OpenMPT manual — Song Properties (and Tempo Swing)

The global switches of a module in openmpt: format conversion, the playback flags (linear slides, fast volume slides, filter range, IT old effects, compatible Gxx, ProTracker mode, Amiga limits), mix levels, the three tempo modes with their formulas, time signature — and, from a second page, Tempo Swing.

Key claims#

• Linear Frequency Slides: period slides move less in low octaves; linear slides use 1/64-note units "so the same slide parameter will always slide the same amount of notes"; keep it on for new songs; MOD and S3M never use it. Fast Volume Slides (S3M) apply slides on every tick, as Scream Tracker 3.0 did. Extended Filter Range doubles the cutoff range from 130 Hz–5 kHz to about 10 kHz. IT Old Effects replay vibrato, tremor, tremolo and offset the old IT way. Compatible Gxx: tone portamento memory not shared with Exx/Fxx, envelopes reset on Gxx + note + instrument, key-off nullified — "more consistent with … Fasttracker 2".
• ProTracker 1/2 mode (MOD): instrument changes on the first tick even with delayed notes; tremolo/vibrato skip the first tick; notes outside C-4–B-6 turn red and are clamped; arpeggios wrap around above the Amiga range; the quirky 9xx. Amiga Frequency Limits clamp notes and slides to three octaves (auto-enabled for 4-channel MODs within range).
• Mix levels: use Compatible for MOD/S3M (automatic) and for IT/XM — "the sample mix levels are identical those of Schism Tracker"; with plugins use OpenMPT 1.17RC3 levels; the two oldest modes make VST instruments 2× / 16× too loud. Compatible (FT2 Pan Law) uses the square-root pan law FT2 used, emphasising centred samples.
• Tempo modes: Classic (legacy formats): ticks per minute = tempo × 24, rows per minute = tempo × 24 ÷ speed, tick = 2.5 s ÷ tempo, with old-school rounding so real BPM can differ between sample rates ("Approximate Real BPM" in the Player menu tells the truth); Alternative: tempo in ticks per second (tick = 1 s ÷ tempo); Modern (MPTM): tempo is exact beats per minute, rows per minute = tempo × rows per beat, speed no longer changes the pace — precision is raised by rows per beat per pattern. Speed = ticks per row everywhere.
• Time signature: rows per beat / per measure for highlighting and metadata; MPTM patterns can override it.
• Tempo Swing (Modern mode, MPTM, global or per pattern): a slider per row of the beat lengthens or shortens that row; rows always add up to the tempo, survive tempo changes, keep plugins on a steady clock, and need no tempo commands; an edit group moves every other row (or pair) together.

Practical takeaways#

For shared IT/XM: linear slides on, compatible mix levels, defaults set; for MPTM: Modern tempo, decimal BPM and Tempo Swing instead of speed-alternation shuffles (shuffle-funktempo).

Notable quotes#

"In OpenMPT, 'Speed' means 'ticks per row'."

Pages touched#

openmpt · shuffle-funktempo · tracker · pitch-slide-and-portamento · volume-slides · protracker · mod-format · stereo-panning