Hey all. I have an issue whereby partway through our set in a live environment the Vocals go horribly tinny. Its important to note that this has happened at the last 3 gigs. at our last gig we had ZERO vocal effects on as it wasn't required so we know its not our singer over doing the reverb when im not looking which is what we initially thought it was. Singer is Female, Hi-Pass filter is on, EQs are set to 0, Gain less than half way, Master Vol set to Zero, faders vary of course but usually around -5. ive tried cutting the high end but it doesn't help.
This never used to happen and as I say, everything is ok for the first couple of songs (its always passible that we don't notice it as our first couple of songs are some of our heaviest)
Equipment.
DESK: Yamaha MG124c
TOPS: JBL EON500
Behringer Feedback Destroyer (connected to the INSERT inputs below MIC 1+2.....Should I be using LINE??)
AMP: Numark
Mics: Samson
Its not an expensive setup, particularly the Mics but its always worked well and sounded excellent.
I always run the AMP at Max level and keep the mixer levels low.
I don't want to go spending big money replacing things without some guidance on what the most likely cause is first.
I am new to PA/Sound engineering and without question an amateur but im not totally inept 🙂 I have to admit I do not know how to use the feedback destroyer, I switch it on and let it do its thing so perhaps there is something in that?
I know the book is Huge on this subject but any advice that anyone can give me is hugely appreciated.
Thanks
Mike
This never used to happen and as I say, everything is ok for the first couple of songs (its always passible that we don't notice it as our first couple of songs are some of our heaviest)
Equipment.
DESK: Yamaha MG124c
TOPS: JBL EON500
Behringer Feedback Destroyer (connected to the INSERT inputs below MIC 1+2.....Should I be using LINE??)
AMP: Numark
Mics: Samson
Its not an expensive setup, particularly the Mics but its always worked well and sounded excellent.
I always run the AMP at Max level and keep the mixer levels low.
I don't want to go spending big money replacing things without some guidance on what the most likely cause is first.
I am new to PA/Sound engineering and without question an amateur but im not totally inept 🙂 I have to admit I do not know how to use the feedback destroyer, I switch it on and let it do its thing so perhaps there is something in that?
I know the book is Huge on this subject but any advice that anyone can give me is hugely appreciated.
Thanks
Mike
Could be anything.
Have you blown a woofer?
What happens when you bypass the feedback destroyer?
Chris
Have you blown a woofer?
What happens when you bypass the feedback destroyer?
Chris
Mike, it's hard to be sure, but from this distance, I would guess the JBL powered speaker(s) are overheating (due to the first few "heavy" songs), and then the internal amplifier that drives the woofer is shutting down.
This would leave you with only the tweeter(s) functioning, which, I'm guessing, is producing the "tinny" sound you described.
If this hypothesis is correct, the next question is, of course, why the JBLs are overheating now, when they never did before.
First step would be to try lowering the volume levels (especially the bass), maybe during a stage-level rehearsal, and see what if anything happens.
If the JBLs have an external heatsink on the back of the case, make sure it's not covered with a layer of dust or dirt, which could affect its ability to transfer heat away from the internal electronics, and into the air.
I have a few questions: you're using powered speakers. What is the Numark amplifier driving? Floor monitors?
And where is the Numark getting its input signal from?
And does the sound from the Numark also become "tinny" when the problem occurs, or is it only the JBLs that produce the "tinny" sound?
If I'm wrong about the JBLs, the answers to these questions can help narrow down where in the electronics chain the problem is occurring.
-Gnobuddy
Mike
Are You sure Your balanced cables are OK ? If one of the leg goes open, strange things can happen. Are the Samson mics needing phantom power ? Are You going from High Impedance to low impedance ? First test the speakers alone without desk ? Say using a cell phone or mp3 player or even a mike. If they work Ok you know the problem relies on the desk or cables.
Are You sure Your balanced cables are OK ? If one of the leg goes open, strange things can happen. Are the Samson mics needing phantom power ? Are You going from High Impedance to low impedance ? First test the speakers alone without desk ? Say using a cell phone or mp3 player or even a mike. If they work Ok you know the problem relies on the desk or cables.
Thanks for all the replies guys. Your right it could literally be anything. The speakers are passive, no signs that i can tell of any overheating and i dont push them any harder than is required for the venue. Our singer is also saying she is loosing volume as the set goes on.
I havent yet done any testing. From all the advice provided i think the first stop is to test without the feedback destroyer and then hire some other tops to see if the problem still happens, its certainly the cheapest place to start.
Thanks again
Mike
I havent yet done any testing. From all the advice provided i think the first stop is to test without the feedback destroyer and then hire some other tops to see if the problem still happens, its certainly the cheapest place to start.
Thanks again
Mike
Hi again, ive done some testing tonight. Everything was fine for about 45 minutes then i lost a huge chunk of volume and the sound went super thin. I then flicked to a different preset on the feetback destroyer and back again and it brought it back to life.
To me that confirms the destroyer is the cause?? Im running it again now and when thw fault comes back i will switch the amo off and back on to see if that has any effect. Ill then run it without the destroyer and see if the fault stays away.
Further suggestions/ideas welcome.
Thanks
Mike
To me that confirms the destroyer is the cause?? Im running it again now and when thw fault comes back i will switch the amo off and back on to see if that has any effect. Ill then run it without the destroyer and see if the fault stays away.
Further suggestions/ideas welcome.
