[CAUT] Semantics

[Escapement]

Boy, this just keeps getting more and more confusing.  I have to disagree
about "amplitude."  Yes, it is a measure of the intensity in wave movement,
but also (and in that very context) of sound level.  

Calling a soundboard an amplifier is misleading (I think, simply) because it
doesn't amplify like a modern stereo system amplifies--i.e., it doesn't
increase the energy level.

But when sound level is increased, when something gets louder, its
corresponding sine/ sound wave increases in "amplitude," (by definition).
Imagine a sound wave: the frequency of the wave determines it's pitch, and
the amplitude (the peaks and valleys) determines it's loudness or intensity.

Right, the string has little surface area so it moves little air, creates
little sound.  The soundboard has a greater surface area, so it moves a
great deal more air. 

The interesting part, to me anyway, is what they do *together* as a coupled
device.  The resonance factor.  The soundboard resonates with the strings in
such a way as to greatly increase the sound energy.

I still don't see the transducer in the soundboard--I just don't see enough
distinction in the energy as it passes from the strings to the soundboard/
bridge. 

I think I see what you're saying, but I guess I just don't quite get it.

To me, the transducer argument *de-couples* the strings and the
soundboard--(by doing this "transducing," taking one thing and making it
another).  That goes against everything I've read about piano acoustics.

But I certainly know when to let an issue rest, and I definitely don't want
to rile any feathers here. So I will bow out of this discussion, scratching
my head a little, but much the richer for having participated.  

Respectfully, Gary   


 

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Don
Mannino
Sent: Tuesday, May 12, 2009 1:12 PM
To: caut at ptg.org
Subject: Re: [CAUT] Semantics

Greg Soule correctly pointed out again that definitions vary. Here are
some more miscellaneous but related ramblings on this topic.

The most general definition for 'transducer' I have found is:

Any of various devices that transmit energy from one system to another,
sometimes one that converts the energy in form, as a speaker that
converts electrical impulses into sound.
Etymology: < L transducere, to lead across < trans-, over + ducere, to
lead
(Websters New World) 

Note the word "sometimes." The most common transducers we deal with are
electrical to mechanical and vice versa, so this is the most common use
of the word.  The word is also correctly applied to a soundboard which
is driven by a large amplitude string movement (of very small area) into
a small amplitude soundboard movement (over a large area).  The large
area is what causes the air molecules to move, and is why we can hear it
a lot better, even though the soundboard is actually moving in a much
smaller amplitude than the string.

If this word "amplitude" confuses matters, it is important to think
about a little, because of its relation to what an amplifier actually
is.  Amplitude does not refer  to volume of sound, but it is related of
course. Amplitude refers to the size of the movement.  So in relation to
a sound, if the air moves with large amplitude it will be loud.  But a
string that moves with large amplitude is not necessarily creating a
loud sound, unless it connects to something that makes the air move.

If you watch a string in the middle of the piano and play it fortissimo,
you can see that the amplitude is pretty large.  It is easy to see and
even measure the string movement.  Now look at the soundboard under a
good light, and hit the same note hard.  Can you see the soundboard
movement?  If so, you have good eyes and good light - it is very
difficult to see, because it is very small.

So this is how the energy is being transduced.  It is changed from a
large amplitude vibration of a small area (string) into a large area
small amplitude movement of the air over the soundboard.

To really argue semantics we could discuss whether it would be more
correct to call the "string / bridge / soundboard system" the
transducer.

Let's not.

So to the original thought that it's OK to call a soundboard an
amplifier, well, any word can have alternate uses that are not really
correct, but are still used anyway.  But it is my preference to say that
the soundboard makes the sound audible.  I stick to calling electrical
things with volume controls amplifiers.  Even "guitar amps" is a
misnomer, because this refers to an amplifier combined with a speaker.
But that's what people call them, so this is another example of a
technically incorrect term falling into common usage.  As long as
someone says "Guitar Amp" or "Keyboard Amp" then I know they are
referring to a system, not just an amplifier.  The technically
inaccurate terminology is understandable, because it is in context.

Related to some of the fine points people have been debating: There is a
correct and widely recognized term for a system which takes a small
_sound_ wave and makes it louder so that people can hear it.  It is not
referred to as an amplifier, but is called a "sound reinforcement
system" which incorporates microphones, amplifiers, and speakers.  So
lets follow this lead, and use the technically correct terminology.
Let's call this device that takes finger movements and turns it into
beautiful music a "Piano Forte" (short form: "Piano")  It incorporates a
variety of components which combine together, hopefully, to the creation
of beauty in our lives.

Don Mannino