Hi Gary, Just think of the transmission on a car. It takes energy from the engine and transmits it to the drive shaft which connects to the differential which spins (at least) one wheel on the car. No energy is created. Some is lost between the engine and the wheels. That is exactly why it is muddy thinking to call the soundboard an amplifier. There are losses at every step between the pianist's finger (or nose or book dropped on the keys) and the sound output. No amplification is done. Lots of tranducing is done, however. And just as in an electric circuit there is impedance. At 05:07 PM 5/10/2009 -0400, you wrote: >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 > > > > > >No virus found in this incoming message. >Checked by AVG - www.avg.com >Version: 8.5.325 / Virus Database: 270.12.24/2107 - Release Date: 05/10/09 07:02:00 > Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T. Non calor sed umor est qui nobis incommodat mailto:pianotuna at yahoo.com http://us.geocities.com/drpt1948/ 3004 Grant Rd. REGINA, SK, S4S 5G7 306-539-0716
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