Analyse your DJ set before you play it, not after

Analysing a set before you play it means analysing a tracklist — the tracks, in order, with their BPMBeats per minute: a track's tempo, and the first number any DJ looks at. and keyThe note and mode a track is written in — what decides whether two tracks sit well together. — rather than a recording of the performance. The difference is not technical. It is that one result you can act on and the other you can only learn from.

There are tools that show you the energy curveThe shape formed by the energy levels of a set's tracks, one after another. of your set and give you a reading of what worked. They are well made and they are useful. But almost all of them work on the recording: you upload the audio of the gig and they hand back the analysis.

Which means the result arrives when there is nothing left to do with it.

The difference is timing, not technology

An analysis after the fact is for learning. It tells you the middle block sagged, that you held the plateau too long, that the close arrived with no fuel left. With luck you remember next time.

An analysis before is for deciding. The middle block has not sagged yet: you can move one track, dropThe moment a track releases all its energy, after the tension that built up to it. another, and see whether the score goes up. It is the difference between a report and a tool.

Both are legitimate and they compete less than it looks. But if you have to pick one, the one that lets you change something is worth more.

The three edits that only exist beforehand

Concretely, what "before" buys you:

• Moving a track. The single most common fix, and the only one that is free. After the gig it is a note for next time; before it, it is a drag.
• Dropping a track. Sets are almost always one or two tracks too long for their slot, and the ones to cut are the ones that flatten a climb rather than the ones you like least.
• Changing where the peak lands. This is the one that depends entirely on your slot, and the one a recording can never advise on, because by then the slot is over.

What you need for it to work beforehand

To analyse a recording, the audio of the set is enough. To analyse a set you have not played yet you need something different: the tracks, in order, with BPM and key. And that is where the real problem shows up — half of any DJ's library has incomplete tags.

Three routes, best to worst:

1. Your tags are already complete. Import the playlist from Rekordbox, Traktor or M3U8 and you are done. The import formats page says which export to produce from each program.
2. The tags are empty but you have the files. The real BPM can be read from the audio, on your own machine, without uploading anything.
3. You have neither. Then it is estimated by position, and the analysis is worth less. It is honest to say so.

Can you analyse a set without uploading the audio?

Yes, and for a tracklist you never need to. Everything the analysis reads — order, BPM, key, energy — comes from tags or from a local read of the file. In EnergyCurve the audio never leaves your browser, which is a deliberate architecture decision rather than a feature: files that never arrive cannot be leaked.

Is the energy score comparable between two sets?

Between two sets of the same genre and slot, roughly. Across genres, no — a psy-trance track dropped into a techno set is judged against its own BPM band rather than the set's, and the same is true of the whole set. Treat the score as a way to compare orderings of the same tracks, which is what it is designed for.

What about the set I already played?

Import the tracklist rather than the recording. You lose what actually happened in the room and you keep the thing you can still reuse: the order, which is usually three-quarters of your next set at the same venue.

Does this replace listening to the set through?

No, and it is not trying to. Listening catches things no number reaches — that a vocal on track 9 says the same thing as track 11, that two basslines are in the same register and muddy each other, that a track you love has a two-minute intro you will never actually use. What the analysis catches is the arithmetic you would have to hold in your head across twenty tracks, which is the part listening is worst at.

The useful order is analysis first, listening second: it tells you which three transitionsThe passage from one track to the next — what the room hears as continuity. to listen to.

What it will not tell you

A prior analysis does not know what the floor will be like. It does not know that at half one a group of twenty walked in, or that the DJ before you went to 160 BPM and left the room on fire. You solve that in the booth, and no amount of preparation replaces it.

What it does solve is the other thing: that the set you brought does not have a hole at minute forty because two tracks ended up in the wrong order.

If you want the whole checklist rather than the argument, is my set in the right order walks the four checks one at a time.

Analyse your next set