[CAUT] Sostenuto

[Kent Swafford]

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
>
>
>