# Pianoforte Innovations



## Enthalpy (Apr 15, 2020)

The highest piano strings produce a short sound, not pleasant and of ill-defined height. Because the metallophone and Glockenspiel do it better, I've proposed to replace the highest piano strings by thick resonators, there and next
 scienceforums
and here too is the sketch









Since we nearly don't hear the harmonics in the altissimo octave, a bent bar with partials 1, 4, 9, 16... should sound just like a string with partials 1, 2, 3, 4... The hammer's shock transmitted to the soundboard is present too, and the depicted resonator shape also produces a lound attack followed by a softer long sustain, like the three strings do. The hammer's felt must matter more than the rest. Also nice: the resonators must accept heavier hammers that fit the piano's mechanic better.

But *how to tune the resonators?*


Don't tune. Invar detunes by 0.1% over 5K, perfect, and elinvar even less, that's why it constitutes tuning forks. Fortunately, it resonates for long too. Orchestral pitch varies between 440 and 443Hz, so 442Hz fits all. I do hear the difference but not in the altissimo range.
Choose the resonators in a set to match the pitch, like 439 - 442 - 445Hz. For 12 or 18 notes it costs negligible 30 metal pieces more. I'd have stiff seats receiving the resonators ends, and maybe soft parts or springs to press the resonator's ends against the seats.
Add mass at an adjusted position. Vibraphonists do it by pressing a mallet's handle near the bar fastening. Picture. Matched tuning of the upper and the lower bars makes a long sustain.










Marc Schaefer, aka Enthalpy


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## Monsalvat (11 mo ago)

Well the important question would be, how does it really sound? I don't particularly think the piano's upper register is unpleasant. It might be a great idea but we would need to hear it to make a judgement.

One of the following must be true:
1. The timbre is unchanged or is imperceptibly affected (in which case, why bother?)
2. The timbre changes (which might or might not be an improvement, and also necessitates a changeover point where the piano's timbre abruptly changes, potentially wreaking havoc in the middle of a passage)

It seems like you have advocated for _both_ of these to be true: how can it simultaneously sound better _and_ sound the same?? And how is this fundamentally different from a celesta, anyway?

But even then I'm still not clear on what problem this purports to solve. Why isn't the modern piano fine as is?


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## Enthalpy (Apr 15, 2020)

The altissimo notes of the piano are too short. They sound more like a shock than a note. Their height is badly defined. They need improvement obviously.

Hear a metallophone: the note lasts for a decent time, the height is well defined. Only the attack by mallets with wooden or metal head is too hard, but piano hammers with felt will let the resonators sound much more like a piano.

The instrument would replace strings with resonators at the note where the sustain is similar.


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## bagpipers (Jun 29, 2013)

Why even bother with notes much above high C anyway,who friggin' cares


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## Enthalpy (Apr 15, 2020)

Suggestions to build *lighter hence louder piano soundboards*.

*Kiri Paulownia tomentosa* makes the japanese koto and others. The figure-of-merit E/rho[sup]3[/sup] tells that spruce _Picea abies_ is the European wood making the lightest soundboard at given size and resonances. That same figure-of-merit claims that a soundboard of kiri is 0.82* as light than spruce, or 1.5* louder. I'd try a board 1.26* as thick as spruce with cross-grain ribs 0.82* as narrow.
scienceforums - scienceforums
Kiri is said to be stable, fast drying, easy to work, but the fibres are supposedly less straight than in spruce. One guitar luthier in the USA tells "If I could obtain enough, kiri would make all my instruments". It grows industrially also in Australia and three European countries but is classified as invasive in the US.

Stiffening *ribs in both directions* would make a thinner lighter soundboard
scienceforums - scienceforums
Difficulty: the piano's bridges are above the soundboard, the transverse ribs below, so where shall the news ribs go? I ridiculed myself when discussing it with piano makers, who were nice enough not to insist. Here's one solution. The ribs parallel to the gain are milled from a thicker plank of sounding wood, glued together before or after, and the transverse ribs are glued below the plate where milling left the full thickness. Here too, the transverse ribs can be narrower as the plate gets lighter.









[PianoRibs2D.png]

Would a sandwich sound good? It must be lighter the spruce-plus-ribs at identical size and resonances.
scienceforums and later
Coming to mind:
*Thin spruce - thin cross spruce - thick end grain balsa - thin cross spruce - thin spruce*, also
*Thin carbon - thin cross carbon - thick end grain balsa - thin cross carbon - thin carbon* (or use 2D carbon)
Plain carbon sounds badly because it resonates lower or is heavier than spruce, but a sandwich is good for that aspect.

Guitar and possibly piano manufacturers use wood glue at the soundboard. It dampens the vibrations. Violin luthiers use non-damping *hide glue*. Try it, including at sandwiches?

Marc Schaefer, aka Enthalpy


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## Enthalpy (Apr 15, 2020)

I suggested to enable *harmonic sounds on the piano* (grand or vertical), there
scienceforums
and here's a sketch










A finger touches the string at mid-length (or 1/3 etc if any advantageous) to create a new timbre like other string instruments do. The piano would have a pedal to move a finger per note with individual elasticity.

Pianos last for a century. If some elastomer is durable enough, it can constitute the fingers or their tips, and maybe the damped elasticity too. Light and ozone degrade natural rubber and many synthetic rubbers. Maybe a perfluorosilicone, which also provides strong damping, is durable enough. Or rather: felt on wood, durable materials already used in pianos.

I suppose the luthéal can play harmonic sounds
wikipedia
one is exposed in Brussels' _Musée des instruments de musique_, an other in Paris' _Musée instrumental_, and their construction could inspire a new design.

The more complex luthéal didn't succeed commercially, but harmonic sounds are easily obtained and they bring much. Try?


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