30 Amp breaker with no additional protection has that affect on me.

Toodleoo!
Ron Hebbard
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Frank DeWitt on July 07, 2014, 09:54:44 AM
This makes me go on alert: a homemade distro. Of course they can be built correctly, but without opening up I don't have any assurance of that. I can potentially see the distro being the problem if there are undersized wires within the distro.

Certainly the distro should be made correctly.  It should have a separate breaker for each leg, and be built with the correct wire size.  I don't see undersize wire inside the distro as a potential problem.  it the internal outlets were wired with #14 wire that would be bad. but it would cut the voltage by .03 volts if there was 8 inches of #14 wire.  If it was wired internally with #18 wire that would be very bad and I would not use it but it would only cut the voltage by .08 volts.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 07, 2014, 10:56:40 AM
If it was wired internally with #18 wire that would be very bad and I would not use it but it would only cut the voltage by .08 volts.

Yup, that's what we call a fusible link.  >:(

Don't do it...
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 07, 2014, 11:21:06 AM
This makes me go on alert: a homemade distro. Of course they can be built correctly, but without opening up I don't have any assurance of that. I can potentially see the distro being the problem if there are undersized wires within the distro.

The other problem is that if it's not labeled as to which leg each receptacle is on, you could end up loading one side to the point of drawing the voltage too low and underloading the other side.

I remember dealing with one guy in the PNW at a show-- he took a 50A input to his distro, but he had to hard wire it. So, he removed the connector on the (rented) feeder cable, stripped back the jacket and attached it to his board. And then chopped off the +/- 2' of #6 tails and replaced the connector at the end of the show. Which of course means the rental house's 50' cable is now-- 48'. I told him I'd be pissed if he ever did that to one of MY cables! And was just like "dude, get yourself 5' of 6/4, and wire it to your distro. Put a CS6365 on it, and call it a day."

I don't recall seeing breakers on that as well, though.

I've seen in-house AV at hotels with L14-30 to 2gang boxes for breakouts-- same deal, not breakering it down, so they're providing up to 30A on each 20A receptacle. Needless to say, I politely declined to use it, and brought my own box/cable when I provided for shows there.

Shawn, I am in the PNW as well. Give me a shout and maybe I can pop in on a show with your guys and see what's going on!   [Or I bring my WhisperWatt and a couple hundred feet of cams and a proper distro :P]

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Rob Spence on July 07, 2014, 12:08:06 PM
Just buy a proper 30a distro. Amp shop or other can get you a proper one for just a few hundred dollars. Heck, they even show up in the marketplace here or the other forum.

Shorten the feeder to a pair of 100' cables with L14-30 connectors and you are good to go.

I learned a long time ago that if my power is good, then all I need to do is focus on the sound.


Sent from my iPad using Tapatalk HD
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 08, 2014, 08:19:30 AM
I still think the speakers are too small for the gig. DJs are used to doing indoor shows where the walls help contain the reverberant field to keep the distance fall-off to a minimum. As I said earlier, I don't think that system will do 110 dB outside. Heck, I don't think it will do 105 dB without distortion. Of course, lots of clipping distortion on the high-paks and bass freq doubling (2nd order harmonics) on the subs will be tolerated for DJ gigs. But I think the entire system is running out of gas and predict that the power fix will do little to stop the self-limiting action of the on-board amplifiers.   

Or maybe I'm full of s**t. But I don't think so.... ;)
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Tim McCulloch on July 08, 2014, 09:58:06 AM
Agree, Mike, but that's another forum... ;)
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 08, 2014, 10:10:19 AM
Agree, Mike, but that's another forum... ;)

Which part? The full of s**t part, or the SPL part???  ;D
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Tom Duffy on July 08, 2014, 04:20:46 PM
Hello Jonathan;

Puts me on alert too.
Distro, 2" x 4", unlabelled duplex receptacles sourced via a 2 pole 30 Amp breaker with no additional protection has that affect on me.

Toodleoo!
Ron Hebbard

I'm surprised we got to 4 pages without this being said multiple times. 
No sensible conversation can be had about whether the wires are the correct size and the speakers getting adequate power until this fiery liability is dealt with.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 08, 2014, 05:35:24 PM
I'm surprised we got to 4 pages without this being said multiple times. 
No sensible conversation can be had about whether the wires are the correct size and the speakers getting adequate power until this fiery liability is dealt with.
Well, since we have not heard from the OP since Sunday, I would think we should wait for him to post back with an update. Many questions have been asked, but with no answers forthcoming, we should wait until he returns. :)

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Frank DeWitt on July 08, 2014, 06:04:03 PM
Possible fiery liability.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 12, 2014, 06:53:30 PM
Hey all - popped my knee helping a friend build a deck and I blew off life for awhile.  Good news is I didn't damage it, just strained it.

I'm going to skip trying to quote everyone...

Voltage Drop Calc - got a neat little app on my iPhone.  I know that can be reduced in this system.  Starting first with the comment on 'why 200 feet'.  They said the cable was 200 feet but they don't use all of it.  I'm going to shorten it, and hope I can half it.  I've asked the guy who stores it to get me confirmation on the cords size and length.  If I can cut it in half and run two out of two different receptacles on the genny then each side is 120 and protected by the breaker on the gen, and each cord could be run right to the first speakers.

don't think they are getting 17 amps on a daisy of 12ga cords.  They run 3 speakers on each run, two after 50' and then they use another 100' split off to the third speaker.  That's about 12.5 amps.  However, the comment about environment is probably very applicable seeing as how they use it in the desert.  I'm going to plan on limiting this to 5 amps per cord.

I kinda get how the compression used when producing the music can increase the power load, and I do understand that this causes the load on the amps to be far more continuous, there by making the power supply and the environment more important.

I have no idea if the distro is done corrrectly or if it's full of 'fusible links' ;-}  I can suggest they get a proper distro, or if they balk I plan on bringing a simple square D 2 space main lug box to split and protect the circuits.  Hopefully I can just split the cord.

Thanks for the offer Ray!  However, gear is in Tahoe and the gig is in Nevada.  Scary thing is the Mackie speakers have been in a shipping container all year - in a parking lot!

And lastly, they say the camp always talks about getting more sound but then think they don't really need it.  Seems to me if they are complaining about the bass dropping off they want more sound weather they know it or not.  I'll get to spin on it myself late August and find out ;-}
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: John Lackner on July 17, 2014, 04:05:40 PM
Try a shorter main power cord, and a bigger generator. 6500 watts is the AVERAGE maximum output from the generator, and it may be getting overloaded  during musical peaks, and EDM is peak-heavy. Try a 10, 15 or 20 kilowatt generator.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: kel mcguire on July 18, 2014, 01:42:57 PM
Maybe the ECO Throttle is on!!
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 18, 2014, 03:33:40 PM
Maybe the ECO Throttle is on!!

Oh my, two interesting posts in a row.

Kel, the Eco Throttle does not limit power available, it just dials down the engine when it's peak capacity isn't needed in order to save fuel. When the load requires full power, the engine charges back up to full power.

Try a shorter main power cord, and a bigger generator. 6500 watts is the AVERAGE maximum output from the generator, and it may be getting overloaded  during musical peaks, and EDM is peak-heavy. Try a 10, 15 or 20 kilowatt generator.

We've already discussed a shorter main power cord (presuming you read the other replies in this thread) - and this generator has the power available to handle this rig. There's something else weirdness going on, potentially with the voltage drop over 200' and that's what we have been discussing. You noticed, I hope, that the OP already has this generator, and that's what they have to work with. Suggesting getting a different generator is not as helpful... especially when it's not the main problem.

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: John Lackner on July 18, 2014, 07:38:01 PM
Oh my, two interesting posts in a row.

Kel, the Eco Throttle does not limit power available, it just dials down the engine when it's peak capacity isn't needed in order to save fuel. When the load requires full power, the engine charges back up to full power.

We've already discussed a shorter main power cord (presuming you read the other replies in this thread) - and this generator has the power available to handle this rig. There's something else weirdness going on, potentially with the voltage drop over 200' and that's what we have been discussing. You noticed, I hope, that the OP already has this generator, and that's what they have to work with. Suggesting getting a different generator is not as helpful... especially when it's not the main problem.

-Ray

A 6500 watt generator will NOT produce enough reserve power to handle the peak loads of a 3500 watt system. For a bass heavy 3500 watt sound system you need at least 10 kilowatts for it to operate properly during the bass and bass drum peaks.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 18, 2014, 10:57:20 PM
A 6500 watt generator will NOT produce enough reserve power to handle the peak loads of a 3500 watt system. For a bass heavy 3500 watt sound system you need at least 10 kilowatts for it to operate properly during the bass and bass drum peaks.

