I am guessing the reason this went 100 years without being proven is because it was an argument against the player piano and not an actual question that needed proving? Any competent pianist can demonstrate that they do this and it is the reason the piano became the dominant keyboard instrument.
The discussion in the linked post is incomplete. Obviously with the use of pedals the pianist has some direct control over timbre. The real question is whether, without the use of pedals, a pianist can control timbre with any degree of independence from volume. The reason to suspect that they cannot is that the action of the piano actually releases the hammer before it strikes the string (otherwise depressing a key for a long time would mute the string with the hammer instead of sustaining the note). It stands to reason that the hammer's initial angular momentum in flight cannot encode separately a note volume and note timbre.
So the mystery is the opposite: given that a mechanical understanding of the piano suggests that the pianist has no control of note timbre, why does it appear that they are able to adjust note timbre? I have my own speculations about this question, but it is not taken up by the article [1] which in fact only speaks of 'perceived timbre.'
In my own opinion, for the reason already given, there is no magic by which timbre is controlled through pressing the key daintily or pressing it with gusto, given that identical volume is achieved in each case. However the sonic environment is very complex and the pianist has considerable control over it through the dampers' connection to the keyboard, independent from the pedals. The process of listening is also very complex. The sense experience of hearing a staccato note is not the same as the sense experience of hearing the first 0.05 seconds of a note that later turns out to be sustained, so even if in fact the state of the piano is identical between the two cases within those 0.05 seconds I may perceive the timbres as different as my brain integrates the whole staccato note into 'one sound' while the sustained note is received as a continuous tone diminishing in intensity.
Ultimately I find the argument that they do not control timbre convincing, and that the piano (sans pedals) allows for as much control over timbre as the harpsichord does over dynamic. But as it is a very expressive instrument there is an illusion that is present for performance that cannot be reproduced through isolated notes. It's not a bassoon.
> The study scientifically confirmed that professional pianists can manipulate timbre mid-performance through subtle key movement differences.
I'm a trained pianist myself and I have a PhD in science. The "timbre" is relative to the speed a key is pressed and the position of three pedals of a grand piano. But this insight is trivial and doesn't require a "scientific study".
The fundamental understanding of piano mechanics is well-known: once the hammer escapes from the action mechanism (just before striking the string), the final hammer velocity is the only physical parameter that determines the string vibration and resulting tone. This is known as the "single variable hypothesis" and has been supported by acoustic physics research. The final hammer velocity is thus the only physical parameter controlling the intensity and the sound of an isolated piano tone, independent of the intrinsic acceleration pattern of the key.
The study's claim about "acceleration at escapement" is particularly problematic from a physics standpoint, since escapement is precisely the moment when the hammer detaches from the key mechanism and begins free flight to the string. What matters after escapement is the hammer's velocity during that free flight, not how it got there. The study does not clearly explain the acoustic mechanism by which different key accelerations would produce different string vibrations if final hammer velocity is controlled.
Yeah, @Rochus is right. Once the action has passed the escapement, its entire point is that you lose all control, else you'd get thudding, reversing the point of the fortepiano's innovation.
That's not to say us pianists have other tricks up our sleeves though. Staccato, slightly delayed playing, damper pedal (which is not just binary but continuous), slower release of key (because you can slowly apply the damper giving it a slight ringing effect), tempo changes, and other techniques get you quite a broad range of feeling. It doesn't however mean that timbre is orthogonal to volume--they are coupled by velocity.
Also, this post doesn't go into methods, so I worry about lack of ABX testing, whether it's a single note or a piece, whether they could see the pianist, etc. Perhaps they addressed that in the paper that they'll publish...
Edit: another thought: why is this even using subjective listeners? You can just measure velocity and run an FFT to see whether they can make a timbre separate from volume and velocity.
It seems acc-escape is measuring how hard the pianist is exerting their fingers/arms, which plausibly indirectly affects the coordination and style of sound that they play, hence the appearance of a different timbre.
My personal suspicion as to how this stuff matters for the timbre of a piano is that there are maybe two mechanisms aside from the obvious one (velocity of the hammer):
1. Subtle movements of the damper, which is linearly linked to the key. You can hear this interference with the string if you get the string loudly and don't completely release the key/pedal.
2. Some second-order effects that alter the post-escapement flight of the hammer. There is still some friction in there, and most piano actions have a lot of wood parts that can flex a little.
I sort of doubt #2 there, honestly.
Another thing you learn as a pianist is that literally nothing matters for the sound except what happens at the point of contact between the hammer (and the damper) and the string. If you want to unravel piano timbre, you should worry about that.
I'm not reading this as saying that pianists can manipulate timbre after the hammer is released, only that pianists can intentionally manipulate timbre with very fine motor control while playing, and listeners of all levels can hear the intended timbre.
Which is trivial, as you say. (The examples of bright/dark aren't encouragingly subtle.)
The article is very poorly worded and ambiguous.
It's not even clear if they were measuring acceleration at escapement directly at the hammer, or somehow inferring it from the key velocity.
