Ringing Out The Room – Channel or Overall PEQ?

[coffee_kingParticipant]

cornelius78

accidentally created a feedback loop somewhere, eg sent an fx return back to its send

I have 4 effects
FX1 Doubler (Vocals and sometimes electric guitar) Mix Return – Input FX1

FX2 2Tap Delay (Vocals) Mix Return – Input FX2

FX3 Gated Reverb (Drums) Mix Return – Input Mix 7-8

FX4 Reverb (Vocals & some drums) Mix Return – Input Mix 9-10

I assume this is set up correctly?

[[XAP]BobParticipant]

Assuming you’re not pushing the fx returns into other fx sends, then that looks Ok

[coffee_kingParticipant]

Assuming you’re not pushing the fx returns into other fx sends, then that looks Ok

Where on the board can I tell if I’m accidently doing that please?

[[XAP]BobParticipant]

Layer 2, select each of the mixes you are using for FX (fx1,fx2, mix9/10, mix7/8) and check that the FX Return faders don’t move.

For added safety you can hold the select button on the left and check that their LEDs are off…

[coffee_kingParticipant]

Layer 2, select each of the mixes you are using for FX (fx1,fx2, mix9/10, mix7/8) and check that the FX Return faders don’t move.

For added safety you can hold the select button on the left and check that their LEDs are off…

I assume you mean the upper layer?
FX Return Faders dont move when I do what?
Select button on the left? I dont have a select button on the left.

[[XAP]BobParticipant]

Select the mixes on e right (activates sends on faders), one of the buttons level with the select strip is marked sel – holding it shows what channels are enabled on the current mix.

[AndreasModerator]

…or simply mute Fx when feedback happens…
…you still didn’t told us, how your feedback sounds like. If you’ve implemented some loop in your Fx settings, that really would sound pretty nasty and would occur regardless of whats happening on stage. I think you’re looking at the wrong place here…

[coffee_kingParticipant]

Select the mixes on e right (activates sends on faders), one of the buttons level with the select strip is marked sel – holding it shows what channels are enabled on the current mix.

Do you mean the “Assign” button?
I cant see this extra SEL button only my usual Green Sel buttons per channel and LR Master.

[[XAP]BobParticipant]

Yes, assign. I don’t have a QU in front of me…

[DoctorGParticipant]

Dick,
You make some good points, however, your experience appears to be limited. I’ve only been doing this for 50 years or so, and I haven’t been in every possible situation, but I tend to make good observations. My comments made it clear that I wasn’t trying to write the book that could be written on this topic, but I could write that book. I was simply trying to point out the issues that needed to be considered, not cover every aspect, and my experience has proven that all the factors I mentioned are indeed pertinent, including the fact that different vocalists can generate different feedback.

My doctorate is in chemical physics, so I understand physics fairly well. Feedback will not occur at a frequency that is not generated in the room in some manner – that’s simple physics. A GEQ is better for eliminating feedback for several reasons, but I’ll just name a couple. Generally, a GEQ will have narrower Q at each frequency, so it can be used to remove feedback, which tends to be a specific frequencies, without unduly affecting overall sound. A true PEQ, where one can narrow or widen the Q is great, but there are usually only three or four of these for a given channel. Most GEQs have 28 to 31 bands, so more feedback frequencies can be tuned out. The more bands one has on a GEQ, the narrower the Q. If you are lucky enough to have a fully parametric 31-band GEQ, then you’re in good shape. Most inexpensive digital mixers don’t have these, as you pointed out.

You seemed to have a problem with what I said about condenser mics. Apparently, you just haven’t used any good condenser mics. Possibly all you know about are SM58s. The low- and high-frequency response of condensers is significantly greater than dynamic mics, and their transducers are much more sensitive, so a different type and amount of EQ is needed, at least that has been my experience. Maybe you just need to compare the frequency response curves of different mics – you do know what I’m talking about, right?

You said, “Again, this is sort of OK, but the statement is rather rigid and many clarifications need to be made to to situational variables.” I stated “I’m assuming you know the factors that you need to consider with each of these.” My statement is only rigid if you assume it is. I was just suggesting one possible procedure that has worked for me many times, but what one needs to do is dependent on the situation at hand. It is not feasible in a forum like this to cover every aspect of every possible situation.