Thanks
Mike
General troubleshooting technique is to isolate one variable at a time while changing nothing else. Consider:
- bent damaged cables/sockets (in/outs of desk, outboard, crossover, amps, speakers)
-> Play some music/noise, wiggle all the cables, listen!
- Sources
-> just with one mic, or any?
-> if with this mic, does the same channel give same prob when CD into line input?
- channels
-> Does this happen on all desk channels - might your fav vocal channel be faulty?
- signal path through desk - all BUSs, all AUXes, etc
-> familiarise yourself with the overall signal path - there's usually a block diagram in the manual
-> If you can record/listen at various points in the desk (channel out, inserts, AUX/BUS outputs, headphone output, main outputs) then this should help you understand where the problem is occurring (if the desk is at fault).
- outboard
-> Looks like you've sussed this
BTW, were you using the "feedback destroyer" because you had a specific problem to solve? Maybe look for acoustic solutions to f/b, rather than technological fixes (which apparently become "gig destroyers" at the worst moment). eg:
-move speakers/monitors
-move artist positions
-flip channel polarity
-better mic technique (careful of artist sensibilities 😀 )
-tighter mic pattern (eg hyper-cardioid, if vocalist happy)
-*reduce* vocal channel compression (really)
Other considerations:
- temperature/humidity (can affect all the above, as others have mentioned)
-> if you 'warm up' your system (music from CD, at high-ish vol) can you reproduce the problem (ie is it really the mike or something overheating)
You get the picture... In your position I would seek to understand the system, as a whole, and at a non-critical time.
Take the time to get the whole rig somewhere you can make noise, get it nicely warmed up and go through *methodically*. Outside in a field with beer, grill, and friends, for example - make a day of it, share the knowledge and experience.
Good luck; HTH,
AP
BTW Don't set amps to max - set the channel/output faders around 0dB, then trim down amp inputs until you have the level you're after. You'll then get a healthy signal to your amps, which then do the final attenuation. Also provides (some) protection against nasty thumps...
Plenty of info about "gain structure" around. If you're new to all this, have a good look at Dave Rat's YouTube channel (Chilli Peppers' engineer).
He's a curious and intelligent lateral-thinker who shares his excellent ideas and insights. Highly recommended.
Start with:
Gain Structure Basics for an Analog Console
Not just beginners, BTW - many experienced "engineers" could learn much from this brilliant 10min discussion:
"The same sound from multiple sources is an unnatural event"
- bent damaged cables/sockets (in/outs of desk, outboard, crossover, amps, speakers)
-> Play some music/noise, wiggle all the cables, listen!
- Sources
-> just with one mic, or any?
-> if with this mic, does the same channel give same prob when CD into line input?
- channels
-> Does this happen on all desk channels - might your fav vocal channel be faulty?
- signal path through desk - all BUSs, all AUXes, etc
-> familiarise yourself with the overall signal path - there's usually a block diagram in the manual
-> If you can record/listen at various points in the desk (channel out, inserts, AUX/BUS outputs, headphone output, main outputs) then this should help you understand where the problem is occurring (if the desk is at fault).
- outboard
-> Looks like you've sussed this
BTW, were you using the "feedback destroyer" because you had a specific problem to solve? Maybe look for acoustic solutions to f/b, rather than technological fixes (which apparently become "gig destroyers" at the worst moment). eg:
-move speakers/monitors
-move artist positions
-flip channel polarity
-better mic technique (careful of artist sensibilities 😀 )
-tighter mic pattern (eg hyper-cardioid, if vocalist happy)
-*reduce* vocal channel compression (really)
Other considerations:
- temperature/humidity (can affect all the above, as others have mentioned)
-> if you 'warm up' your system (music from CD, at high-ish vol) can you reproduce the problem (ie is it really the mike or something overheating)
You get the picture... In your position I would seek to understand the system, as a whole, and at a non-critical time.
Take the time to get the whole rig somewhere you can make noise, get it nicely warmed up and go through *methodically*. Outside in a field with beer, grill, and friends, for example - make a day of it, share the knowledge and experience.
Good luck; HTH,
AP
BTW Don't set amps to max - set the channel/output faders around 0dB, then trim down amp inputs until you have the level you're after. You'll then get a healthy signal to your amps, which then do the final attenuation. Also provides (some) protection against nasty thumps...
Plenty of info about "gain structure" around. If you're new to all this, have a good look at Dave Rat's YouTube channel (Chilli Peppers' engineer).
He's a curious and intelligent lateral-thinker who shares his excellent ideas and insights. Highly recommended.
Start with:
Gain Structure Basics for an Analog Console
Not just beginners, BTW - many experienced "engineers" could learn much from this brilliant 10min discussion:
"The same sound from multiple sources is an unnatural event"
I would say it's likely, but an alternative possibility exists: the power amp overheated and caused the fault, and it cooled off and returned to normal operation while you were changing presets on the feedback destroyer. (Unlikely, but a possibility.)
Why not remove the feedback destroyer entirely from the signal chain and see if the fault re-occurs or not?
If you confirm that the problem is indeed the feedback destroyer, next question is, why is it misbehaving? AFAIK they look for excessive continuous energy at one single frequency, which they interpret as feedback, and then a notch filter is inserted at that frequency. Is there something odd about the last song you're playing before the problem occurs? (Eg. long sustained guitar note, etc)
Incidentally, as far as I can tell via Google, JBL EON 500 series are all active speakers, which is what confused me earlier. Did you mean you have JBL EON 305 speakers? Those seem to be the only passive EONs.
-Gnobuddy
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