Charles E Faulk wrote: > List > > This is a new one for me. Maybe some of you have encountered a phenomenon > like this. > > A customer in Topeka has just purchased a new Petrof grand. He initially > said that he was hearing some echoing or 'ring through' after playing and > releasing the damper pedal. Well damper ring through is not that > uncommon; I told him it was probably some offending bass damper that > wasn't seating. > > Just yesterday he called me to say that another technician had looked at > the piano and decided that the ringing was caused by a plate strut > vibrating sympathetically with certain notes. He said he could stop the > ringing by simply touching one of the struts. > > I'm more than a little sceptical, but who knows. My appointment to see > this piano is next week. Has anyone ever encountered a 'singing strut'? > > Charles Faulk > Manhattan, KS ------------------------- Yes, and singing hitch pin panels as well, though they're less common. Usually nose bolts take care of the singing panel problem. One of the functions of the nosebolt is to couple the plate panels to the more acoustically dead wood rim & belly brace assembly. (They aren't there just to adjust downbearing, you know :-) If the resonant frequency of a plate strut (it has mass and elasticity) coincides with the frequency of a note, or notes, on a piano, it can sing. Cast iron does have fairly good damping properties, but it is not "acoustically dead" as is usually assumed. If you find that this is indeed the problem, please pass on some details. -- ddf
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