You seem to be good at picking fights. You chose not to read my comments carefully and misinterpreted several of them. I don’t feel it is necessary to point out all of the instances. I just chose a few. I noticed that you failed to offer any advice before I made my comments — why was that, if you’re so knowledgeable? Why don’t you go ahead and give us the procedures one should follow and provide all the clarifications needed? I’d like the opportunity to critique your recommendations. And BTW, there is a 1024 KB maximum file size for our comments, I think. I doubt that you’ll exceed it.

[AndreasModerator]

Hey, no need to make a personal fight out of this!
We all have our own experiences and methods to operate some live situation, particular feedback.
I personally never had any musician on stage who causes a feedback problem, it always was some mic/gain/speaker issue. Except the guitarist with eye glasses…
For my opinion we still do not yet pinpoint out the cause of the feedback of the OP.
We still didn’t get the information how it sounds to determine, if it is coming from the room or suboptimal PA placement.
Talking about feedback from monitors isn’t helpful at all, since it was stated quite early that the band already uses IEMs.
Talking about some high end GEQ with all bands full parametric (that would be a PEQ, btw.) does not help either, since the GEQ inside the Qu does not offer that functionality and effectively does affect more than just the critical frequency.

But since I’m more on Dick’s side while reading your post, my experience obviously is quite limited as well. I can live with that.

…two weeks ago you stated “First, let me be clear that I do not have an A&H console”, did that change?

[coffee_kingParticipant]

Hi
A little update. Firstly thanks for all your advise.
I had the opportunity to play in a very small pub at the weekend with my three piece rock band where I only needed to put vocals through the PA.
I didnt have much time but I rang the room out quickly with the vocal mics finding and dropping the problem frequency on each channels PEQ with as narrow a point as possible.
It worked a treat and I managed to have the vocals nice and high in the room.
I’m sure I couldve rang it out again to find more slightly less problematic frequencies but for the pub it was fine.
The only issue I did experience with feedback was when I left the system on unmuted by error when I walked away from it and it just about managed to start to feedback after a while.
God knows why though.

[Dick ReesParticipant]

You make some good points, however, your experience appears to be limited. I’ve only been doing this for 50 years or so, and I haven’t been in every possible situation, but I tend to make good observations

Doc…

I started out in the late 1950’s by making my own microphones from telephone equipment and my own amplifiers out of old radios. Since then I’ve made my living as a musician and technician doing performing, live audio, recording, broadcast audio and audio for camera video shoots. I haven’t read your entire reply yet, but the first sentence was enough for a reply.

No one can argue with another persons experience, but in communicating this in your initial post you’ve put in some erroneous info and some popular audio misconceptions as fact. I always correct those statements, disagreeing with the inaccuracies themselves, not the person stating them. I’m sure you’re a fine old fellow a few years younger than myself, but I’ve been doing this professionally for nearly all my life and do know whereof I speak.

DR

[av8en1Participant]

Dr. G and Dick:

Keep the conversation rolling! I, for one, am enjoying it immensely. I’ll read what you both have to say, then take from it what I want and incorporate it into my own sound reinforcement cognitive schema.

[AndreasModerator]

@coffee_king: Am I right that you do not intend to disclose further information on your stage/PA layout and/or how the feedback sounds? Making it somewhat hard to provide useful hints.
Sure, if you’re in a very small room with hard walls controlling feedback from the PA may indeed be an issue, but decreasing the overall volume would be a possible cure as well.
I still believe you’re trying to deal with symptoms not the problem. While this may work more or less, this is the hard road to go.
And if the particular feedback indeed originates from a room resonance, why not adjusting the single PEQ in the mains instead of every mic channel?
If its not a room resonance but a high pitched direct feedback from PA to mic, then PEQ probably does not help much if the microphone can move around the stage. Changing the mic location will result in different feedback frequencies. Turning down the volume (reducing compression, if used at all. Didn’t told us that either) is your only option.

Or, in other words: If you face similar problems in any room you are performing, its likely not a room problem…

[Author]

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