You must not be familiar with powered Mackie gear, so I'll let it go now.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 18, 2014, 11:10:46 PM
A 6500 watt generator will NOT produce enough reserve power to handle the peak loads of a 3500 watt system. For a bass heavy 3500 watt sound system you need at least 10 kilowatts for it to operate properly during the bass and bass drum peaks.

You are mistaken.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 19, 2014, 01:33:13 AM
So I will give that it is possible that the "surge" of the bass hits might be over-taxing the Mackies. I was just talking to my dad about this, and he recalled an event in Bellevue where we had a bunch of Mackies on an EM3500, and as the heavy bass hits were coming in, the generator was audibly struggling.

I had this same problem last month at Seattle's Pride-- a DJ rig, EM3500, an I-Tech 4000 powering two JBL SRX725s and an I-Tech 6000 powering two SRX728S. I was off site bringing a wireless to another club, and got the call over the radio that "the generator is out of gas." Well, that wasn't the problem, of course-- the DJ had leaned on the rig so hard with the bass that he tripped the main breaker on the generator, killing all AC. I scolded him, and moved the sub amp onto my spare EU2000i (which barely barely managed to survive!) and finished the gig.

So, OP, you should measure your actual current draw during Burning Man. If you're taxing the peak capabilities of the EU6500, that might explain your lack of performance, and a generator with more power might be a good investment.

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: John Lackner on July 19, 2014, 11:55:13 AM
You are mistaken.

I am not mistaken. go back to electrician school.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 19, 2014, 12:27:54 PM
I am not mistaken. go back to electrician school.

It's a narrow margin on this, but the 6500 is not the most of the problem.  You've probably read every post in the thread, so you know that the operative factors here are too long a cable run (and in desert temperatures), too small wiring gauge, funky home-mafe "distro"  and driving the speakers into thermal compression.

While it is true that class D amps are nice and efficient, their lack of "heavy iron" in the power supplies does make them get a bir funky when power is close to minimum specs.  The power loss between the generator and the speakers is enough to cause problems given the deployment and use, but the 6500 @ 54 amps should handle the 6 Mackies @ a rated draw of 8 amps each.

Yes, it's close to the bone.  But addressing the setup and cabling issues are first priority for the OP as he's seeking a way to get the most out of what he has.  You can recommend a larger generator and be correct in a sense, but so are those who recommend more powerful speakers.

Neither recommendation addresses the OP's desires to work with what he has even though such recommendations are correct in essence.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 19, 2014, 12:33:31 PM
I am not mistaken. go back to electrician school.

Comments like that are not helpful, John. If you disagree with Dick (who is, I might add, one of the more highly respected members of the forum) then please explain where you're coming from.

The active Mackie gear is quite energy efficient, but with them being plugged in at the end of a 200' run of 6/4 wired to the L14-30 output on the generator -- well, the 6/4 is helping to negate the voltage drop a bit, but it's probably still present, and probably what's contributing to these sags.

What might help is if the OP were to check the generator while it is running, which helpfully has an output reading to show how much it's actually using. See what that does during those bass hits, and see if that helps narrow down the problem. And use a shorter main feeder cable. :) And fix the distro setup!

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: John Lackner on July 19, 2014, 12:58:25 PM
Comments like that are not helpful, John. If you disagree with Dick (who is, I might add, one of the more highly respected members of the forum) then please explain where you're coming from.

The active Mackie gear is quite energy efficient, but with them being plugged in at the end of a 200' run of 6/4 wired to the L14-30 output on the generator -- well, the 6/4 is helping to negate the voltage drop a bit, but it's probably still present, and probably what's contributing to these sags.

What might help is if the OP were to check the generator while it is running, which helpfully has an output reading to show how much it's actually using. See what that does during those bass hits, and see if that helps narrow down the problem. And use a shorter main feeder cable. :) And fix the distro setup!

-Ray

You an also connect a voltmeter at the load (amp) end. If there a lot of voltage fluctuations the genny could be overtaxed.
If the average load is 3500 watts the peak load could be much more than that. Some of these smaller generators might work fine on an average loads but come up short during peaks. Of course the easy fix would be to turn the bass down a bit. But try telling that to EDM DJ's. Go ahead. Try it.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 19, 2014, 01:07:11 PM
Of course the easy fix would be to turn the bass down a bit. But try telling that to EDM DJ's. Go ahead. Try it.

Depends on your relationship with the DJs. The anecdote I gave above, I knew the guy and had worked with him before, so I was able to tell him to go a bit easier on the bass. Of course, dropping the sub amp 10dB helped as well.

Most DJs, though, will prefer a sound systems that is actually ON and will stop juuuuust short of destruction of the generator. One would hope, at least. :D

Anyways, we're in agreement that the bass is probably taxing the generator, and that plus the voltage drop over 200' of feeder is the cause(s) of the complaints from the OP. But, since this is all that they have to work with, the key here is to help them make the most of it!

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 19, 2014, 01:48:41 PM
You an also connect a voltmeter at the load (amp) end. If there a lot of voltage fluctuations the genny could be overtaxed.
If the average load is 3500 watts the peak load could be much more than that. Some of these smaller generators might work fine on an average loads but come up short during peaks. Of course the easy fix would be to turn the bass down a bit. But try telling that to EDM DJ's. Go ahead. Try it.

John..

I believe you should be calculating the power draw in amps, not watts.  One watt is defined as one joule (amount of energy) per second (time) and as such defines the RATE of energy conversion.  Are you saying that rate is more applicable than amperage available or do the two measurements combine to predict the probable outcome...based on program content in this case.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: John Lackner on July 19, 2014, 01:56:37 PM
Depends on your relationship with the DJs. The anecdote I gave above, I knew the guy and had worked with him before, so I was able to tell him to go a bit easier on the bass. Of course, dropping the sub amp 10dB helped as well.

Most DJs, though, will prefer a sound systems that is actually ON and will stop juuuuust short of destruction of the generator. One would hope, at least. :D

Anyways, we're in agreement that the bass is probably taxing the generator, and that plus the voltage drop over 200' of feeder is the cause(s) of the complaints from the OP. But, since this is all that they have to work with, the key here is to help them make the most of it!

-Ray

Last but not least, that 30 amp connector on the genny could be getting a bit old and flimsy, limiting current flow. Also, check for any dirt or corrosion or loose screws on all the power cords and connectors . Actually, the cables and connections should be inspected FIRST. This could save a lot of time and money on bigger gennies and more gear.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Rob Spence on July 19, 2014, 02:10:54 PM
Depends on your relationship with the DJs. The anecdote I gave above, I knew the guy and had worked with him before, so I was able to tell him to go a bit easier on the bass. Of course, dropping the sub amp 10dB helped as well.

Most DJs, though, will prefer a sound systems that is actually ON and will stop juuuuust short of destruction of the generator. One would hope, at least. :D

Anyways, we're in agreement that the bass is probably taxing the generator, and that plus the voltage drop over 200' of feeder is the cause(s) of the complaints from the OP. But, since this is all that they have to work with, the key here is to help them make the most of it!

-Ray

Actually, don't forget the 100' extension cords to the speakers and that one stack is getting its power from the other stack so that is 300' to the first stack then what ever to the second.

I agree that I would make the 6-4 feeder shorter. With the rig blasting no one is going to hear the generator. Putting a sheet of ply between it and the stage should let you shorten things up a lot. I would try to get it well below 100' if I could.

Next, I would make up a pair of quad boxes with 10-3 from the distro to the base of each stack then plug in the speakers with shorter iec cords.

That should stiffen up the power and perhaps remove some of the sagging.



Sent from my iPad using Tapatalk HD
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 19, 2014, 02:17:28 PM
Actually, don't forget the 100' extension cords to the speakers and that one stack is getting its power from the other stack so that is 300' to the first stack then what ever to the second.

I agree that I would make the 6-4 feeder shorter. With the rig blasting no one is going to hear the generator. Putting a sheet of ply between it and the stage should let you shorten things up a lot. I would try to get it well below 100' if I could.

Next, I would make up a pair of quad boxes with 10-3 from the distro to the base of each stack then plug in the speakers with shorter iec cords.

That should stiffen up the power and perhaps remove some of the sagging.

Absolutely, this has always had a pretty simple solution...
- Position the gennie 30-40' behind the stage
- Get a 25' L14-30 cord
- Get a breakout box/rackpack to split the L14-30 into 4-20A circuits
- Run short cables to each speaker stack-- sheesh, life is good!

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: TJ (Tom) Cornish on July 19, 2014, 02:22:30 PM
I am not mistaken. go back to electrician school.
I would suggest waiting until you have a few more than 22 posts before being obnoxious.

Mackie's web site lists the "recommended amperage service" of the SR1530 as 8 amps.  This almost certainly has peak draw already factored in; the "500w" amp rating already represents peak power, as all music - even EDM - has a crest factor - a ratio of the peak to the average, meaning that probably more like 50w continuous are put to the drivers. 

