Mic'ing an amp

[johnjohn320]

Was at a rock concert last night, and noticed that the bass guitar amp was mic'd, obviously so the amp could be run through the huge speakers at the front of the stage. But I found myself pondering how that's possible. Whenever you hold a mic up to a speaker or amp, you get screeching feedback. Whenever I've played in a band with a PA, we had to make sure the vocal mics were all far enough away from the amps to avoid the feedback. So, how does this work?

 

[radioouman]

The mic output doesn't go back into the speaker input.

 

[broon]

This explains how feedback works.

 

[imported_Imp]

Interesting topic. First time I went to a concert, I was wondering what the ****. I always thought they someone linked the amps to the speakers as opposed to a mic offset 2" from the amp.

 

[imported_Solace666]

Amps are no different than a voice. It's just a sound making device. All you have to do is limit the output as an amp is obviously louder than a voice.

 

[aircooled]

The amps are not channeling the sound from the mic, so no feedback.

 

[Heisenberg]

Originally posted by: radioouman
The mic output doesn't go back into the speaker input.

Yeah. The amp gets the signal from the bass, and the microphone is far enough away from the big speakers that it won't feed back.