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

Ed, I have no doubt that what you are working on has great merit. I have looked into the L mode problem in some depth and believe addressing this is pivotal to building a supreme sounding piano. The fact that you have made a rigorous study of this and implemented a carefully calculated solution is a credit to you.

I just think it should be a matter of utmost priority to include some sound examples of what your modifications do to the sound of a piano. The discussion itself is very interesting and stimulating, but it really needs the sound example for the points to be driven home.

I think you are vastly overstating the effort and difficulty of making some recordings and posting them. There are any number of ways you can post recordings quickly, easily and for free. They don't need to be hosted on your own site at this point. All you need is some clickable links in threads like this one and you will be greatly advancing this debate.

If you want any help or suggestions with how to do this, feel free to PM me. It's really quite easy. As far as making the recordings goes, there are numerous portable recorders that are capable of very high quality and save in various formats that are ready to transfer to a suitable host that we can all access (I myself use a very inexpensive Roland R-09 digital recorder, it's more than adequate for this purpose - built in high-fidelity stereo condenser mics, able to record in wav or mp3 format of any quality level). I urge you to give this some thought.

The more difference, the worse the recording can be! Chromatic scales are sufficient. You might be able to do it with a phone or a laptop computer. You can always listen and decide for yourself if it shows what you want it to show.

1° Sorry for the rant, ED

WHat I say is that when we talk of L modes we should record them, we can hear them so they can be recorded.

Then the specrtra shows the amount of L mode in a given note.
They are particularly easy to point in recordings as their frequency does not change.

Anytime I am unsure of what I hear, and if time permit I record it and look at the display when listening to the recorded note.

Anyway this is a very pretty basic part of any acoustical work and should be included as part of the proof when a theory is theorized.

It is done for tunings , it is done for voicing, it is done for testing wire quality, the factories use spectra analysis since the 50's and now the equipemnt is availeable to any computer owner , so no need for "laboratory material"

Even accelerometers can be find if the theory is to be worked at a higher level .

But I record with a simple H2 on a laptop, so I dont get how studies on tone can be done without recordings, this is simply missing to your credibility.

I had a demonstration of a goodie that is p^roduced by a Swiss tech, that is supposed to help the tone by neutralizing some disturbation to high frequencies caused by static electricity (or some similar concept)

Difficult to say if it works as we are in placebo effect range there.
I heard something, others also, some hear nothing, I even heard a less good tone on a less than good piano.

Then if there is ANY tone change, it can be recorded.
I recorded and seem to find a cleaner spectra BUT there it was difficult the differnce is almost not audible.

SO I left the analysis and recording job to the inventor of the goodie, who is also making speakers, si he is supposed to know a thing or twoo about spectras.

NNpe, no proof with graphs , then the audience and buyer have to "believe" ... I amf French, we are Cartesians, I dont accept such proposals.

The same with all that talk about tuning and tone quality, the samples are rare , the spectra analysis nonexistent, and no description of tone is given.

I will agree that the job is usually done by people that are not the best in Maths or physics but when some are prentending to theorize they should give us more material, so the audience can make up his mind without having to pay too much.

That is the way the things are sold that annoy me, most often, I have lost enough time with so called new concepts (I probably also lost my listening ability at some point due to the partial match theory of tuning taken too precisely)

Analysis is a very important part in any concept, but the rules have to be given.

About tone, this is another subject, anything that helps to even tone from note to note is good, not anything that allow to clean the spectra.

That is fun and interesting , as we can see extreme samples in many directions today. All kind of energy preservation and spectra optimisation devices...

My comments about double-blind listening tests were informed by the vast body of evidence from psychoacoustics . You may poo-poo it, but the evidence unambiguously shows that human perception of tone quality is incredibly suggestible. We all tend to think, myself included, that we hear what we hear, and that we can't be fooled, but the truth is far different. So, I'll repeat, any listening tests that purport to differentiate sound quality are simply not worth much unless done blind.

