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KLX-F1,
Thanks for your interest. My US Patent is #9,117,421. There is a thread on PW that include "Fully Tempered Duplex Scale in the title. There is also one on PTG.org Pianotech Forum.

I will be giving a class on FTDS at the PTG Convention in Lancaster Pennsylvania this July. I am bringing a 1979 Chickering 501 that includes it. Hope to see you all there!

Just keep in mind that a patent is granted on only one basis: that there is no previous patent that covers the same thing. All the patent does is give the grantee the right to defend infringements in court, at which point the patent may be upheld or nullified in the process of disputing the infringement. The patent is not a guarantee that the patented device does anything that it is claimed to do.

BDB,

Though what you say is true, it does not seem necessary to cast doubt as you have UNLESS of course you have personal experience to the contrary, so as to be able to speak thus.

Though I have not as yet seen it in action, I have heard from others who have applied it that it does in fact fix the defects built into the Steinway aliquot arrangement. I am interested to see it perform before I make a judgement.

Planning to be there in Lancaster.

Pwg

Interesting!
Do you have demonstration video or audio sample of piano with FTDS?

I do not know what the supposed defects in the Steinway aliquot arrangement are, so if I heard one of the pianos, I would not be able to tell whether it fixes them or not.

I do know that some of the claims made about it make absolutely no sense mathematically or physically. I also know that the biggest defect that things like this are designed to fix are often the hollow sound in one's wallet. So it is always well to be reminded that "It Ain't Necessarily So!"

Of course, some of the problems come from restringing. The standard wire used today is significantly stronger and harder than the wire that many if these instruments were originally strung with. That in itself seems to aggravate the front aliquots (in my experience). So of course if the original design was done in reference to the type of wire used then (obviously so), then we would expect some difficulties now. Same as if we strung an American made piano with Asian wire. It's not going to be the same and there might be unintended consequences.

I think Ed' s research is valuable. It is not uncommon for a design "on paper" to be a bit different in practical application. And sometimes it need a to be "re-thought". Of course, whether the re-application is worth the expense of doing so is a question that cannot be truly answered by us here and now. But if it consistently can be proven to have turned a mediocre piano into a fantastic one...well, that is certainly worth digging into IMO.

Pwg

If BDB has never heard any "noises' in a piano with a standard duplex scale, he either has an incidence of good fortune equal to the odds of being struck by a meteorite thrown by an extraterrestrial, or he is deaf to the problem.

I agree.

Except believe that "a meteorite thrown by an extraterrestrial" is the most likely of explanations here!

Norbert

I have heard noises in pianos with duplex scales. I cannot attribute them to the duplex scale, though, unless it is something that I have been able to alleviate without redesigning the piano.

I think there was someone here with the tag line: If the only tool you have is a hammer, everything looks like a nail. I have acquired a few more tools in my kit.

BDB, Making in-situ test modifications to an existing standard duplex is how I first tested the precepts used to derive FTDS. If using those design tools is not good enough for you, what do you use?

I use whatever works. It is difficult to say precisely what the method is when it depends on what the problem is.

One thing I do know is that if there is a problem that shows up on one sample of a model of piano and does not appear on another, it is not a design issue. That is a logical conclusion. Logic is one of my tools.

But tolerances vary from piano to piano and are changed over time and drift with time so an intended design at one point is often no longer extant. I employ logic as well, but logic must not be misused to simplify away factors that exist. The foremost tool in logic is Occam's razor.

Occam's Razor says that if someone can do something simply, that someone who needs to do it in a far more complicated way is wrong.

I have never been to Yogyakarta. Maybe one day....

BDB, Occam's razor says that you test the simplest explanation first. There is much art in deriving the simplest explanation. That art can involve much study of seemingly minor details. With musical instruments, the context of use is often the most difficult part to understand all of the possibilities.

Another issue with aliquot scales is that they can have false beats as bad or worse than SL strings. Just the nature of the beast.

Pwg

How does one tune a duplex? Rhetorical question. If the metal pieces of the duplex are off by a millimeter or less and pitches are slightly out of phase it seems like this could be a problem. I’m not a technician but common sense says if you have a series of strings
that cannot be fine tuned (obviously not) then this opens the opportunity to hear beats and sound out of phase. To avoid this every piano would have to have duplexes that are exactly custom for that piano rather than a one size fits all.

I am more interested in the meteorite thrown by the extraterrestrial at BDB.

The only element of a duplex scale that aids tone is when the string lengths between the V-bar and/or agraffes and the string rest before the tuning pins are able to provide the maximum pivot termination effect.

Piano wire is very stiff so allowing the string to move on both sides of the termination allows for more energy input by the hammer and strengthens the fundamental of the speaking length.

In essence the wires stiffness communicates vibratory information outside of the speaking length boundaries.

The duplex lengths must not be "tuned" in a mode relation to the speaking length modes or they produce an abnormal sounding spectrum of frequencies.

As someone with some patents, and therefore someone who has had a number of discussions with patent attorneys, I can say unequivocally that what you say is incorrect. Yes, the device described in the patent must be original, but that is not sufficient to receive a patent. It must also describe something that is not obvious to someone schooled in the art. The meat of a patent is in the claims section, and the patent examiners carefully look over all the claims to see if they are justified. If any are in doubt, the patent will be rejected, and the person or law firm that put in the application is given the opportunity to defend, revise, or eliminate the claim or claims in question. As one patent attorney said to me, if a patent goes through without objections, the application was not claimed broadly enough.

While the patent examiner can't guarantee that the device will do all that is claimed, the examiner attempts to make such a judgment. One must keep in mind that there is a quid pro quo for a patent--in order to receive one, the patent must reveal how the device works to the extent that any reader of the patent should be able to duplicate the device. That is why some companies, in some cases, prefer to try to keep a certain invention secret as opposed to patenting it. As is usual with most things, patents are more complex than they at first might seem. BDB is correct in one sense--anyone can challenge a patent. This is usually done by a company purposefully infringing on a patent, and then seeing if the patent holder will sue. I was involved in such a suit, and as one of the patent signers, was deposed by the attorneys for the company that was infringing. Just for the record, we (the patent holders) won!