Ringing out the room...

http://www.youtube.com/watch?v=m0HaNtwlyKs
 
Earlier this year, someone here taught me the term 'ringing out the room' to mean using EQ to try to remove feedback.
 
I just learned to use the infinity compression setting with a low threshold on a compressor to hold the feedback so you can see it in a spectral analyzer and eq it.
 
In this video, I try to eq 2 mics, and MXL V63M and MXL Guitar Cube. Both condensers with phantom power.
 
I bring the two mics in on channels 1+2 which each has a separate EQ.
I route the tracks to outs 1+2, each with separate EQ
 and those to the DBX 162 SL and then back into inputs 5+6, again EQ,
to the mains with yes, another EQ.
 
Anyway, I haven't done this often. I'd be game for any advice I can get on how to do this better/faster. I was using mics that would cause feedback on purpose, of course.
 
Thanks for any who have the time to watch!

This is interesting for sure and thanks.  What I think I got from it was the idea of using a limiter to stop the feedback getting too loud but you can control this too in other ways.
 
I find that once I get a front system sounding pretty flat and nice I get less trouble from that in terms of feedback.  For me the bigger problems are with the foldback system.  It is the speaker system which is pointing directly at the rear of the mics too unlike FOH which should be further forward and pointing to the audience. ie FOH has to be flamin loud before it should take off.  Start by getting FOH well balanced spectrum wise first.  Then you will find you won't need to ring out FOH anywhere near as much.  Pink noise is OK but your test ref CD is a must here. For me it is Steely Dan. (CD only 'Two Against Nature' or 'Everything Must Go') Once that is sounding natural and well balanced I know FOH is pretty close to ideal.
 
Back to folback. I use the approach of having the vocal mics all setup and in position. Pref with a musician standing in front of them too and even close to the mic.  The mics are usually SM58's in this case.   I just increase the gain in each foldback wedge slowly and keep doing so until the foldback starts to ring out at a certain frequency.   If you have got a spectrum analyser connected it is fairly easy to pick what freq it is.   And then make the corresponding adjustment to the foldback EQ. I then continue on adding gain until another freq starts up. I find after doing two or three, the FB system is now ridiculously loud and would blow the head of the performer without feedback and this is good because you only have to back off from there which reduces the feedback possibilities even more.
 
With FOH I tend to leave all the vocal mics up that are going to be up (Including drum mics too) and just ease the gain of the whole FOH level until FOH starts taking off a bit and it too will be at a certain frequency.  Then fine tune FOH EQ as well. Once again two feedback freqs at most there as well. There will always be one freq which will be way more unstable than others.
 
The best way for me in terms of how to connect the spectrum analyser is just use the measurement mic plugged directly to the analayser and it will pick up all the feedback it hears pretty easily.

mike_mccue
I am used to ringing out a room with analog 31 band EQs. The easy access to all the physical knobs at 1/3 octave makes it seem quick and easy.
 
It takes just a few minutes, or less, with each send. e.g. The mains, and the various monitor wedges or side fills.
 
With the mains, I just jam the main mix outputs until I hear the ringing and grab a EQ knob and pull it back. I try to get to a place where the output is way hotter than we will use once the music starts so I know I have lots of leeway. I do the same thing for each monitor send... I like to make the monitors scary loud without feedback so the first thing the musicians say is "turn down the monitors" when they do a sound check.
 
I use the track EQ to sculpt the sound for the tonality and then I use a 31 band EQ on the mains and each monitor send to suppress feedback.
 
At some point you can get so quick at it that you will not even know why you grabbed the frequency that is ringing... you'll just grab it and make it go away.
 

Same here.
 
Doing this you will not only avoid feedback but also get a much better balanced overall sound.
 
As an aside, years ago I used to use a Peavey Autograph to analyse the room. Some of the curves it came out with were way strange but always sounded great!

Mike I am sorry for the confusion. I totally agree with you in terms of ringing out the room and using the actual mics on stage to do it for sure.  If there are people around I find getting them to stand roughly in the position of the performers helps too because that can alter things slightly.
 
I was only referring to the measurement microphone feeding into some sort of spectrum analyser as a means for it to simply pickup any feedback that is going on in the room either from FOH and foldback so you can simply see what frequencies are popping up in order to know quickly which graphic sliders you need to notch down.  You could patch a spectrum analyser into either foldback or FOH directly or what I was suggesting is just use a mic to pickup the feedback from anywhere in the room, it will still show you what you need to know.   After all it is already there having done the pink noise tests previously.
 
I also agree with moving a mic or speaker only a small amount can have a large impact on feedback for better or worse.   I prefer to start with that approach first.  Another thing I like to do is feed my ref CD up into the monitors and have a good listen there too just to see how they are holding up. Often that is useful.  Sometimes they can sound a little peaky here and there and if you flatten out the foldback and get them sounding more smooth you now have a monitor that won't be favouring some freqs over others.  Also I tend to roll everything off above about 7 to 8 Khz in foldback speakers. You can still maintain reasonable highs in there but it avoids those horrible very high freq feedback loops that can sometimes happen if a foldback speaker is far too trebly or toppy.
 
What I find very annoying though is where some venues actually mount their FOH speakers, sometimes right on the same axis line as where the mics are.  (literally in line with the mics!) If they had just mounted them forward by a foot or two it would have made a huge difference.
 
I am convinced with care you can produce huge amounts of level for musicians in foldback speakers and be nowhere near feedback and the same can be said of FOH too.

My quote: I am convinced with care you can produce huge amounts of level for musicians in foldback speakers and be nowhere near feedback and the same can be said of FOH too.
 
Except I should back that up with the mics being SM58's and artists being right on them too.(kiss the mic!)
 
I take my hat off to you if you are using quailty LDC mics on stage. To be honest I have not had a lot of experience with that. I do sometimes put up some nice SDC's over the drums as OHeads and they are often the mics that give me the most trouble. The good thing though is if the drummer is reasonably loud you can keep the gain on those down a lot and still hear them.
 
So I guess your ringing out work would be much more difficult and harder with LDC's on stage all over the place. I suppose you could use the same approach I have taken with SM58's (thank god for SM58's! LOL) but just carefully work your way through them one at a time. Be good to have a combination of close vocal mics (SM58's) and the LDC's for instruments here and there. That might be easier.
 
The basic concept of ringing out the room is still a good one. The other thing too is when you are advancing gain the trick is to just get that feedback to start and figure out what freq it is and get it down quickly. The idea is to never let it get in full on feedback which some engineers seem to do when ringing out rooms.
 
 

There are some relatively popular SDCs made just for live stage hand held singing; The Shure Beta 87A/87C and the Neumann KMS 104/105 are good examples. They have built in windscreens.
 
You can also see mics like the Schoeps SDCs mounted in front of vocalists such as the Three Tenors, and they usually have the Foam windscreens mounted over the capsules.

I have a Shure SM86. I gave it a try. Looks like the same EQing works pretty fairly for the different mics. Should I be using fairly narrow Qs? I was just adjusting Q to take care of the job and no more.