[I posted this one originally on caut, and the thread seems to have died there now gracefully.] Let's take another of my favourite hypothetical pianos and make friction close to zero at all bearing points by some magic (no gunk). It seems to me that this would be desirable provided there is no inherent instability in the front or back lengths, e.g. flagpoling, fiesty pins, unpredictable friction between pin and pressure bar, and so on. Without friction at the v-bar (and bridge), any instability in the non-speaking portions of the string will bleed through to the speaking length. Conversely you need some friction (aka pressure bar bearing angle) to protect the speaking length from instability in the front length, however it may originate. So add to my hypothetical piano with friction-free bearings perfectly stable front (and back) lengths as well. To deflect one possible argument against, namely that the strings would be unstable during hammer impacts, I would respond that: (a) during the impact the string is not vibrating as a standing wave anyway, so instability of tension is irrelevant, (b) the conventional configuration traps any change in tension in the speaking length, therefore the effect from hammer impact is greater than it would be with my hypothetical piano, since changes in tension from the piano will operate over the entire string length, including the front and back lengths, so they have less influence on the speaking portion. In fact, from (b), the longer the non-speaking length portions the better, contrary to conventional wisdom. So? Can anyone see a problem with this hypothetical piano? Stephen -- Dr Stephen Birkett Piano Design Lab Department of Systems Design Engineering University of Waterloo, Waterloo ON Canada N2L 3G1 tel: 519-888-4567 Ext. 3792 Lab room E3-3160 Ext. 7115 mailto: sbirkett[at]real.uwaterloo.ca http://real.uwaterloo.ca/~sbirkett
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