The amplifiers have some energy storage built-in, which softens the peak draw, and the generator has rotational inertia that also effectively is some amount of reserve capacity.

If it were me and I had to decide between using the very adequate EU6500 that I already owned or ponying up $20K for a real 20KW entertainment generator (and all the permitting and logistics that entails), I would invest the money in some more efficient gear in order to get more output on existing power.  That is not difficult - reducing the audio level 3dB cuts the power draw roughly in half.  It wouldn't be very hard to find speakers 3dB more efficient than the Mackies in question, meaning that the same or more output is available for considerably less electrical power.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 19, 2014, 02:47:46 PM
Mackie lists long-term output of those cabs as 123dB.  I would call them "moderately loud speakers", not loudspeakers.

I can run my four EV trap tops and four 600W SB180's all day long on two x 20 amp circuits and do 130dB+ at the speakers, over 100dB @ FOH 75' from the stacks.  The MacroTechs do not sag...
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 19, 2014, 10:56:23 PM
I am not mistaken. go back to electrician school.

Johnlackner, I'm the moderator here, and we don't behave like that on this forum. There's a lot of smart people here with a ton of experience offering solid troubleshooting suggestions, so best to watch and learn. Don't make me get out my ax...

Mike Sokol
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Guy Holt, Gaffer on July 23, 2014, 07:07:51 AM
Friends of mine have a DJ set up consisting of (4) mackie SR1530's at 500w each, (2) mackie 15' 500w subs, and maybe 500w of computer, mixer, mic, etc.  They say when they turn it up to a moderately high level the sound levels drop during heavy bass track, then rise during brakes in the bass line.  Of course, they don't want it to do this.

I think Shawn is correct that his problem is voltage drop, but it is a kind of voltage drop that cannot be compensated for by increasing the wire gauge of his distro cable. Where the DJs are concerned about hearing the noise of the generator during quieter songs, I would bet they are operating the generator with its’ Eco-Throttle. The Eco-Throttle used in conjunction with a “spider-box” (what I would call a “splitter box”) may be causing sensing errors on the part of the generator’s microprocessor engine control.

What makes the Honda EU6500is incredibly quiet, as well as more fuel efficient, is what Honda calls its’ microprocessor controlled Eco-Throttle. 

Eco-Throttle is simply the marketing name Honda uses to describe two of the characteristics that make inverter generators considerably quieter than conventional Automatic Voltage Regulated (AVR) generators. First, with their multi-pole rotors and small stator, inverter generators produce more electrical energy per engine revolution than is produced in conventional AVR generators. Their greater efficiency, and the fact that the frequency of the power they generate is not linked to engine speed, means they can run at much slower RPMs for a given load than a conventional AVR generator. 



The second reason that inverter generators are quieter is that their Pulse Width Modulated (PWM) inverter modules permit their engine speed to vary with load. Which means that, at less than full load, the engine can slow down which tremendously reduces the noise it generates. Put simply, an inverter generator is much quieter because the engine speed is load dependent – it does not have to run at full speed constantly as is the case with conventional AVR generators (use this link for more details:http://screenlightandgrip.com/html/emailnewsletter_generators.html#anchorProduction%20Features (http://screenlightandgrip.com/html/emailnewsletter_generators.html#anchorProduction%20Features).)

(http://www.screenlightandgrip.com/images/generators/Pro_Sound_EU7000is_Voltage_Charactistic_Curve.jpg)

It also means that the voltage generated by the inverters is load dependent. Above is the Characteristic Curve of the voltage output of the Honda EU7000is’ inverters as a function of load. As you can see here that without a load the voltage generated by the inverters start out at about 125/126V and then drops gradually as the load on the inverters increase and reaches 120V at full load.

In order for the Eco-Throttle to function properly, it requires a fairly balanced load. This is because Honda has designed the EU6500s with two inverters. To provide more 120V power, the generator has a 120V/240V selector switch, which when set for 120V, aligns the two inverters in series for greater 120V capacity (see illustration below.) To provide 240V power, the 120V/240V selector switch, set for 240V, aligns the two inverters in parallel at a phase angle of 180 degree to generate 240V, but at the expense of 120V capacity. In both cases, the two inverters see the same load and are balanced. In 120V mode with 120V loads the two inverters see the same loads. Since 240V loads are by nature balanced loads, in 240V mode, the two inverters see equal loads on each.  As such, when the engine control unit (ECU) varies the speed of the engine and hence the power (as a function of load), both inverters receive the same power.

(http://www.screenlightandgrip.com/images/generators/Op_Man_Circuit-Diagram.jpg)

Given this design, you run into trouble when you start to split-out 120V circuits from the 240V receptacle and load them unevenly. If you don’t meticulously balance your loads over the two legs (two inverters), then one inverter will be over powered while the other is underpowered when the ECU sets the rpm of the engine for the average of the two. In this case, since the bass woofers in the Mackie SR1530's draw 300w each (500W is the load of the whole system) and the 15” sub woofers in the Mackie SR1501s draw a full 500w, if they are not meticulously balanced (one SR1501 and two SR1530s on each inverter), when the load between the two inverters is averaged and the engine rpm adjusted accordingly, the inverter carrying the higher load (the 15” sub-woofers) will be under-powered and the inverter carrying the lessor load (the SR1530s) will be over-powered. Consequently, the voltage on the underpowered inverter will drop in accordance with the Voltage Characteristic Curve discussed above and the voltage on the over-powered inverter will not. Since it is the sub-woofers that are throwing the system out of balance, the voltage-drop on one inverter and not the other exhibits itself as dampened bass frequencies. Increasing the gauge of wire serving the load will not compensate for this voltage drop because it is not a function of cable resistance, but voltage droop of just one of the inverters as a function of the greater load.

One benefit of using our Transformer/Distros in place of a spider box is that it assures that the generator’s inverters are evenly loaded. Basically nothing more than a tricked out 240V-to-120V step-down transformer, our Transformer/Distros split the 120V load plugged into their secondaries evenly between the two legs of their primaries. Since the Transformer/Distro’s primary is the generator’s load, and not the 120V loads on the Transformer/Distro’s secondary, the generator’s two inverters are perfectly balanced. As such, when the ECU adjusts the engine rpm for the average load of the inverters, each inverter is fully powered.

A good example of this benefit is the Rap Music Video production pictured below. For this video, our Tranformer/Distro was able to power both a 4k HMI Par (36A w/PFC) and the amplifier for the monster stack of speakers on which the girls are dancing (22A) without either load being affected by the disparity between them. It did so by creating a single 60A/120V circuit from the two 30A/120V circuits of the 240V twist-lock receptacle. Where neither the 4k HMI Par, nor the speaker amplifier, could be operated on the 120V circuits of the generator's factory equipped power output panel, they could be operated on the larger 60A/120V circuit because  the Transformer/Distro split the combined load evenly over the generator’s two inverters (29A a piece.)

(http://www.screenlightandgrip.com/images/generators/Boomtown_Scene_Comp.jpg)
2010 BET Hip Hop Awards "Director of the Year" Nahala Johnson, aka "Mr. Boomtown", directing his latest Rap Video: an outdoor dance party with DJ and dancers on top of a speaker stack (upper left.)

Our Transformer/Distro not only enabled the production to get more useable power out of the generator; but it also greatly simplified the distribution of power on set. To run power around the Rap Video set, breaking out to 20A Edison outlets at convenient points, we used standard 60A Bates extension cables, 60-to-60 Splitters, and fused 60A GPC-to-Edison Breakouts (snack boxes) with our 60A Transformer/Distro (see pictures below.) The best part about using a transformer as a Distro in this case was that no matter where in the distribution system we plugged in the 4k HMI, speaker amplifier, set monitor, camera battery charger, or DIT station in the course of the day (it changed from set-up to set-up), the Transformer/Distro automatically balanced the load on the generator, so that we didn't have to spend the time to meticulously do so.

(http://www.screenlightandgrip.com/images/generators/Boomtown_SetUp_Comp_Web.jpg)
Our modified Honda EU6500is supplies power to set (far left.) Our 60A Full Power Transformer/Distro compensates for line-loss of 300' cable run (left center) to assure 120V line level to 4K HMI (far right), Speaker Stack Amplifiers, Set Monitors, Battery Chargers, & DIT station (Center.) 60A Bates Splitters, Extensions, and Gang boxes distribute power from Transformer around set (right center.)

