EQ tips for cheap P.A.? (Feeding back!)

[Adam Bomb]

Hi:

OK - I've read the first 3 pages of this forum, as well as the stickies, and didn't see this issue addressed. But I am sorry if it gets beat to death here.

Short version: How do I tweak my EQ to get max volume without feedback?

This is what I am rocking:
Mic (SM58 or Beta58) => tiny Alto mixer => a pair of [Invalid or Expired Link Removed]

With everything - knobs on the speakers (hi/low/level), knobs on the mixer (gain/level/hi/low/master) - straight up, at noon, it feeds back.

Lower - say, everything the same but the master, dialed back to about 9:00 - there's no feedback, but you can barely hear me. (Three loud guitars and a hard-hitting drummer.)

Everything at noon except the highs on the board cut a *lot*, there's no feedback, but I'm muffled, and you can't hear me.

So. Is there a rule of thumb re which set of controls to tweak first/only/more - the speakers or the board? Both are quite minimal, so it's not like there's a lot of control with either one.

I cut the lows a lot, to try to give the speakers less to do (my vox only going through them, and I'm a low tenor). Makes my voice sound thin though.

Also, which mic is better in this situation? The Beta58 is hotter, of course, but I wonder if what I gain in gain I lose in headroom, i.e., system seems more prone to feedback with the Beta.

Also, currently, the speakers are a little bit in front of me and to my right, so they are not blowing straight into my mic but they don't have their backs to me, either. Nothing I can do about that. (Not my rehearsal space.)

Perhaps the answer is "Get a better P.A." but let's assume that's not an option.

Any thoughts? Beuller? Anyone?

--Bomb

 

[drooldud]

Speakers on the ground, on there side, tilt them back and up and use it as a monitor

Get a 31-band EQ - put everything in middle, slowly turn up and then reduce the higher frequencies while feedbacking to see which frequencie is causing the issues

Both mics will suffer the same issues.

 

[Hactar]

Feedback is a tricky beast.

Your primary issue is that you are trying to control feed back with a two band EQ.
This is not going to work, as the two bands of EQ available are very wide.

First of all, you should be setting your gain structure properly.
In other words, set your master fader and channel fader to unity gain (not necessarily noon!) and, while speaking into the mic, bring up the trim until you are touching 0dB on the meters. Then bring up the gain on the Behringers until it is loud enough.

To properly control feedback, especially in a variety of rooms, you will need at least a 15 band EQ, or better yet a 31 band EQ.
You will only need a single channel of EQ.

Then, with the EQ, start ringing out the system. (I will happily elaborate on that if you need me to.)

Hope that helps, speaker placement is also a factor, but I am unable to weigh in on that without seeing a picture of the speaker placements.

 

[Adam Bomb]

Feedback is a tricky beast.

Your primary issue is that you are trying to control feed back with a two band EQ.
This is not going to work, as the two bands of EQ available are very wide.

First of all, you should be setting your gain structure properly.
In other words, set your master fader and channel fader to unity gain (not necessarily noon!) and, while speaking into the mic, bring up the trim until you are touching 0dB on the meters. Then bring up the gain on the Behringers until it is loud enough.

To properly control feedback, especially in a variety of rooms, you will need at least a 15 band EQ, or better yet a 31 band EQ.
You will only need a single channel of EQ.

Then, with the EQ, start ringing out the system. (I will happily elaborate on that if you need me to.)

Hope that helps, speaker placement is also a factor, but I am unable to weigh in on that without seeing a picture of the speaker placements.

I am printing this out and taking it to my next rehearsal. Thank you!!!

If it helps:

My mic is just out of the shot, far right, pointing even further off to the right.

This will be my P.A. at smaller gigs as well (also known as most of our gigs), so I was gonna get some stands. I suspect that if I put them on the floor, at gigs at least, my vox will get lost in the onslaught of constant caterwauling - I mean, in all the wonderful guitar.

I am going to make do with this mixer for now, but, for future reference, what is "ringing out the system"?

Also, I am tempted to run a little bass through them, but I figure that if I'm having problems as it is I probably shouldn't.

Thanks again!

--Bomb

 

[seamonkey]

Feedback eliminators work great
They EQ everything to the room

skinner notches
Very little coloration
Turn it on, let it do it's calibration, and you're set.

Invalid Link Removed
Many other choices, and some have double use of the filters where you can use them as an parametric EQ also.

 

[Adam Bomb]

Feedback eliminators work great
They EQ everything to the room

skinner notches
Very little coloration
Turn it on, let it do it's calibration, and you're set.

Invalid Link Removed
Many other choices, and some have double use of the filters where you can use them as an parametric EQ also.

This looks pretty amazing.

So it's a full-on preamp? Like, I can go mic => this thing => my powered cabs?

Thanks!

