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Author Topic: X32 on Honda EU6500 problem?  (Read 2756 times)

Wes Garland

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X32 on Honda EU6500 problem?
« on: July 03, 2018, 08:52:56 AM »

Hey, folks --

I played a show this weekend and had the damnedest time with the kick drum.  Every time I turned up the kick, I got this weird feedback that I just couldn't kill.  It was around 65 Hz, which is close to the fundamental of the drum, and that is an area I normally boost about 6dB on my EQ.  It sounded like a sine wave with low volume even-order harmonics to me (similar to the output of a bridge rectifier, but more fundamental).

I changed kick mics, cables, and physical inputs on the X32. I even turned the nearest FOH speaker off, in the vain hopes that was acoustic feedback (outdoors with good positioning).........nope. I finally wound up not-boosting that frequency and running the kick low in the mix and it kept things under control for the show.........

Could I have done anything differently from a troubleshooting POV?   Power was from a Honda EU6500 inverting generator supplied by the client.  Power run to FOH 50 feet  (outlet to inlet). 16 awg the whole way, I believe.  FOH and stage running on different circuits in the EU6500.

FOH equipment was a pair of Yorkville PS15Ps (bass guitar and playback sounded great!), augmented with a pair of NX55Ps for off-axis coverage.

The generator had no trouble with frequency stability for the show - I would have noticed, I play Hammond organ which goes out of tune if the frequency moves even a tiny bit.    This is why my rider normally says "NO GENERATORS" but I accepted the EU6500 this time based on its reputation and inverter stage.

My only hypothesis is that there was some kind of 65Hz noise (hitting both the 60 and 70Hz bars in the RTA) on the power, and that this was somehow making its way into the kick signal.  But I think my hypothesis is weak.

Thoughts?  I have another show on the 14th, but on wall power.  I'm planning to haul a drum kit, the X32 and the FOH into my backyard for some testing this weekend.
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Scott Holtzman

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Re: X32 on Honda EU6500 problem?
« Reply #1 on: July 03, 2018, 01:37:20 PM »



My only hypothesis is that there was some kind of 65Hz noise (hitting both the 60 and 70Hz bars in the RTA) on the power, and that this was somehow making its way into the kick signal.  But I think my hypothesis is weak.


Exceptionally doubtful and it would have made its way into the bass.  I still vote for acoustic feedback.  Did you try another mic?
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Scott AKA "Skyking" Holtzman

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Art Welter

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Re: X32 on Honda EU6500 problem?
« Reply #2 on: July 03, 2018, 02:09:15 PM »

Every time I turned up the kick, I got this weird feedback that I just couldn't kill.  It was around 65 Hz, which is close to the fundamental of the drum, and that is an area I normally boost about 6dB on my EQ.  It sounded like a sine wave with low volume even-order harmonics to me (similar to the output of a bridge rectifier, but more fundamental).

I changed kick mics, cables, and physical inputs on the X32. I even turned the nearest FOH speaker off, in the vain hopes that was acoustic feedback (outdoors with good positioning).........nope. I finally wound up not-boosting that frequency and running the kick low in the mix and it kept things under control for the show.........

Could I have done anything differently from a troubleshooting POV?   Power was from a Honda EU6500 inverting generator supplied by the client. 
My only hypothesis is that there was some kind of 65Hz noise (hitting both the 60 and 70Hz bars in the RTA) on the power, and that this was somehow making its way into the kick signal.  But I think my hypothesis is weak.
Wes,

If the resonant frequency of the kick is around 65 Hz, the low frequency 60 Hz generator noise may have been enough to sustain the resonance, which you could see on the RTA.

The kick drum could have been in a position on stage that increased the LF generator noise, while you were in a null and wouldn't hear it.

Engaging a noise gate and/or a pillow in the kick probably would kill the problem, since running the kick at low volume eliminated the "weird feedback".

