Meter
- Simple: each beat divides into two (2/4, 3/4, 4/4).
- Compound: each beat divides into three (6/8, 9/8, 12/8). A 12/8 has four beats in triplet feel: the feel of many soul ballads and much slow blues.
- Irregular: 5/4, 7/8, 2+2+3 groupings.
Subdivision
The same BPM can be filled with eighth notes, sixteenth notes, triplets or thirty-second notes: it is the subdivision, more than the BPM, that decides how fast the track feels.
Half-time
The snare goes from 2 and 4 to 3 only: the perceived tempo is halved. A trap track at 140 BPM feels like 70.
Half-time pattern (one bar in sixteenth notes):
- kick: x......x..x.....
- snare: ........x.......
- hi-hat: in sixteenth notes, with rolls in thirty-second notes and triplets.
Double-time
The opposite: the snare on every beat or the subdivision doubled (hi-hats in sixteenth notes over a slow beat): energy without changing BPM. Used in bridges, pre-drops, rap flow changes.
Compositional use
- Going from normal time to half-time in the pre-chorus creates suspension; returning to normal in the chorus releases energy.
- In a DAW it is best to set the “full” BPM (140) even if the track feels like 70: you get more resolution for hi-hats and rolls.
Real-world example
“Rosanna” by Toto (1982) is the famous case of a half-time shuffle, played by Jeff Porcaro; modern trap has made half-time its signature.