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Self-Tuning Piano
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Subject: Self-Tuning Piano From: NicoleC Date: 05 Dec 02 - 05:58 PM What's next? A self-tuning banjo?! Self-Tuning Piano Set to Make Sweet Music Thu December 5, 2002 11:21 AM ET LONDON (Reuters) - An inventor has developed a piano that can tune itself in 40 seconds and which will hit the market next year. Conventionally, pianos are tuned by manually adjusting the tension of the strings struck when a piano key is pressed. But Don Gilmore's invention warms the strings using an electric current to reduce an excess of tension deliberately built in when the piano leaves the factory. "Gilmore's system will go on sale in some grand pianos made by American piano maker Story and Clark by the end of next year," New Scientist magazine said on Wednesday. "The system...tunes the piano using a warming current to ease the tension of the strings," the magazine explained. A frequency analyzer, microcomputer and power transistor are incorporated into the system to tune the string to the correct frequency. Gilmore, who is based in Kansas City, Missouri, trained as a classical pianist before becoming a mechanical engineer and inventor. The company planning to use the invention in their pianos said it was too early to say exactly how much it would add to the price of their instruments. |
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Subject: RE: Self-Tuning Piano From: Gloredhel Date: 05 Dec 02 - 06:22 PM What I want to know is, do you have to press a button or does it do it automatically when something isn't right? |
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Subject: RE: Self-Tuning Piano From: Neighmond Date: 05 Dec 02 - 06:56 PM as a piano tuner I can tell you I hope to God that you can still tune the thing manually. Tuning a piano is an art, and i cant help but think of the old Hammond drawbar organs with the tone wheel generator that had to have vibrato built in because the sound was so sterile. FWIW C |
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Subject: RE: Self-Tuning Piano From: NicoleC Date: 05 Dec 02 - 07:33 PM From what the article says, it just sounds like an internal climate control system, not really a replacement. I doubt if concert halls will be relying on it any time soon, but I think it'd be great for schools and churches and such that tend to move their pianos around but *never* get them tuned properly. No doubt the new gizmo will need to be serviced as well. |
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Subject: RE: Self-Tuning Piano From: JohnInKansas Date: 05 Dec 02 - 09:18 PM A real "quick and dirty" feasibility look - probably riddled with errors, and possibly based on an incorrect interpretation of the invention: To lower the pitch by one semitone, you must reduce the frequency to about 94% of the original frequency. Since frequency is proportional to the square root of the tension, the tension must be reduced to about 89% of its original value. A typical piano string is at about 160 pounds tension, so the change in tension for a semitone change in pitch is about 17.6 pounds. Most useful core wires will have a yield strength of at least 120,000 psi, and will be "tuned" at 80 or 90% of yield - or at around 96,000 to 110,000 psi, so for a rough calculation, a core wire area of something like 0.00145 square inches is likely. (This give a core wire diameter of about 0.04 inches - possibly good for at least some of the strings.) An 18 pound change in tension changes the stress level for the hypothetical string by 18/0.00145 = 12,414 psi. Since the "elasticity" of a steel (or bronze) core wire is on the order of 30 million psi for each inch/inch of stretch, the change in length is on the order of 12,414/30,000,000 or 0.000413800 inches "stretch" per inch of original string length. The thermal expansion coefficient of steel is on the order of 0.000012 inches/inch for each degree F. Dividing 0.0004138/0.000012 gives the temperature change needed, or 34.5 degrees F. You would probably want the "in-tune" temperature higher than the warmest ambient in which you want the tuner to work, so you would likely choose a "design temperature" of at least 120 F - in a 95 F ambient. It should be noted that both the strings and the soundboard will expand and contract more or less in the same direction, so the amount of tuning required would not vary too much if the room temperature changes. It would also be possible to heat only the "short end" between the end anchor and the bridge to change tension on the whole string. This would avoid burning hammers, but would require a larger temperature change (because of the shorter length affected). The biggest drawback is that warming each string by 15 to 30 degrees F would likely require at least a couple of watts per string. Because the resistance of the wires is low, you would need a low voltage but high current power source. With 230 strings in a typical piano, you might have to have a portable arc welder for a tuner power supply. Of course the resistance of the wires goes up quite rapidly once they start to glow... Altogether - it seems like something that could be built. Why is another question. John |
