Richard, Do this as a test to aurally verify pitch change for tuned unisons: Tune the middle strings of F3-A3 to approx 7 bps. Then tune one outer string of A3 to the middle. You will then have a 2-string unison. If you have a perfect unison, the beat rate for F3-A3 will be just a bit slower with the unison with two strings than just the middle string and F3. If this difference is not perceptible, then tune the middle string of A4 to the perfect 2-string A3 unison. Make F3-A4 beat exactly the same as F3-A3. Exactly. Then tune one outer string of A4 to make a perfect unison. You will notice a "big" difference in beat rates from just the middle string alone. The F3-A4 beat rate will now be slower. To verify this, put your mute back on the outer A4 string, allowing just the middle to sound. Compare F3-A4 beat rates, then remove the mute, and listen to the 2-string A4 with F3. You should hear a pretty good difference in the beat rates then. Each string in an aurally tuned unison may not necessarily be the exact same frequency. Some will be just a hair flatter than the others, depending on which part of the scale you are in. The overall pitch of three strings together will be a little flatter than the middle string that was first tuned, assuming you begin with the middle string. The flatter tuned unisons is why Virgil E. Smith tunes without a temperament strip, using only two mutes to tune the entire piano. I have been using his octave (not his temperament) method for several weeks now, and have noticed a big improvement in the sound of the finished piano. Tune unisons as you go, then tune the octaves, listening mainly at the 2:1 level, but hearing all the others as well. Get the best octave sound possible. Best regards, John Formsma Blue Mountain, MS -----Original Message----- From: owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf Of Richard Moody Sent: Saturday, January 15, 2000 12:35 AM To: pianotech@ptg.org Subject: unisons by ear or machine "hold the phone" as they used to say in Virginia. Let me get this straight. You tune the individual strings in a unison with the RCT and it reads all three strings together as 0.5 cents flat?? That should make an audible difference in a Fifth at middle C. And what does that unison sound like to the ear? What happens if you tune each string in the unison by ear and then scope it with the RCT? This interesting because I have always suspected that the unison when declared "in tune" by two or more technicians might not measure out the way theory predicts. I could test Tunelab on this.... ---ric (has suspected wrong before) ps. What happens if you measure from the other side? ---------- > From: Roger Jolly <baldyam@sk.sympatico.ca> > To: pianotech@ptg.org > Subject: Re: Counter bearing treatment > Date: Wednesday, January 12, 2000 10:05 PM > > Hi Ron, > I've done quite a few measurements on the string coupling effect. > When an average 3 string unison is tuned for full blush (RCT) on each > individual string, > 2 strings played together will show about 0.3 cent flat, 3 strings will > show 0.5 cent flat. > I'm not so sure what the imformation is telling me. > Regards Roger > > >
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