Sustenuto adjustment: The new sustenuto pivoted/sprung tabs make adjustment easier than the old semi rigid tabs which were adjusted so that the sustain pedal would raise the tabs less than the key rise of the tabs so that: When a damper is held up with the sustenuto and the sustain pedal is pressed, the sustenuto tabs lifted by the sustain pedal do not reach the sustenuto blade. The sustenuto blade catches only the tab held up by the key slightly but positively and misses the rest tabs because they are not high enough. The blade should pivot no higher than 90° and sometimes less and on return should miss the tabs lifted by the sustain pedal or gently brush by them. The key/damper lift is limited by the damper up stop and the sustenuto will push the damper lever into the up stop felt. Many pianos with the pivoted individual sustenuto tabs can be misadjusted so that the sustenuto blade may have a time getting past the raised damper tabs. The solution may be to first limit the pivot the pedal blade to 90° and possibly move the blade in its entirety back to a little more than barely catch the damper sustenuto tabs. If the damper pedal lifts the dampers too high, the sustenuto pedal blade may not readily get by dampers held up by any keys. In any event, the damper sustenuto tabs should not be contacted by the normal damper lift. Dan Gurnee RPT, HSU Retired On Dec 28, 2008, at 8:45 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 > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut_ptg.org/attachments/20081228/37fb3af4/attachment-0001.html>
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