0 3 7 lab — techniques & theory (summary)

Prose and data extracted from 037-lab, a single-file browser app that teaches music theory in semitones for tracker musicians. Twelve "chip & tracker techniques" cards, eight theory cards, an interval table and the app's scale / chord / progression data tables.

Key claims#

• Chip arps: cycling chord tones on one channel at roughly 25–50 notes/s fuses into one chord; 10–15 notes/s reads as a deliberate arpeggio riff. 0 3 7 minor, 0 4 7 major, 0 3 6 diminished (chord-arpeggio).
• A fast arp is heard mostly by its highest note; choose inversions (0 3 7 / 0 4 9 / 0 5 8 are the same minor chord) so successive top notes move by small steps — a hidden second melody (chord-inversions).
• Fake echo: repeat each note after 3 or 6 rows at ≈40 % volume, again at ≈15 %; delay times that match the tempo groove (fake-echo).
• Delayed vibrato (straight attack, vibrato fades in) makes long notes sound intentional; most trackers use 4xy (vibrato).
• Tone portamento (3xx): slide up into a phrase's peak, down at its end, slow bends for lead-guitar feel. In SID-Wizard, $30–$60 is the everyday zone (a semitone in ~140–40 ms), $08–$20 slow and dramatic, $80+ a one-frame snap; every +$18 doubles the speed (pitch-slide-and-portamento).
• Octave bass 0 12 0 12… in 8ths or 16ths; variants: octave on off-beats, or two octaves up every 4th hit (octave-bass).
• Detune two channels 5–10 cents for a fat "chip supersaw"; a quarter tone is seasick (detune).
• Pulse duty cycle character: 50 % hollow/round, 25 % brassy, 12.5 % thin/nasal; sweeping it (PWM) is the classic SID shimmer; sample trackers fake it by switching between pulse samples (pulse-width-modulation).
• Sidechain pump: duck chords/bass on every beat with a volume-slide (Axx) or a retriggered volume envelope (sidechain-pump).
• One channel, two jobs: interleave bass on even 16ths and melody on odd ones; also kick + bass (channel-interleaving).
• Instrument design beats note count: fast pitch drop → kick; a couple of frames of noise before a tone → snare/pluck; tiny downward pitch envelope → punchy bass. Build a small library (instrument-design).
• Arrangement in 4- and 8-bar phrases; add/remove one element per phrase; copy a section up a fifth or an octave for the finale (arrangement).
• Theory: semitones are the only unit (semitone-math); scales as palettes with moods (scales-and-modes); diatonic chords are not always 0 3 7 (diatonic-chords); tonic/dominant/subdominant and stock progressions (chord-progressions); melody rules (melody-writing); strong rows 0 > 8 > 4, 12 and syncopation (rhythm-and-groove).
• Export conventions of the app: OpenMPT IT clipboard text (ModPlug Tracker IT, 11-char cells, middle C is C-5, === note-off, Gxx = xx/16 semitone per tick at speed 6) and DUET SID-Wizard clipboard text (DUET SW, 9-char cells, 03xx slides) — see openmpt, 037-lab.

Practical takeaways#

Everything is written as the numbers you type into a tracker. The cheat sheet card is a one-screen reference: chord formulas, inversions, scale formulas, progressions by degree, transpose rule, strong rows.

Relevance#

Backbone of the theory concepts and of several platform-independent technique pages; complements the SID-Wizard manual with the why and the general-tracker (3xx, 4xy, Axx) side.

Pages touched#

Created: 037-lab, openmpt, impulse-tracker, chord-arpeggio, chord-inversions, fake-echo, vibrato, pitch-slide-and-portamento, octave-bass, detune, pulse-width-modulation, sidechain-pump, channel-interleaving, instrument-design, arrangement, semitone-math, scales-and-modes, diatonic-chords, chord-progressions, melody-writing, rhythm-and-groove, tracker.