<HTML>Thank you, Dale. It's been a while since I've seen the piano.  The fundamental where the resonance starts is much lower on this one; G# (or G#1, can't remember).  That note is louder, and all the partials above it... ex. the octave, twelfth (sp?) and up along the overtone series. The biggest problem is when a resonance partial beats against the note it's closest to as I'm trying to tune, partials not being equal-tempered and all.  The customer hears the resonance, too, and doesn't like it. I'll check the screws, though I expected the rebuilder to have covered that base.  Presumptions kill.  If that's not it, I'll also try fiddling with the spider (gently). I don't have enough training in acoustics to know whether inconsistencies in a soundboard/ribs can resonate like this.  The soundboard builder is a fine craftsman, but I don't know if he has any more acoustic design training than I do. Any more clues, anyone? Karin Schmitt Karintunes@aol.com Florida Keys/Key West Dale's message of 01/25/2002: > A customer of mine has a very old M&H Grand with a new soundboard that has > me, and the rebuilder's head technician, stumped. > It is resonating at all the partials in the overtone series of one note.  > It's not the string tails, and not the spider. 5 >>>>>>>>>>>  Hi Karen       I too am a rebuilder  and have recently had a smilar problem on a Mason A that I just put a board in. In my case however and for the first time I discovered that the arms on the spider(centripetal resonator) were actually loose. Now I must admit that I did spend an anxious hour  looking for  the problem and at first dismissed the spider  it until I started pulling and pushing on it. It's worth a double check. The notes that were most affected in my A  were around c-5. I ended up tighting 3 of the arms and the vibration/overtone went away. Wish it were always that simple. I am unclear as to your description of the problem. Perhaps you could clarify your "its resonating at the partials of one note" statement. It is loudest in the curve of the case.            >>>>>>>>>>Mine was loudest at the belly rail. Sound travels. Karen it's is usually something simple you just have to keep looking. Tighten all the trap screws and any case screws. If I get any brain storms I'll get back. Right now my brain is begging to be fed.                  Regards--Dale Erwin</HTML>