guitar/vocal amp feedbackking

[Ibanex0110]

so for my band, we use a 120 crate guitar amp for vocals, i run a mic through my mixer, and the sub outs into the amp, or the main outs when im not using the mixer for anything else. I know this isn't the best set up, but regardless, im having trouble with it. The singer is only loud enough when he either holds the mic really close to his mouth, or sings really loudly....even then he is barely loud enough, and if we turn it up anymore, it feedbacks terribly. I've tried taking away all the treble and whatnot, but it still doesn't really get loud enough. any suggestions, besides him standing 5 miles away?

[Hadji]

First step I'd say is to try using a mic stand. Position the amp so that it doesn't point towards the front of the mic to cut back on the feedback.

[Ibanex0110]

but he doesn't play anything else, so I think he would get bored with just standing there. wouldn't that be the same as just holding the mic away from the amp?

[Hadji]

Except he's more likely to tip the mic up or cover it with his hand or do anything that will just do enough to cause feedback.

[fuzzyhair]

isnt there something you can buy to prevent feedback? I have this same problem.

[diesel]

Feedback is not one of those problems you can just throw money at to get rid of.

You said you were using a mixer, that will be the best way to get rid of your feedback without physically moving anything. Start with the EQ flat on your channel, then bring the channel fader up while your singer is singing, until you hear ringing. Once you get this ringing, turn your treble up a little and see if it will drive you into feedback, if it does, turn that down. Move along through your mids and lows the same way. That will give you the most gain without changing positions in any way.

If you have a "sweeping" mid knob, you can do even more. Do the same as before, bring your fader up until you start to ring, then turn the mid level knob up a little bit, then move the frequency knob until you hear the ringing turn into feedback. Then turn the level knob down, and that should give you a little more gain.

Other things you should consider:

Can the amp be moved up to or close to ear level, thus reducing the needed volume?

How is the amp positioned? If it is flat on the floor like you'd have for a guitar, most of your sound will end up in the wall, not your ears. The best way would be to lean it against the wall, then have your singer stand right infront of it, either facing towards the side or at the wall.

Is the feedback caused by the amp's sound bouncing off a wall directly behind the singer? Can the singer be moved so he has empty space behind him?


All things said, you can buy devices that will reduce feedback automatically, but they are usually both expensive, and ineffective in this situation. Feedback reducers are simply multi-band (usually ten) parametric EQs. They detect when one frequency is remarkably higher than the rest, and automatically move the filter to reduce it. In this case, so many frequencies would be in feedback at the same time, that it would be jumping all over the place, and likely do very little to help.


One more thing, you do realise that you have mismatched levels here? Your mixer would be setup for a low-impedience, line level output, either -10db or +4db output, and the amp is expecting a high-impidence, instrument level signal, about -50db if I remember correctly. You may not get proper gain out of this amp regardless of how little feedback there is.

[airborne50caliber]

The side effects of pretending not to realize that your crate is made to amplify an electric guitar, not your vocal chords. Anyway, the best solution lie in EQ, specially semi-parametric mids as diesel said, and positioning.