Hi Gary,
I think that at some point this whole discussion has become one of being unbelievable. I have been an RPT for thirty nine years and have seen things like this the whole time that I have been a member. There are times when people seem to get too technical and over state things. Sometimes it is from a good amount of knowledge and sometimes I think that it is just talk to hear one's self. We had a member of the Guild who makes soundboards give our chapter a talk on the science of soundboards. This gentleman was invited to go in with Baldwin on studies of the soundboard. After much research, it was discovered that the science of soundboards was mostly guess work. What looked good in theory and research was always thwarted by the fact that each individual piece of wood reacted differently than what was expected. In short too many people are trying to reinvent something that has worked great for years regardless of what terms are used.
God bless
Bill Balmer, RPT
University of Findlay and Ohio Northern University
In a message dated 05/10/09 16:08:08 US Eastern Standard Time, escapement at comcast.net writes:
Reading my post back after submitting, I realize I might come across as a
bit stodgy. Not my intent.
I have a great deal of respect for the contributors here--I have learned a
lot about piano technology and tuning in the last month or so reading this
list (and pianotech).
It's not my intent to offend anyone here and I should have prefaced my post
with my initial thanks for all the contributors. This list and pianotech
are a godsend to me and I appreciate all of you and the vast knowledge here.
I also appreciate your generous spirit.
But I honestly find this issue a bit confusing.
Gary
-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Escapement
Sent: Sunday, May 10, 2009 4:48 PM
To: caut at ptg.org
Subject: Re: [CAUT] Semantics
I'm new to the piano tuning world but I do have a background in computer
science and have worked with signal processing. I just read through these
posts and have to admit I was thrown for a bit of a loop when I read that
it's now agreed that the soundboard should be called a "transducer."
My understanding of a transducer has always been that it is a device that
takes one form of information or energy and converts it into another form.
(Like the speaker example given where *electrical current* is converted to
physical vibrations through the electromagnetic voice coil). The speaker
isn't a transducer because the voice coil vibrates the membrane -it's a
transducer because it takes the *electrical current* in the wire and
converts it to vibrations *(sound)*. In the same way that a microphone is a
transducer because it takes *sound* and converts it to an *electrical
signal*.
But with the soundboard I don't see this conversion. My understanding of
how a piano works is that the vibrations in the strings are coupled with the
vibrations in the bridge/ soundboard. But it's vibrations to
vibrations-sound (though very slight) to sound (much louder). I suppose you
could call the piano itself a transducer in that it (along with the player)
takes the information on the music page and converts it to sound. But
calling the soundboard a transducer seems odd to me.
I agree that technically, the soundboard doesn't amplify the string energy,
per se, but it does make the sound louder because it is far more efficient
at taking that little bit of energy and converting it into sound energy.
My understanding of the soundboard is that it is a *resonator*-that it
reinforces and emphasizes the sounds generated by the strings, that the
strings and the soundboard work together to make the sound. It is this
*resonance* that increases the sound output of the piano.
But I don't see the big deal in saying the soundboard amplifies the sound.
Though it doesn't amplify the energy, acting as a *resonator* it does take
that energy and (a great deal more efficiently) converts it to a much
*louder* sound. And we measure loudness by *amplitude* of the sound/sine
wave. So, saying the sound is "amplified" by the soundboard seems
reasonable to me.
I mean, are we supposed to say that the soundboard "transduces" the sound to
higher amplitude? Is that really more instructive than, "the soundboard
helps to amplify the sound?" To me, it just sounds confusing. Again, my
understanding is that the soundboard acts as a resonator and reinforces the
sounds made by the strings to increase the sound output. to make it louder.
to amplify the sound.
I don't see a transducer in the soundboard.
When you strike a tuning fork and place it against a table, don't you say
the table amplifies the tuning fork? Would anyone really argue with this?
Would you really say the table becomes a transducer? Would it be more
correct to say that the table resonates along with the fork and increases
the sound output? The table isn't a transducer. the fork vibrates, the
table vibrates (resonates). And part of the definition of a resonator is
that it "amplifies" vibrations (but again, in the sense described above).
With respect,
Gary Hodge
PTG - ASSOCIATE MEMBER
-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Fred
Sturm
Sent: Saturday, May 09, 2009 10:22 PM
To: caut at ptg.org
Subject: Re: [CAUT] Semantics
On May 9, 2009, at 3:46 PM, David Love wrote:
> However, why can't one say "the volume of sound produced
> formerly limited by the inconsequential mass of the vibrating string
> alone
> is increased when the energy is transduced to the soundboard whose
> greater
> mass and area allow for the greater movement of air". Substitute the
> colloquial meaning of amplified for increased and I don't think the
> physical
> world as we have come to know it will cease to exist or all soundboard
> science will be endangered.
Yes, a "larger volume of sound" is produced by a vibrating string
coupled to a soundboard than is produced by a string vibrating but not
coupled to a soundboard. But I would ask you to read Del's posts
carefully. It doesn't really matter that an uncoupled string makes
sound. The driver of a speaker's membrane makes negligible sound. The
sound is produced by the vibration of the speaker membrane. The
speaker membrane isn't increasing the sound of the driver. It is
producing sound in response to the driver's vibration (the driver's
vibration causes the membrane to vibrate, which moves air molecules).
This is very much analogous to what happens with a string and a
soundboard assembly.
This doesn't mean that someone who thinks that a soundboard makes a
string sound louder is stupid. It does mean that someone who holds
that opinion is ill-informed. It is a natural and even logical kind of
misinformation, which is why it is so widely held. It doesn't help
that advertising folks for piano manufacturers have been spreading the
misinformation.
In any case, it is important to understand the mechanics. And this
ties back to the original topic, which had to do with the theory that
string vibrations could be coupled, through accujust hitchpins, to the
plate, and could make the plate vibrate/resonate in some way. If we
want to try to see if the analogy between a stake driven into the
earth, abraded by a hoe, and a string terminated on a vertical pin,
driven into a hole in a mass of cast iron, has any validity, well, it
helps to have some knowledge of the mechanics/physics involved, and to
use words carefully in describing what happens.
All the hurt feelings and notions of disrespect and anger are very
much beside the point, and waste a lot of our collective time and
energy. Let's lose those arguments, okay?
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu
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