Jerry, I'll be extremely interested in what you find. I agree with David. Look first for excessive tightness in the brackets' hold on the blade; it may be that all that is needed is to simply loosen/lubricate things so that the blade can turn more freely. Kent On Dec 28, 2008, at 10:45 PM, David Love wrote: > No, if the sotenuto rod is too close to the tabs that would mean > that the > rod would engage the tabs when you depressed the sostenuto pedal by > itself. > Check that the brackets that are holding the sostenuto rod are not > overly > tight around the sostenuto rod itself preventing it from turning > without > excessive friction. The combination of the spring tension in the > tabs plus > friction might be causing the delay. > > David Love > www.davidlovepianos.com > > > -----Original Message----- > From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf > Of Jerry > Cohen > Sent: Sunday, December 28, 2008 7:46 PM > To: 'College and University Technicians' > Subject: [CAUT] Sostenuto > > Last night I tuned a Yamaha CFIII 9ft. grand for a concert. This is > a new > piano and is on loan from Yamaha Artist Services. The pianist was > having an > occasional problem with the sostenuto which made a loud slap under the > following condition: > > First the sostenuto pedal is depressed holding the appropriate > notes. With > the sostenuto still depressed, she would use the damper pedal. So > far no > problem. Then with the damper pedal still depressed, she would > release the > sostenuto pedal. Finally when the damper pedal is released, a loud > slap > occurs. > > What I found is when the sostenuto pedal is released with the damper > pedal > engaged, the sostenuto blade cannot rotate back to its rest position > because > the spring tension from 70 sostenuto tabs collectively are locking > the blade > up. Finally when the dampers are released, the blade can rotate > back, along > with the free falling linkage which makes the slap. With only > minutes before > the start of the concert, I could not try any adjustments. > > Last February, Kent Swafford presented a very detailed check out for > the > sostenuto system, and he described exactly this condition which I > quote. > > > "Depress sostenuto pedal. While continuing to hold the sostenuto pedal > down, depress the damper pedal. While continuing to hold the damper > pedal down, release the sostenuto pedal. The immediate flipping of > tabs should make a noticeable sound as the blade returns to its rest > position. (If the blade is held too tightly in its mounting brackets, > there might be an inappropriate delay in the return of the blade to > its rest position. The tabs should not be able to keep the blade from > returning to its rest position.)" > > I have a few questions regarding this condition. > > Since the blade could not return to its rest position with the dampers > engaged, does this mean the sostenuto rail was positioned too far > in, thus > overlapping too much of the tabs? > >> From a piano performance point of view, is this a "legal" use of the > sostenuto? After all, even if the blade could return to rest, there > would > still be the ugly noise from all the individual tabs flipping. > > I tune this piano every week, so next week I could have a chance to > make > some adjustments. In every other way (I think), the sostenuto was > working > perfectly. > > I would appreciate any advice. > > Jerry Cohen, RPT > NJ Chapter > > >
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