Our Transformer/Distros can also eliminate "Line-Loss" from long cable runs without resorting to larger more expensive gauge wire. A common problem with portable generators, even the super quiet Honda Inverter generators, is that by the time you move them far enough off set that you don't hear them, you have significant "Line Loss" (often referred to as "Voltage Drop") from the long cable run back to set (if you use regular cable.) To the problem of line loss, as we saw in the Voltage Characteristic Curve of the generator above you have the added problem that as you add load, the voltage drops on the generators. For this reason we tap our  Transformer/Distros so that you can boost the voltage their secondaries in 5% (6v) increments. This feature enables you to operate the generator at a distance without suffering from voltage drop.

(http://www.screenlightandgrip.com/images/generators/Select_Transformer_Switch_Sm.jpg)
"Select" Models allow you to adjust for line-loss to maintain 120V on set

This Rap Video is also a good example of the benefit to being able to boost line voltage with our Transformer/Distro. Even though the generator was 300 ft away, the boost capacity of our Transformer/Distro assured that line level on set did not drop too low. By comparison, had we run 300' of standard 14 Awg electrical cord to set we would have experienced severe line loss.

(http://www.screenlightandgrip.com/images/generators/Boomtown_Distro_Comp.jpg)
Our 60A Full Power Transformer/Distro is outfitted with a 60A Bates receptacle so that you can use standard film style distro such as 60A Bates Splitters, Extensions, and Gang boxes to distribute power around set.

Our Transformer/Distros greatly simplify set electrics so that you don't have to be an experienced electrician to distribute power on set. The iMonitor display on the EU6500igenerator control panel makes it especially easy to load our modified Honda EU6500is inverter generator to full capacity. Simply plug in lights. When the load wattage displayed on the iMonitor reaches 7500 Watts you are fully utilizing the power capacity of the generator. An overload alarm on the iMonitor display will tell you if you inadvertently overload the Transformer/Distro. It is that simple.

Guy Holt, Gaffer
ScreenLight & Grip
Lighting Rental and Sales in Boston
Cell 617-224-85634
rentals@screenlightandgrip.com

Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Steve M Smith on July 23, 2014, 08:30:37 AM
I'm probably going to get flamed for this, but here goes!!

Someone should make a pair of transformers to allow long distances between generator and stage to be covered by high voltage.  Step up at the generator, step down at the stage.

Yes, I know.  The safety factors far outnumber the benefits but it seems to work for the electricity companies...


Steve.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Frank DeWitt on July 23, 2014, 09:21:39 AM
I'm probably going to get flamed for this, but here goes!!

Someone should make a pair of transformers to allow long distances between generator and stage to be covered by high voltage.  Step up at the generator, step down at the stage.

Yes, I know.  The safety factors far outnumber the benefits but it seems to work for the electricity companies...


Steve.

That is part of what screenlightandgrip.com is offering.  240 from the generator to right next to the distro and a transformer at the distro to supply 120.

Assuming the correct plugs and other hardware are used I see no reason why the amps and powered speakers couldn't be run on 240 volts.  as you point out it would have less voltage drop because of lower current for the same power, and it would provide a even load to the generator

Page 7 of the SA1232 speaker manual explains what happens when the speaker can't get enough power and ends with this

 The 230 volt AC systems are more stable and run into far fewer current supply problems. In fixed applications where  20-
230 volt service is available, we highly recommend using the SA1232 in 230 volt mode. The power supply in the SA1232 can be switched between 115 volt and 230 volt setting.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Jonathan Johnson on July 23, 2014, 11:06:39 AM
Our Transformer/Distros greatly simplify set electrics so that you don't have to be an experienced electrician to distribute power on set. The iMonitor display on the EU6500igenerator control panel makes it especially easy to load our modified Honda EU6500is inverter generator to full capacity. Simply plug in lights. When the load wattage displayed on the iMonitor reaches 7500 Watts you are fully utilizing the power capacity of the generator. An overload alarm on the iMonitor display will tell you if you inadvertently overload the Transformer/Distro. It is that simple.

Guy's response is bordering on advertising (which is normally forbidden in this forum) BUT he's an invited manufacturer's rep, each post clearly indicates that, and the response WAS more informative than advertisive.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 23, 2014, 11:14:13 AM
Guy's response is bordering on advertising (which is normally forbidden in this forum) BUT he's an invited manufacturer's rep, each post clearly indicates that, and the response WAS more informative than advertisive.

Guy, yes you're getting into advertising mode so please be mindful that manufacturers are not permitted to promote products in this forum. But we're good for now since we invited you to respond.

Mike Sokol
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Tim McCulloch on July 23, 2014, 11:27:05 AM
Guy, yes you're getting into advertising mode so please be mindful that manufacturers are not permitted to promote products in this forum. But we're good for now since we invited you to respond.

Mike Sokol

Agree that Guy's contributions are informative, educational and very useful.  That his firm makes a product to address issues specific to the production industry _illustrates_ both the need for such items and Guy's understanding of the factors involved.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Spenser Hamilton on July 23, 2014, 12:43:59 PM
This thread has turned out to be quite informative. Thanks Guy for sharing, and of course Mike for facilitating this forum.


Sent from my iPhone using Tapatalk
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: kel mcguire on July 24, 2014, 03:00:38 PM
Oh my, two interesting posts in a row.

Kel, the Eco Throttle does not limit power available, it just dials down the engine when it's peak capacity isn't needed in order to save fuel. When the load requires full power, the engine charges back up to full power.


-Ray

In my experience when the Hondas are set on eco throttle that some lag happens when demand goes up quickly, like a loud mastered track hits with extra low end demands or varying dynamic range of live music. Am I wrong?
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 24, 2014, 03:53:00 PM
In my experience when the Hondas are set on eco throttle that some lag happens when demand goes up quickly, like a loud mastered track hits with extra low end demands or varying dynamic range of live music. Am I wrong?

You are not wrong.  Eco throttle is OK for static loads, but dynamic loads like PA should be run at "full"throttle.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 24, 2014, 04:07:22 PM
You are not wrong.  Eco throttle is OK for static loads, but dynamic loads like PA should be run at "full"throttle.

I think that should read "full throttle, baby"....  ;D
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: kel mcguire on July 24, 2014, 07:37:29 PM
You are not wrong.  Eco throttle is OK for static loads, but dynamic loads like PA should be run at "full"throttle.

ok, thanks. That's sort of why I suggested it as a possible problem to the OP's sagging Mackie's performance. Seems obvious but I've made that mistake a couple times on EU2000 & 3000
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on July 24, 2014, 10:06:15 PM

Our Transformer/Distros can also eliminate "Line-Loss" from long cable runs without resorting to larger more expensive gauge wire. A common problem with portable generators, even the super quiet Honda Inverter generators, is that by the time you move them far enough off set that you don't hear them, you have significant "Line Loss" (often referred to as "Voltage Drop") from the long cable run back to set (if you use regular cable.) To the problem of line loss, as we saw in the Voltage Characteristic Curve of the generator above you have the added problem that as you add load, the voltage drops on the generators. For this reason we tap our  Transformer/Distros so that you can boost the voltage their secondaries in 5% (6v) increments. This feature enables you to operate the generator at a distance without suffering from voltage drop.

This Rap Video is also a good example of the benefit to being able to boost line voltage with our Transformer/Distro. Even though the generator was 300 ft away, the boost capacity of our Transformer/Distro assured that line level on set did not drop too low. By comparison, had we run 300' of standard 14 Awg electrical cord to set we would have experienced severe line loss.


I certainly agree that Guy's distro/transformer has a place and can be a useful tool-but every tool has its place.  If a load operates in a satisfactory manner on a traditional on a traditional 120/240 volt distro, the cost for a 4 wire feeder vs a 3 wire feeder is the only savings by using the transformer distro.  Obviously, if triplen/harmonic currents exist in sufficient magnitude to create problems the equation changes.

With all due respect the transformer distro cannot eliminate "line loss"-unless it also repeals the second law of thermodynamics.  A 5% voltage sag on the secondary side = a 5% voltage sag on the primary side that voltage multiplied by the current draw equals the power loss in the cable.  If you have to turn up two taps-10%-then 10% of the energy being generated is being dissipated in the cable and is no longer available for the load, thus a 7500 watt generator becomes a 6750 watt generator.  Of course, this feature is useful in voltage sensitive equipment, but it cannot solve a problem where the issue not enough energy at the end of the feeder.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 24, 2014, 10:54:04 PM
One thing I would like to see is to simply do an experiment that eliminates the 200 ft. distro run. By simply parking the generator in the middle of the action plugging the powered speakers into the shortest run of distro possible, the OP would know if the distro had anything to do with this. If the bass DOESN'T sag on heavy bass, then you know it's the 200' distro causing the problem. If it DOES sag, then it's likely the generator's inability to supply peak currents during heavy bass.

While it may not be practical for this sort of remote gig, the next step would be to power the systems from A) a really big rental generator as an experiment, or B) plug it into solid house power that you know won't dip. In those cases if the volume still seems to sag on bass, then there's some sort of internal limiting happening internally to the speakers.

