[pianotech] phenomana - Another ETD Check

[David Renaud]

    Interesting hypothesis.

   One set of raw data that relates and would be easy to collect would be inharmonisity
Readings for a set of given notes on the a given piano throughout the year.

   I would suggest C1,C2,C3,C4,C5, and also the bottom couple tenor plain strings, whatever they might be.

   If the inharmonisity readings change from the highest humidity of the summer, to the driest months of the winter on account the board being stiffer innsummer, or more free in winter,  then the resulting "ideal" tuning would also have to change.

  Never tried to test or monitor this, actual numbers on a variety of pianos, old and new would be interesting to look at. 

  I have a Steinway A2 , and a Yamaha U1 at home I can measure any time I want though out the year. If a few others would do the same we could have seasonal sets of numbers on a few dozen pianos, enough to establish a working hypothesis to continue to test. 

  I do think master tunings will evolve as strings age also. They become more brittle, stiffer, more liable to break as the molecular structure aligns itself and the harmonics tend to creep increasingly sharp with the increased stiffness. Again, a hypothesis I'd love to see real data on. 
How quickly do the strings change from new, how much?

  Volunteers to monitor some pianos and share the numbers? I'll monitor 2 pianos.

   I might hypothesis that if seasonal variation proves true, then also, an old piano with a flat board won't show much seasonal variation, and one with lots of crown more. Also a design like Stienway grands with low bearing, more variation since a small numerical change in the board is a greater% of the bearing change, and a design with lots of bearing like Yamaha perhaps less seasonal change, since the board is already stiffer with more bearing, and changes are a smaller % of the overall bearing and stiffness.

.......just thinking out loud here. I do expect to see variations in this effect(if present) between old and new pianos, and between designs with high bearing and low bearing.  We will see.

      Be a fascinating experiment.

                                                   Cheers
                                                     Dave Renaud 
Sent from my iPad

On 2012-05-15, at 9:29 AM, Ron Koval <drwoodwind at hotmail.com> wrote:

> Ok - seeking data - I like that!
> 
> I'd be willing to take a look into this - we're currently around 45%RH indoors around here.  Obviously, this will be a long-term project!
> 
> Does it matter what size/kind of piano?  I have a wide variety at the college.
> 
> I've sent emails out to a few individuals that may have done this already, to save me some time and effort.
> 
> I'll let you know if I get anything back...
> 
> Ron Koval
> chicagoland
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