---------- > From: rhohf@idcnet.com > To: pianotech@ptg.org; pianotech@ptg.org > Subject: Re: Recrowning/arched spruce demo > Date: Tuesday, June 03, 1997 8:03 PM > > > First, a matter of semantics: neither the arched spruce board nor a piano > soundboard are amplifiers. Amplification implies an _addition_ of energy to a > signal. A stereo amplifier takes a weak signal and increases it by > electonically _adding_ energy. Both the arched spruce and piano soundboard are > _transducers_. Transduction involves the passing of energy from one element of > a system to another _without_ the addition of energy. If a sound gets louder, > it means that the transduction changes in some way. I mention this just for > clarity--it's a good idea to use the proper terms when we can. I forgot what the energy is called that is in a compressed spring or an arched sound board. But as long as we are on semantics, might this "latent" energy some how _add_ to the sound? Of course the point is the sound gets louder whether from amplification or transduction. Why this happens is what makes it interesting. > > > Here is what I think is happening: under some circumstances, a piece of wood > can be induced to vibrate with a standing wave. Perhaps a clarification of the term "standing wave" could follow. I might be confusing this with resonance. If that arched demo could be activated such as by bowing, it should produce a note of its own. Is this related to a standing wave? > Doing this stuff is fun and many more experiments are suggested by this, but > someone on the list asked, "What does this mean in a real piano?" The answer > is, "Absolutely nothing." But then why are all sound boards crowned? Richard the Wonder(ing) Kind
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