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| [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).
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| (c) 2025 Trouw |
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.
Ultimately, it is the hammer which, at the moment it is released from the piano’s action mechanism, independently carries the cumulative timing and dynamic input of the performer. Its subsequent trajectory toward the string—and the resulting timbre—is determined by its momentum, defined by the combined effects of its velocity and mass.
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
I am excited you shared this article since I have recently been looking more into piano technology! I think using pianos to study timbre is more difficult than any other instrument, given the sheer amount of moving parts, all of which will affect the timbre. Pianos have hundreds of friction points which can change the acceleration from one performance to the next, depending upon the humidity and temperature in the building as well as how heavy-handed the previous pianist performed. Just goes to show how important it is when learning piano to practice on different pianos - so you build up the ability to adjust fine motor movements based on how the piano responds!
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