Cutting feedback

C

Clive Hugh

New member
Guys,
My band has a slight problem, we have a hall available to practice in but it has dreadful acoustics and the last time we had feedback from hell. I was thinking if we chucked a couple of folded blankets over the PA cabs would it work in cutting feedback?
Any suggestions would be appreciated.
 
You might try setting the PA cabs at a slight angle instead of parallel to the walls. This will help to break up the projected sound waves and sometimes helps. Keep all mics as far behind the PA cabs as possible, on a small stage this isn't always easy. Rooms with a lot of echo are a real pain, if this is the case, the angled PA cabs will help. You might also EQ off some lows and highs and stay in the midrange or flat. If all else fails, you may just have to play at a lower volume.
 
Dani Pace said:
You might try setting the PA cabs at a slight angle instead of parallel to the walls. This will help to break up the projected sound waves and sometimes helps. Keep all mics as far behind the PA cabs as possible, on a small stage this isn't always easy. Rooms with a lot of echo are a real pain, if this is the case, the angled PA cabs will help. You might also EQ off some lows and highs and stay in the midrange or flat. If all else fails, you may just have to play at a lower volume.
Click to expand...
Dani, we have about done all of the above, muffling was a sort of desparate last resort.
I just thought of something else, I heard once that putting a speaker up against a wall helps break up the sound.
We are sort of stuck for places to practice as we like to go through a full on "dress rehearsal" before a gig and home is out of the question, we can't even open the windows as the building is aircon.
 
Get yourself a Behringer Feedback Destroyer. I've played in my share of crappy rooms and that unit has saved my ass many times. When used correctly it won't butcher the sound the way a graphic EQ does.
 
Clive Hugh said:
Guys,
My band has a slight problem, we have a hall available to practice in but it has dreadful acoustics and the last time we had feedback from hell. I was thinking if we chucked a couple of folded blankets over the PA cabs would it work in cutting feedback?
Any suggestions would be appreciated.
Click to expand...

I have a lot of experience with this; I have had practice halls in the places I have lived for the past 25 years or so. I have tried many things.

Here's what I have found that works for me in what used to be a 2 car garage: I have a cluster of monitor wedges in the center of the room, with the mics in a circle around them. All the instrument amps are along the walls pointing inward. Drums are in a corner with his own monitor.

I treated the room somewhat; I carpeted the floor with several layers of carpet scraps, and paved the ceiling with cardboard fruit crates (similar to egg crates). I have hung foam pads on about half the exposed wall surfaces. I used a pink noise/RTA to set the EQ curves on the monitors.

The monitor cluster is the key that makes the system work. All the mics are the same distance from the speakers, and all the mics point the null (the dead spot in a cardioid pattern) toward them. A bonus is that we stand in a circle, so we can watch each other and communicate. We can crank up pretty loud and still we can all hear the vocals with minimal feedback probs.
 
ggunn said:
I have a lot of experience with this; I have had practice halls in the places I have lived for the past 25 years or so. I have tried many things.

Here's what I have found that works for me in what used to be a 2 car garage: I have a cluster of monitor wedges in the center of the room, with the mics in a circle around them. All the instrument amps are along the walls pointing inward. Drums are in a corner with his own monitor.

I treated the room somewhat; I carpeted the floor with several layers of carpet scraps, and paved the ceiling with cardboard fruit crates (similar to egg crates). I have hung foam pads on about half the exposed wall surfaces. I used a pink noise/RTA to set the EQ curves on the monitors.

The monitor cluster is the key that makes the system work. All the mics are the same distance from the speakers, and all the mics point the null (the dead spot in a cardioid pattern) toward them. A bonus is that we stand in a circle, so we can watch each other and communicate. We can crank up pretty loud and still we can all hear the vocals with minimal feedback probs.
Click to expand...
We won't be able to put things like egg cartons but The idea of being in a circle is worth a try, thanks.
Clive
 
Clive Hugh said:
We won't be able to put things like egg cartons but The idea of being in a circle is worth a try, thanks.
Clive
Click to expand...

It should help. I tried for a long time to make it work with PA speakers in two corners of the room, but mics were all different distances from the speakers, pointing in different directions, and feedback was a constant major irritant. With unlimited funds, you could give everyone wireless in-the-ears, but if you're like me, trying to make it on the cheap, this works pretty well.

Oh, another thing - I've got the mons all packed together as tightly as I can get them to minimize the floor space that they occupy, and they are all raised a couple of feet from the floor. Raising them made a big diff, too.

Whatever you can do to the walls to minimize the reflections back into the mics will help as well. If you have two parallel flat hard walls in the room, standing waves and multiple reflections will limit how loud you can get, and that includes the floor and ceiling. If you can't do anything about the ceiling (I just used a heavy stapler and those cardboard fruit trays), then you'll want to kill the floor. I have about three layers of carpet scraps on the floor, all obtained for free from various sources.

Do the clap test. Stand in the middle of the room, clap once, and listen to how long it takes for the sound to die out. The shorter the better.

Good luck.
 
Clive Hugh said:
As it is a scout hall with 4 hard shiny reflective walls we can't do too much but carpet we can do.
Click to expand...

Ah, so it's not a permanent installation. Well, best of luck to you.
 
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