First I have to admit: I cannot keep up with all the messages. So maybe this is already stated: One string brings in an amount of energy to the soundboard. The fixed end is not a fixed end anymore. So the actual length of the string should be slightly enlarged to calculate the strings frequency out of it. Now three strings in unison bring their energy to the soundboard. I presume this is more mass, more energy. The 'fixed' end on the bridge is even less fixed. If this is true, than the amplitude of the 'fixed'spot is bigger, thus the corresponding additional calculating length is bigger. Thus the resulting tone lower. Why should it occure in the upper middle and lower treble side? Because this is the spot where the central area of the soundboard is, and pressue........., and string tension........ etc. true? John Meulendijks Tilburg the Netherlands ----- Original Message ----- From: Richard Moody <remoody@midstatesd.net> To: <pianotech@ptg.org> Sent: Monday, February 19, 2001 3:50 AM Subject: Re: ETD question re: unisons > > > ----- Original Message ----- > From: Michael Jorgensen <Michael.Jorgensen@cmich.edu> > To: <pianotech@ptg.org> > Sent: Thursday, February 15, 2001 4:05 AM > Subject: Re: ETD question re: unisons > > > > 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? > > -Mike Jorgensen > > > Of course the sound board is vibrating along with the string(s) And the bridge > in between also. But let us not forget that ETD's like all measuring machines > have limits. At one point in our investigation we have to ask the question, > what are the limits, are we at the limit?. > Another consideration that has not been addressed is that ETD's do not > actually measure the vibration rate of strings themselves. They give us a read > out of what the microphone is picking up from sound vibrations excited by a > soundboard excited by piano strings. AND some are converting to digital. It > would be interesting to see if magnetic or ceramic pickups gave the same or > different readings. > This gets to the determiniation of the accuracy of the instrument. If two > instruments (of different design) always give the same reading it is reasonable > to assume the readings are "true". This begs the question, "how do the 3 ETD's > (RCT, SAT, and TL (TuneLab) read a unison then a single string of that > ison? ---ric >
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