What is Half Time?
Also called: half time feel, double time
Half time is a rhythmic feel where the drums play as if the tempo were half as fast, usually by moving the snare from beats 2 and 4 to beat 3, while the actual BPM stays the same. Double time is the opposite: the groove feels twice as fast.
In a half time section, the song's other parts often keep their original speed while the backbeat slows down, which creates a heavy, spacious feel without changing the tempo. Trap and a lot of bass music use it, and many rock and pop songs switch to half time in a bridge or final chorus.
It is also why tempo detection sometimes reports half or double the number you expected. A track at 140 BPM with a half time groove can feel like 70, and a tool counting the feel rather than the grid may report that.
When you match tempos for DJ mixing or sampling, 70 and 140 BPM, or 85 and 170 BPM, often work together for this reason.
Put it to work
Detect the key and BPM of a song, with the half and double tempo shown for reference.
Detect Key and BPM