What ETD are you using? Don't they all have a built in PR program nowadays? I'm using Tunelab and find that the machine-calculated overpulls put pitch right on the money, amazingly so. In the olden days, I was using a Yamaha PT-100 II which didn't have the calculated overpulls. They recommended pulling it up (or down as the case may be, and I THINK I remember these fractions right, others may need to correct me) of 1/3 the difference in the bass, 1/5 the difference in the low tenor (about 6 unisons), and 1/4 the difference in the upper tenor and treble. So if the bass is averaging 18 cents flat, for example, you'd tune it 6 cents sharp. Anyway, my point is that that method used to be very accurate, also. Alan Barnard Salem, Missouri ----- Original Message ----- From: David Nereson To: List Pianotech Sent: 07/07/2006 2:28:36 AM Subject: post pitch-raise creep? I do many many many pitch raises -- almost every piano I tune, for the last 27 years. (Almost everybody lets them go too long.) I've found that the ideal average overpull is halfway between 1/3 to 1/2 the amount sharp as it was flat. In other words, a 41% overpull of the amount it was flat. For an easy-figuring example, say the piano is 18 cents flat. Half of that is 9 cents and a third of that is 6 cents. Half-way between 6 and 9 is 7.5, so I pull it 7.5 cents sharp, and almost invariably A4 ends up right on 440 Hz, or very close. However, if the piano is a half-step flat, I don't pull it 41 cents sharp. That would be too much. There's some degree of flatness where the usually-ideal 41% overpull has to taper off. For a half-step pitch raise, I usually overpull so that A4 is beating about 5 beats sharp. That's approximately 20 cents, I believe. Sometimes more is required, sometimes less. It varies. That's here in Denver -- probably different elsewhere. But what I often experience is: even though after the pitch raise, A4 is at 440; after I've gone through the fine tuning and pulled in unisons, when I go back to do the final check and touch up anything that has slipped, I find that the whole middle section is sharp! Why? --David Nereson, RPT -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20060707/de54fa61/attachment.html
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