ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 [3] 4 5 ... 10   Go Down

Author Topic: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass  (Read 12074 times)

Frank DeWitt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 922
    • LBP DI Box
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #20 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 .....
Logged
Not to Code

shawn swanson

  • Newbie
  • *
  • Offline Offline
  • Posts: 14
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #21 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.
Logged

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 17227
  • Wichita, Kansas USA
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #22 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.
Logged
"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1754
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #23 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.
Logged
Steve Swaffer

dick rees

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7246
  • Duluth
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #24 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'?
Logged
Pay no attention to the man behind the curtain...

Ray Aberle

  • Classic LAB
  • Hero Member
  • *
  • Offline Offline
  • Posts: 2871
  • Located in Vancouver, WA (and serves OR-WA-ID-BC)
    • Kelcema Audio
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #25 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
Logged
Kelcema Audio
Regional - Serving Pacific Northwest (OR, WA, ID, BC)

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1754
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #26 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?
Logged
Steve Swaffer

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2939
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #27 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. 

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 17227
  • Wichita, Kansas USA
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #28 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.
Logged
"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Ron Hebbard

  • Full Member
  • ***
  • Offline Offline
  • Posts: 138
Re: EU-6500 running 3500 watts of sound - Volume lowers during heavy bass
« Reply #29 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
Logged
Pages: 1 2 [3] 4 5 ... 10   Go Up
 


Page created in 0.112 seconds with 17 queries.