Pinch Harmonics

A pinch harmonic occurs when a vibrating string hits a small obstruction near a node-of-vibration for one or more harmonic overtones. Such harmonics (having a node at the obstruction) are unaffected while other harmonics (such as the fundamental) are attenuated or even made inaudible. The net effect is that the pitch jumps to that of the harmonic, typically an octave or fifth above the fundamental.