----- Original Message ----- From: "Ron Nossaman" <RNossaman@KSCABLE.com> To: <pianotech@ptg.org> Sent: December 21, 2001 4:06 PM Subject: Re: Sound waves(The behavior of soundboards) > > Oh, sorry. Since you only asked that once in passing, I mistook it for just > another diversion and didn't give it much weight. As far as I know, there > isn't one. You see, the strings moving the bridge is my own theory, dreamed > up by me, based on sound mechanical and physics principles, so it isn't > likely to be on a university web site anywhere. Oddly enough though, two > piano designers, builders, and fellow rebuilders who have against all > apparent odds actually given it some thought, seem to hold similar views. > Imagine such a thing! ... At least one of whom came by it independently, having studied both the real-world motions of a variety of soundboards and bridges (attached to both soundboards and psuedo-soundboards) and the computer-modeled motions of soundboards. My conclusion, after all of this, is that vibrating strings--regardless of what is happening at the molecular level--physically move the bridge they are attached to. If the bridge is physically attached to a soundboard, then that soundboard moves in concert with the motion of the bridge. If the bridge is not attached to a soundboard, but to something like a set of force transducers, there is still a transfer of vibrating energy due to the physical movement of the bridge caused by vibrating strings attached to it. (My reason for introducing the idea of Baldwin's Electo-SD-6--or whatever it was called.) (John wrote:) > > >No one is claiming that there is no disturbance or stress at the > >meeting of the string with the bridge, otherwise no sound would be > >transmitted, but to claim that this disturbance results in the bodily > >movement of the bridge and drives the soundboard as a solenoid drives > >a loudspeaker is nonsense. Solenoids are cylindrical coils of wire surrounding a moveable iron core that moves along the length of the coil when an electric current is passed through it. Solenoids are used as switches and relays, for example, in a motor vehicle to complete the circuit between the battery and starter motor. Loudspeaker voice coils, while similar, are not the same thing at all. But then, I gave the analogy of the loudspeaker, not as exact description of soundboard function, but as an analogy. Del
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