Intense feedback as gain turned up and I'm not playing anything

M

mgray

New member
Excuse my obvious newbie question concerning feedback. But I'm trying to get an understanding how it works and how to prevent it.

I'm trying out a California Blonde II with my Martin HD-28V. There's been a few times that as I'm setting the gain and volume, not playing the guitar, howling feedback just starts on its own. The first time I think was because all the tone controls on the K&K preamp were set full, but even after I turned them down, at high enough volumes the guitar will start to feedback on it's own without me even playing anything. Even if I mute the strings with my hand, the feedback will continue.

Is this my guitars natural feedback frequency causing me trouble? Is this normal?

With my electric Strat, I can get feedback when I play loud, but I can control it easily with location and can stop it instantly by muting the strings with my hand.
 
Its quite normal for guitars to feedback if they are close to an amp, its used for good effect as well as bad. Just turn the volume knob on your guitar down when your not playing it, and keep the front of your guitar away from any amps and behind our speakers...
 
This does happen with hollow body guitars. I have seen semi-acoustics (ES335 style) stuffed full of that sound absorbing wadding used in speaker boxes for this very reason. Move the guitar away from the speaker box, turn the volume down, or use a parametric eq to put a notch at the feedback frequency can all help.

Amanda
 
Why does this happen? A guitar is a resonating box, and because it is plugged in, it is subject to interference. At a high enough gain, the slightest sound can start the feedback loop. Just touching it could be enough. Even in a room that is *absolutely* silent (ain't gonna happen in the real world), if the guitar is close enough to the amp, electromagnetic interference can create enough noise to start the feedback loop. The solution? No problem. Play in an absolute vacuum with a magnetic pickup, The gloves on the space suit sure make it hard to play though. It gives the term "vacuum tube" a whole new meaning. Seriously, get farther from the amp, don't point the amp at the guitar, reverse the phase if you are feeding back, and learn to use notch control.-Richie
 
Yo Jamit! When you are recording acoustic guitar, feed back should not be a problem, because an amp should not be involved. Acoustic guitar >mic> preamp> recorder. The only exception would be a live or live studio recorder of an acoustic with a band. No amp, PA, modeler, preamp, pickup, or any other system can properly capture the sound of an acoustic with one or more mics properly placed. That's why they call it *acoustic*. There shouldn't be any feedback, because there shouldn't be a speaker. Feedback control is for live performances, not for a studio.

Electric guitar can produce feedback, especially hollowbodies, if you are mic'ing an amp. In that case, the guitar and the amp should be isolated from each other, preferably in different rooms. Usually, feedback is not an issue with solid bodies in the studio, unless you are cranking an amp that is way too big for studio recording..-Richie
 
This happens because the guitar is designed to vibrate sypathetically with the sound of the strings. Of course it will vibrate like that with any sound in the room. Feel the top of the guitar as you talk and you will feel it vibrate.

Any time you amplify that guitar to the point that the sound coming out of the amp can vibrate the guitar, it will feed back. That howl is the resonant frequency of the guitar body.
 
You must log in or register to reply here.
Back
Top