> 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.