Art


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Len Zenith Jr

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Re: X32 on Honda EU6500 problem?
« Reply #3 on: July 03, 2018, 04:26:42 PM »

Could even be the stage vibrating at 65 hz resonating the drum head. As mentioned a gate is your friend.
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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #4 on: July 03, 2018, 05:29:09 PM »

Thanks for the feedback.  I remember reaching for the gate, but I'm not sure if I had it engaged or not now.  Next time I will pay more attention.  I do remember being extremely frustrated that I couldn't tell if the button was lit on the mixer on not.  Sound check was at 12:30pm, sun directly overhead, stage cover not anywhere near dark enough.

I'm not convinced it was acoustic feedback, even though it behaved a lot like it.  It continued with the speaker in front of the bass player turned off.  It was much harder to hear, though, I had to walk over to the speaker to be sure it wasn't my imagination.

The kick was mic'd with a mic placed on a pillow inside the drum.  I did try reorienting it, no change.

Safe from stage resonance: concrete slab.

I did change kick mics. The usual mic is an EV something or other. I also tried an Apex 125 the drummer had on hand.  Identical symptoms.  I had a pair of 902s in the van, but the van was a 3 minute walk away at this point and it was like 95 degrees with about 75 percent humidity.  We were DYING.

Here's a pic of the stage. We were not pushing the rig hard. Generator was about 12 feet behind the stage, roughly behind the leslie. See temperature comment above, we don't normally look like slobs (especially me, I'm a smart dresser most of the time):

« Last Edit: July 03, 2018, 05:31:48 PM by Wes Garland »
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Rob Spence

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Re: X32 on Honda EU6500 problem?
« Reply #5 on: July 03, 2018, 06:19:09 PM »

Two things...

I have had floor tom feedback from bass player reinforced through floor wedge. I thought it was kick too but not.

Second, kick drum in PA with #16 power? You should have #12 at least.



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kel mcguire

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Re: X32 on Honda EU6500 problem?
« Reply #6 on: July 03, 2018, 07:09:56 PM »

Two things...

I have had floor tom feedback from bass player reinforced through floor wedge. I thought it was kick too but not.

Second, kick drum in PA with #16 power? You should have #12 at least.



Sent from my iPad using Tapatalk Pro

yea. Leslie bottom mic can ring too. At the right distance from the two mains, there could be a nice alley lobe focused at the middle. Moving a main a few feet can help. Turning up the mains after setting up until something rings, then finding a couple trouble spots on the graphic or para can gain you a few dB of mains room. A whacked out EQ on the channel or mains can ruin your headroom. A "more me" drum wedge monitor request because the band is too loud can do that too
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Scott Holtzman

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Re: X32 on Honda EU6500 problem?
« Reply #7 on: July 03, 2018, 08:57:55 PM »

Thanks for the feedback.  I remember reaching for the gate, but I'm not sure if I had it engaged or not now.  Next time I will pay more attention.  I do remember being extremely frustrated that I couldn't tell if the button was lit on the mixer on not.  Sound check was at 12:30pm, sun directly overhead, stage cover not anywhere near dark enough.

I'm not convinced it was acoustic feedback, even though it behaved a lot like it.  It continued with the speaker in front of the bass player turned off.  It was much harder to hear, though, I had to walk over to the speaker to be sure it wasn't my imagination.

The kick was mic'd with a mic placed on a pillow inside the drum.  I did try reorienting it, no change.

Safe from stage resonance: concrete slab.

I did change kick mics. The usual mic is an EV something or other. I also tried an Apex 125 the drummer had on hand.  Identical symptoms.  I had a pair of 902s in the van, but the van was a 3 minute walk away at this point and it was like 95 degrees with about 75 percent humidity.  We were DYING.

Here's a pic of the stage. We were not pushing the rig hard. Generator was about 12 feet behind the stage, roughly behind the leslie. See temperature comment above, we don't normally look like slobs (especially me, I'm a smart dresser most of the time):


Major Kudos for dragging that organ and cabinet out in the heat. 

Sent from my VS996 using Tapatalk

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Scott AKA "Skyking" Holtzman

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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #8 on: July 03, 2018, 10:15:59 PM »

Major Kudos for dragging that organ and cabinet out in the heat.

