<html xmlns:o="urn:schemas-microsoft-com:office:office" = xmlns:w="urn:schemas-microsoft-com:office:word" = xmlns:st1="urn:schemas-microsoft-com:office:smarttags" = xmlns="http://www.w3.org/TR/REC-html40"> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; = charset=us-ascii"> <meta name=ProgId content=Word.Document> <meta name=Generator content="Microsoft Word 10"> <meta name=Originator content="Microsoft Word 10"> <link rel=File-List href="cid:filelist.xml@01C45471.1F9802B0"> <o:SmartTagType = namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="date"/> <o:SmartTagType = namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="time"/>  <style>  </style>  </head> <body lang=EN-US link=blue vlink=purple = style='tab-interval:.5in'> <div class=Section1>  I’ve been told by the = owner that there is no change to the temp/RH settings between uses. When I was = tuning yesterday I could see that the AC was cycling on and off frequently, so = I would expect that the temperature wouldn’t vary by much. In the past I = have kept a close watch on RH levels in the winter and although it was low = (mid to upper 20’s) it was steady. This is the first time that I’ve = noticed the problem with the AC. <o:p></o:p>  I have certainly seen an almost = immediate effect on pitch from temperature changes caused by sunlight moving = across the room and hitting the plate and strings of a piano*, but in this case the = change was rather extreme and so not surprising. In this case, although I = haven’t actually measured the temp change I can’t imagine that it could be = more than a couple of degrees – less than I would have thought capable = of producing such a sudden and dramatic pitch = fluctuation.<o:p></o:p> <o:p> </o:p> - Mark<o:p></o:p> <o:p> </o:p> * The other case where I saw a = large pitch change caused by a sudden temperature change was years ago when, after = tuning, I tried to solve a tight action center problem with an electric hair-dryer = on a very damp spinet piano just before a show without first removing the = action from the piano. D’OH!!!<o:p></o:p> <o:p> </o:p> -----Original = Message----- From: J Patrick Draine [mailto:draine@comcast.net] Sent: = <st1:date Month="6" Day="17" Year="2004">Thursday, June 17, = 2004</st1:date> <st1:time Hour="7" Minute="19">7:19 AM</st1:time> To: Pianotech Subject: Re: Unstable = Yamaha C7 <o:p> </o:p> On <st1:date Month="6" Day="16" Year="2004">Jun 16, = 2004</st1:date>, at <st1:time Hour="22" Minute="26">10:26 PM</st1:time>, Mark Dierauf = wrote:<o:p></o:p> <?fontfamily><?param Times New = Roman><?color><?param 0000,0000,8080><?bigger><?bigger>This cycle kept repeating as I watched. Has anyone ever seen such a problem? = Did you find any solutions?<o:p></o:p> <?/bigger><?/bigger><?/color><?/fontfamily> The obvious solution is to control the heating and AC flow. Either the = studio should move the venting, or the position of the piano. In addition the = heat or AC should be as constant as possible (ie they don't turn the AC on only = when the tuner or player shows up). Patrick<o:p></o:p> </div> </body> </html>