I also tune for rural churches in the Nevada and Oregon. I have a system which has been pretty good: they heat the building up as if it were meeting day, and I tune at the regular worship service time. Although I'm aiming at a moving target, I'm recreating the conditions under which the instrument is used, and the results have been pretty good. On measuring pitch and predicting, Gene, I do have one datum. A cold room in a church has a heater that blows directly down into the works of a former player upright. Just to see what was going on, I started to tune at A440, did the temperament, extended it an octave, and measured the A 49 pitch at 20 cents flat, which was the result of 110-degree air hitting a 50-degree piano for 15 minutes. I've tried turning off the heat and tuning, but the last time I did that piano, I just closed the vent. I tune at the same season each year, and the basic pitch stays within a few cents now, for the tuning. Playing it with the case closed and the heat on might see it drift a bit more. When I encounter a cold piano, I put my A fork on the plate (which doesn't mean the meal is over) while I'm cleaning and checking the mechanical functions as part of my service approach. When the fork stabilizes, I measure the sharpness of the fork, set A 49 to that pitch, and tune relative to that pitch. You can do this with an ETD if you keep checking what A 49 reads and adjust accordingly, or you can do octaves by playing the lower note and dialing in the stretch you're using and tuning the top note: on a rotating display, you note the roll rate of the lower note, tune the top one still, then get almost the same roll for the next note up. So, as we know, you're trying to hit a moving target, but you're in the car in the next lane over... well, not the nicest analogy, but the physics idea is that you are in the same frame of reference. It works well for me. I tune below the temperament entirely by ear, so that half of the piano stays with the temperament as the instrument heats up. --John Ashcraft, RPT Gaston, OR On Tue, Jan 11, 2011 at 2:03 AM, Don <pianotuna at accesscomm.ca> wrote: > Hi, > > I sometimes have rural churches that are much cooler during the week. The > only strategy that works is for the heat to be at "service" temperature for > 24 hours before I tune. > > I have experimented with resistance heating controlled by a thermostat > inside the piano, but have not had satisfatory results, even with a > damppchaser and back cover. (the heating was added after to try to > stabilize the piano). > > When the temperature is low I consistantly find the piano is sharp, and > unevenly sharp. Of course the unisons that we all so dearly love to be > "clean" are also compromised. > > For concert halls I found that preheating the piano with a 500 watt spot > light for about 3 hours gave me the best results. Tune 'em while their hot? > 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/ > > 3004 Grant Rd. REGINA, SK, S4S 5G7 > 306-539-0716 > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20110111/c4451a1a/attachment-0001.htm>
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