Thanks, Scott.  I'm the only local guy still dragging furniture, and I drag it pretty much everywhere I go. (I also do rentals if any of you guys ever have a need in south-eastern Ontario. :) )  This particular load-in, other than being hot as heck, was ideal for an organ gig.  Back the van up to the stage, wheel it out, dropping 4".  Once you are set up for moving organs -- dollies, covers, ramps, vehicle -- it's not so bad. I can unload solo and load back in solo, although 30 seconds of help saves me 20 minutes and a lot of work on that segment.  Organ AND PA on a super hot day, though.  Holy cow I was ready for bed when I got home.

Re. intermodulation with Leslie etc - I can eliminate that; my sound check order goes like this
 - Mute everything
 - Unmute one monitor at a time and line-check with talkback mic
 - Check mains with talkback mic
 - Line check the drummer's mic
 - Check the kit, starting with the kick drum

I do my FOH sound check from the audience position (until things go wrong) via iPad and EV RE2/ND767A for talkback.

I was also starting with a mix from a recent SMALL venue gig (80 cap). Same stage package, different FOH.

I can also eliminate monitor feedback, I think.  I'll double check my mixer, but this band is supposed to be set up with no drum kit in the monitors at all, except mine (over by the organ), since I use that wedge to mix  (for certain values of mix).  I'm also fairly sure I tried sorting it out with the monitors muted, but I won't swear to it.  The drum kit is in my wedge at -10dB (post-fader mix).

Rob Spence: interesting comment re #16.  The speakers come with 25' #16 IEC cables.  I added on a 25' extension cord rated at 15A, which I'm pretty sure is #16 wire. Circuits are typically 15A in Canada, I was surprised to see 20A plugs on the generator.  I don't have any 20A-rated distro, although I DO have a couple of monster 50' extension cords that are either #10 or #12 that I didn't use that day. (And I know where to rent 20A distro if I need it).

Is your concern for the wire gauge power transmission/heat characteristics, or instantaneous voltage drop when the kick hits? 

Speakers are rated 1400W "program", this probably means a max draw of 700W RMS and a continous draw around 175W.  They are also rated 4400W "peak", but I expect this is only achievable for the duration of the time it takes for the power supply capacitors to discharge....that's 37A.

At 2 x 700W RMS -- max draw, I will never hit this -- I am okay for a 15A circuit, just barely.  (Up here, a 15A breaker means 12A continuous working load, and #14 wire in the wall).

I look at the UL chart (https://www.stayonline.com/reference-circuit-ampacity.aspx) and I see that #16 wire is cool for 13A continuous working load up to 50' -- so I have a fair bit of buffer here, I think?  I know you don't recommend stuff for no reason, so I'd like your feedback here if possible so I can make informed decisions going forward.  Right after I double-check all my distro to make sure I've got my numbers right.

Thanks,
Wes
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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #9 on: July 03, 2018, 10:27:22 PM »

Quote from: Kel
At the right distance from the two mains, there could be a nice alley lobe focused at the middle.

I had to think about this for a minute.  I've never considered this type of interference before. Thanks for teaching something new.

This is power alley, only pointing backwards at the band.  Of course, it's bidirectional. I just never thought of it like that before.

These particular speakers DO pound for 15" speakers on sticks.  They are almost subwoofers with horns.  Yorkville understands LF.
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Stephen Kirby

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Re: X32 on Honda EU6500 problem?
« Reply #10 on: July 03, 2018, 10:33:50 PM »

Bass amp, floor tom, any LF can set off a kick drum.  Putting the mic inside the drum makes it worse.  Similar to a vocalist cupping a mic.  Boosting eqs gives it a center frequency to ring at.  I'm almost always gating kick drums unless they're full of pillows.  The decay goes with getting some amount of tone and what is appropriate to the genre of the music.  Indoors I gate tighter as the room usually has plenty of overhang and simulates sustain.
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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #11 on: July 03, 2018, 10:43:22 PM »

FWIW - I think the drum kit was set up in anti-node.