I'm a big experiment guy, and while I really like thinking about and discussing theory, at some point you need to run a few real-world experiments and gather some empirical data. That's the only way to know if you're on target with your hypothesis or simply blowing smoke.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: g'bye, Dick Rees on July 24, 2014, 11:17:28 PM
One thing I would like to see is to simply do an experiment that eliminates the 200 ft. distro run. By simply parking the generator in the middle of the action plugging the powered speakers into the shortest run of distro possible, the OP would know if the distro had anything to do with this. If the bass DOESN'T sag on heavy bass, then you know it's the 200' distro causing the problem. If it DOES sag, then it's likely the generator's inability to supply peak currents during heavy bass.

While it may not be practical for this sort of remote gig, the next step would be to power the systems from A) a really big rental generator as an experiment, or B) plug it into solid house power that you know won't dip. In those cases if the volume still seems to sag on bass, then there's some sort of internal limiting happening internally to the speakers.

I'm a big experiment guy, and while I really like thinking about and discussing theory, at some point you need to run a few real-world experiments and gather some empirical data. That's the only way to know if you're on target with your hypothesis or simply blowing smoke.

Beware the "sag".

This is the OP's subjective assessment of what's happening and is only one possibility.  Th only hard info we have is regarding the gear itself.  And I, for one, take all this with a rather large grain of saly given the deployment, funky "distro" and wiring as well as the expectations of getting any serious sound out of the woefully inadequate speakers.

I would lay odds that a first-hand evaluation would reveal a slew of issues from inferior gear, inept operation, unrealistic expectations and such as well as myriad unmentioned possibilities.  It is highly suspect to focus attention on the generator alone when SO many other issues lurk.  To me, it would seem that the salient and compounding factor is OE.

Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 24, 2014, 11:24:01 PM
With all due respect the transformer distro cannot eliminate "line loss"-unless it also repeals the second law of thermodynamics.

Yeah, but if you could use a transformer to step up the voltage by something like a factor of 10 to 1,200 volts (no, don't do this) when step it down by the same winding ratio, then the voltage drop over a long run with the same size wire would be reduced by a factor of 10. That's just due to 1/10 of the amperage needed to supply the needed wattage. Of course, I'm not considering transformer losses and such in this scenario, but this is exactly why Tesla/Westinghouse and not Edison won the first electrical distribution wars.

But TANSTAAFL (There Ain't No Such Thing As A Free Lunch) so this won't squeeze any more power out of that genny. But I can see where using a generator's 240-volt feed with a step-down transformer to get it back down to 120-volts at the end of the long distro would be beneficial since you could choose to use half the copper weight in the distro run if you were willing to accept the same voltage drop, or half the voltage drop if you wanted to use the same amount of copper in the distro run.

That being said, I'm still not convinced that triplen harmonics in a 120/240-volt split phase system will contribute to overheating in the neutral conductors, notwithstanding Guy's detailed explanation of his technology. Again, I'm not arguing that triplen harmonics don't exist in such a system when powering triac loads because they certainly do. I'm just not sure they're relevant to neutral overheating in single phase distro as they are in 3-phase WYE systems. And that was my original argument about triplen currents in this scenario.

However, I'm going to discuss this with one of my EE buddies who happens to be a sub-station power engineer up near Niagara Falls. One would think that those guys would be able to answer that simple question about triplen currents as they relate to neutral overheating in single or split-phase disto.

BTW: I'm starting to get my vision back after 10 days of bumping around the house, so I'll try to stay on top of these threads a bit more. But this sure is interesting stuff to think about with a lot of potential applications for pro-audio power distro.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 24, 2014, 11:31:21 PM
Beware the "sag".

This is the OP's subjective assessment of what's happening and is only one possibility. 

You're probably correct. In many cases just getting some good "ears" on a system will tell you a lot about what's really happening. One of my buddies who does mixing for a lot of a-list acts around the world can point out a single fried HF driver near the top of a big stack of speakers. I know this because I've actually seen him do it, then crawled up the stack to check for myself and found he was correct. And like crime witnesses, most end users are really bad at describing what they're hearing, choosing to make up or borrow words rather than providing any real technical description. Not that they don't try or are trying to mislead you. But I need to hear things for myself if I'm going to fix a non-obvious problem.   
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on July 25, 2014, 09:04:13 AM

I'm a big experiment guy, and while I really like thinking about and discussing theory, at some point you need to run a few real-world experiments and gather some empirical data.

Technically OT in this thread, but a major question mark for me regarding triplen harmonics in single phase systems.  Guy offered no emperical evidence because they don't believe in setup that might cause them. Understandable.

I am reminded of the man standing on a street corner in a midwestern US city waving a pitch fork around.  When asked what he was doing he replied, "I'm keeping he elephants away, doing a good job ain't I?"  You need to show me the elephants before you prove that you got rid of them.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Guy Holt, Gaffer on July 25, 2014, 11:09:38 AM
A a major question mark for me regarding triplen harmonics in single phase systems.  Guy offered no emperical evidence because they don't believe in setup that might cause them… I am reminded of the man standing on a street corner in a midwestern US city waving a pitch fork around.  When asked what he was doing he replied, "I'm keeping he elephants away, doing a good job ain't I?"  You need to show me the elephants before you prove that you got rid of them.

I'm still not convinced that triplen harmonics in a 120/240-volt split phase system will contribute to overheating in the neutral conductors… However, I'm going to discuss this with one of my EE buddies.

So that, this thread doesn’t get hijacked by a debate over whether triplen harmonics do or do not contribute to overheating the neutrals and inverters in paralleling generators I will answer these questions as part of the original thread that is available at: http://forums.prosoundweb.com/index.php/topic,150582.0.html (http://forums.prosoundweb.com/index.php/topic,150582.0.html)

Guy Holt, Gaffer
ScreenLight & Grip
Lighting Rental and Sales in Boston
Cell 617-224-85634
rentals@screenlightandgrip.com
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Steve M Smith on July 25, 2014, 12:11:09 PM
That is part of what screenlightandgrip.com is offering.  240 from the generator to right next to the distro and a transformer at the distro to supply 120.

Assuming the correct plugs and other hardware are used I see no reason why the amps and powered speakers couldn't be run on 240 volts.  as you point out it would have less voltage drop because of lower current for the same power, and it would provide a even load to the generator

Here in England, that is just normal as our supply is 240v already.  I was thinking (note - not suggesting!) stepping it up a bit, perhaps 1000v, then stepping back down to 120/240 at the other end.

Probably not something to make up yourself but I'm sure the generator companies could find a safe way to do it.


Steve.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on July 25, 2014, 01:22:31 PM
600 Volts would probably be a practical limit-that seems to be the voltage much equipment is rated for-including SO cable, etc.

The other factor in economics is the distance.  It takes the same step up/step down transformer no matter the distance.  Power transmission runs for miles.  I am not sure you would save much money or weight for even a 500 ft feeder (when you consider cost/weight of both cable and transformers) unless you were changing voltage by a factor of 10 or more.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 26, 2014, 07:17:10 AM
Beware the "sag".

All this talk of harmonics and neutral heating got me thinking about the differences between inverter generators such as the Honda units discussed here, and old-school constant speed generators with nothing but spinning copper and magnets.

So consider that many, if not most, modern amplified speakers use switched power supplies, there's going to be a non-linear load applied to the power source. In fact, plain old bridge rectifiers on a transformer feeding big capacitor cans draw power only on the peaks of the 60-Hz cycle (or 50-Hz for other countries).

While a constant speed generator that we might rent probably doesn't have electronic current limiting on it's output short of a circuit breaker, I'm sure that Honda and Yamaha inverter generators are constantly monitoring current and can go into limiting mode, much like our modern power amplifiers do to protect their output stages.

So can using amplifiers with switched power supplies on an inverter generator cause the generator to over-react to these non-linear currents (triplen maybe?) and go into current limiting, which reduces it's output voltage at power levels less than rated? That is, do you need to derate a 6500 watt generator to maybe 3K or 4K worth of non-linear loads (Mackie speakers with switched power supplies)? 
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Scott Wagner on July 26, 2014, 05:06:16 PM
Skye describes the set up as having the speakers all point inward from the corners of a 50' square.  He doesn't think they are pushing them that hard.
I realize that this is an Electrical forum, but this may be (another) key piece of the puzzle.  With speakers placed at the corners of a "50' square" facing each other, there will be noticeable cancellations.  This could, in turn, be causing the DJ to drive the system much harder than he thinks (just because it doesn't SEEM to be overdriven, doesn't mean it isn't).  Something else for the OP to consider.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Mike Sokol on July 27, 2014, 04:57:37 PM
I realize that this is an Electrical forum, but this may be (another) key piece of the puzzle.  With speakers placed at the corners of a "50' square" facing each other, there will be noticeable cancellations.  This could, in turn, be causing the DJ to drive the system much harder than he thinks (just because it doesn't SEEM to be overdriven, doesn't mean it isn't).  Something else for the OP to consider.

