TERRIBLE Squealing

[John Deacon]

We have a PA system and we are running two mics off of it. When my mike and the other mike is turned on, there is a horrible squealing noise. If i turn mine off, it mostly stops, but you can still hear a little bit. I already know that our vocal mikes are picking up our amps and drums because i can hear it through the PA speakers. We are in a bit off a cramped space, its not too too cramped though. Even if we have our mikes on and dont play our instruments, it still starts to squeal. But the instruments seem to make it worse. Any suggestions? Thanks!

[crazyguy832]

Simply put, from what I can tell, you have a feedback loop. A tiny bit of noise goes into the mic, goes through the system and out the speakers. Mic picks up noise from speakers, sends noise to the system, system amplifies noise again. Rinse and repeat until your ears explode.

What microphones are you using, if you don't mind me asking? It's entirely possible that you're using a mic meant, well, to pick up everything in the room when you should be using a mic that only picks up whatever's right in front of it (IIRC, a cardioid... something or another... ).

[John Deacon]

Originally Posted by crazyguy832

Simply put, from what I can tell, you have a feedback loop. A tiny bit of noise goes into the mic, goes through the system and out the speakers. Mic picks up noise from speakers, sends noise to the system, system amplifies noise again. Rinse and repeat until your ears explode.

What microphones are you using, if you don't mind me asking? It's entirely possible that you're using a mic meant, well, to pick up everything in the room when you should be using a mic that only picks up whatever's right in front of it (IIRC, a cardioid... something or another... ).

Sure, we are actually just using the mikes that came with the package, a couple of Fenders.

[Deacon_Blues]

How have you set the gain knob on the mixer? I've found that a higher gain setting makes the mic more prone to feedback, for some reason...

Check the angle between the center of the speaker and the microphone. Most vocal mics take up the least noise from speakers if they aren't pointing straight away from the speaker, but in a 30° angle.

Then check the eq. The feedback frequencies usually are in the range 2,5 - 5 kHz, so dampening THESE frequencies slightly should help.

Then check how you hold the mic (if you do). If feedback occurs, don't cover the mic with your hand, it only makes the feedback worse. Instead shut down the mic channel, lower the gain on the mic and turn the volume up slowly again.

If nothing so far is helping enough, buy another mic or a feedback destroyer. I'd try the former first.

[John Deacon]

Originally Posted by Deacon_Blues

How have you set the gain knob on the mixer? I've found that a higher gain setting makes the mic more prone to feedback, for some reason...

Check the angle between the center of the speaker and the microphone. Most vocal mics take up the least noise from speakers if they aren't pointing straight away from the speaker, but in a 30° angle.

Then check the eq. The feedback frequencies usually are in the range 2,5 - 5 kHz, so dampening frequencies slightly should help.

Then check how you hold the mic (if you do). If feedback occurs, don't cover the mic with your hand, it only makes the feedback worse. Instead shut down the mic channel, lower the gain on the mic and turn the volume up slowly again.

If nothing so far is helping enough, buy another mic or a feedback destroyer. I'd try the former first.

We have everything flat. I have my mike on a stand. Is it possible that it is also an electrical issue if i still get feedback when we arent playing?

[fenderhutz]

Are you using any kind of gate?

[modulusman]

I don't think that fender makes microphones. What exactly are you using for a PA? My guess is you are trying to turn up louder than the room will allow. You need a graphic EQ or a feedback destroyer or at least some decent microphones.

[derrico1]

An honest question for the folks recommending feedback eliminators: has it been your experience that putting a budget feedback eliminator in a modest PA run by novices has improved matters more than fixing the gain structures, eq, and monitor-to-mic positioning would?

I wouldn't guess that an FE would be a magic-bullet without a certain level of operator experience, but I'd be happy to be wrong.

[John Deacon]

Originally Posted by modulusman

I don't think that fender makes microphones. What exactly are you using for a PA? My guess is you are trying to turn up louder than the room will allow. You need a graphic EQ or a feedback destroyer or at least some decent microphones.

Um, yeah they do. Its written on the mike itself. I believe this is it. It came with mikes.

http://www.musiciansfriend.com/produ...-PA?sku=480665

[modulusman]

Fender does not make that microphone. Furman does. At $59.00 I doubt they are very good. For that matter that PA is more suited for a solo or duo act playing music at low volumes. If your a rock band you had better upgrade before you start playing out.

[John Deacon]

Originally Posted by modulusman

Fender does not make that microphone. Furman does. At $59.00 I doubt they are very good. For that matter that PA is more suited for a solo or duo act playing music at low volumes. If your a rock band you had better upgrade before you start playing out.

