Octatrack Clickless Loop Reference

Companion to "Sound-on-Sound Looping with the Octatrack", revision of 5 September 2026.

When a record trig arms the recorder, the Octatrack derives the buffer length in samples from the

master tempo. The length must be a whole number of samples. A loop is clean when that division

comes out exact, i.e. when RLEN x 15,876,000 divides evenly by the internal tempo value.

tempo24 = 24 x whole BPM + INT((23 x tenths + 4) / 9), truncating.

The displayed tenth is not the real fraction: .1 is 3/24, .5 is 13/24, .6 is 15/24, and so on.

Calculator - enter any BPM, RLEN and clock multiplier in the yellow cells to test a combination.

Clean Combinations - every clean BPM/RLEN pair, 30.0 to 300.0 BPM, RLEN 2 to 64.

Golden BPMs - tempos clean at every RLEN from 2 to 64, at a clock multiplier of 1.

Bar Lengths - tempos clean at 16, 32 and 64 trigs, at a clock multiplier of 1.

Every figure in this workbook is computed by formula from the two constants above; nothing is

a pasted result. Change a BPM or an RLEN and the sheet recalculates.

RLEN is measured against the master clock, so a fixed RLEN ignores the track's own clock. When RLEN

is set to MAX the recording instead runs to the next record trig, and its length is the track's own loop:

S steps at whatever speed that track is running. The condition becomes 15,876,000 x S / (M x tempo24)

must be a whole number, where M is the multiplier. Changing M changes which tempos are clean, so the

tables in this workbook assume M = 1. Use the Calculator sheet for anything else.