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Subject: RE: Self-Tuning Piano From: katlaughing Date: 05 Dec 02 - 10:26 PM you might have to have a portable arc welder for a tuner power supply. Of course the resistance of the wires goes up quite rapidly once they start to glow... LMAO...priceless, John. Thanks! katSparky'sdaughter&pianoplayer |
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Subject: RE: Self-Tuning Piano From: momnopp Date: 05 Dec 02 - 10:36 PM Link to the article referred to -- click HERE. And Gloredhel -- in answer to your query, from the article, "All the pianist has to do is hit a switch and wait for 40 seconds while hidden electronics tune the strings." Peace, JudyO |
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Subject: RE: Self-Tuning Piano From: GUEST,ozmacca Date: 06 Dec 02 - 02:11 AM Now when are they going to do the same thing for guitars, mandolins and banj.... no never mind the banjoes. Nobody I know has managed to tune one of them properly for two tunes in a row, so why start now. How about a system of strain gauges, one on each string, settable by the player to suit the note wanted, and connected to a miniature motor on the machine head. Simply set the note wanted for the open string, press the button and hey presto.... buzzzzzzz, whirrrrr, twanggggggggg. Perfectly adjusted and ready to play. Might need the transformer out of JohninKansas' arc welder to run the thing, but think of the revolutionary new steps in getting money out of string players' wallets. |
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Subject: RE: Self-Tuning Piano From: JohnInKansas Date: 06 Dec 02 - 03:29 AM As described by Reuters, you must bring the string to the appropriate temperature to produce the "right" pitch. This means that you must keep it at the "right" temperature in order to keep it tuned, so the power would have to stay on until you've finished your performance. Of course, since the heat will leak from one string to the next, and to the soundboard, the "right" temperature will change continuously; so we'd have to assume a "closed loop servo" configuration that constantly "tracks" the pitch of each string and adjusts the heating current as required. There's no way that any reasonable rate of heating could bring a 300 pound soundboard to "stable/constant" temperature in 40 seconds. As the soundboard warms and expands, it will increase the string tension, leading to an additional requirement for heat to the string - - at least until "stable" temperature gradients are achieved, "active" tuning would need to continue. While it's not difficult to generate any particular frequency, or to compare it to another frequency, the existence of the "other frequency" is a bit problematic. You can't tell at what frequency the string will vibrate - unless it vibrates. So does the piano "hum" for you the whole time the tuner is adjusting itself???? And do you have an 88 note drone accompaniment until the system is stable??? There is a "tuning problem" to which this system might have some application. Large concert halls are frequently not kept "at temperature" except for performances, and the heat load from a large audience can change the room temperature significantly; so the piano tuner may have to work at an ambient temperature significantly different than the temperature that will prevail for the performance. In the rare instance where this is a known problem the proposed system might have some merit - if it actually works. For the banjo player problem, the solution is simple. If the string is out of tune, heat it 'till it burns their fingers. Or just accept and enjoy the characteristic "unpitched twank" they make. It's really part of their charm. John |
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Subject: RE: Self-Tuning Piano From: BanjoRay Date: 06 Dec 02 - 06:46 AM It's wonderful to see all engineering types out there explaining why bees can't fly! Also - anyone who says banjos emit an unpitched twank is an unpitched twanker Cheers Ray |
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Subject: RE: Self-Tuning Piano From: Schantieman Date: 06 Dec 02 - 07:42 AM The New Scientist report says that the current is about 500W and the operating temp. is about 35deg.C. (~92deg.F). It does stay on all the time. The strings are tuned slightly sharp beforehand - so in a warmer environment some modification would be needed. I get the impression that it does stay on all the time the piano is in use - and the very slight sound is scarcely audible. ...now let me see: 500w per piano.... concert halls.... ... schools..... music colleges... theatres..... private homes..... probably one or two new power stations will be enough. ;-) Steve |
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Subject: RE: Self-Tuning Piano From: Amos Date: 06 Dec 02 - 10:20 AM Yeah...and if one of the strings is flat, do they chill it out to sharpen its tone? There are semiconductors that do this -- they get cold if the current goes one way and hot if it goes the other -- but, honestly, I think this one will take off like a pregnant polevaulter. In another few years they'll be able to load a piano up with micro-electro-mechanical devices (MEMS) that can do the job mechanically in either direction, which strikes me as a more sensible approach for pianos. A |