This reminds me of a little music festival I attended with my kids maybe 10 years ago. Really small stage with a pair of Peavey 2-way speakers on sticks for mostly vocal PA. As I crossed the field in front of the stage I noticed that the vocals completely nulled out in the center. Of course I showed my kids this (11 and 9 and 9 years old, I think) and they had fun moving side to side a few feet and making the vocals disappear. The band was getting a bit worried about the four of us jumping side to side in front of the stage and laughing, so I told them they were just a science experiment (but they still ROCKED). When I explained to them that one of their PA speakers was wired out of phase and cancelling the vocals in the center, the didn't seem to understand and told me they borrowed the speakers from a little church up the street. Of course in a room you would have a lot of wall reflections to create "some" vocals in the center (even though all phase cancelled), but an outside field is nearly as good as an anechoic chamber for this sort of demonstration. Too much fun.   
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Guy Holt, Gaffer on July 30, 2014, 02:25:49 PM
I'm sure that Honda and Yamaha inverter generators are constantly monitoring current and can go into limiting mode, much like our modern power amplifiers do to protect their output stages.

A while back I tested both the Honda EU6500is and the Yamaha 6500 for limiters with a load bank and came up with some interesting results. Both machines have an electronic master breaker upstream of the overcurrent protection of the individual circuit breakers.  Where the master breaker in the Yamaha 6500 trips at 54A (6500W at 120V), the breaker in the EU6500is does not trip until 65A (7800W at 120V.) Further testing of the EU6500is with a load bank suggested that the actual continuous load capacity of the EU6500is is 7680 Watts. Where that is much higher than Honda’s stated continuous load rating (5500W) for the EU6500is, let me explain how we arrived at that figure in more detail.

First we modified the generator in order to tap the output of the inverters upstream of the individual branch circuits. Then following the load parameters as set forth in the manual, we used the generator's overload sensor to empirically test its' capacity with a load bank. The load parameters as set forth in the manual are as follows:

"If the generator is overloaded, or if the inverter is overheated, the red overload indicator will go ON.... When an electric motor is started, the red overload indicator may come on. This is normal if the red overload indicator goes off after about five seconds.... When the generator is operating overloaded, the red overload indicator will stay ON and, after about five seconds, current.... will shut off"

Gradually increasing the load with the load bank, we found that we could power a continuous load of up to 7680 Watts without the overload indicator coming on. When we exceeded 7680 Watts, the red indicator blinked intermittently. When we exceeded 7800 Watts the red indicator came on continuously, the limiter kicked in, and power was cut off to the receptacles after 5 seconds. Since, according to the Honda Manual it is normal for the overload indicator to come on for short front-end loads, like electric motors starting, our results suggested that the continuous load capacity of the EU6500is is actually 7680 watts (at first glance it seemed an odd number, but made perfect sense after further investigation.) When you consider that electric motors require up to three times more power to start than is required to keep them running, the manual suggests that the peak rating is actually well above 7680W.

Since our load bank tests suggested that not only is the limiter much higher than one would expect, but also that the inverter modules of the EU6500is generator are in fact capable of generating more power than is provided to us by the North American Power Output panel, we investigated the capacity of the EU6500is further and found that, in fact, it is engineered to generate 7680W of continuous power. In order to understand why it is possible with a modification to get that much continuous power out of a Honda EU6500is generator, one must first appreciate two things about the continuous load ratings given for generators. First, the factors generator manufacturers use to derive load ratings include not only the mechanical components (engine & alternator), and the electrical components (circuitry & wiring), but also the prevailing electrical codes of the market for which it is intended (where & how it will be used) and the brand image of the manufacturer (life expectancy of the product.) A quick survey of the wide range of continuous load ratings (5000W-7000W) of generators, by manufacturers other than Honda, using the same Honda GX390 engine as the EU6500is supports this fact. Second, when Honda engineered the EU6500is it was not only for the North American market. Like a car, Honda engineered a base model for the world market that they then customize for the different national markets. The difference between the various national models is primarily in the power output panel, which is configured according to the electrical standards and prevailing codes of the national market in which the generator will be used (use this link -http://www.screenlightandgrip.com/html/emailnewsletter_generators.html (http://www.screenlightandgrip.com/html/emailnewsletter_generators.html) -  for more details on how generator manufacturers arrive at their continuous load ratings.)

When you compare how Honda outfits the comparable UK model of the EU6500is generator, the EU65, for the UK markets, where the standard circuit for domestic power is 240 Volts and 16 Amps (3680/3840 Watts), to how Honda outfits the same generator for the North American Market, where the standard circuit is 120 Volts and 20 Amps (2400 Watts), one realizes that Honda does not give us access to all the power available from the generator. That our empirical testing of the EU6500is revealed that it will power exactly two UK 240V/16A circuits (3840 Watts/circuit x 2 circuits = 7680W) is not just  a coincidence. An examination of the wiring schematics for the UK version, the EU65, reveals that the 7800W master breaker and load sensor alarm setting of 7680W are set for the equivalent of two UK 240V/16A circuits (2x3840W/circuit = 7680W.) It would make sense that Honda would engineer the base model to generate more power for national markets, like the UK, India, Australia, etc. that use 240V power. Unfortunately the power output panel of the North American model, the EU6500is, does not give us ready access to this power without the use of a transformer/distro because of our electrical standards and prevailing codes. Based upon these results, I can say with confidence that the OPs problem is not related to a limiter.

Guy Holt, Gaffer
ScreenLight & Grip
Lighting Rental and Sales in Boston
Cell 617-224-85634
rentals@screenlightandgrip.com
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Guy Holt, Gaffer on July 30, 2014, 02:28:29 PM
All this talk of harmonics and neutral heating got me thinking about the differences between inverter generators such as the Honda units discussed here, and old-school constant speed generators with nothing but spinning copper and magnets…

The primary factors limiting the use of non-linear loads on portable generators are their inefficient use of power and the harmonic currents they generate. Because of their radically different designs, inverter generators, like the EU6500is, and conventional AVR generators, like the ES6500, react very differently to these factors. The harmonic currents generated by non-linear loads, in fact, have less of an adverse effect on inverter generators than they do on conventional AVR generators and so do not require de-rating as conventional AVR generators do.

Harmonic currents cause two major problems in conventional AVR generators: heat and voltage waveform distortion.  The first problem is that harmonic currents generate heat in the windings, core, and in the electromagnets of the rotor of conventional AVR generators. Since generator ratings are limited by allowable temperature rise, harmonics act as derating factors. In derating, the magnitude of the current is of obvious importance, because losses are proportional to the square of the current. Increased frequency causes increased core losses and increased copper loss from skin effect. 5th and 7th harmonics are the offenders here because they are in the 600 Hz range.

The second difficulty caused by harmonic currents is voltage waveform distortion. According to Ohm’s law, as each harmonic current encounters the impedance of the power distribution system, it will cause a voltage drop at the same harmonic voltage. Because, the capacitors of switch mode power supplies only draw current at the peak of the voltage waveform, this voltage drop occurs only at the peak of the voltage - leading to a flat topping of the voltage waveform.

The more harmonic content in the current, the more voltage distortion occurs throughout the distribution system. This includes the output terminals of the generator where the generator’s source impedance (particularly the subtransient reactance or “Xd”) will create the greatest voltage drops. If the flat topping distortion at the generator’s output terminals is severe, it can cause voltage regulator sensing problems (Self-Excitation or SE) and inaccurate instrument readings.

The effect that harmonic currents have on the generators is factored into the rating limits given them. How rating limits are affected by load can be illustrated in a “Limit Characteristic” graph that plots kVA and kW versus Power Factor. The fluctuations in the kVA line in the illustration below represent the generator’s operating limits depending on whether its load has a leading or lagging Power Factor. It is important to note that a generator’s Limit Characteristic graph will vary by the type of generator. The illustration below (courtesy of Caterpillar) is for a conventional AVR generator. Since the power quality of an AVR generator is intractably linked to its' engine - the effect of harmonics on the engine's governing system is the primary limiting factor. How the engine and its' governing systems are affected by lagging and leading power factor loads is illustrated by the engine kW limit line below.

(http://www.screenlightandgrip.com/images/generators/R_Gen_Rating_Limits.jpg)
A Limit Characteristic graph for a generator illustrates the effect of leading
or lagging Power Factor on the generator's output.
 

