Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum "Fully Tempered Duplex Scale" Tech article coming March

Bechsteins with 88 agraffes have bad false beats when the string path between the speaking length and the tuning pin through the agraffe is not straight.

The first duplex arrangement I know of was Steinway "Monitor" grands which had 85 agraffes.

My Fully Tempered Duplex Scale, (FTDS), in it's most beneficial employment would have special agraffes in the capo. I have yet to do that version.

As Olek also points out, I will add though that note 88 strike point is usually just under 3mm from the termination point. With 88 agraffes there is no room to get that close without gluing the top hammers on longer and at a rake to tip them back towards the ideal strike point.

Duplex scales of the prior art have noises and create uneven tone where the typical capo bar scale switches to agraffes and the top treble is weak and often ugly, sometime awful ugly! My FTDS solves those problems.

Ed, when over centering shanks, are not the angle of the shanks to hammer's center line obtuse and the hammers are bored slightly short ..?

I might disagree here, We pay careful attention to termination, belly work and voicing.

I believe we have a fairly seamless transition from agraffe to capo ....

Ed,
On the 2 I have re-hammered, I lengthened bore slightly and swept a rake into the bore on the top 10 or so hammers-so as to avoid over-centering there-because any hammer wear will shift strike point shallower more rapidly.

Larry,
I am sure your work is fine. But I have proven my FTDS makes a treble better. I am not proposing that without it your trebles will all be dead-but it does make an even, clean, singing, more easily tuned, treble compass possible. All prior art duplex scales can not be voiced as evenly nor as powerfully as an FTDS scale. You will have to hear it to understand.
Ed Sutton has been quite skeptical of Techs who think they have invented something new, at the 2012 convention I invited him to hear two of my pianos and after 15 seconds of playing and looking the first words out of his mouth were "now THAT is different".

The full complement of elements I am describing have yet to be done all in one piano. I have filed for 44 claims, of course I will probably not get them all, I may not get any if the patent office just throws up their arms and says that there is too much prior art. I may have to take a piano to the Patent office because hearing is believing.

Ed,

I have read Jim Ellis's work, plodded through Conklin's work, studied Theodores 1872 patent on Duplex's, have a copy of Helmholtz third edition, Transcription by Ellis and am reading through that attempting to understand his potential influence on Theodore ..... what defines yours as different?

Well that is how it was on older Bechstein, with a larger rake angle sometime, but only to allow the strike near the string termination enough.

(over center (or overblow) was also used just to adapt to the large plate deformation noticed on some pianos at older times. I noticed one up to 6mm differnce between center and the extremes, and the original hammers had then that overblow and 94 ° rake angle- very bad for the core of the knuckles in the end, due to the lateral pressure on them they bend)

The larger rake angle is not an obligation, as there is generally a large angle coming from the bridge (may be less on Bechsteins in the end but 3° are not uncommon on Steinways)

The shape of those old hammers was so thin they often twist in time, unfortunately. it is always a problem when changing them.
Hopefully a few mm more on the shank is not that a problem in the high treble.(but the front side have often to be filed a lot for the last high treble notes)

Overblow (with 1° angle minimum) is considered as a security to allow more open FFF nuances, via probably more shank flexing.

Hello Ed,

This is great news but I wonder if you are not mistaken?

When did this take place?

I was under the impression that only members of the PTG and paying subscribers were allowed to view the journal.

Why would some have to pay for it and others not?

Larry,
There are several problems capo bars with duplex scales have and I am sure you have heard them all.
The problems are:
Snare drum, sizzle like sound that is heard at the fundamental frequency.
Pulsing, chiming sound that pulses with the fundamental but includes pulsing at higher partials.

The snare sizzle can be from either and/or; a too rounded V bar or a duplex length that is too close to a harmonic ratio with the speaking length.

The chiming sound is from the beats that arise between L-modes due to the divergent speaking lengths of the unison strings both at the V bar and at the duplex rest.

The pulsing, chiming sound is L-mode beats coming in and out of strong coupling with T-mode- again because of divergent speaking lengths plus duplex lengths too long for this place in the compass.

I do not know how to verify these descriptions with measurement. I do not see how the L-modes could be measured because the strings are so close together that there is no room for discrete magneto pickups. But I think my hypotheses is proven by the design it inspired. There are simply no other vibratory mode mechanisms to use to describe the origins of the sounds. Ellis's work proves L and T-mode beating/coupling.

Let take the venerable Stein B as an example;
C52 is the first capo/duplex note. On all the stock B's I have ever heard the tone of this note compared to B51 has an extra metallic shimmer to it that limits how full it can be voiced. Note 51 often has false sounds and duller tone due to poor string spacing and too soft string rest felt. Note 52 has a too long duplex and note 51 can have a too soft string rest which create a tonal scale break that most people probably just take as a fact of life that nothing can be done about.

You ask me what is different from Ellis and Conklin; they studied L-modes in the lower half of the compass.
Different from Helmholtz; I don't remember him having much to say about L-modes beyond the fact that they occur.
Different from Steinway; They got the front duplex ratios wrong in the patent, the hitching lengths (rear duplex) are better left closer to the fundamental, L-modes can not travel through the string over the bridge, I place the non-harmonic duplex ratios in the compass in such a way so as to maximize pivot termination (the pivot termination principle Steinway got right), at the highest point in the compass and blend the pivot effect into the reduced pivot conditions where the agraffe section begins. I eliminate, (at least in all the ones I have done so far) pulsing, chiming L-mode interactions by using a duplex string rest that essentially damps L-mode but not T-mode and that is very slippery to the string.

