A
pinch harmonic (also known as
squelch picking,
pick harmonic or
squealy) is a
guitar technique to achieve
artificial harmonics in which the player's thumb or index finger on the picking hand slightly catches the string after it is picked, canceling the
fundamental frequency of the string, and letting one of the
harmonics dominate. This results in a high
pitched sound which is particularly discernible on an electrically amplified guitar as a "squeal". By using string bending, a
whammy bar, a
wah-wah pedal, or other effects,
electric guitarists are able to modulate the pitch, frequency, and
timbre of pinch harmonics, resulting in a variety of sounds.