What this generator’s Limit Characteristic graph tells us is that, operating a capacitive non-linear load (the leading power factor quadrant right of the Unity Power Factor center line), this AVR generator first reaches a thermal limit as a consequence of heat generation in the generator's rotor from harmonic currents. And since, conventional AVR generators regulate voltage by means of a power feedback loop from the generator Stator (via the Sensor Coil), through the Exciter (Voltage Regulator), to electromagnets in the Rotor, Armature flux generated by harmonic currents in the Stator leads to erroneous Self-Excitation (SE) and therefore voltage. Put simply, lower power factor loads cause instability of the generator’s voltage output. Finally, since there comes a point as the Power Factor of the load decreases, when harmonics inhibit the successful operation of the generator’s Automatic Voltage Regulator all together, and hence the generator’s capacity to generate any power at all, the kW output eventually drops to zero. Since the voltage instability in conventional AVR generators is a function of the non-linear loads they power, the conventional wisdom is to limit the amount of non-linear loads it can power by roughly half of the generators capacity.

(http://www.screenlightandgrip.com/images/generators/EU_Gen_Rating_Limits.jpg)
The Limit Characteristic graph for an Inverter generator.
Note the negligible effect that leading Power Factor loads have on the generator's power capacity.
 

As the Limit Characteristic graph for an inverter generator above illustrates, it is a completely different situation with inverter generators. Because the speed of the motor is always changing, inverter generators cannot maintain voltage output by the conventional means of regulating the excitation current in Rotor electromagnets. Instead, inverter generators use permanent magnets in place of electromagnets. 
A permanent Magnet is an object made from a material that is naturally magnetized (Neodymium in this case) and hence creates its own persistent magnetic field. Since permanent magnets do not require an excitation circuit, armature flux created by harmonic currents will not cause voltage instability as it does in conventional AVR generators.

(http://www.screenlightandgrip.com/images/generators/waveform_elec_ballast_AVR-I.jpg)
Left: Conventional AVR Generator w/1200W non-pfc electronic ballast. Right: Inverter Generator w/1200W non-pfc electronic ballast.

And since the generator’s inverter completely processes the raw power generated by the permanent magnet (converting it to DC before converting it back to AC by means of a micro-processor), the AC power it generates is completely independent of the engine. By switching IGBTs according to Pulse Width Modulation control logic, an inverter generator is much better able to sustain output voltage against transient loads and, therefore, it has a much lower internal reactance compared to conventional AVR machines. Finally, since the Impedance encountered by harmonic currents that causes voltage waveform distortion is a function of the internal reactance of the generator’s engine to changes in load, a second benefit to using permanent magnets in place of electromagnets in the generator’s Rotor is that as is evident in the oscilloscope shots above, inverter generators consequently are much less susceptible to voltage waveform distortion.

(http://www.screenlightandgrip.com/images/generators/Inverter_Gen_Comp_Chart.jpeg)
TABLE COURTESY OF KIRK KLEINSCHMIDT.

The end result is that leading power factor loads do not cause voltage regulation errors in inverter generators as they do in conventional AVR generators. Inverter generators are able to hold their voltage stable within ±1% of the mean voltage, as opposed to the ±3% of conventional generators using analogue AVRs and are much less susceptible to voltage drop and AC Frequency (Hz) as a function of load (see table above.) 

The rock solid power and low sub-transient impedance of inverter generators enable you to operate larger non-linear loads on them than can be operated on conventional AVR generators. For instance, we have struck 6kw HMI Pars on a modified Honda EU6500is inverter generator without problem.

These power quality issues have been vexing film electricians for years, to learn more about how we have learned to remediate the adverse effects of harmonics read a white I have written on the use of portable generators in motion picture production available at http://www.screenlightandgrip.com/html/emailnewsletter_generators.html (http://www.screenlightandgrip.com/html/emailnewsletter_generators.html).

Guy Holt, Gaffer
ScreenLight & Grip
Lighting Rental and Sales in Boston
Cell 617-224-85634
rentals@screenlightandgrip.com
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Guy Holt, Gaffer on July 30, 2014, 02:32:19 PM
… can using amplifiers with switched power supplies on an inverter generator cause the generator to over-react to these non-linear currents (triplen maybe?) and go into current limiting, which reduces it's output voltage at power levels less than rated? That is, do you need to derate a 6500 watt generator to maybe 3K or 4K worth of non-linear loads (Mackie speakers with switched power supplies)?

Since the harmonic currents created by switch mode power supplies react poorly with the high impedance of conventional AVR generators (illustrated in the Limit Characteristic graph above), the conventional wisdom is to limit the number of non-linear loads you use on them to roughly half (65%) of the generators capacity. An inverter generator by comparison can be loaded to near capacity with non-linear loads because the extremely low harmonic distortion (less than 2.5%) of the original AC power waveform of inverter generators and low sub-transient reactance results in virtually no distortion of the power waveform (use this link - http://www.screenlightandgrip.com/html/emailnewsletter_generators.html -  for more details about the adverse effects non-linear loads have on portable generators and how it affects their continuous load ratings.)

Guy Holt, Gaffer
ScreenLight & Grip
Lighting Rental and Sales in Boston
Cell 617-224-85634
rentals@screenlightandgrip.com
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Barry Singleton on July 30, 2014, 11:26:26 PM
  Hello Guy;

  I didn't jump in before the other thread closed so I will take this opportunity to thank you here. I read the entire news letter that you were so kind to share with us over several times and learned a TON!!! 

  A mere thank you does little to express my sincere appreciation for your work, knowledge and generosity.

  I need to get it in a PDF and saved for ever!

  All the best,
                     Barry.
 
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on June 27, 2017, 01:15:20 AM
I would like to thank everyone for all the information collected here, and bring y’all up to date in hopes I can learn a bit more.
I’m the OP of this thread.  I’ve learned a bit more about the sound system, electrical stuff and how the sound system is used.  I’ll detail this and then ask about a possible upgrade/change and how it may affect the set up.

Here is what we (I am now part of the camp and I manage the PA) are working with.  Honda EU6500 as stated.  Gen is set to 240v and we run with the Eco Throttle off.  An 8/3 SO cord of 110 feet plugs into the twist lock and runs to a jbox.  In the jbox (2) 10/2 SO cords are wire nutted to spit the 240v into (2) 120v circuits.  In other words, (1) 120v circuit is tied to Black and White while the (2) 120v circuit is tied to the Red and White.  Each 10/2 is about 50’ long and ends in a quad outlet box.  At the quad outlet box (1) SR1530 is plugged directly in, and the second SR1530 is plugged in via 75’ to 100’ of 12 ga extension cord.  This same configuration is duplicated on the other 10/2 cord.  An old school 1202 mixing board and any computers used are plugged into one of the two 10/2 cords.  The two Mackie 1501 subs failed and have been taken out of the PA system.

Last year I upgraded the main run from the gennie to the dance floor from 10/3 to 8/3 and shorted the run to 110’ from about 150’.  I used the 10/3 to make the splits out to each side (called 10/2 above since I only use one hot and the neutral).  This year I will buy a small Cutler Hammer CH main lug panel and use it to create a distro box.  Other than having over-current protection via the breakers, I don’t see this as being electrically different than the wire nutted set up above.  Can the act of installing a panel with a main bus and neutral / ground bars effect things like any load carried back on neutral, or shift return current from the neutral to the opposite leg?  Can it effect any ‘triplen harmonics’ or other issues possibly caused by a nutty jbox?  Put aside that this is Burning Man and there are LOTS of trippin’ harmonics…

The gennie is run out 100 feet from the floor because we will hear it otherwise.  We play a unique set of music, ranging from Ludovico Einaudi to Black Eyes Peas to Skrillex to Afro Celt Sound System to Carlos Nakai.  Well, I’ve never actually heard Skrillex on our floor, but other intense Dubstep.  In the middle of the set no one will notice the gen but it can be heard during quite piano and the like.  I *wish* I had thought to run the dam gennie out to the floor and try taking the 8/3 out of the equation like Mike suggested! 
Even after going to 8/3 and shortening we still get the volume drop when pushing the system.  I try to keep the DJ’s from compensating by turning it up louder and most comply.  I notice that the effect increases when the volume is pushed harder.  I have also noticed that some DJ rigs have less of a problem than other do.  I am assuming some rigs put out more signal power and that helps the amps not work as hard?

The transformer/distro Guy talks about sounds great but I’m afraid to inquire as to how much it costs.  According the his post #62 I can set the gen for 120v operation only and the two internal inverters with run in series to increase the 120v capacity and balance the load.  The manual show that I can use two specific receptacles on the face of the gen and tap each one of the inverters.  Would it help to run a second 8ga cord, skip the distro and run the two sides of the dance floor all the way back to the gen?
We do play a fair amount of EDM with all the other sweet and wacky stuff (Cake’s version of Mahna Mahna is a favorite of mine).  Are there tricks for dealing with overworked voice coils?  Other than turning the music down…  I’ve heard of electricians using a ‘buck boost box’ on long extension cord runs to keep their hole hawgs happy with full voltage.  Would getting a couple of these and boosting voltage help with overheating?  It might help with delivering watts, right?