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Subject: RE: Self-Tuning Piano From: Bee-dubya-ell Date: 06 Dec 02 - 11:05 AM Here's a link to a previous thread about a self-tuning guitar. Bruce |
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Subject: RE: Self-Tuning Piano From: JohnInKansas Date: 06 Dec 02 - 04:08 PM Banjo Ray - I thought this engyneer's explanation was that this bee can fly. I even threw in a (perhaps gratuitous) note to justify (maybe) why some people might find it useful. As a (mainly) mando player, the "unpitched twank" note was in hopes of staving off - for serious banoists - what seems to have happened to the mandolin in my area. So many people think its "cute" that we now have many more "mandolinists" than musicians. Hopefully if they are allowed to make their little jokes about banjos, they'll stay away from them so things won't be so overcrowded when I get my banjo - as I do intend to do. Shantieman - 500 watts ain't much. It's about on a par with the total of the little music lights that the string section clips on their music stands in the average symphony - and they all use batteries so they're chemical polluters too. The arc welder analogy refers to the supposition that the system would require rather low voltage - but substantial current, which is somewhat "inefficient" relative to other kinds of power, but not unworkable. It's hard to find a city block in my neighborhood where at least one guy doesn't have a portable arc welder in the garage. A typical coffee pot probably pulls around 800 to 1200 Watts while it perks, and probably 300 - 500 watts "at idle" if it's one of those "keep-warm" kind. I'm personally gratified that the cited 500 watts is so close to my off-the-cuff estimate of a "couple of watts for each of 200+ strings. It's a "theoretically workable" concept. (Although it's probably not the way I'd choose to solve the problem.) Whether it's a useful one depends on the "market analysis," which probably was at least informally done by the inventor - who probably encountered out of tune pianos in his previous life. John |
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Subject: RE: Self-Tuning Piano From: katlaughing Date: 06 Dec 02 - 06:12 PM Or maybe he's tone deaf?:-) |
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Subject: RE: Self-Tuning Piano From: Stilly River Sage Date: 06 Dec 02 - 07:40 PM With a self-tuning piano, should the Unthinkable happen and the pianist carelessly spill a drink on the keyboard, they won't make that mistake a second time! zzzzzzzzzzzzppppptt! SRS |
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Subject: RE: Self-Tuning Piano From: JohnInKansas Date: 06 Dec 02 - 08:00 PM Naw SRS The power level may be pretty high, but it's just a mild bit o' warmth. 'Nuff to raise the bouquet on his brandy. John |
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Subject: RE: Self-Tuning Piano From: rangeroger Date: 06 Dec 02 - 10:26 PM Alison Kraus' new CD "New Favorite" has a hidden track at the end, that creates one of the best sound pictures of a banjo exploding that I have ever heard. Massive unpitched twank. rr |
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Subject: RE: Self-Tuning Piano From: GUEST,.gargoyle Date: 06 Dec 02 - 11:09 PM As a musician whose, .... ..........................................first and most lasting instrument,is piano, ............................................... I can assure the "worried piano tuners of the universe" (who know the peculiar quirks and spurts of the performers and are laughing up their sleeves at poor Mr. Gilmore and his ideas-perversey)... their jobs.......................................
are secure,,,,,,,,,,,,, in the knowledge that....technologyno matter how fucking brillant! will never compare to the fine nuances of a well-tempered intrument, artfully played, And HAND tuned by a master
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Subject: RE: Self-Tuning Piano From: Stilly River Sage Date: 06 Dec 02 - 11:38 PM I read an interesting article in the New Yorker a couple of years ago about a woman who sells Steinways in New York City. Interesting background, nearly went into a performing career herself. Can't remember her name, but a search at the magazine's web page would probably bring it up. Erica someone. Its a science to match the right piano to each player. And pocketbook! I remember a piano tuner who came to the house when I was a child--the few times he was over, he always played something. Maybe it's because we were kids and as impressed as could be--and it was probably more expertise than any of us ever brought to the instrument! SRS |
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Subject: RE: Self-Tuning Piano From: GUEST,.gargoyle Date: 07 Dec 02 - 12:25 AM Mr. Ranger-Sage.
I devoure the American nuanciaes langangue....
While my tone has a vibratin' tone of a crack thread...reverbatrating through yo head.....
your's has the tranquile hummmmm, of meth...androma-hom....spinning through the drome of the drome ad-homin-o-homn.
Sincerely |
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Subject: RE: Self-Tuning Piano From: Amos Date: 07 Dec 02 - 11:24 AM Far out, Garg!! Wayyyyyy!!! ***BG*** A |
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