Library & files
Smart playlist
A smart playlist is a saved rule rather than a saved list. You describe what belongs in it — tempo band, genre, rating, date range — and the software fills and refills it as the library changes.
Measured in real DJ libraries
BPM is filled on 99.0% of a real DJ library and star rating on just 17.7% — a smart playlist only reaches the fields you actually filled in.
Build rules on the columns the software fills for you and they match almost everything; build them on the columns you were supposed to fill and they match a sliver. That is the whole design constraint. Tempo, key and date added are reliable enough to carry a rule on their own; genre is usable with a fallback; rating, label and year are not rules so much as filters over a minority of the collection.
99.0%
Have a BPM
97.1%
Have a key
72.7%
Have a genre
17.7%
Have any rating
| Field | Filled | Safe to build a rule on? |
|---|---|---|
| BPM | 99.0% | Yes |
| Key | 97.1% | Yes |
| Genre | 72.7% | With a fallback |
| Label | 34.4% | Only as a filter |
| Rating | 17.7% | Only as a filter |
| Year | 9.5% | No |
Updated daily from Rekordbox collections DJs have imported to Mixgraph. Method: why the rating column is so empty.
Why it matters
The appeal is that it never goes stale. A crate you built in March is a snapshot of March; a rule for "house between 122 and 126 added in the last ninety days" is correct every time you open it, which is what you want from a warm-up folder you are not going to maintain by hand.
The limit is that a rule can only see fields that are filled in, and most libraries are far patchier than their owners think. A brilliant rule built on rating or label matches a small fraction of the collection and silently omits the rest, which reads as "I do not own many of these" rather than "I never filled that field in".
Frequently asked
What is the difference between a smart playlist and a crate?+
A crate holds the tracks you put in it; a smart playlist holds whatever currently matches a rule. One is a decision you made once, the other is a decision that keeps applying.
What makes a good smart playlist rule?+
One built on fields that are actually populated — tempo, key, date added — and narrow enough to be usable. "Everything house" is a genre folder; "house, 122 to 126, added this quarter" is a warm-up crate.
Do smart playlists export to a USB stick?+
They export as their current contents rather than as the rule, so the stick holds a snapshot. Re-export before a gig if the rule depends on recent additions.
Related terms
Crate
A crate is a folder of tracks inside your DJ software, named after the boxes vinyl DJs carried. A track can sit in as many crates as you like without being copied, because a crate holds references rather than files.
Playlist vs crate
A crate is a collection of tracks you might play; a playlist is a running order you intend to play. The distinction is order — a crate is a box, a playlist is a sequence.
Star rating
A star rating is a one-to-five score you assign a track by hand. Nothing writes it for you, which makes it the most deliberate field in a library and the one most often left empty.
Search filter
The search filter narrows the browse list on a player by typed text or by field — genre, artist, key, BPM band, rating, colour — so you can find a track on a stick of thousands without scrolling through them.
Explore: Library health check · Crate to tracklist · Crate · All DJ terms