| A fact of life for guitarists: most of the world's guitars do not play in tune.
There are a number of reasons why this is so. The spacing of the frets may be
inaccurate. (Some of the worst offenders on fret spacing are individual guitar
builders whose work may be otherwise highly regarded.) The fingerboard may be
distorted: backbow, or too much forward bow, or a crook at the 12th fret. The
most important reason why guitars don't play in tune, however, is that the scale length is
not properly compensated. Compensation for intonation is adjusting the string length
to deal with the fact that pitch changes because of stretching the string when fretting. I
do several things to my guitars to make them play in tune. My fingerboards are
precision slotted to machinist-grade accuracy with a special custom-built jig. In
addition, the nut and saddle are adjusted for each string, using compensation values which
have been thoroughly tested electronically. I also use neck attachment techniques
and an upper body design which give optimum protection against fingerboard fret surface
distortion. The result is that notes, and particularly intervals, which play in tune
in one position on a Jacobson guitar will play in tune on any other part of the
fingerboard.
For theoretical background on this issue, go to my article on Intonation. |