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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #12 on: July 03, 2018, 10:49:36 PM »

Bass amp, floor tom, any LF can set off a kick drum.  Putting the mic inside the drum makes it worse.  Similar to a vocalist cupping a mic.

Would putting the mic on a stand help?   That is how I normally mic kits, but this drummer likes his mic inside.  He is all about optimizing the load-in. :)

Thanks for gate tips.  I am still learning how to use these effectively.  Going digital this year has given me a wider pallette with which to ruin things, ;) .   I have been re-mixing shows I recorded with my X-Live, and have learned that without drums in the room to help me out...it is very easy to wind up with a horrible sounding drum if the hold/release times are too short!
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Scott Holtzman

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Re: X32 on Honda EU6500 problem?
« Reply #13 on: July 03, 2018, 11:50:56 PM »

   I have been re-mixing shows I recorded with my X-Live, and have learned that without drums in the room to help me out...it is very easy to wind up with a horrible sounding drum if the hold/release times are too short!

The first time you mix in a room our outdoors where the stage contribution is insignificant is the moment you realize that you are in way over your head. 

Then you get used to having all the control and going back to a small room sucks.

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Scott AKA "Skyking" Holtzman

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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #14 on: July 04, 2018, 09:26:10 AM »

Follow up on the wire gauges for the curious - it turns out I was using a 14awg 25' extension split feeding a pair of 25' 18 awg IEC leads.

My "monster" 50' cords are 12 and 10 awg, but were not in use that day.  Good to call this out, pretty sure it's unrelated to this issue, though.

Scott - you're sure right about that!   Re-mixing shows recorded with the X-Live has been an invaluable learning experience.
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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #15 on: July 15, 2018, 10:39:05 AM »

Okay, you guys were right.  It was acoustic feedback.

I'm royally perplexed at WHY it's feeding back, but I spent some time yesterday during sound check setting up a gate and managed to get rid of the feedback without destroying the sound of the kick drum.
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Weogo Reed

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Re: X32 on Honda EU6500 problem?
« Reply #16 on: July 16, 2018, 01:02:04 AM »

Wes,

Are you running 120V or 240V?

Thanks and good health,  Weogo


Follow up on the wire gauges for the curious - it turns out I was using a 14awg 25' extension split feeding a pair of 25' 18 awg IEC leads.

My "monster" 50' cords are 12 and 10 awg, but were not in use that day.  Good to call this out, pretty sure it's unrelated to this issue, though.

Scott - you're sure right about that!   Re-mixing shows recorded with the X-Live has been an invaluable learning experience.
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Wes Garland

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Re: X32 on Honda EU6500 problem?
« Reply #17 on: July 16, 2018, 09:14:24 AM »

Wes,

Are you running 120V or 240V?

Thanks and good health,  Weogo

We are running 120V. Total system load hits a maximum of 8.1A when averaged over a couple of seconds.
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Steve Litcher

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Re: X32 on Honda EU6500 problem?
« Reply #18 on: July 16, 2018, 11:23:32 AM »

Piling on to the "generator oddity" thing here...

We did a weekend gig and used a Honda EU7000iS generator. Normally have had fantastic results with these - we rent them for around $75/weekend from a reputable local rental house.

This weekend, however, I heard an odd "click/whiz/whir" noise in the mains when the PA was otherwise silent. Not loud, but audible.

Our dLive gear was running off of a SurgeX double-conversion UPS. The subs (JTR Captivator C212Pro) and mains (RCF TTL-6A) were running straight off of the generator. Only heard the noise in the mains, so it was above 100Hz.

Could the generator have had something going on to generate that noise? It didn't get louder or softer with content/fader movement. It was just "present" in the mains.

And... FWIW, running 4x C212Pro, 2x TTL-6A, 5x DSR112, and the mixing gear, the generator was showing 1400-1800VA load most of the time. That was with us hitting 95dB A-weight and 103-104dB C-weight at FOH (about 60-feet back from stage, under a 40x100 tent). I thought that was incredibly low/efficient...

ProSoundWeb Community

Re: X32 on Honda EU6500 problem?
« Reply #18 on: July 16, 2018, 11:23:32 AM »


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