A corpus-based method for controlling guitar feedback

The use of feedback created by electric guitars and amplifiers is problematic in musical settings. For example, it is difficult for a performer to accurately obtain specific pitch and loudness qualities. This is due to the complex relationship between these quantities and other variables such as the string being fretted and the positions and orientations of the guitar and amplifier. This research investigates corpus-based methods for controlling the level and pitch of the feedback produced by a guitar and amplifier. A guitar-amplifier feedback system was built in which the feedback is manipulated using (i) a simple automatic gain control system, and (ii) a band-pass filter placed in the signal path. A corpus of sounds was created by recording the sound produced for various combinations of the parameters controlling these two components. Each sound in the corpus was analysed so that the control parameter values required to obtain particular sound qualities can be recalled in the manner of concatenative sound synthesis. As a demonstration, a recorded musical target phrase is recreated on the feedback system.