Jim Bryant wrote: >The >sustain time on a unision is slightly longer on a note with a slight roll, >but I will leave it to the theoreticians out there to tell us why. I don't know if I can answer to the name "theoretician", but I think I know why. If the unisons are exactly at zero-beat, then all three strings will be pushing down on the bridge at the same time, thus transferring maximum energy out to make sound. The faster energy leaves the vibrating string, the shorter the sustain. If the unisons have some roll to them, then shortly after striking the note the three strings will be at a random phase relationship with each other. One string might be pushing down on the bridge while another string is pulling up. (Well, not really pulling up since the down bearing biases all forces downward.) This causes the bridge to appear "stiffer" to the individual strings. The stiffer the bridge appears, the less energy will leave the string, so the sustain lasts longer (but quieter). Bob Scott Ann Arbor, Michigan
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