A measurement of piano playing
How much the closing bars are broadened relative to the music just before them.
The same passage — Ravel Pavane, bars 70–72 — 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.
log2 of the coda's tempo divided by the previous section's. -0.60 means the coda runs at about two thirds the speed.
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 |
|---|---|---|---|---|
| Schubert Op. 142/3 | 9 | -1.62 | -1.26 | -0.84 |
| Ravel Pavane | 33 | -0.82 | -0.49 | -0.18 |
| Träumerei | 31 | -0.64 | -0.34 | -0.02 |
| Fantaisie-Impromptu | 20 | -0.51 | -0.24 | -0.03 |
| Pathétique II | 47 | -0.63 | -0.23 | 0.01 |
| Bach Prelude in C | 27 | -0.66 | -0.19 | -0.05 |
| Nocturne Op. 9/2 | 32 | -0.25 | -0.06 | 0.11 |
| Schubert Op. 90/3 | 43 | -0.44 | -0.05 | 0.11 |
| Chopin Étude 10/1 | 31 | -0.15 | -0.05 | 0.03 |
| Chopin Étude 10/12 | 19 | -0.17 | -0.03 | 0.18 |
| Gymnopédie 1 | 23 | -0.07 | -0.02 | 0.03 |
| Brahms Op. 118/2 | 28 | -0.13 | -0.00 | 0.14 |
| Chopin Ballade 4 | 12 | -0.20 | -0.00 | 0.41 |
| Mozart K. 545 | 37 | -0.07 | 0.00 | 0.10 |
| Clair de lune | 27 | -0.27 | 0.14 | 0.54 |
| Ravel Ondine | 61 | -0.18 | 0.17 | 0.45 |
| Rachmaninoff Prelude | 29 | -0.03 | 0.40 | 0.67 |
| Nocturne Op. 48/1 | 27 | 0.17 | 0.51 | 1.14 |
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 0.13. solid This dial survives transcription intact: where one recording sits on it can be argued from.