>Ron, it does seem like you have isolated the effect of playing by noting the >difference between the front and rear bridge pins. I'm not clear, though, >why you are discarding the effect of rendering due to tuning. It would seem >that some performance pianos are tuned more frequently than there are >humidity swings. Are you perhaps noticing a shape in the groove that would >indicate vertical movement rather than the horizontal shape rendering would >produce? > > Regards, Mike It's just a matter of numbers. In a performance piano, how many times is a string hit (and a speaking length termination stressed) between tunings, even if the piano is tuned before every performance? The height of the bridge pin skid mark, by my thoughts, would be determined by the number and severity of humidity swings, but the difference of the depth between the rear and the front pin would be primarily the result of play. There should be slightly more wear at the v-bar and agraffes as a result of tuning, but I would think it would be negligible compared to impact damage from play. I would expect that, in a performance piano, you would see skid tracks in the bridge pins that are proportionally deeper in relation to the height, than in a home instrument, but I would attribute that to play more than tuning frequency, again, because the string is played more, and possibly harder, than it's tuned. If the speaking length of any given string in a piano was terminated by the same system and material on both ends, perhaps we could separate the effects of play and tuning more effectively. Then again, with the majority of the hammer impact being reflected and contained by the front termination, we couldn't be sure even then because the front termination should take more abuse from both tuning and play. Ron
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