----- Original Message ----- From: Howard S. Rosen <hsrosen@gate.net> To: Pianotech <pianotech@ptg.org> Sent: June 27, 2000 6:53 AM Subject: string pressure on board > Hi everyone, > > Is there any one good with numbers out there, who can calculate the > *approximate* difference in string pressure on a typical baby grand or > upright, between 440 hz and 435 hz? Please duplicate answer to me privately. > > I've heard techs state that the difference is "many tons", but my gut tells > me that is an exaggeration. Am I right? > > > Howard S. Rosen, RPT > Boynton Beach, Florida > hsrosen@gate.net > > ----------------------------------- It probably could be calculated, or at least approximated, but a lot more specifics would be needed. However... The typical overall string load on the modern piano is somewhere between 35,000 (very low) to upwards of 45,000 pounds. The difference in overall tension between A=435 and A=440 is relatively small. Without figuring it out, I'd say a few hundred pounds. Maybe a thousand, even. Depending on the age and condition of the soundboard, soundboard loading will range from approximately 0.0% to 1.0% (despite notions to the contrary, this would be quite high) of this amount. For most pianos that are more than a few years old, this figure is probably around 0.1% to 0.25%. The variation in soundboard loading between a given piano tuned to A-435 vs. A-440 would be on the order of a couple of pounds. Del
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