Pinch Harmonic - Technique

Technique

A pinch harmonic is produced when the thumb of the picking hand lightly touches against the string immediately after it is picked. This action is sufficient to silence the fundamental and all overtones except those that have a node at that location. This is generally accomplished by holding the guitar pick so that very little of its tip protrudes between the thumb and forefinger (roughly 3–5 mm), allowing the thumb to brush the string immediately after it is picked.

The technique must be performed at one of the appropriate harmonic nodes for the note to sound. For example, to produce a pinch harmonic one octave higher than the fundamental of a string stopped at the third fret of a guitar, the string must be plucked halfway between the third fret and the bridge (i.e., the 15th fret, as fret spacing is logarithmic). Other overtones of the same fundamental note may be produced in the same way at other nodes along the string. The point at which the string is plucked therefore varies depending on the desired note. Most harmonics have several accessible nodes evenly spaced on the string; so it is no surprise that the nodes used in practice are normally those around where the string is normally picked (around the pickups on an electric guitar), rather than those above the neck as these are the easiest to access with the picking hand from normal playing.

Overtones with a frequency of a multiple of the intended overtone (i.e. its own harmonics) will share the nodes of the lower overtone, so won't be muted. They will, however, be at a much lower volume and since they form the selected overtone's own harmonic series, don't detract from the sound of the note. If the string is pinched at the antinode of the intended overtone, no higher overtones will sound.

A single harmonic overtone is far quieter than a normal note with its many overtones. Amplification and related techniques such as distortion or compression are often used to improve the overall sound. Thicker strings, stronger pickups, and adjustment to amplifier settings (increasing gain) are some ways of doing this. Note that as only one fundamental sounds, it has a different volume through different pickups, depending on the proximity of nodes or antinodes to the pickup. The different volumes of overtones are the reason pickups sound different. The outcome of this is that if a node is directly over a pickup, it won't sound through that pickup.

Joe Satriani's signature "Satch Scream", heavily utilized in his song "Satch Boogie", is achieved by depressing the whammy bar and sounding an open string pinch harmonic, usually on the G and B strings, then slowly raising the whammy bar to produce the scream.