Piano World Home Page Forums Our Most Popular Forums Piano Forum Fabulous Fandrich re-Fabrication

As many of you are aware, Mr. Del Fandrich is one of the most innovative piano designers and technicians who is practicing today. Earlier this morning, he announced a breakthrough in piano technology. I reprint it here in full.

"I’ve been installing Wessel, Nickel & Gross action parts for some time now. I consider them to be a significant step forward in the ongoing developing development of the piano action. In particular I like the hammer shanks and I have now discovered a heretofore unknown benefit—the hammershanks themselves can be “voiced” to enhance the tone performance of the piano.

The thought occurred to me, as I was gluing hammers to the Wessel, Nickel & Gross carbon fiber shanks, that what we have here is a finite cylindrical pipe. In other words, the hammershank itself forms a cylinder with a fixed internal diameter and a finite length. When a flow of air is passed over the open end of a finite cylindrical pipe—i.e., as when a note is played and the hammer is accelerating toward the strings—it causes the air within the pipe to resonate at a pitch determined by the diameter and the length of the cylinder and this pitch is, to some extent, tunable.

The internal diameter of these hammershanks is fixed but we can still change their resonant frequency by changing the length of the pipe and this can be done by partially filling it with some rigid material such as epoxy. This has to be done carefully to get just the right pitch in the resonating pipe. (A good overview on the character of finite cylindrical pipes and calculating their pitch is given in The Physics of Musical Instruments by Fletcher & Rossing.) The principle here is to match the pitch of these resonating pipes to the frequency of one of the resonating partials in the strings. (As supplied by Wessel, Nickel & Gross their pitch does not reinforce the pitch of the notes played and, indeed, may detract from it.) These resonating pipes are tunable to a certain extent by trial and error; if you put just a bit too much epoxy into the hollow hammershank and get its pitch a little high you can always drill it out—albeit with some difficulty—to lower the pitch of the generated tone.

The volume of the tone generated by the resonating column of air in the hammershank/pipe is directly proportional to the velocity of the hammershank hence it is advantageous to keep the mass of the hammers low and, by extension, their potential velocity high. It is fortuitous that the volume of the tone generated by a moving finite cylindrical pipes is relatively low at pianissimo velocities and somewhat louder at forte levels of play thus the tone generated by the moving pipes appropriately and automatically reinforces the tone created by the hammers and strings across the power spectrum of the piano.

Obviously my work to date with Resonant Hammershank Voicing is in its early stages and has, thus far, only scratched the surface; much work remains to be done before we can exploit the full potential of this new technology. There are at least two areas that have already revealed a need for more research: 1) Shank protrusion, by allowing the hammershank to protrude slightly beyond the hammer molding seems to reduce the air turbulence immediately adjacent to the hammer molding making the tone generated by the resonant pipe clearer and stronger, and 2) Hammer shape, the shape of the hammer affects the flow of air around the felted portion of the hammer and this can affect the flow of air past the opening in the resonant pipe (if the airflow is not clean and smooth a certain amount of “falseness” can be detected in the resonant tone).

As well, new shapes for the hammershanks themselves should be explored to better match the tone generated by the resonant pipes to the natural voice of the piano. If the weight of the carbon fiber hammershanks can be kept low enough, for example, it would be interesting to explore hammershank shapes approaching that of a true Helmholtz resonator. Since it is often claimed—albeit probably incorrectly—that Helmholtz influenced the design of the early Steinway pianos this would finally bring the relationship between Helmholtz and the piano full circle."

It seems to me that if this creative approach were combined with Mr. Bill Bremmer's "Pipe Organ Effect," the perfect piano might finally be a reality.

LOL

What's the date?

Here I was thinking darn it, I just got a piano without that technology

The hammershank materials could be changed to similar materials used by woodwind instruments or even bamboo. I wonder if Del has considered drilling holes on the shank to specifically tune the shanks to the correct partials to the pitch of the strings. I would love a completed hammer replacement for my piano with this new technology.

This is a very innovative way of looking at the WNG hammer shanks. I agree with Del on this point, and further, we have been working on a way of accentuating this effect by adding a mechanism to the traditional piano action.

This addition will add a percussive strike to the hollow hammer shank at the exact moment that it is striking the string. This additional vibration will then be carried over to the string through the hammer itself causing sympathetic resonance. This will increase the overall tone of the piano substantially.

We live in exciting days!

Rich, What you are describing sounds like a "New Age" Rinky Tink. You can have that with a few extra "special" crystals to scatter between the soundboard and plate. For years I've had customers ask me to make their Jesse French spinet sound like a $200,000 piano. Now in just a few we can actually reverse that process and easily make a $200,000 piano sound like a Jesse French or perhaps a Winter!!

I was actually giving this some thought until I looked at my calendar.

When I first read the OP I felt that there might be an element of the hoax about it, however having thought about it I am convinced that this idea of hammer shank resonance could be a major breakthrough. A couple of points occur to me however. Firstly the technique of filling part of the hammer shank with epoxy resin to tune its resonance is going to be difficult to control properly and it would surely be preferable to manufacture shanks with an internal thread which could accept a grub screw for accurate regulation.

What strikes me as potentially the most radical and beneficial idea would be to have a dynamic hammer shank resonance system. This system would rely on a hammer shank fitted with a piston which could be dynamically controlled. This would allow for the shank resonance to be altered by the player to achieve the tone required by any particular piece. Ultimately however, there will be a system capable of adjusting in real time the resonance of each hammer shank. Suppose for example that the player plays a chord in the left hand. The built-in computer responds by adjusting the resonance of each hammer shank
so as to produce the sound best suited to the chord being played.

I think that in years to come people will look upon pianos without DHSRI (Dynamic Hammer Shank Resonance Imaging) in much the same way as we now look upon square pianos; charming relics in their own way but of no practical use today.

J-C

Interesting idea, but I'm not really too sure how much this could really change things. Hammer shanks aren't terribly long or thick, so there wouldn't be that much resonance to begin with. However, I would be interested to see if this really would affect the sound. Sure does sound good on paper, though.

The minute I started reading about "cylindrical pipes" it sounds rather "bong" like
musical bongs LOL!, I smell burnt oregano..

J-C,

Do you propose that each shank would have a mini-processor or that all shanks be controled by a central system? DHSRI seems to be very viable. I suggest that you patent it immediately.

Finally some good humor for April 1st!

Humor?

This is very serious. In fact, it has just been announced that Mr. Fandrich is up for a Nobel Prize in acoustical engineering acknowledging this great achievement.

HAHAHA Amazing! You had me for the first 30 seconds

OK, this was actually a fairly decent joke you played there, bucko.

LOL how many turns does the lowerst shank/pipe have? And what's their diameter?

quick estimate, lowest note around 30Hz, 300m/s, around 10 meter or 5m for half wavelength... shanks maybe 20cm maybe max? So I get then around 25 turns

BTW one or two shanks in my piano sometimes resonated just a little when they fell back and it was bloody irritating if you heard it. I think the tuner fixed it some time ago

Fascinating. Have you graphed this out? Have you consulted with Del?

No, forget that. Just use coffee grinds. First, it's easier to fill and second, it'll make the piano smell good.

Only if you are playing the Coffee Pot Cantata!