The Eminence bass
While dwelling around that end of the bass for a change, I decided to try a birch-ply tailpiece as an experiment. I was keen to find out how it might affect the instrument.
The tail-gut would thread through the string block easily, and I wanted to avoid using the end-pin, which on many basses ends up pulled sideways in its socket, due to the combined strain of string tension and the swinging weight of the instrument. To have an end-pin which has no other function to perform is a blessing worth preserving.
I hoped that inclusion of a tail-piece might prove useful
a) to fit a string without having to thread it through the tail-block,
b) to broaden the spacing of the strings,
c) to suppress the sustain of the strings,
d) to assess the offset of the strings, as a result of the slight neck offset after a historic repair.
...was tied with a nylon Wittner tailgut through string-holes 2 and 4 of the tailblock. It had an immediate effect on the angle of the bridge, which now sat more upright, when before, it was leaning back towards the tailplate. The string angles were more consistent over the bridge crest, where before the angle of the thinnest string was much less pronounced because of the lower action on the treble side. The tailpiece "equalized" the average angles because it tracked the adjustment of the bridge and has the same curvature, i.e. the tailpiece closer to the body on the treble side. The thin string's tone was beefed up as a result, more consistent with it's neighbours. Most noticeably, however, the bass was harder to tune, frequently it was a quarter-tone flat on all strings when it was fresh out of the bag, even after weeks of bedding in. The sustain was not reduced as expected, and the overall tone was duller. The strings felt lower in tension when played, and I concluded that the tailpiece, being wide but short, was see-sawing on the tailgut. So...
...was tied with steel rope through string-holes 1 and 5 of the tailblock, after re-drilling the tailpiece. This reduced the see-sawing, but the tuning remained unstable, the tone still slightly dull. By now I was glad to have used slots for the strings (though the slots are not visible in the photo, obscured by the felt washers) and didn't mind the constant refits so much. Using holes 1 and 5 helped to centre the assembly, which helped to confirm the strings needed a 10mm offset from dead-centre to align well with the fingerboard. While not concerned by this anomaly, I was conscious of the bridge feet wanting to find a happy home without any potential drift to one side.
...is where I am now, with the wood bolted to the tailblock to recover some tone, and the tuning stable. Following this adventure, I can be more confident that the final version will need to
a) retain the extended spacing, which keeps the bridge more upright;
b) mirror the bridge's curvature, thus keeping the angles over the bridge more consistent from string to string, and hopefully tone too;
c) be fixed, like the original tailstock, to maintain a bright tone;
d) be offset by 10mm, the fat string about 20mm from it's original anchor point.
Just room left on the page for a picture clue, which is about to be set upon by a bass player with a drill. But that's for another day.