Solco · How we measured
Solco against rekordbox 7: how we measured.
The home page says Solco wrote a USB in 12 minutes where rekordbox took 3½ hours, and that its beat grids are 12% better on beats and 38% better on downbeats. Those two are relative improvements in F-measure, the standard accuracy measure for beat tracking, on the 998 excerpts of the GTZAN set: Solco's score divided by rekordbox's, minus one. This page is how all of these numbers were made, with everything needed to check them.
The USB export
Both apps put the same 493 already-analysed tracks on the same 250 GB SanDisk USB stick (FAT32) from a Mac mini M4. rekordbox 7.2.6. We timed three runs of each and report the median: Solco 12 minutes 18 seconds, rekordbox 3 hours 30 minutes.
Beat grids
The test set is GTZAN with the GTZAN-Rhythm annotations: 998 excerpts of 30 seconds in ten genres, with every beat and downbeat marked by people. It is the only public beat set Solco's beat model never trained on. rekordbox 7.2.6 analysed it in its Auto mode with high-precision grids, using the owner's own settings; Solco analysed it with its own grids and no corrections. Both read the same files.
The grids are scored with the standard mir_eval conventions: F-measure, where 1 is perfect; a beat counts if it is within 70 ms of a marked one; the first 5 seconds are skipped. Overall, Solco scored 0.859 on beats against rekordbox's 0.767 (12% higher) and 0.736 on downbeats against 0.533 (38% higher).
For each genre we report the paired difference with its 95% bootstrap interval (10,000 resamples). "Clearly" below means that interval excludes zero.
Solcorekordbox 7.2.6F-measure, 1 is perfect
Downbeats, by genre
Ahead in all ten, clearly in nine (blues within the margin).
- BluesSolcorekordbox0.520.44
- Classical0.480.10
- Country0.810.69
- Disco0.960.74
- Hip-hop0.900.70
- Jazz0.590.36
- Metal0.730.54
- Pop0.940.75
- Reggae0.610.31
- Rock0.810.69
Beats, by genre
Clearly ahead in five, within the margin in four, level on reggae.
- BluesSolcorekordbox0.750.70
- Classical0.650.23
- Country0.890.81
- Disco0.970.96
- Hip-hop0.990.90
- Jazz0.770.58
- Metal0.830.80
- Pop0.950.91
- Reggae0.890.89
- Rock0.900.90
The numbers as a table
| Genre | Excerpts | Solco beat F | rekordbox beat F | Difference (95% interval) | Solco downbeat F | rekordbox downbeat F | Difference (95% interval) |
|---|---|---|---|---|---|---|---|
| Blues | 100 | 0.753 | 0.700 | +0.053 (−0.011 to +0.119) | 0.521 | 0.441 | +0.080 (−0.018 to +0.174) |
| Classical | 100 | 0.652 | 0.232 | +0.421 (+0.345 to +0.495) | 0.484 | 0.103 | +0.381 (+0.308 to +0.455) |
| Country | 100 | 0.894 | 0.811 | +0.084 (+0.024 to +0.147) | 0.807 | 0.688 | +0.119 (+0.032 to +0.204) |
| Disco | 100 | 0.968 | 0.960 | +0.008 (−0.001 to +0.021) | 0.956 | 0.737 | +0.219 (+0.136 to +0.303) |
| Hip-hop | 100 | 0.986 | 0.896 | +0.090 (+0.045 to +0.140) | 0.900 | 0.697 | +0.203 (+0.120 to +0.290) |
| Jazz | 99 | 0.767 | 0.576 | +0.191 (+0.124 to +0.259) | 0.594 | 0.365 | +0.228 (+0.126 to +0.329) |
| Metal | 100 | 0.827 | 0.796 | +0.031 (−0.015 to +0.079) | 0.727 | 0.543 | +0.185 (+0.112 to +0.264) |
| Pop | 100 | 0.952 | 0.907 | +0.045 (+0.021 to +0.076) | 0.936 | 0.750 | +0.186 (+0.118 to +0.263) |
| Reggae | 99 | 0.890 | 0.892 | −0.002 (−0.048 to +0.049) | 0.610 | 0.309 | +0.301 (+0.211 to +0.392) |
| Rock | 100 | 0.903 | 0.895 | +0.008 (−0.039 to +0.055) | 0.814 | 0.685 | +0.128 (+0.056 to +0.204) |
| All | 998 | 0.859 | 0.767 | +0.093 (+0.075 to +0.111) | 0.736 | 0.533 | +0.203 (+0.176 to +0.229) |
How we measured
USB export: both apps put the same 493 already-analysed tracks on the same 250 GB SanDisk USB stick (FAT32) from a Mac mini M4; rekordbox 7.2.6; median of three runs.
