Michael Jorgensen asked: > If the increased energy/power yeilded by having additional strings is >the cause of unison pitch drop, why wouldn't playing louder also cause a pitch >drop? The theory being offered does not say that the increased energy/power is what is responsible for unison pitch drop. Instead it says that the bridge appears to be easier to move when strings are cooperating. That notion is independent of how far you actually try to move the bridge. As others have said it is the bridge impedance that matters. Michael goes on to add: >Few piano strings are stable at a single pitch throughout all of attack, >(prompt sound), and die off, (after sound). My general observation is this: >The pitch of the unison is EQUAL to the lowest registering pitch AT ANY TIME in >the attack/decay cycle by ANY ONE OF THE THREE STRINGS. Check this observation >and see if you find it so. Many individual strings can full blush for several >seconds (be very close), only to suddenly register flat-- a whole cent flat for >a brief instant and suddenly return to full blush. Could the soundboard be >forcing/imposing a frequency against the will of the string and simply winning >the battle for a second or less? It is important not to believe everything an ETD tells you. Just because the ETD appears to show a sudden jump in pitch that does not mean anything really jumped. I know from experience in writing this kind of software that when the actual sound is reduced to a pitch indicator (like the spinner you alluded to), some close decisions have to be made. Those decisions can go either way. When the decisions flip around, the display shows a sudden change. This difficulty is in the process of taking something that is inherently complex - like the actual piano sound - and trying to reduce it to something simple - like an unambiguous pitch indication. For example, false beats can produce a sound that indistinguishable from two closely-spaced tones of equal strength. Which pitch should be reported? The ETD tries to decide, but it can't always make up its mind. Your observation about the pitch of a mistuned unison relates to this same ambiguity. When there are several different tones present, the pitch reported by an ETD depends on how the ETD makes its difficult decisions. It is not something that is inherent in the sound itself. -Robert Scott Ypsilanti, Michigan
This PTG archive page provided courtesy of Moy Piano Service, LLC