Piano touch unraveled. Touché?

[From Kuromiya et al., 2025: Figure 1B]

[Adapted from interview by Elleke Bal, Trouw, 3 October 2025]

Two professional pianists may perform on the exact same piano, in the same concert hall, and even play the same notes at the same tempo. Yet, through the way they touch the keys, they are able to produce strikingly different sounds from the instrument.

This so-called timbre—the tonal color or quality of sound—has long been a subject of fascination and debate among musicians and listeners alike. Consider, for example, the crystalline clarity of Glenn Gould versus the warmth of Sviatoslav Richter. But what exactly constitutes clarity or warmth? For pianists, these are intuitive concepts. For scientists, however, the challenge has been to find objective evidence that such distinctions arise from unique motor actions at the keyboard.

The researchers examined which motor skills underpinned these differences. They found that timbral variation was strongly associated with a limited set of keystroke parameters: the velocity of key descent, the temporal spacing between successive key presses, and the synchrony between hands. Crucially, one factor emerged as particularly decisive: the acceleration of the key movement at the precise moment the hammer disengages. According to the authors, this acceleration largely determines the resulting timbre (Kuromiya et al., 2025).

This study demonstrates the extraordinary precision achieved by highly trained pianists. Nuances in timing and velocity of a few milliseconds can shape timbre in ways that are musically significant. These micro-timing differences are the product of extensive practice and experimentation at the instrument. However, the study overlooked one key factor: the velocity of the hammer striking the string. Without measuring hammer dynamics, the account of timbre remains incomplete. Companies such as Yamaha have long recognized this; their Disklavier Pro system, for example, replicates hammer velocity to convincingly reproduce the playing of pianists like Glenn Gould.

Does reducing the artistry of great pianists to numerical parameters diminish the magic of a performance? I don’t think so: This research only reinforces the extraordinary dexterity, control, and timing that distinguish master pianists.

References 
Kuromiya, K., et al. (2025). Motor origins of timbre in piano performance, Proc. Natl. Acad. Sci.,122 (39) e2425073122, https://doi.org/10.1073/pnas.2425073122 
Goebl, W., & Palmer, C. (2008). Tactile feedback and timing accuracy in piano performance. Experimental Brain Research, 186 (3), 471-479 DOI: 10.1007/s00221-007-1252-1