---------- > From: Michael Jorgensen <Michael.Jorgensen@cmich.edu> > To: pianotech@ptg.org > Subject: Re: Duplicity on a Grand Scale > Date: Wednesday, March 10, 1999 6:29 AM > > Ron, > That is pretty interesting. I wonder if various confugurations of > duplex (i.e angle and length) result also in a change in timber of the > tone which bleeds across. > -Mike > > > > Ron Nossaman wrote: > > > > Hi gang, > > > > > Then, still holding the key down, I plucked the duplex and the speaking > > length sounded at the fundamental. Cool! Proof positive that string energy > > bleeds past the v-bar to the next segment. . What do you suppose > > happens at the agraffes? I then went down to the tenor section and plucked > > the, roughly, 10 mm long segment between the understring felt and the > > agraffe. The speaking length sounded the fundamental. The > > bearing angle here was much steeper than in the treble ( about 20 degrees), > > and the segment was super short and muted by cloth, and the brass of the > > agraffe was much softer than the v-bar, but it still worked. What the heck, > > I thought, let's try the bass. Yep, same thing, in spite of the even steeper > > bearing angle through the agraffe. > > > > Later, I tuned a new console. I've got to try the bass too. Key down, I > > plucked the segment between the upper bearing pin and the tuning pin and the > > speaking length didn't sound like anything I could identify because the > > segment I plucked drowned it out and turned the combined sounds into > > garbage. > > > > Ron On two uprights the very short segment between the upper bearing ridge and the pressure bar when tapped with knife blade sounded the fundamental loud and clear. In the bass however this did not work. I noticed the string went over a hump right behind the upper pins. If this works on a grand there the string goes up the "ski slope" over felt it must be because of the free segment between the felt and agraff. The segments behind the bridge don't do this, or not any more than tapping on the bridge. Um... I don't suppose by a fantastic stretch of the imagination that these sgements duplexed or not act as sort of a sonic flywheel? That the shock of percussion sets these segments vibrating which then feed back into the speaking segment? I bet that would keep old Hermann and Theo up all night. Ric Holtz
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