--Bomb

 

[mdeguzman1]

The Beta58 is a supercardoid mic. It has a little tail behind the mic that pics up sound as well (see link below). The SM58 is a cardoid mic--no tail.

[Invalid or Expired Link Removed]

I've also generally found that systems tend to feedback more when pushed to their limits--compared to the same dB volume with a bigger amp.

 

[spigmu]

Are there any monitors at all in this equation, or are you using the PA speakers themselves to hear yourself?

I get that it's a compromise situation, but if the PA has some direct wave action happening toward your mic you'll be eq'ing much more than you'd need if you could deal with the speaker positions at least a little.

$200 of mini-monitor will probably get you more than $200 of feedback eq.

 

[modulusman]

Buy a 31 band EQ as it is the right tool for the job. .

 

[4Mal]

1. The Behringer feedback eliminator ahs anflat out horrible reputation. Check the pro sound forums. Peavey and DBX fare much better amongst the pros. Yes they cost money but then again they actually work...

2. I think your issue is simpler to fix. Looks like you may be in a relatively small space.
A. Your mic is too close to the speakers
- you are singing facing the speakers, yes? If not - that is your problem

B. Sound bounces off glass, so if your mic is oriented correctly with the ball end away from the speakers but you have glass behind you, the reflections will cause feedback. I hate stages with glass behind them...

C. Spl - too loud in too small a space, your'e going to have feedback issues, no matter what.

Yes, an EQ, preferrrably one that shows which bands have the most energy will help -if you know how to run it. Feedback elimination is frankly not for the new... Nou really have to know how to work with it lest you create a sonic mess.

Solve the issues above first, then add gear if you must. Dollars too donuts - you're asking too much of the room and your mic placement by playing too loud for the space.

 

[seamonkey]

Shark FBQ100 is a new model
The DSP100 was the old model, and now it's been improved.
It still only has 8 filters, higher priced feedback eliminators have more.
The shark has it's use, especially for single mic situations.

Set up and feedback eliminators is easy.
Set up, turn it on, and set it to learn. It sends out pulses and measures to the amp and speakers and listen at the mike for ringing. Then zero's in a notch on the ringing.
It turns up the volume and repeats.
It ends testing at a higher volume than your playing at. You do not have to reset it after you turn up.

There is another mode that it listens live and tries to hone in on feedback live. This mode very difficult to use for music. It's better to EQ before the music starts.

 

[Adam Bomb]

The Beta58 is a supercardoid mic. It has a little tail behind the mic that pics up sound as well (see link below). The SM58 is a cardoid mic--no tail.

[Invalid or Expired Link Removed]

I've also generally found that systems tend to feedback more when pushed to their limits--compared to the same dB volume with a bigger amp.

TY for this. I will experiment with both mics. Yeah, I recently expanded to two speakers for this reason. It looks like overkill but clearly it is not.

Are there any monitors at all in this equation, or are you using the PA speakers themselves to hear yourself?

I get that it's a compromise situation, but if the PA has some direct wave action happening toward your mic you'll be eq'ing much more than you'd need if you could deal with the speaker positions at least a little.

$200 of mini-monitor will probably get you more than $200 of feedback eq.

These speakers are for me and anybody else I am trying to let hear me. Since I am reluctant to buy more gear I agree that I absolutely need to work on placement. What do you suggest? Me and the speakers all facing the same way, speakers in front of me?

Buy a 31 band EQ as it is the right tool for the job. .

Even though I may not act on this right away, I know that it is true.

1. The Behringer feedback eliminator ahs anflat out horrible reputation. Check the pro sound forums. Peavey and DBX fare much better amongst the pros. Yes they cost money but then again they actually work...

2. I think your issue is simpler to fix. Looks like you may be in a relatively small space.
A. Your mic is too close to the speakers
- you are singing facing the speakers, yes? If not - that is your problem

B. Sound bounces off glass, so if your mic is oriented correctly with the ball end away from the speakers but you have glass behind you, the reflections will cause feedback. I hate stages with glass behind them...

C. Spl - too loud in too small a space, your'e going to have feedback issues, no matter what.

Yes, an EQ, preferrrably one that shows which bands have the most energy will help -if you know how to run it. Feedback elimination is frankly not for the new... Nou really have to know how to work with it lest you create a sonic mess.

Solve the issues above first, then add gear if you must. Dollars too donuts - you're asking too much of the room and your mic placement by playing too loud for the space.

Option C is on the nose. Five old dudes in a tiny room with their gear cranked up to 11. It is so much fun. But, yeah, also a problem. It sounds like gigs could actually have fewer feedback issues *knock wood* - more space, better placement. *knock wood*

I think I have noticed that, when I back too far away from the speakers, and get too close to the wall behind me, that's a hot zone as well. So I have experienced option B as well.

I may try one speaker on the floor, pointed right up at my face, not that loud, and another pointed completely away from me, cranked.


Thanks all--

--Bomb