Then why is Fender stamped on the mikes? And i have to disagree. We have a friend who plays gigs with it, and he is in a blues/rock band, and it works great for him.

[JKT]

Originally Posted by John Deacon

We have everything flat. I have my mike on a stand. Is it possible that it is also an electrical issue if i still get feedback when we arent playing?

At any appreciable gain level and no graphic EQ, you most likely can't get away with a flat channel EQ. You will have to d some negative EQ'ing
with the mids and highs.

JKT

[John Deacon]

It sounds fine, except from the squealing, we have vids, and its sounds great, besides the squealing.

[modulusman]

Originally Posted by John Deacon

Then why is Fender stamped on the mikes? And i have to disagree. We have a friend who plays gigs with it, and he is in a blues/rock band, and it works great for him.

Do an internet search on the microphone and you will see that furman makes the mic. Fender may put its name on them but they don't make them. Buy a stereo 15 or 31 band graphic EQ and learn how to use it or turn down those are pretty much your only choices.

[Munjibunga]

Originally Posted by derrico1

An honest question for the folks recommending feedback eliminators: has it been your experience that putting a budget feedback eliminator in a modest PA run by novices has improved matters more than fixing the gain structures, eq, and monitor-to-mic positioning would?

I wouldn't guess that an FE would be a magic-bullet without a certain level of operator experience, but I'd be happy to be wrong.

I don't think you're wrong.

To the OP, how have you got the mics situated with respect to the speakers? You should have the mics behind the speakers. You should never orient the mics so speaker output would go into the mics.

If you're using stage monitors, their arrangement will depend on the pattern of your mics. If you're using cardioid mics (which yours probably are) the heel of the mic should point directly along the axis of the monitor cabinet. For super- or hyper-cardioid mics, the monitor should be placed off to one side, so they project off-axis to the mic at about 60 degrees.

In small rooms, you won't be able to get a lot of GBF (gain before feedback), so you can't crank up the volume.

[el_Kabong]

Originally Posted by derrico1

An honest question for the folks recommending feedback eliminators: has it been your experience that putting a budget feedback eliminator in a modest PA run by novices has improved matters more than fixing the gain structures, eq, and monitor-to-mic positioning would?

I wouldn't guess that an FE would be a magic-bullet without a certain level of operator experience, but I'd be happy to be wrong.

Yes they do work. IME they work best in their most basic (roving) mode, practically no setup required. If you add properly set gates as well you can get sigificantly more gain before feedback. Whether they work better than 'fixing' monitoring that has been setup incorrectly is an impossible question to answer, how bad is the starting point?

To the OP, the more mics you add to the system, the earlier the PA will feedback. That's why it helps when you turn one mic off and why gates help, they effectively 'turn off' mics that are not being used (when the input signal drops below a threshold). A mic that's been damaged/dropped can be very prone to feedback, compare the mics and make sure they are both the same. (ie see how much gain before it feeds back, each mic in turn set in the same physical position). Make sure you know the polar pickup pattern of your mics and position your foldback speakers appropriately. Also the front of house speakers must be in front of your mics.

[lemur821]

Originally Posted by John Deacon

We have everything flat. I have my mike on a stand. Is it possible that it is also an electrical issue if i still get feedback when we arent playing?

No, you don't need to be playing to cause feedback. Having the mic open near a speaker is enough. Playing can "kick start" the feedback, but it's not necessary unless you're balanced on the edge.

[Surp]

Originally Posted by el_Kabong

If you add properly set gates as well you can get sigificantly more gain before feedback.

Can you please explain how gates will give you more gain before feeback?

[Deacon_Blues]

Originally Posted by Surp

Can you please explain how gates will give you more gain before feedback?

A room with a PA turned on is seldom dead quiet. Even when nobody's playing, there's for instance humming speakers, people moving around making all kinds of small noises, and drumskins that start resonating along to the slightest noise. The higher the gain is turned up, the easier the mic picks up these noises and at some point you will get feedback. Of course the room size and distances to the noise sources also matters. Anyway, with a gate you set the minimum level at which point the gate opens up the signal and thus you can prevent the noises from being picked up by the mic.

Someone else might perhaps elaborate more on the topic.

[Bruce Lindfield]

Originally Posted by modulusman

Fender does not make that microphone. Furman does. At $59.00 I doubt they are very good. For that matter that PA is more suited for a solo or duo act playing music at low volumes. If your a rock band you had better upgrade before you start playing out.

I agree - that is an "acoustic- level" setup - push it too hard and it will feed back - Munji ought to know that you need at least 1,000 watts for a decent, rock-level PA!!