Yamaha C7 tuning instability

[Kent Swafford]

Um, I'm a little surprised no one has suggested that you inquire if the 
AC could be turned off while you tune. If the problem is the stopping 
and starting of the air flow, this should solve the problem and let you 
tune without having to hit a moving target.

Kent Swafford



On Jun 17, 2004, at 2:31 PM, Mark Dierauf wrote:

> Thanks to all for the responses. I did check the plate screws, but even
> my biggest square-shanked screwdriver with a wrench on it couldn't do
> more than just crack a few of them a hair. The studio is not large and
> there are vents everywhere, so I don't think that it's possible to get
> this piano out of the line of fire. The blanket is a good idea for
> tuning, but it doesn't help once I'm gone. The engineer usually either
> removes the lid altogether or else raises it until it is vertical and
> leaning against a piece of foam that he has located on a wall for that
> express purpose. I was thinking about trying one of the Edwards wool
> string covers, but I assume that this would change the sound (and
> volume) and throw off his miking procedure. Has anybody used one of
> these covers who could comment? Would a DC bottom cover across the top
> of the case (in place of the lid) be likely to help?
>
> - Mark
>
> -----Original Message-----
> From: Don Mannino [mailto:dmannino@kawaius.com]
> Sent: Thursday, June 17, 2004 1:24 PM
> To: 'College and University Technicians'
> Subject: RE: Yamaha C7 tuning instability
>
> Mark,
>
> As you surmised, this problem has nothing to do with the piano, and
> everything to do with the air changing the string's temperatures.
>
> The best approach is to move the piano so that it is not in a drafty
> spot
> during tuning, then move it back when you are done.  Make sure the
> studio
> owners are aware of the draftiness problem - you can demonstrate it for
> them
> using your tuning machine easily.  Simple zero out the display, then
> 'huff'
> hot air on the strings while playing it - the display will begin to 
> move
> right away.  Well, at least it works well with my unusually large
> quantity
> of hot air ;-)
>
> This problem could possibly be solved by redirecting a heating vent, or
> getting air deflectors for one or two vents that are blowing on the
> piano.
>
> A blanket or cover draped over the piano could help during tunings, 
> too.
>
> Don Mannino RPT
>
>
> -----Original Message-----
> From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org] On Behalf Of
> Mark
> Dierauf
> Sent: Wednesday, June 16, 2004 7:27 PM
> To: caut@ptg.org
> Subject: Yamaha C7 tuning instability
>
>
>
> I take care of an older Yamaha at a recording studio that has a tuning
> instability problem that I've never encountered on any other piano - 
> the
> pitch fluctuates by as much as 3 or 4 cents over the course of only a
> few
> minutes. It took me quite a while to realize that this fluctuation ran
> in
> sync with the forced hot air heating system. Now that it's summer, the
> air-conditioning from the same vents is having the same effect. The
> piano
> has a complete DC unit installed with a bottom cover, is tuned at least
> 20x
> annually, and is very pitch-stable in the long term. It is not located
> in
> direct sunlight and the temperature doesn't vary much, certainly not
> within
> seasons. In the winter there is a humidity control system adding
> moisture
> through the hot air ducts. The studio is in an old New England barn 
> that
> had
> several hundred thousand dollars worth of renovation, and so is very
> well
> finished and insulated, but in the time that it takes me to work 
> through
> the
> temperament the first notes tuned have already moved substantially. 
> Once
> after chasing the pitch all through a tuning I repeated A4 for several
> minutes and watched the pitch rise about 2 cents above the starting
> point
> then fall about 2 cents below. This cycle kept repeating as I watched.
> Has
> anyone ever seen such a problem? Did you find any solutions?
>
> - Mark
>
>
>
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