sandell@batcomputer.tn.cornell.edu (Gregory Sandell) (08/28/89)
Can anyone tell me what determines the pitch (frequency, really) that an electric guitar will feedback at? Anybody out there who knows enough about guitars, audio and acoustics to explain this phenomenon? Now I know if the gain is high enough and the guitar pickup is close to the speaker, you'll get some squeal. This is not what interests me. I'm interested in when a guitarist sustains a note, and in addition to the pitch of the note, an extra high note (which is clearly feedback) comes in. I can cite three prominant examples of this on the Who's LIVE AT LEEDS album. Two are on "My Generation" at 12:26 and 14:03, and another is on "Magic Bus" at 6:10. I would like to believe that the pitch of the feedback tone(s) is related to the spectral envelope of the the particular guitar timbre at the time. For example, if there is a spectral peak (formant) at 1200 Hz, will there be a tendency for the feedback to squeal at that pitch? Thanks in advance, Greg Sandell