[CAUT] Semantics

[Greg Soule]

Wow, this has been an interesting thread.  (some of you probably  
abandoned it long ago)

When I wrote, "I think it is incorrect to consider sound and vibration  
as two different types of energy.  Sound IS vibration." I hoped it  
would elicit responses (and I think it did) that would finally clarify  
to me why it is claimed the soundboard is a transducer.  The way the  
term "sound" was repeatedly defined simply as "what we hear" I found a  
distraction, because it said nothing to differentiate the types of  
energy found in the string, board, air, etc., which is the key to  
understanding the whole kaboodle.  It sounded to me more like some  
fuzzy philosophical tangent on human perception ("If a tree falls in  
the forest . . .").

So, bear with me while I lay this all out, and tell me if I'm on track  
here . . .

The energy of the string or soundboard has the characteristic of  
vibrating from a fixed point, and the vibrating body is under tension;  
these factors cause it to want to return to a point of repose.  The  
vibration has frequency and amplitude.  (Finer points of distinction  
could be made between the ways the string and the board vibrate, but  
not by me.)

Although the vibrational energy imparted to the surrounding air also  
has frequency and amplitude, air is a very different kind of medium  
because air molecules are not anchored to anything.  Since the energy  
has no fixed point of vibration, it disperses in all directions like  
ripples in a pond.  It is a vibration that leaves its point of origin  
and never goes back unless acted upon by an outside force.  This is  
the critical distinction of acoustic energy.  Sound IS acoustic energy.

Del Fandrich's illustration brings it home . . . a panel of wood that  
vibrates when struck CREATES acoustical energy in the surrounding  
air.  This is a different type of energy than that of the string or  
soundboard, and this is why it is proper to refer to the soundboard as  
a transducer.

Furthermore, even though the term "transducer" in its most common  
usage is borrowed from electrical engineering, and electrical  
engineers might scratch their heads in confusion when they hear piano  
technicians use it about their pianos, it is indeed the best term to  
apply to how the energy changes between the soundboard and the  
surrounding air.  We use it knowingly and confidently.

For further reading class, please see:
http://www.pianobuilders.com/soundboards.html
http://en.wikipedia.org/wiki/Sound
http://en.wikipedia.org/wiki/Acoustics
http://www.sfu.ca/sonic-studio/handbook/Theme_sound_medium.html

Forgive me for being both dense and persistent, thank you for your  
patience and I respect you all very highly,
Greg Soule
(and with a final flourish of self-deprecating humor, he returned to  
join all the other lurkers)