Piano Forum

Topic: Mechano-electrical Adjustment of a Piano's Tuning to Just Temperament  (Read 1347 times)

Offline justpiano

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Hello, all. I'm glad to be a new part of this forum. OK, deep breath, here I go...

I have decided to undertake a project to mechanically and electronically retune a piano to just intonation/temperament. For a more in-depth explanation of what just intonation is, visit https://www.justintonation.net/. Essentially what I am trying to do is retune the piano in each of the twelve different keys (not all at the same time). Every string would relate to the tonic by simple frequency ratios (i.e. 3/2 for an interval fifth, 5/4 for a major third, etc.) This is the way most other musical instruments play, because the ear hears these ratios as pure. All brass, strings, and woodwinds play unknowingly in just temperament because it just sounds right.

However, the piano, up til now, has not been tuned this way. If one were to tune a piano to just intonation in A, the piano would only sound right in A. Any song not in A would be plagued by what are known as "wolf" tones, dissonant notes caused by an incorrect tuning for that song. Because it takes so much more time and effort to tune a piano than most other instruments, piano tuners reached a sort of musical compromise. The modern piano is tuned in equal temperament, which is based on the 1200th root of two. This system works for songs in all keys, but it is only an approximation of what the ear really thinks is right. Unfortunately, pianists are so used to hearing equal temperament that they never have seen the benefits of just temperament.

Music and instruments playing in just temperament have a beauty that the piano has never enjoyed, specifically harmonic partials. The piano has what we call "warmth" because its partials (integer multiples of the fundamental frequency) do not align in chords. Although piano strings are very slightly inharmonic because of the bar-like qualities they exhibit under tension, the main reason their partials do not align in chords is their frequency ratios are not simple frequency ratios (just temperament) but roots of two (equal temperament). For some notes, just temperament and equal temperament disagree by up to 30 cents!

Another gentleman, Mike Harrison, has done some similar just tuning on a piano by extensively modifying a grand piano and applying his "Revelation" tuning by means of a pedal system. Many non-Western instruments, most notably the Indonesian gamelan, are tuned in some form of just temperament. I know that a piano in just temperament would not sound too exotic; rather it would be nearly vibrato-less and full of partials rarely heard from a piano.

What I plan to do is to modify the tuning of a piano by attaching electric motors to the tuning pegs and controlling all of the 222 motors by computer software. The motors I have found are strong enough to turn the pegs quickly (60 rpm), but I have heard that turning the pegs that fast will damage the pins and destroy the pin block. I also have to deal with the great amount of tension change on the metal frame of the piano, which currently is bearing some 35,000 lb. of tension.

What I am wondering is: Am I off my rocker?
Would some piano tuner please tell me how slow I need to turn the pegs to ensure I don't end up destroying my experiment. I am working with senior physics professors on the electronics and mechanical end of this project. They, however, have no musical background and I needed to go to the source for piano know-how.

Offline gfiore

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  Sorry, you are way out of your element. For one, this has already been accomplished, although not the way you are trying to do it. It is impossible to use any kind of motor to torque a tuning pin. How would it set the pin and strings over their bearing points to hold a tuning for that string?
 The way it was done  a few years back,  was through the use of electronic devices to actually heat the strings to raise or lower the pitch.  A master tuning was rendered on the piano at the factory as the default tuning. The self tuning engineering was just used to clean up any unisons that were not correct.
George Fiore  aka "Curry"
 Piano Technician serving the central New Jersey Area.
My piano- A 2004 Bosendorfer Model 214 #47,299 214-358

Offline c18cont

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My Korg,...( but NOT my grand),

Can play in any tuning, and allows for personal tunings as well...(see under the instruments "global" section...)

Seems the easy way out, as sooner (rather than later) electronics is going to be good enough to be thought of in a serious manner in piano sound...they are getting close.

John
 

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