TW #58–59 — The Finishing Touches (Catspaw)

catspaw's two-part guide to "the finer technical points of writing module-based music", in ST3/IT notation (| C#5 16 48 H83 | = note, sample, volume, effect). Greg Heo later pointed readers here for frames and tempo.

Key claims#

Part 1 (#58) — looping and transitions

• Songs that loop or sit in playlists break when the last pattern sets AFF (speed 255) for a pause but never issues C00, and when the first pattern relies on the default speed/tempo/panning — defaults only apply at start, so on loop the song is still at speed 255. Fix: initialise everything with commands at the start — a silent dummy first pattern with ^^^ note cuts, Xxx pan positions, T7D and A06 (tempo 125, speed 6) and a C00 break; and put C00 on the same row as the final AFF so the song pauses a moment then restarts cleanly. (The Cubic player stops instantly on C00, so give it a row or two at AFF first.)
• Speed changes mid-melody (A06 → A07) sound abrupt. Slide the tempo down over the last beats instead (T7A, T75, T70, T6C, T68, T64, then back to T7D with the new speed): tempo doesn't disturb volume slides and retrigs that depend on frames per row.

Part 2 (#59) — spring cleaning, frames, volume slides, retrigs

• Delete unused patterns (one early tune carried "almost 30k in dead patterns") and forgotten samples; Alt-L twice + clear block in ST3/IT.
• Use effect memory: a 00 parameter repeats the last value (D10, D00, D00; G03, G00; Q43, Q00) — "especially important for cutting down the size of chip songs"; beware shared memories (Exy/Fxy and others, format-dependent).
• Reset global volume at the start if you fade it out at the end, or the song loops silently.
• Frames: a tick of the clock; speed Axx = frames per row (speed 6 → 24 frames over four rows). A volume slide D0y moves the volume by y × (speed − 1) per row: at speed 6, D01 = −5, D02 = −10; D03 at speed 4 = −9. Use this to plan fades exactly (34 → D01 → 39 → D02 D02 → 59), and combine volume-column values with slides and vibrato (K20, UC3, E0E …).
• Retrig Qxy: y = frames between retrigs, so at speed 6 Q03 hits again exactly halfway through the row, Q02 gives three hits; avoid odd speeds (5, 7, 9) because a half-row retrig is impossible — use tempo to get the feel. The x digit changes the volume per retrig (0 none, 1–5: −1 −2 −4 −8 −16, 6: ×2/3, 7: ×1/2, 9–D: +1 +2 +4 +8 +16, E: ×3/2, F: ×2). Recipes: ride cymbal Q43 (32 → 24), snare roll Q53 then Q43, and the tom "thwump" QC2 from volume 04 up by 8 each frame.
• Cites Basehead's tracking-tips article in TW #15 as the model for pattern diagrams.

Relevance#

Source of the new technique pages song-init-and-looping and volume-slides, and of the frame arithmetic in retrigger and tracker.

Pages touched#

catspaw, song-init-and-looping, volume-slides, retrigger, tracker, arrangement, chiptune, scream-tracker-3.