Compound radius

A fingerboard whose radius flattens progressively along its length, usually curving tighter near the nut and flatter up at the high frets.

The idea is to have both advantages: a rounder radius for comfortable chording and barres in the low positions, and a flatter surface for bent notes and fast lines where a strongly curved board makes the string fret out. To work properly, the flattening has to be conical, so the fretboard is machined on a cone rather than a cylinder and the frets follow that surface. String action and relief are then set differently across the board.

Example: a guitar with a ten-inch nut radius flattening to sixteen at the body lets a player bend a whole tone high on the neck without choking.

Compound radius

See also