Library & files
Batch analysis
Batch analysis runs the tempo, key, grid and waveform detection across many tracks at once rather than as each one loads. It is processor-heavy, takes hours on a large library, and only has to happen once per track.
In practice
Analyse everything before it reaches a stick, and pick the right grid mode rather than accepting the default.
Use the fixed or normal setting for electronic music, which is almost all of it, and reserve the dynamic setting for disco, funk, live recordings and anything played by hand. Run the batch overnight — it will use every core you have — and then do the human pass afterwards: sort by BPM to catch the octave errors, spot-check grids on anything with a long intro, and fix them once and permanently.
Once
Times per track
Fixed
The mode for electronic music
Dynamic
The mode for hand-played records
Where these come from: Analysis-mode behaviour in common DJ software and standard preparation practice — not catalog figures. For what we can measure, see what the analysis gets wrong.
Why it matters
Doing it in advance is what makes a club player instant. If a track has never been analysed, the work happens the moment you load it, on hardware far slower than your laptop, while a record is playing — which is the worst possible time for it.
It is also the moment to choose the right setting rather than the default. Fixed-tempo analysis produces a clean grid on anything programmed to a click; dynamic analysis follows a live or hand-played record but will happily invent tempo changes in a track that has none.
Frequently asked
How long does analysing a library take?+
Hours for a large one, because it decodes and processes every file. It is an overnight job, and it only has to happen once per track.
Should I use dynamic or fixed analysis?+
Fixed for anything programmed to a click, which covers most electronic music. Dynamic for disco, funk and live recordings, where the tempo genuinely moves.
Do I need to re-analyse after editing tags?+
No. Tag edits do not touch the audio, so the tempo, grid and waveform are unaffected. Re-analysis is only needed if the audio file itself changes.
Related terms
Analysis file
An analysis file is the small companion file DJ software writes beside each track holding its waveform, beatgrid and cue data. The audio file is untouched; everything the player draws comes from here.
BPM detection
BPM detection finds the repeating pulse in a track by measuring where energy rises and looking for the interval that best explains those onsets. It returns a tempo and a grid, and both can be right about the wrong thing.
Key detection
Key detection estimates a track’s musical key from the audio by measuring which pitches dominate and matching that profile against major and minor templates. It is an estimate, and it is confident even when wrong.
USB prep
USB prep is exporting the tracks, grids, cue points and playlists you need onto a drive a club player can read. What is not exported does not exist once you are behind the decks.
Explore: Song key and BPM finder · Beatgrid · Analysis file · All DJ terms