Coming from a synth background I assumed that any timbre variation that pianists can achieve came about via envelope manipulation. That and possibly volume related overtone production I suppose.
What makes this study flawed is that they had pianists performing actual pieces of music. Pianists will change their attack to express different tone qualities, sure. But this has more to do with your muscles being imprecise and not the physics of the hammer itself. You have to use a variety of arm, wrist, and hand movements to get the exact subtleties of volume and note spacing correct.
17 comments
[ 4.7 ms ] story [ 40.1 ms ] threadSo the mystery is the opposite: given that a mechanical understanding of the piano suggests that the pianist has no control of note timbre, why does it appear that they are able to adjust note timbre? I have my own speculations about this question, but it is not taken up by the article [1] which in fact only speaks of 'perceived timbre.'
In my own opinion, for the reason already given, there is no magic by which timbre is controlled through pressing the key daintily or pressing it with gusto, given that identical volume is achieved in each case. However the sonic environment is very complex and the pianist has considerable control over it through the dampers' connection to the keyboard, independent from the pedals. The process of listening is also very complex. The sense experience of hearing a staccato note is not the same as the sense experience of hearing the first 0.05 seconds of a note that later turns out to be sustained, so even if in fact the state of the piano is identical between the two cases within those 0.05 seconds I may perceive the timbres as different as my brain integrates the whole staccato note into 'one sound' while the sustained note is received as a continuous tone diminishing in intensity.
Ultimately I find the argument that they do not control timbre convincing, and that the piano (sans pedals) allows for as much control over timbre as the harpsichord does over dynamic. But as it is a very expressive instrument there is an illusion that is present for performance that cannot be reproduced through isolated notes. It's not a bassoon.
[1] https://www.pnas.org/doi/10.1073/pnas.2425073122
I'm a trained pianist myself and I have a PhD in science. The "timbre" is relative to the speed a key is pressed and the position of three pedals of a grand piano. But this insight is trivial and doesn't require a "scientific study".
The fundamental understanding of piano mechanics is well-known: once the hammer escapes from the action mechanism (just before striking the string), the final hammer velocity is the only physical parameter that determines the string vibration and resulting tone. This is known as the "single variable hypothesis" and has been supported by acoustic physics research. The final hammer velocity is thus the only physical parameter controlling the intensity and the sound of an isolated piano tone, independent of the intrinsic acceleration pattern of the key.
The study's claim about "acceleration at escapement" is particularly problematic from a physics standpoint, since escapement is precisely the moment when the hammer detaches from the key mechanism and begins free flight to the string. What matters after escapement is the hammer's velocity during that free flight, not how it got there. The study does not clearly explain the acoustic mechanism by which different key accelerations would produce different string vibrations if final hammer velocity is controlled.
That's not to say us pianists have other tricks up our sleeves though. Staccato, slightly delayed playing, damper pedal (which is not just binary but continuous), slower release of key (because you can slowly apply the damper giving it a slight ringing effect), tempo changes, and other techniques get you quite a broad range of feeling. It doesn't however mean that timbre is orthogonal to volume--they are coupled by velocity.
Also, this post doesn't go into methods, so I worry about lack of ABX testing, whether it's a single note or a piece, whether they could see the pianist, etc. Perhaps they addressed that in the paper that they'll publish...
Edit: another thought: why is this even using subjective listeners? You can just measure velocity and run an FFT to see whether they can make a timbre separate from volume and velocity.
isn't this the case for many studies in the past decade? just confirming what we've known all along
1. Subtle movements of the damper, which is linearly linked to the key. You can hear this interference with the string if you get the string loudly and don't completely release the key/pedal.
2. Some second-order effects that alter the post-escapement flight of the hammer. There is still some friction in there, and most piano actions have a lot of wood parts that can flex a little.
I sort of doubt #2 there, honestly.
Another thing you learn as a pianist is that literally nothing matters for the sound except what happens at the point of contact between the hammer (and the damper) and the string. If you want to unravel piano timbre, you should worry about that.
In my opinion, the insight is this:
> express in piano playing were perceived as intended by both pianists and musically untrained individuals
Obviously pianists have known this for more than a century. But do average listeners hear the same "thing"? It's a question worth asking.
Which is trivial, as you say. (The examples of bright/dark aren't encouragingly subtle.)
The article is very poorly worded and ambiguous.
It's not even clear if they were measuring acceleration at escapement directly at the hammer, or somehow inferring it from the key velocity.
https://soranews24.com/2025/10/04/research-in-japan-proves-t...
What makes this study flawed is that they had pianists performing actual pieces of music. Pianists will change their attack to express different tone qualities, sure. But this has more to do with your muscles being imprecise and not the physics of the hammer itself. You have to use a variety of arm, wrist, and hand movements to get the exact subtleties of volume and note spacing correct.
Leszek Możdżer - Piano ( - Exploris, .. ) https://www.youtube.com/watch?v=QOicB0vcbf8&list=PLMigLc8yVp...
- moreover, he may indeed be touching strings occasionally - with or without using the hammers :)