[CAUT] temperature and pitch

[Don]

Hi Ron,

I guess that MC gauge ought to have to be a similar thickness to a sound
board and finished in the same manner.

At 03:10 PM 12/17/2009 -0800, you wrote:
>
>It's been said so many times for so many years by so many 
>people, with so many rational explanations, and it doesn't 
>seem to make a bit of difference. Immediate and short term 
>pitch change is temperature related. Humidity changes take 
>much longer. As long as people ignore temperature effects and 
>speculate that the piano went out of tune before they finished 
>it because of a sudden humidity change, It's shouting down an 
>empty well.
>
>Make a decent MC gage, which will demonstrate wood's reaction 
>to humidity changes rather than measuring RH% directly. Find 
>yourself a practice room with a window that opens, and leave 
>the MC gage in the piano for a week to acclimate. Next week, 
>take some accurate pitch readings from the piano, accurate 
>temperature and RH% readings, and note the reading on the MC 
>gage. Close the door, open the window, open the piano. Wait 
>out in the hall for ten minutes, so you won't freeze. Go back 
>in and repeat your temperature, RH%, MC, and pitch readings. 
>Note that the pitch has changed, as has the temperature and 
>RH%, but the MC hasn't. If the pitch changed from the RH% 
>change, how did it manage to do that without the MC change in 
>the wood? Devise your own test, one that is intended not to 
>demonstrate any one thing to prove you're "right", but rather 
>to discover to whatever extent possible what is actually correct.
>
>It never has been more difficult than this. Account for as 
>many of the variables as possible, and you get more realistic 
>information. Take one reading and make wild guesses at the 
>rest, and you can "prove" anything. This subject will appear 
>on list again in the not distant future, starting, once more, 
>at the beginning.
>Ron N
Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.
Non calor sed umor est qui nobis incommodat

mailto:pianotuna at yahoo.com	http://www.donrose.ca/

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