Vocal Feedback...how do I stop it!?

I

ishou

New member
Wasn't sure where to post this one.
OK, here's the problem: In my garage, all our equipment is set on one side (drums, amps, PAs), and my unidirectional microphones are on the other side, facing outside and away from the large speakers. I cannot turn up the mic loud enough to hear vocals while we are practicing without getting an extraordinary amount of feedback. The speakers/amp are loud enough if there wasn't feedback; I've played a tape through it. What can I do to reduce or eliminate the amount of feedback I'm getting? I've had this problem for at least a year now, and it drives me crazy!
 
u either gotta use headphones , turn the pa down (i know you dont want to do that) , so have you thought about running a long mic lead into another room , i know this sux for stage pressence but hey , at least itll fix the feedback prob..Do u mic everything , or just vocals?? also what sort of mic do u have ?? maybe someone knows if different mics are more prone to this problem ... anyway good luck ...
spider
 
Using a Shure SM57 and a AKG C1000S, just micing vocals. Isn't there any other way? because all of these detract from playing; i mean we really can't practice without the singer in the room, and i'd rather not use headphones. The garage door is open and the mics are pointing out and away from the PAs. Really, I think this just shouldn't be a problem...or is it common?
 
Diagnosis

There are some techniques and tools that can help.The first thing would involve using a spectrum analyser to try to determine what frequencies are most responsible for triggering the feedback,then using parametric(sweepable)EQ to dial in and attenuate(bring down) that or those frequencies.You can omly cut so much,however,before it starts to eat up your sound,so it will be a question of finding a livable compromise.Another trick would be to put gates on the vocal mics so that only loud sounds close to the mic,e.g. the singer's voice,are strong enough to open the gate and sounds further away while the singer is not singing don't make it through.BTW,this is also a good trick for gigs where the band is doing their own sound teching, it sure beats having to run over to the board in a panic to cut a howling mic in mid song!Finally,contrary to popular belief,there are mics on the market that have more gain before feedback than Shure 58's and 57's.They cost a little more money,but how bad do you want to solve the problem? One type of mic that I've had very good results with at gigs is the Audix OM series.They are dynamic mics and you can go pretty damn loud with 'em before they squeal.The one I use is the OM-5 for which I paid $175 in 1996.There's also the more cost effective OM2 and the top of the line OM-7.I've actually used my Audix while standing in front of my mains with the mic facing the speakers w/o feedback (I WAS using a gate as described above,however).Cheers!
 
this is kinda of wierd but what if you put the singer behind the foam blocks used to isolate drums? if you build the blocks just up to the mic the singer should still be able to hear. I have never done this though.
 
the gate sounds like the go ... so simple yet could well do the trick , good thinking virtual.. yet if the feedback in the main part of the vocal , i mean the stronger signal that opens a gate then this may not work. I was thinking about this band i played in years ago .. we use to practise in this tiny room , drums , bass , guitar and vocals .. we had a small vocal pa .. we had it just loud enough so the singer could comfortably sing and we could all hear him , yet we never had a feed back problem .Perhaps this is a simple question of volume ?? Maybe we should look at how we avoid feedback at gigs.. FOH says a bit of it , where are the pa speakers ?? maybe try setting up like a gig .. do u have fold backs ?? these can be handy at directing a good monitor mix during rehearsals.. well i think mics would only matter if u were using a large diaphram mic like the nt1 or 2.. Whats the akg like ? i havent seen it myself ... well i hope u can sort this soon cos that must really suck at rehearsals ... anyway goodluck
spider
 
Is there any way to get the singer behind the front of the PA speakers? Can you move them into the room a bit (away from the wall), maybe three feet or so, then have the singer stand behind the plane formed by the fronts of the cabinets? (Moving them off the garage wall might also help the overall sound too because there will be less accentuation of the bass frequencies.)

-AlChuck
 
ishou;

What are you useing for a mixer and does it have a multi band EQ, or just a two or three band for each channel or both. Are there any switches on the mains for the horn freq.
And last are you useing good 12 guage speaker cable. I found the 4k freq is a killer with my system. If you cut it out you could crank the system with no worries.

Good luck;
RussP
 
vocal feedback...

I have used a delay to stop vocal feedback at rehearsals.
Only monitor the delayed signal (100%) and not the source (15%). Make the delay time very,very short with no repeats. This makes it impossible to loop. The tradeoff is a very short delay. (almost un-noticable). U can almost sing in front of the mains!
 