I also have claims regarding capo bar shape, capo bar mounting or stiffening methods, capo bar vibration control elements, agraffe mounting methods, hitching length proportions across the compass, and string contact elements at the bridge.

Does this help clear it up some? I do hope all who are interested will read my article carefully so I do not have to rewrite it a 100 times here. But I do appreciate the attention!

I have been able to download the article on a couple computers. So I think it's accessible to anyone from the above link.

I wonder whether there is a correlation between the use of a capo bar and higher string tensions? Most of the pianos of which I am aware that use agraffes all of the way to the top tend to be European, such as the Bechstein. My understanding is that the new C.Bechstein line has a capo bar, and is designed to have more power, etc. Is this scale higher tension?

Sorry Ed. You posted while I was writing.

Roy,
The new Bechstein scale may have a capo but it most certainly does not have a "Fully Tempered Duplex Scale"!

I suppose it doesn't!

I would like to hear one of your pianos. I was in Seattle last summer, but somehow missed it.

Thanks Ed for your explanation.

I did read your article.

Yes, Helmholtz doesn't list longitudinal comments in either the contents or index.

Ellis cites the enormous difficulty in terminating longitudinal mode. Could you comment on how you are able to terminate this mode?

As far as the difficulties with the B scale at B4 and C5, I have been able to resolve the issues you describe. Terminations, Belly design, hammer choice, regulation and voicing have been sufficient. I don't attribute all of the instances you describe to the design as you describe it. I like the B scale as designed.

We have been working with a Dr.of Physics, His T/A and the local University for the last couple of years on Longitudinal modes in piano strings. His T/a will be by this Thursday for some "quality" time with a couple of pianos. Resonant vs non resonant front and back scale questions are actually on the table.

I am not questioning that you have achieved a successful sound and I would like to hear what you have done. I do want to HEAR what you say has been "eliminated" as well as "added". Any chance you will be at MARC this year?

Ed,

I read your article, which contains many interesting ideas. It seems to me that an implicit assumption you make is that a front tuned duplex is necessary, or at desirable. There are some pianos that are designed not to require a tuned front duplex because the shape of the bearing point of the strings as they go under the capo bar, and the angle of the strings as they come off the capo are such that no (or de minimis) energy leaks across the front termination. In such a design, there is no possibility of loss of string energy due to a somewhat lossy termination (i.e., the transmission of string energy across the capo bar is not perfect), there are no longitudinal modes in the duplex section because there are no string vibrations in the duplex section, and therefore the various noises, whistles, and chimes that you describe can't exist.

The advantages claimed for pianos designed not to have string energy bleed across the capo are an increased sustained, and an improved tone. It seems from your description that a piano using the front termination taught by your patent may well sound very similar. I am interested in your comments.

Thanks

Ed, is there a piano with your FTDS in New York City? Or will you have one at MARC or the Chicago convention?

It sound difficult to admit that Lmodes can pass thru the capos easily, however the front segment could be exited by, as energy seem to be able to attain even the tuning pin.
Any string segment may work as a resonator, but for Lmode I like to see what is the level of motion that correspond to the frequencies.

or do I miss something in the Lmode transmission schemes ? it seem clear (!) when I thing of the bridge and the wire itself, but the agrafe or capo part seem neutral enough to me.

the excitation that is perceived at the pin side, is it coming from the wire, or from wave reflected waves in the case and plate ?

Roy123,
I most definitely have proven that a FTDS duplex design in the treble makes the tone better than any other prior art. I have the single most important proof; the pianos! Now we are left to argue why. I have tried my best to use what is known about L-mode and T-modes and their interactions to explain why. The FTDS is the result of the test of my hypotheses.

The counter bearing angle of the duplex string segment has no relation to L-mode reflection. Since L-mode is carried internally in the string, some of it from the localized tension differences the hammer strike produces it with, go right over the V-bar. It then can be reflected by the duplex rest. This is how each unison generates 6 different fundamental L-modes.

BB Mason/Hamlins have steep duplex counter bearing and they always have several notes that chime.

Monotone duplex designs can have the duplex damped or undamped with felt. The damped ones usually have no duplex noises but the tone sustains less and is more nasal. Monotone duplexes do not optimize pivot termination conditions across the compass. The Acetal co-polymer duplex rests I use, (and any other suitable material that damps L-mode and doesn't damp T-mode are claimed) damp L-mode and do not damp T-mode. This is different than the prior art. Felt damps T-mode.

Larry,
The L-mode termination issue Ellis struggled with is related to bridge rocking and resonances within the monochord structure.

Most pianists and technicians have come to expect and ignore many of the subtle duplex chiming noises the duplexes of the prior art all contain. I think if you listen carefully to your pianos you will find some-especially if you voice the treble up fully to equal the rest of the compass in volume for playing effort expended. Most pianos have weak trebles-especially if they have wonderful basses to contrast it with. All prior art duplexes have a tonal break where the agraffes end and capo begins.

I very much like the tone of the B scale. One of my FTDS pianos is a 1984 B. It has the best treble tone of any piano I have ever heard in my life. It did not sound that way before I modifies it to FTDS.

I have not been invited to either MARC or 2013 PTG Institute. I would be open to bringing a piano and presenting a lecture if the conditions were workable.

I am immediately suspicious of proofs of any sort of esthetics, since not everyone has the same esthetic values. The use of the word "proof" in your article is inaccurate.

Recordings might be more convincing than claims of proof.