afterlength

Afterlength is a term used in the physics of stringed instruments to describe the portion of a string that lies beyond the fretting point toward the fixed end of the string, typically toward the nut on a guitar or similar instrument. When a note is fretted, the vibrating length is the segment between the fret and the bridge, while the afterlength is the remaining segment between the fret and the nut. This afterlength is not the primary vibrating length, but it can influence the instrument’s overall tone through subtle resonances and coupling with the vibrating portion.

Acoustically, the afterlength can participate in sympathetic vibrations and affect the harmonic content of the sound, especially on longer scale lengths, lighter gauges, or when the fret is placed at positions that promote certain resonances. The impact is generally subtle and varies with scale length, bridge and nut geometry, and playing dynamics. In some contexts, the afterlength is analyzed as a secondary resonator that can interact with the main vibrating length to alter timbre, sustain, and brightness.

In practice, luthiers and players may consider afterlength in setup and adjustment, though it is usually a secondary concern to intonation, action, and the vibrating length. Adjustments that influence afterlength, such as nut slot alignment or precise fret positioning, can modestly shift resonant behavior and perceived tone.

See also: scale length, vibrating length, intonation, harmonics, nut, fret.