Now for the change part.  The EU6500 has to be carried out to the desert and back each year and that has become an issue for the person who does it.  We are hoping to find a way to leave out gen with the rest of our gear.  Our camp has two shipping containers that we store our stuff in.  These two containers stay in the desert all year (or in the general vicinity).  Because the containers are subjected to some wild temp swings throughout the year we do not leave the PA in them.  We also do not leave the gas powered EU in there.  Our camp has raised some money this year and I’m thinking of changing to a Generac propane powered 11kw or 14kw household back up generator.  A Guardian series.  My hopes are two fold; I would have enough head room to be sure to meet the power need, and we could mount the thing to a pallet and leave it in the shipping container without it’s tank or battery.  Each year we change the oil, connect the charged battery and a fresh tank and away we go.  Or so I hope.  Does anyone have any thoughts on this?  Generac tech support is no help at all.

Thanks again for all the discussion on this thread, and for the forum!
Shawn
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on June 27, 2017, 11:37:21 AM
So my first concern (thanks for the update, of course!) is your lack of utilizing the grounding wires. Is there a reason for that decision?

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on June 27, 2017, 12:59:17 PM
From a safety standpoint, Ray is 100% correct-that is a HUGE safety issue-both for personnel and for equipment.  There is a reason every dgenerator supply 120/240 VAC has a 4 wire receptacle for that.

Buck/boost transformers alone won't help with power transfer.  They can bump the voltage up so voltage sensitive equipment can run properly, but they can't re-create the energy that is lost in the cord (that would violate the second law of thermodynamics!).  Watts = volts times amps.  If I put a 100 watt light bulb across 120 volts, I have a 120 volt voltage drop and just under 1 amp-multiplied it gives me 100 watts.  If I have a 4 volt drop on a cord of whatever length (not unlikely by any means) pulling 25 amps, well 4 X 25 = 100 watts-that energy is being used to heat up the power cord.  Of course, a 100 foot cord won't feel hot becasue of the area to dissipate that heat-but nonetheless that energy is wasted as heat and can't be reclaimed with any sort of magic to power your rig.  The only way to avoid that loss is bigger wire as bigger wire has a lower resistance and a lower voltage loss.  Or, you ca do like the POCO and step the voltage up at the genny, then back down at your distro (but at the cost of TWO transformers and an increased hazard of a higher voltage) which lowers the current.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 09, 2017, 06:27:41 PM
Thanks for coming back to this after all the time that has passed.  I had formatted my last post with a few more paragraph breaks but I guess I lost them in the cut and paste from word...

Ray -
Aside from being a little lazy, no.  Though driving ground rods in the playa (what we call the ground at BurningMan) would be a little tricky.  I have learned a bit about electricity since I started this thread and realize the value of grounding the gen, and hence all the gear.  I'll bring some acorns and drive a few 3' rebar stakes then connect them up to a ground wire.  I'm not going to get an 8' bar, or two, into the ground out there with the tools will have to hand.

Steve -
My thought on the buck boost was this - The gen is capable of putting out more than twice the power the system is using.  If the PA is dropping volume due to low voltage then maybe it can pull a bit more amperage to make up for it.  My assumption on buck boost is that they do just that, pull more amps than needed and transform the extra amps to voltage.  According to the math the power cables have plenty of head room for a small increase in amperage.  And, maybe pulling more amps will keep the gen in production mode if there is a lag between bass hit and gen response.  I have not actually looked up how a buck boost works.... hence I 'assumed', which in this case only makes me look like a donky if i'm incorrect ;-}
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Ray Aberle on July 09, 2017, 07:18:29 PM
Ray -
Aside from being a little lazy, no.  Though driving ground rods in the playa (what we call the ground at BurningMan) would be a little tricky.  I have learned a bit about electricity since I started this thread and realize the value of grounding the gen, and hence all the gear.  I'll bring some acorns and drive a few 3' rebar stakes then connect them up to a ground wire.  I'm not going to get an 8' bar, or two, into the ground out there with the tools will have to hand.

I was not referring to grounding RODS, but the actual grounding WIRE connecting the generator and your equipment. All US 110V AC lines have three lines- the hot, the neutral and the ground. Your statement indicates that you are not using the grounding wires, to wit:
Here is what we (I am now part of the camp and I manage the PA) are working with.  Honda EU6500 as stated.  Gen is set to 240v and we run with the Eco Throttle off.  An 8/3 SO cord of 110 feet plugs into the twist lock and runs to a jbox.  In the jbox (2) 10/2 SO cords are wire nutted to spit the 240v into (2) 120v circuits.  In other words, (1) 120v circuit is tied to Black and White while the (2) 120v circuit is tied to the Red and White.  Each 10/2 is about 50’ long and ends in a quad outlet box.  At the quad outlet box (1) SR1530 is plugged directly in, and the second SR1530 is plugged in via 75’ to 100’ of 12 ga extension cord.  This same configuration is duplicated on the other 10/2 cord.  An old school 1202 mixing board and any computers used are plugged into one of the two 10/2 cords. 

This configuration is electrically unsound and should not be utilized at all.

-Ray
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 09, 2017, 08:35:08 PM
I was not referring to grounding RODS, but the actual grounding WIRE connecting the generator and your equipment. All US 110V AC lines have three lines- the hot, the neutral and the ground. Your statement indicates that you are not using the grounding wires, to wit:
This configuration is electrically unsound and should not be utilized at all.

-Ray
I'm sorry to have given that impression.  The 10/2 SO cord I referred to actually 10/3 with Ground.  4 conductor cord.  In this application I'm using it for a single circuit so I said 10/2 which I agree is misleading.  There is a ground wire connected to each green screw at each outlet and each jbox.  These all connect to the green wire in the 8/3 with ground going back to the gen.  And there it ends.  The gen is not grounded to earth at all.  I intend to build a small panel to land the 8/3 and then pull off each 120 circuit via breakers.  And I figure we have 100's of people wondering through the camp each day, I should probably provide a path for any errant currents to find happy and safe dissipation.   
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Stephen Swaffer on July 09, 2017, 10:44:35 PM
To degree you are correct on the buck-boost transformers.  The actual equation would look something like this:

load amps X load volts=(genny amps X genny volts) - (voltage drop in feeder X amps flowing in feeder)

As long as the genny can supply power used plus the loss in the line, in theory you should be OK.

The caveat is the dynamic nature of an audio load.  There are a couple of other threads recently that deal with that aspect.  One here and one in the LAB started by Debbie.  Transient loads can be several times the average load-which makes the voltage drop on the feeder several times the average-since most buck-boost transformers are fixed, you can't allow for that without running higher than normal voltage.  Then too, you add the transformer impedance, which makes it harder for the system-genny plus transformer-to react to a transient load.

In the end, you "get what you pay for".  Heavier cable will give less loss and better performance.  Almost always for portable sound voltage drop/loss in the cable is a far more critical consideration than ampacity.

BTW-conductor counts in cable can be confusing.  When specifiying NM (romex) the grounding conductor is not counted-so 10-2 usually means 3 wires (black, white, bare).  Typically SO is specified counting all the wires-so a 10-2 would have 2 (black and white), 10-3 would have 3 (black, white, green) and so on.  For portable use you should be using SO and usually that should be 10-4 (or 8-4!) using black, white, green and red.  NM should never be used for portable sound-so we typically don't use that nomenclature.
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: shawn swanson on July 29, 2017, 04:08:59 PM
Typically SO is specified counting all the wires-so a 10-2 would have 2 (black and white), 10-3 would have 3 (black, white, green) and so on. 

Ah Haaa.  Then my main cable is 8/4 and the feeds to each side of the floor are 10/4, all SO.  Thanks for clairifieing. 

I actually have a whole new idea on this system.  Batteries - inverter/charger - smaller gennie for charging.  I'm going to search the forum for info and if I can't find info I will start a thread about 'batteries and inverter for remote sound system'
Title: Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
Post by: Jean-Pierre Coetzee on July 30, 2017, 03:39:23 AM
We're sure that this is not just the limiters kicking in on the Mackie speakers? It sure does sound like it to me.

From the calculations I see the cables have acceptable voltage drop for the distances they are running.

I just believe this a not enough rig for the gig issue.

Added to that this is in a desert so the DJs are probably already trying to compensate for power compression.

I would recommend keeping the same power setup and maybe communicating with someone here about renting a bigger system next year and seeing if the problem goes away in-stead of purchasing a larger generator and trying to mess around with buck-boost transformers and such.