tailpiece to saddle

[Hardrock]

Hey. How does the distance between the string anchors in the tailpiece and the string saddle make? I see different guitars with way different spacing.

Is there a magic number?

Thanks a heap
-jbb

[Alan Carruth]

I'm assuming you're talking about the 'afterlength' of the strings between the bridge and tailpiece of something like an archtop guitar? As far as I can tell there are two effects.

One thing that can make a difference is the pitches of the strings between the bridge and the tailpiece. These can line up with higher partials of the played notes, and change the sound. The back strings steal energy from the played part, and that alters the attack and sustain of those partials. Usually the back strings are short, so those pitches are high relative to the played part of the same string, but the back string vibrations of the lower strings can match lower overtones of the high strings on the guitar. A lot of folks damp out the back strings by weaving in a piece of ribbon or some such.

Depending on how the tailpiece is attached, it can swing up and down or twist around. If the natural pitch of this motion matches a played note, or a resonance of the guitar, it can alter the tone. The swinging of the tailpiece is 'coupled' to the bridge through the back strings: the shorter those are the more the tailpiece vibrations can push on the bridge and make sound.

In a talk he gave at a luthier's convention something like 40 years ago, Jim D'Aquisto said that he could change the tone of an archtop guitar a lot with the tailpiece. He knew what he was talking about.