I've hear rumors that you are a VT owner. Yes? Terry Farrell On Aug 5, 2009, at 10:40 PM, John Formsma wrote: > On Wed, Aug 5, 2009 at 5:23 PM, PianoForteTechnologies <pianofortetechnology at saol.com > > wrote: > I am at the moment only an aural tuner, due to etd’s being extremely > expensive for a South African with regards to the exchange rate, but > that’s my problem, could you explain in aural terminology and could > you explain at what point the strings become overstretched? How > many semitones can one overpull without the strings being > overstretched? > > > The "standard" answer for how much overpull is about 30% in the > midrange, 20-25% in the bass, and 33% in the treble, but tapering > down to 25-30% in the topmost notes. > > A 200 cent pitch raise to A442? You can't safely use a 30% overpull > in this case as that would be 60 cents above pitch. So, set A4 > about 20 cents above your pitch source for your first pass. If > you're using a a fork, that would be about 5 beats per second sharp > of the fork. > > However, you should first determine if the piano is structurally > sound before doing the pitch raise. For this reason, many tuners > would start by tuning A4 to A442 (not going higher than that) on the > first pass. By the time you finish, you'll know if strings will > break, or if the plate has cracked. <slight grin> Seriously, you > might be dealing with a piano that can't be tuned at A442 for > various reasons: wasn't designed to be tuned there, the plate could > be cracked, or the pinblock separated from the back, etc. > > If the structure is solid, it might be a good time to do a "blind" > pitch raise first. Find out how much the pin needs to move to get > the pitch fairly close to target. Then move the rest similarly, but > less in the bass. At least that will get you closer, and it will > take just a few minutes to do that. > > Things are going to change a lot as you add tension. Therefore, set > your goal to get closer and closer. I'm an aural tuner, but haven't > had a pitch raise that large yet. (The largest so far was about 130 > cents.) I'd figure on at least 3 passes and leave it in a musically > decent but not finely tuned state. In other words, just get it in > the ball park the first session. Then I'd come back in 1-2 weeks and > try a fine tuning. But it may well be you'll have to do another > small pitch raise the second session. > > -- > JF -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090806/c94007d2/attachment.htm>
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