Relief

The small forward curvature built into a guitar neck so the vibrating strings clear the middle frets, measured as the gap between the string and a fret.

It exists because a string's vibrating arc is widest in the middle of its speaking length, so a dead-straight neck buzzes in the middle positions. Relief is set with the truss rod, typically a few thousandths of an inch on an electric and a little more on an acoustic, and it is checked by holding a string at the first fret and measuring at the eighth or with a notched straightedge on the board. Too much relief raises the action and makes the guitar harder to play.

Example: a guitar buzzing around the fifth to seventh frets often just needs a quarter turn more relief in the neck.

Relief

See also