[edit] I thought it appropriate to add that double blind tests need not be expensive. For example, a test could consist of 2 pianos behind a curtain with people listening and a third party playing one or the other, or it could be two pianos whose innards are not visible, both of which can be played by various people. There are many ways of doing double-blind testing, and many of them are not expensive.

Well, any pivoting across the capo represents T-mode energy that bleeds across--some, or all of which is ultimately lost to heat, and which therefore can detract from sustain. The extent to which the string can pivot over the capo is the extent to which the capo does not terminate the string but instead simply enforces a node in the string at that point. Clearly the string doesn't pivot at the bridge--why is that not a problem?

The chamfering of agraffe holes may improve tone by providing a cleaner termination instead of by providing improved pivoting. Only careful testing, not listening, would be able to discern the difference. You say that the string "must" be able to pivot at the front termination. This is a strong claim, and until you or someone else shows by a well designed test that a non pivoting termination is nonfunctional, I'll have to be skeptical.

If my memory serves me correctly neither the Steingraeber nor the Walter grands use tuned front duplexes. As such, I believe they are designed to minimize or eliminate to the extent possible any energy bleed across the capo. I believe this is a stated design goal of the Walter grands. Are you really suggesting that these two piano companies produce grands with poor sustain and nasal tone in their treble sections?

Olek,
Accelerometers on the v-bar could tease out L-modes from T-modes but I don't know how to measure the L-mode damping in the duplex segment by the duplex string rests.

I don't think I am as far out there as the "Static electricity" guy. The present state of the art acknowledges L-modes as being significant to piano tone.

To Ando and Olek,
I must admit I have a bit of antipathy to archived qualitative media such as video, pictures or spectra for something as multi-sensory as a musical instrument. I have never been one of those piano guys with all the pretty piano pictures that are supposed to impress my customers about how good my pianos play and sound. I try to have potential customers play examples of my work to judge for themselves.

ROY 123,
Listening tests are significant but very hard to control. Psychoacoustics is a very real discipline and in my early work as a tech I independently coined the term before I knew it was already used.

The evidence from witness memory shows clearly how our memories can be manipulated and I think it is obvious our aural perceptions are subject to that as well. I have always been blessed with an excellent tone memory. I have tested my technical protocols in blind tests and so far no surprises.

It is string stiffness that drives the need for pivot terminations. I have done A to B chamfered /pivot optimized agraffes against stock configurations. The increased warmth, clarity and sustain is obvious.

I have never seen a forward termination that could function as a complete reflexion point except in a piano with a V-bar 0.25" wide and flat! Ugly tone to the Nth power that one was. THIS termination turned struck string motion to heat at the V-bar much more than the flexing of T-modes in the duplex segment. If piano strings were perfectly flexible, and the only restoring force acting upon them was tension, you would be correct about only reflecting terminations.

I don't know--the whole topic seems a bit fuzzy to me. For example, even if we assume that the capo provides a pivot termination, it is certainly highly anisotropic--i.e., the degree to which the string can pivot vertically is different from the degree to which it can pivot horizontally. In the latter case, T-mode vibration of the string would tend to scrub against the capo. I wonder if the anisotropy of the string termination can cause muddy tone or even false beats on occasion.
I also wonder how much pivoting really goes on when you have string angles of 10 to 15 degrees off the capo. It shouldn't be too hard to measure T-mode string vibration before and after the capo--a magnetic pickup mounted close to the bearing point, equidistant from either side might do the trick. It might also be interesting to mount two piano strings in a test fixture that would allow quick comparison of different termination schemes side by side.

Finally, I still wonder, if a non-pivot termination is death to tone, why the bridge as we know is almost universally used. The ordinary offset pins used on the bridge don't provide a pivot termination, and although bridges with agraffes, which could potentially provide a pivot termination, were tried in the past, they were largely abandoned.
Lots to think about; many experiments to try.

Would it be possible to send a pdf of the article to save time and postage costs?

