Sound in soundboards

[Ron Nossaman]

>Yes, according to Del and you it SHOULD be the case but my intuition 
>tells me that it will not be the case at all and that though my 
>massive clamping structure may absorb a proportion of the energy, the 
>effect on the bass of the piano will be slight enough to enable the 
>piano to be played and to sound quite satisfactorily.

Then you'll just have to try it and see for yourself, won't you? There may
very well be some leakage, I can't say how much, and the string alone will
move some air and make some sound, but the sound produced will be
considerably short of satisfactory for a piano.


>>I'm more of a classicist than an electrician and to me transmit means 
>"send through..." and transduce would mean "lead through..." if it 
>were in Webster's dictionary, which it aint in mine.  At any rate I 
>can't visualize the difference in effect.  I think I'll take a gamble 
>and stick with "carry" and with my assertion that sound travels ONLY 
>as a compression wave in whatever medium.

Then you need a better dictionary. A transducer changes energy from one
form to another, whether it's electronic or analog. And once again, we're
not talking about sound transmission in the soundboard, we're talking about
string energy that the soundboard ultimately converts into sound. 


>>Like a ripple, with the stiffness of the transmission medium (soundboard
>>assembly)...
>
>I guess you mean the transduction medium?!

No, I don't. The soundboard is the medium, transduction is the function.
Energy is transmitted through the medium and transduced into sound, with
some absorbed as heat.


>So the sound travels as a ripple.  And since I've taken my arbitrary 
>stand, I obviously have to be consistent and say that it can't, 
>simply because that's not the way sound travels, but _always_ as a 
>compression wave.  I say also that the transverse movements of a 
>piano string differ from a ripple in that the peaks and notes are 
>static, but however that may be the sound produced by transverse 
>moments is linear and at right angles to the string.

Yes, sound does travel as a compression wave, but we're not talking about
sound. Does a piano hammer transfer sound to a string, or energy? And is
this arbitrary stand you've taken here an honest attempt at understanding
something, or purely argumentative?   

>>Then why does changing the rib height and feathering have so much more
>>effect than thinning the panel? The long grain stiffness has more of a
>>constrictive, than a transmission enhancing effect in practice. That's why
>>floating the soundboard in the tail enhances the bass in a small piano so
>>well. It relieves the built in excessive constriction of long grain
>>stiffness, and shifts stiffness control to the ribs, where it is more
>>manageable.
>
>Well that's not a contradiction of what I say.  If ultimately the 
>soundboard was not induced to move up and down, and to move 
>differently at different places, then we'd have no sound at all, 
>because to produce the compression waves that reach our ears through 
>the air, the air must be amply moved.  

True, the soundboard must move to produce sound, but you ducked the question.


>The sound from the string alone 
>is not ample, that produced by conversion of the energy from the 
>string to vertical movements of the board is.  In that sense the 
>soundboard is most certainly an amplifier, though since I'm not an 
>electrician I would never use the term.
>
>JD

No, it isn't, and the fact that we aren't electricians is of little
interest because this isn't an electrical function, and we still aren't
dealing with sound except as a final output of the transducer. After we
hear it, the process is over. We're talking energy, imparted by the hammer,
moving the bridge and soundboard, and being converted at least in part to
sound. 

Ron N