----- Original Message ----- From: "R Moody" <remoody@midstatesd.net> To: "Pianotech" <pianotech@ptg.org> Sent: Thursday, December 25, 2003 10:16 PM Subject: Re: "Self tuning piano" questions > Earlier you mentioned you could do this with chips from Radio Shack for > under $10. I have not bought an ETD because they are too expensive. $150 I > thought I would never see, but when Robert Scott offered his Tunelab95 for > free trial I jumped on that but found just as with any tool, (complicated > machine actually) there is a learning curve, both for how to use it and what > it can actually do for you. But a device accurate to 1/600 cents from off > the shelf parts for $10?--- I will be forced to become a machine tuner. ; ) > (as if) (but you never know). Well, the technology relies on the fact that I have an individual pickup for each string. That means no interference, no background noise, a clean signal, and a signal that is sustained at a constant volume. This lends itself to easy measurement of the signal, especially when your goal is simply to store and repeat a value. If you want to use a microphone signal and separate partials, see changes with decay, etc. it would not be as useful. And actually the "$6 at Radio Shack" only counts the active components: the Schmitt trigger, the oscillator and the counter. I still have to use a microcontroller chip to program, trigger and read the counter and an amplifier for the coil signal. Still it's less than $75 worth of stuff if you want to measure one string at a time. > I read an article describing in depth the self tuning system, I assume > it was by you but I forgot where. Journal?, Music Trades? Did someone mail > me a clipping? Is it in html or on the net? The in-depth article was in the July 2002 issue of the Journal. It has also been covered in the New York Times, Reuters, New Scientist Magazine (England), Der Spiegel (Germany), Intermediair (Holland) and the Nikkei Marketing Journal (Japan). I have done radio interviews on NPR, CBC Canada and local stations in Canada, South Africa and Australia. It was also mentioned on Paul Harvey's noon broadcast. > From the article, the system seems feasible it only remains to be seen > if it is practical. It has to be made and put into a piano without alarming > the accounting dept. I was hoping to see one at NAMM last Jan, in fact I > think it was announced but the head of QRS would only say it was not going > to be exhibited. When I tried to ask specific questions he did not seem > anxious to get into that discussion. That was Tom Dolan. I originally licensed the patent when his father Dick Dolan was CEO. Tom became CEO shortly after that and decided not to get it ready for the Jan. show as previously planned. Tom remains firmly commited to producing it, but feels that several other of my inventions should be given priority right now. We have been working on them this year and they will be out very soon. In the meantime the self-tuner has undergone intense scrutiny by myself and the electronics consultants recently and is ready for the final design work. It's all a waiting game with this invention stuff. > So I am wondering how well will it actually perform as far as a piano > tuner is concerned. Especially unisons. Since most ETD users tune the > unisons by ear, (don't they?) I wonder how your system will fare. > Regarding your demo model, have you demonstrated it in front of a group of > piano tuners, and can it really tune a 3 string unison to their > satisfaction? This is a trick question because the your goal is made when > the piano sounds OK when playing music, after all it is QRS the player piano > people who are interested and I know from my own player piano that it can be > way out of tune but still sound OK when a roll is played, but sounds > horrible when I sit down to play it. So I think if your system comes close > but not up to professional tuning standards it will still suffice for the > listeners and most important the customers. It is not intended just for use in player pianos. In fact the original design didn't take the player system into account and could not have been put in the same piano. We decided that there may be people who want both systems and modified the design slightly so that they can coexist. There have been a number of techs involved throughout the process, some from Story & Clark, some from Mapes, some from Dongbei, some private techs. > I have seen how the SAT III does---superb on everything but unisons. But > if your micro second counting system really is accurate to 1/600 (the SAT is > 1/10 cent ??) AND gives unisons (as good or better and faster than by ear), > you stand to make out quite well in the ETD market > So you don't produce a tuning, only measure and record and reproduce that > record? But could you have the strings tuned to something like > 440*2^(1/12)? > Somewhere it was mentioned there might be historical tunings offered. Would > these have to be tuned by hand first and then recorded by your system, or > can you program the system to produce a particular temperament? Sure, within reason. The wilder you get with your tunings, the more range you are likely to use up. The planned tuning system will have a little more than 20 cents' range (or possibly more...it's still a debate). Actually you can have any range you want if you are willing to pay more money for the system. The biggest annoyance is the fact that the strings take very low voltage (about 2 volts) at a relatively high current (as much as 2 amps). So, though the wattage of the system is not that great, a power supply that supplies 575 watts at 2 volts is just not an off-the-shelf item. > You indicated you would explain in more detail the square wave aspect of > your system. I am interested. From what I pasted in below, I think I get > the gist. My synthesizer has a square wave, or kind of one. Is this the > same kind of square wave you are talking about? The synth square wave is > composed of only the odd harmonics? So that means when I play a major 3rd I > will not hear the 4th harmonic of the top note which means the 5th harmonic > of the bottom note has nothing to beat with. Very strange hearing an ET > major 3rd not beating. If you or anyone can explain why the synth square > waves only gives odd harmonics I am all ears. Well, I don't actually make it into a square wave for musical reasons (no one ever actually hears this signal anyway) so overtones don't matter in this application. I square the wave to make it a digital "on or off" type of signal. It's just easier to work with electronically that way. A square wave with a frequency of 440 Hz turns "on" exactly 440 times per second, which is easy for a digital circuit to deal with. It simply measures the time between two "ons". Don A. Gilmore Mechanical Engineer Kansas City > ----Richard Moody
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