Beat grids: the 998 30-second excerpts of GTZAN with the GTZAN-Rhythm annotations, people's marks of every beat and downbeat; the only public beat set Solco's beat model never trained on. rekordbox 7.2.6 in its Auto mode with high-precision grids, Solco with its own grids and no corrections, both given the same files. Scored with the standard mir_eval conventions (a beat counts within 70 ms; the first 5 seconds are skipped). "Clearly" means the 95% bootstrap interval of the paired difference excludes zero.
GTZAN is not a DJ set: it shows the grids hold beyond four-to-the-floor, not that Solco is ahead on any one club genre.
The numbers as a table
| Genre | Excerpts | Solco beat F | rekordbox beat F | Difference (95% interval) | Solco downbeat F | rekordbox downbeat F | Difference (95% interval) |
|---|---|---|---|---|---|---|---|
| Blues | 100 | 0.753 | 0.700 | +0.053 (−0.011 to +0.119) | 0.521 | 0.441 | +0.080 (−0.018 to +0.174) |
| Classical | 100 | 0.652 | 0.232 | +0.421 (+0.345 to +0.495) | 0.484 | 0.103 | +0.381 (+0.308 to +0.455) |
| Country | 100 | 0.894 | 0.811 | +0.084 (+0.024 to +0.147) | 0.807 | 0.688 | +0.119 (+0.032 to +0.204) |
| Disco | 100 | 0.968 | 0.960 | +0.008 (−0.001 to +0.021) | 0.956 | 0.737 | +0.219 (+0.136 to +0.303) |
| Hip-hop | 100 | 0.986 | 0.896 | +0.090 (+0.045 to +0.140) | 0.900 | 0.697 | +0.203 (+0.120 to +0.290) |
| Jazz | 99 | 0.767 | 0.576 | +0.191 (+0.124 to +0.259) | 0.594 | 0.365 | +0.228 (+0.126 to +0.329) |
| Metal | 100 | 0.827 | 0.796 | +0.031 (−0.015 to +0.079) | 0.727 | 0.543 | +0.185 (+0.112 to +0.264) |
| Pop | 100 | 0.952 | 0.907 | +0.045 (+0.021 to +0.076) | 0.936 | 0.750 | +0.186 (+0.118 to +0.263) |
| Reggae | 99 | 0.890 | 0.892 | −0.002 (−0.048 to +0.049) | 0.610 | 0.309 | +0.301 (+0.211 to +0.392) |
| Rock | 100 | 0.903 | 0.895 | +0.008 (−0.039 to +0.055) | 0.814 | 0.685 | +0.128 (+0.056 to +0.204) |
| All | 998 | 0.859 | 0.767 | +0.093 (+0.075 to +0.111) | 0.736 | 0.533 | +0.203 (+0.176 to +0.229) |
What this does and doesn't show
GTZAN is not a DJ set: it shows the grids hold beyond four-to-the-floor, with live drummers and changing tempo, not that Solco is ahead on any one club genre. On beats, Solco is clearly ahead in five genres, within the margin in four, and level on reggae. On downbeats it is ahead in all ten, clearly in nine.