On 9/21/2010 1:36 PM, jimialeggio wrote: > >> It is, once again, coming from the back scale. That's why pulling it >> sharp and pounding it makes it drop again. The string is pulling >> through the bridge. There's no way to "read" what the back scale >> tensions are during tuning, >> >> Ron N >> > Not familiar with this piano...what is the challenging condition in the > back scale?... the length? I have no idea. I notice it in Asian pianos, mostly, usually Yamahas. When I get a call to tune a piano that was tuned a week ago by someone I expect to have done a good job, this is what I find. The pitch responds immediately to anything done at the tuning pin. This indicates that there isn't a friction problem between the bridge and the tuning pin, but on a firm blow, the speaking length pitch will drop a couple of beats. Further hard blows won't do it again. This also will happen on a string that hasn't been touched since it was tuned a year ago, so the pin is undisturbed. That isn't "hammer technique". The string is pulling across the bridge. This same thing will happen on the same piano once a year, year after year, so it's not a one time event like settling the coil. A little more friction at the bridge, or a little less, and we wouldn't notice it. It happens in environments where the piano changes pitch significantly with seasonal humidity changes. I don't find it in climate stable pianos, so it's the seasonal movement that's leaving the back scale low in tension at some part of the cycle. If the piano is tuned at that point in the cycle, this happens. At a different point in the cycle on the same piano, it won't. The only advice I have is to test for it when you tune, by whacking the bejeebers out of a note in the capo section and see if the pitch drops. If not, good. If so, you're going to have to whack everything from about A-4 on up at least once. Again, there is no hammer technique that will make this not happen. It has to be hit. Ron N
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