Sound & signal
Fill
A fill is a short break in the drum pattern — a tom run, a snare roll, a beat left out — marking the end of one section and the start of the next.
In practice
Use fills as the boundary marker: when one lands, the next phrase is starting, and that is where a mix belongs.
Count from the fill rather than from where you dropped the record — it is the arrangement’s own account of where a section ends, and it is more reliable than a mental count that has survived four minutes of a mix. If two records’ fills land at different moments you are out of phrase by whatever the gap is, which is usually a beat or a bar and is fixed by nudging rather than by rebuilding the mix.
Last bar
Where a fill sits
8 or 16 bars
Typical phrase it closes
15.24s
8 bars at 126 BPM
Where these come from: Arrangement conventions plus one arithmetic figure — eight bars of 4/4 at 126 BPM, the median tempo across the 273,725 house, techno and trance tracks we hold. Our analysis reads whole tracks, so we can tell you a record’s tempo and how it compares to its genre, but not where its fills land. For what we can measure, see the phrase a fill closes.
Why it matters
Fills are free signposting. A record you have never heard announces its phrase boundaries with them, so you can hear where a mix wants to land without knowing the arrangement or reading the waveform.
They are also the thing that goes wrong when two records are a beat out of phrase. Two fills landing at different moments is instantly audible in a way that two kicks slightly apart is not, which makes a fill the fastest test of whether your phrasing is right.
Frequently asked
What is a drum fill for?+
Marking the end of a phrase and the start of the next. It is the arrangement announcing a boundary, which is exactly the information you need to know where a mix should land.
How do you use fills when mixing?+
Count from them. A fill tells you a section is ending, so the bar after it is where the next record belongs — and it is more trustworthy than a count you have been holding in your head all through the blend.
Why do the fills in my mix land at different times?+
Because the two records are out of phrase, usually by a beat or a bar. Nudge one until the fills coincide; matching tempo alone will not fix it.
Related terms
Phrase
A phrase is a block of bars a track is built from, usually 8, 16 or 32. Electronic music changes at phrase boundaries, so a mix that starts on one keeps both tracks structurally in step.
Snare
The snare is the sharp drum that answers the kick, usually on beats two and four. In dance music it is often a clap or a layered mix of both, and it is what tells you where you are in the bar.
Bar
A bar is four beats in 4/4 time — one full cycle of the kick pattern. DJs count in bars rather than seconds because a bar is the same length of music at any tempo, and seconds are not.
Build-up
A build-up is the climb out of a breakdown — a riser, a snare roll, filters opening — that tells a floor the drop is coming. It is arranged to land exactly on a phrase boundary rather than wherever it happens to finish.
Explore: Beats-to-time calculator · Phrase · Mixing guides · All DJ terms