Ron and List I had a S&S B with string noisey dampers and a noticable thump at pedal release. Thge strings were rusty only under the dampers. Cleaning the strings and dampers solved that problem. To reduce the thump, I regulated the damper lift so that the bass dampers lead the treble slightly (1/8 inch for the length of the damper tray). This "tapered" lift was asked for by a teacher who owns two Bosendorfers. He works at the college level and is a marvelous musical technician. He preferred the treble being damped ahead of the bass to allow some bass to sustain through treble passages. I don't understand that level of piano playing but he liked it and so did the B owner and others that I've done that way. It does help diminish the thump.
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