Title detail pages show a “Sound profile” box under the metadata. It is an automatic estimate from the audio file – not a manual analysis, and not a substitute for listening.
The values come from the middle of the track (two minutes at most). Tempo (BPM) stays a separate figure and is still taken from the start.
Key
Estimated tonal centre: major or minor. With free improvisation this is often uncertain. Two keys (for example A minor → D major) mean the start and the middle differ. Major and minor of the same root (D minor / D major) are not treated as a hard change.
Stability
How long the same pitch stays in the foreground. High means the harmony holds. Low means it wanders. This is independent of whether start and middle name the same key.
Character
How many audible onsets per minute – attacks, accents, new notes. This is not tempo. The steps are loose, busy, dense and very dense. Improvisation often lands on busy or dense even when the piece is slow.
Harmony
Share of sustained tones versus impulses (attacks, cymbals, percussion). A rough balance, not a verdict on whether the music is “harmonic” or “beautiful”.
Meter
Estimate of whether the piece sits in 4/4, 3/4 or 6/8. With free improvisation and triplets this is often uncertain – then it reads “uncertain”. The ear comes first.
BPM reading
The stored BPM may be the fast pulse (eighths or triplets). Tactus is the slower beat you would count along with. Example: pulse 161 as eighth-note triplets, tactus around 53.
Timbre
warm, medium or bright – a rough estimate of whether the sound feels dark-warm or bright-sharp. Measured from the spectral centre, not from loudness.
What the sound profile cannot do
It does not recognise instruments. Who plays is listed under contributors. Small deviations in free improvisation are normal – the profile is a guide, not a verdict.