Moisture Content.... -----Original Message----- From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Kidwell, Ted W Sent: Thursday, December 17, 2009 3:11 PM To: caut at ptg.org Subject: Re: [CAUT] temperature and pitch What is MC? Ted Kidwell, RPT California State University, Sacramento Capistrano Hall, rm. 153 6000 J Street Sacramento, CA 95819-6015 916.278.6737 -----Original Message----- From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Ron Nossaman Sent: Wednesday, December 16, 2009 4:32 AM To: caut at ptg.org Subject: Re: [CAUT] temperature and pitch Elwood Doss wrote: > Now Ron, we all want to know what you have to say. Your wisdom is > valuable to all of us. Elucidate, sir! 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
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