Gentlemen:

If you came up with a way to eliminate tooth decay, should you ignore it so that dentists could keep thier business? If you could invent a way so that you would never have to change a car's oil, would you abandon it to avoid slowing down the work at Jiffy Lube? Probably not...unless you're a Luddite!

This device is not the death-knell for tuners, nor was that ever my intention. There are over 1,000,000 NEW pianos produced each year. If I thought my system could be intalled in even one percent of those, and never retrofitted, I would jump for joy.

Besides, who do you think is going to be doing the installation? You might be able to comfortably retire on these things!

I don't think this would work. Think about the overpull that's needed before the string actually renders. To get the front duplex to expand this much, by thermal means only, I think you'd need to heat it red-hot. Even more so on those strings where the front duplex is very short relative to the speaking length, e.g. lowest/farthest row of tuning pins in mid-range or tenor. And in the bass, one can actually see the rendering movement, if the string is more than a few cents off. Given the short length of the front duplex, that's a huge movement to achieve only by thermal expansion of the front duplex.

Methinks you'd turn your pie-anna into a veritable toaster.

(Purely intuitive. I haven't done any calcs involving thermal expansion coefficients here.)

Mark:

I was having the same second thoughts, and like you have not done the math.

No, the entire string is warmed, from the tuning pin to the hitch pin. This avoids differential tension across the agraffes and bridge that normally has to be pounded out with heavy playing, like when a conventional tuning is done.

The smaller, duplex segments of string expand less, since linear thermal expansion is a function of the total length, and these segments are obviously shorter than the vibrating part of the string. But "strain" is also a linear function of total length and is what relates the change in length to the change in tension. So a given change in temperature results in a given change in tension, regardless of length. The tension on the short side of the agraffe changes by the same amount that the long side does and there is no net difference across the agraffe and no need to pound it out.

Mr. Gilmore:

Thanks for the clarification. I would think the the heat sink properties of the pin and agraffe would keep the non-speaking segment at a slightly higher tension than the speaking segment, assuming that the tensions were equal before the current was applied. But that is normally a good thing. The hammer striking the speaking portion can only increase it's tension, never decrease it, so it is better to have the non-speaking portion a little higher in tension for reasons of stability.

I see all sorts of possibilities, as well as hurdles (-:

According to how well the current (by which I mean "current" or "i") algorithm is written and "adapts" to the speed with which a string reaches its desired pitch - this could work very, very well.

Yes, it is very dependent on the reference tuning and that in turn is very dependent of the individual tuner/technician (not to offend anyone by not giving them their full professional title, etc.)

As long as you don't let the room get TOO much hotter than the 95 (or so) degrees at which the reference tuning was done - but who wants to PLAY in those conditions anyway ? (-:

The principle of this idea is sound, and there's no doubt that it is possible to accurately reproduce a reference tuning. As an engineer I've bought off-the-shelf (albeit expensive) components to build rigs measuring displacement to within 0.3 microns, sampling at 20,000 samples per second. Blimey, when you think of what a scanning electron mircroscope can do, there is no doubt whatsoever that an engineering solution can out-perform a human.

So, let us focus on the 'reference tuning'. Why not provide this solution from a different angle. The basic factory tuning is close, but sharp so that heating can produce the desired correction in pitch. Why not then have your local tuner do your tuning for you:

1) you have a button on the keyslip for selecting the key to tune: you press the button, and play the key you want to tune. This note is then 'selected'.
2) you then press the same or another button to toggle between the three strings of the note (if it's a trichord). That individual string is then selected.
3) the tuner then uses his or her felt and wedges as normal, but instead of a tuning hammer, presses a '+' or '-' button to alter the pitch of the selected string, by 1/100 of a hz or whatever you choose.

Brilliantly, having set the pitch of a given string, it can be held to that pitch as the rest of the instrument is tuned. Also, tuners won't get so much elbow and shoulder ache!

Secondly, if this system works, get rid of the wooden pin block and tuning pins which are not required for a one-off or once-in-a-blue-moon adjustment. Surely a means can be found to 'apply' and fix a pre-conditioned string under tension, in the factory using specialist equipment. This would eliminate a relatively labour intensive part of the process, which is one of the usual parts that fails in time.
Imagine a piano with hitch pins at either end of the string? The saving would cover the cost of the electronics which you've added.

Personally, I'd never modify any of my current pianos as I view them as historical instruments. However, if I was buying a new instrument, and the self tuning part was a really neat, invisible installtion, I'd get one!

Good luck Don!

Screw stringer, or geared stringing - Brinsmead, built in the UK around 1880....

http://www.pianoworld.com/forum/ubbthreads.php/topics/1484727/Brinsmead_piano_pin_block.html

I think Mr. Gilmores' invention would be a nice feature for some people. I'm not threatened by it. Like he says, there are so many pianos out there already. Dealers could offer it as an add-on at the point of sale. Maybe it would help sell some pianos. I think that the greater overall struggle, for all of us, is to get the public more interested in pianos. If this helps, great.

If a company were to produce a piano with an alternative tuning system today, then piano owners would be able to tune their own piano without this invention. In the days when the Brinsmead and the M&H screwstringer were built, the owner would have had to call a tuner anyways. A tuner would have still been needed to set the temperament, etc. So, it didn't save having to call a tuner. And tuners probably didn't like have to fidget with this device, when they we already accustomed to tuning pins. So, I can see why it didn't become more popular at the time. But now, there are many electronic tuning devices. If pianos had gear tuners, piano owners could easily tune themselves. Each piano could be provided one relatively simple ETD. It wouldn't have to be as complex as the one's technicians use. It wouldn't have to measure inharmonicity to accomodate different pianos, for example. All that could be preset for one piano. This might be the more practical way forward in the future to make pianos tunable by owners.