What is Delay?
Also called: echo
Delay is an audio effect that plays back a copy of a sound after a set amount of time, creating one or more echoes. Delay times are often matched to the song's tempo so the echoes fall in rhythm.
The main controls are the delay time, the feedback (how many repeats there are), and the mix between the original and the echo. Filters on the repeats make them darker or thinner so they sit behind the original sound.
To sync a delay to the song, you work out the length of a note value at the song's BPM. One beat (a quarter note) lasts 60,000 divided by the BPM in milliseconds. Dotted and triplet values are popular because they create a rhythm that plays against the beat.
Very short delays, under about 30 milliseconds, stop sounding like echoes and instead thicken or widen the sound.
Example
At 120 BPM a quarter note lasts 500 ms, an eighth note 250 ms and a dotted eighth 375 ms.
Put it to work
Calculate delay times in milliseconds and hertz for any tempo and note value.
BPM and Delay Time Calculator