There is one obvious difference between the terminations at the bridge and the capo or agraffe. The purpose of the bridge is to transfer some energy whereas the capo and the agraffes should conserve it.

Well, the bridge is designed to transfer energy to the soundboard. The bridge is not meant to provide a lossy string termination, which would simply waste string energy as heat.

I had thought about saying the purpose of the bridge is to transfer some energy at each vibration and conserve as much of the rest as possible (to sustain the note). The slight kinks in the wire at the bridge pins appear to be a simple way of doing that reasonably well.

May be the duplex is just there to slow /filter the returning waves on the little part of the sounding lseght (between hammer and capo/agrafe)

Whaj/t I seem to hear is an advantage at the moment of attack, then indeed it also create all sort of high pitches that blend in the "normal tone"

ROY 123,
String termination anisotropy most definitely contributes to string falseness-If the string path over the pivot is sideways even slightly-the duplex segment and struck segments will influence horizontal displacements, H-mode). The string stiffness lets the segments "disclose" each others position and this will induce H-mode. The effective string lengths are different for H-mode and Vertical mode.

Bridge agraffes have always produced L-mode because of the rocking bridge T-modes. They make metallic whines that sound sort of like T-mode beats. They also are heavy. The bridge is the string termination that is supposed to damp the string by coupling it to the air. Voila, tone appears!

It would be interesting to know if the more modern bridge terminations, like those used by Steingraeber Phoenix and Stuart & Sons suffer from those problems.

Even if the string is not at an angle as it goes under the capo, there should still be anisotropy, as the capo is anisotropic, i.e., it is roughly circular or parabolic along the string axis, and linear normal to it. The shape of the capo, as well as the string angle and details of the termination beyond the capo, may tend to favor horizontal or vertical T modes. Any system will tend to go into a minimum energy-dissipation configuration. For a piano, I think that in general that would favor horizontal vibrations.

Ed,

Where are you with your patent?

If you have filed, it should be OK to post some specifics of your design here. We would have an opportunity to review more authentically.

Ed,

At the least, perhaps you will let us know when your patent is filed and available to the public.

I look forward downloading a copy and reading it.

I hope you will be available here to answer questions about the specifics.

I am working on getting my website up and first on the site will be a version of the article with some more pictures. Once up I can link from pianoworld.

Larry,
The patent application is filed with 44 claims. It awaits the claim review process which can take up to two years. Now with the sequester maybe more. The US patent office actually returns a profit to the general fund.

I don't want to debate claims anywhere else but with all the interested parties that show up during the review process.

Are you interested in licensing the technology?

Roy123,
Have you heard a Phoenix or Stuart agraffe bridge? Or a Sohmer or Paulello?

I shape my capo bar profiles to a definite V. Have done so for over 25 years. If the string path is straight across the V-bar up to the tuning pin very little H-mode is induced there. At the bridge is another thing because of side stagger. However the reflections from the pivot capo helps push the string back towards V-mode T-modes. V-mode provides a more and quicker onset for unison coupling at the bridge.

Good Morning Ed,

At the very least, I am interested in reading it.

It is best to hear a piano "in person", although until I can do that, as some have mentioned, I would also like to hear a recording of one of your pianos.

It is certainly easier to discuss the attributes of your claims from the advantage of having heard one of your pianos.

You might consider sharing some of your testing methods and some of your formulas and computations. For example, how you measure, record or otherwise compute things like Longitudinal modes specific to the front scale.

I have a 212 Phoenix Steingraeber here in Lowell. Many have seen it including Roy123.

Larry,
I have not measured L-mode in my work. The evidence for it is based on the placement of duplex rests that are soft enough to damp L-mode and not damp T-mode. Placing those in a piano removes the high whistles many notes of a duplex scale have. I don't think any other explanation is possible than controlling L-modes.

I am very pragmatic in my work. I use the known physics to frame postulates and then do A to B tests.

As Larry mentioned, I've played the Phoenix at his shop and didn't notice any undesirable sounds.