Here's what you do....

I am thinking that you obviously have a graphic equalizer onthe system right? If you don't, don't bother reading on, get on down to the music store, or look in the local classifieds and get one!

Set everything up like you normally do. Turn up the mic volumes till the just start to feedback. Turn it down just a hair.

Now, go to your graphic eq, and turn up induvidual bands one at a time till you find the one that is causing the mics to now feedback. Remember to turn back down any band that is not offending here to the setting it WAS at before.

Once you have found the band that is causing the feedback to occure, turn that band down from it's original position about 2 or 3 db.

Now, turn the mic up again until it feeds back.

Go through the above steps until a desired volume is achieved.

Now, that is how you can get more volume on the PA without feedback, but there is nothing in the world that says it is going to sound any good at all!!!

Some of the problems you may be experiencing is:

Crappy speakers.

Crappy cross overs between the bass speaker and horn.

Crappy Equalizer.

Crappy mic preamp on the mixer.

Crappy cable (yes! I once let a singer use a Monster
Studio Pro 1000 cable during a rehersal. We didn't change any setting at all, and got about 3 db more gain, and no feedback out of the PA. He was shocked...:) )

Hard reflections in the room.

It is waaaaaaaaaaaaaay too loud.

With all but the last, you will just plain old need better equipment.

With the last, well, TURN THE DAMN BAND DOWN!!!

I have done live sound for many, many years now. I have mixed on little 12" and horn systems with about 200 watts of power to 4 way systems with over 100,000 watts of power. Little dinky rooms to 3,000 seat theaters to festivals. Teenage local bands doing their first gig to Grammy winning artists. I have mixed em all and in every situation imaginable.

You know what I have noticed? The less experienced the band, the louder they played. The less tight they were the louder they played. But all in all, all but the biggest time bands I have mixed, and a few locals with great musicianship play way to loud for the room they are in. Rooms have a sort of "saturation point" for sound. If you exceed it, you will never get a good sound without feedback. Small places suffer the most from this.

Also. I would take the damn C-1000S out of the mix here. You just don't need a condensor mic for vocals, and that particular mic tends to be very high end heavy as it is, and will create all sort of problems when used on voice.

You wanna know the best vocal mic overall I ever have used for live sound? The one that time and time again delivers excellent output vs. feedback, excellent feedback rejection, very clear even sound?

You got it. The old standby SM-58. Not the Beta 58. Not the wanna be 58 48. Not the wanna be Radio Shack 58. The good ol' SM-58. Anyday of the week I would take that mic over any other for live sound, UNLESS, I have worked extensively with the performer and they have excellent mic technique, and can really belt it out over the band, stuff like that, would I EVER consider another vocal mic for live. I used to mix for a band a lot and the singer had his own Audix OM-5. It worked very well on his Barritone voice, and we used it everywhere. But this was the exception rather then the rule for live vocal mics.

Get rid of the 57 and C-1000 and get a couple of 58's. I am not saying that virtual ray's endorsement of the Audix OM series is bad, but I have had way better luck with 58's with a majority of singers. Plus, if you take your 58's with you to a club that has sound and a soundman, they will more then likely already be using 58's, and will be prepared for yours as far as having the monitors "rang out".

Good luck.

Ed
 
Wow, sonusman, thanks...real nice to have actual professional help.
One question, though...I always hear that the SM-57 and SM-58 are identical besides the head of the microphone. Is the 57 that much worse than the 58? (I double my mics for recording, too, so I'm not about to get rid of them cause I's po. I probly will trade in my AKG one day.)
 
It may be.....

that the 57 and 58 are identical except for the pop screen, but the 58 sounds superior then the 57 in 99.9% of all vocal applications. No need to get rid of that 57, it sounds better in 99.9% of all instrument applications over the 58.

I have a C-1000S (that I bought two weeks before the price dropped by half!!! damnit....) I have found only one consistently good use for it in the studio, for the Ride Cymbal. Really. I have tried it on many different things and really just not liked the sound at all. But here and there is makes an appearence on another instrument track. But on vocals, it just plain sucks to my ears. You might want to keep it around. For live purposes, it works fairly decent as a drum overhead, or hi hat mic. Maybe on percussion too, or the top end (horn) on a Leslie cabinet.

Good luck.

Ed
 
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