A measurement of piano playing
How much single beats are stretched and squeezed, after the shape of the phrase has been taken out.
The same passage — Nocturne Op. 9/2, bars 2–3 — from the recordings that sit lowest and highest on this measurement. Every clip is a note list replayed on one sampled grand at one gain, so the only difference you are hearing is the playing.
The same calculation as arch depth, applied to what is left once the one-bar trend is removed.
Every piece in the library, with the range across its recordings. The units mean the same thing in every row, except for basic tempo, which is in each piece’s own beat.
| Piece | Recordings | Lowest | Median | Highest |
|---|---|---|---|---|
| Bach Prelude in C | 27 | 4 | 6 | 14 |
| Gymnopédie 1 | 23 | 3 | 7 | 11 |
| Pathétique II | 47 | 5 | 7 | 11 |
| Chopin Étude 10/1 | 31 | 5 | 8 | 15 |
| Rachmaninoff Prelude | 29 | 6 | 9 | 11 |
| Brahms Op. 118/2 | 28 | 8 | 11 | 14 |
| Mozart K. 545 | 37 | 7 | 11 | 15 |
| Nocturne Op. 9/2 | 32 | 8 | 11 | 17 |
| Chopin Ballade 4 | 12 | 11 | 11 | 15 |
| Schubert Op. 142/3 | 9 | 9 | 12 | 15 |
| Fantaisie-Impromptu | 20 | 7 | 12 | 17 |
| Nocturne Op. 48/1 | 27 | 10 | 13 | 20 |
| Träumerei | 31 | 9 | 14 | 20 |
| Ravel Pavane | 33 | 10 | 14 | 17 |
| Schubert Op. 90/3 | 43 | 10 | 14 | 21 |
| Chopin Étude 10/12 | 19 | 11 | 14 | 18 |
| Clair de lune | 27 | 11 | 16 | 20 |
| Ravel Ondine | 61 | 14 | 19 | 24 |
A Disklavier capture — the pianist’s own key sensors, no microphone — was rendered to audio, transcribed as if it were a recording, and re-measured. The error the transcription step introduces, as a multiple of how far pianists actually differ on this dial, is 0.16. solid This dial survives transcription intact: where one recording sits on it can be argued from.