SID Music Guide

This is a learn-by-building guide for the Crusty Studio SID Music Workshop. We will make an original, roughly 30-second cue, Neon Patrol, from an empty tune to a working crustyBASIC player include. The Workshop also includes a separate, roughly three-minute Neon Patrol — Warehouse Mix that turns the same ideas into a complete rave cue.

The Workshop is inspired by the practical tradition of C64 music programming: a patch is a small program, a player updates the SID every refresh, and three voices can imply a much larger arrangement through timing, motion, and careful rests. The goal is to understand those decisions and apply them to your own music.

The workshop in one sentence

Compose three reusable note streams, assign programmable instruments, add per-row effects and shared filter movement, audition both SID models, then export a generated .cbi player include.

Before you begin

The Workshop preview is a musical workbench, not a cycle-exact electrical simulation. Use it to compose and compare ideas, then test the generated player in your target emulator or hardware.

Load the full demo

The Craft tab includes Load 3-minute demo. Use it when you want to hear a finished reference before composing, or when you want a rich project to take apart and study.

Neon Patrol — Warehouse Mix is about 3:04 at 120 BPM and contains 20 named patterns across 46 song-order entries. It hits immediately with a four-on-the-floor groove, jumping bass runs, a nonstop acid lead, and chord/percussion stabs layered across all three voices. The groove drops away twice for short, high-register lead breaks before the final overdrive. Its late-80s/early-90s arcade-rave character is an original nod to the energy of acts such as 808 State and Monty on the Run, not a quotation of any one track. The arrangement demonstrates every Workshop technique: fast arpeggios, delayed vibrato, pitch slides, filter events, pulse-width motion, programmed waveforms, voice time-sharing, hard sync, ring modulation, and chip-model colour.

The full demo is intentionally a listening reference rather than the first exercise in this guide. Choose New tune for the plain baseline, then come back to the demo and compare how each technique changes the same kind of three-voice material. Loading it does not overwrite a file until you choose Save tune.

A useful mental model

The SID has three independent voices, each with an oscillator, pulse width, waveform, control register, and ADSR envelope. One shared filter can colour selected voices. A classic player writes those values repeatedly, so a note can evolve after it starts.

Think in four layers:

  1. Song order decides which patterns play and whether they loop.
  2. Tracker rows decide which note, instrument, and effect each voice receives.
  3. Instrument patches decide the sound and how it changes over ticks.
  4. Chip settings decide PAL/NTSC timing, 6581/8580 character, master volume, and shared filter colour.

The Workshop keeps these layers separate so you can change an instrument once and hear that change everywhere it is used.

Import a MIDI sketch

Use Import → MIDI in the Workshop header to convert a Standard MIDI file into an editable SID project. The converter quantises PPQN timing to sixteenth-note tracker rows, maps low notes to the bass voice, the upper line to the lead voice, and a second melodic track to the counter voice. MIDI drum hits are time-shared onto that third voice. Up to 64 patterns (2,048 rows) are preserved; longer files are clearly marked as clipped. The result is an intentionally editable sketch: use the tracker to clean up overlaps, choose SID patches, and add arpeggios, filter movement, or voice-time-sharing after import.

Use Import → GoatTracker SNG to convert a GoatTracker v2 .sng file. The importer reads the first subtune's three channel order lists, patterns, instruments, and modulation tables, then creates an editable .c64music.json-style project. Notes, ADSR, core waveform controls, pulse width, basic vibrato, and simple modulation are carried across; advanced per-row/table commands that do not have a direct Workshop equivalent are listed in the import status. Multiple subtunes are currently limited to the first subtune. Save the converted tune under a new name, then export its .cbi player include for the game.

How the preview mimics a SID

The browser preview is a lightweight musical model, not a replacement for the silicon. For every note, Crusty Studio renders a short PCM buffer with a triangle, saw, pulse, or noise oscillator, then applies the instrument's pulse-width motion, ADSR envelope, arpeggio, vibrato, pitch slide, ring modulation, sync reset, and programmed waveform changes. A Web Audio filter approximates the selected 6581/8580 colour and the shared cutoff/resonance controls.

Long songs are rendered into complete preview buffers before playback begins. The Workshop shows rendering progress and a memory estimate for long previews; if the estimate is unsafe, play an individual pattern or shorten the arrangement. This affects only the browser preview, not the exported game player.

The real SID is register-driven: three voices have independent oscillator and envelope controls, while the filter is shared. The player include therefore writes SID.FREQ, SID.ADSR, SID.CTRL, SID.PULSE_WIDTH, and filter registers as a crustyBASIC routine. The browser model helps you compose and audition; an emulator or physical SID is the authority for cycle timing, analogue filter behaviour, oscillator leakage, and chip-to-chip variation.

The song preview renders one bounded mixed buffer and plays it through a single loopable source. That keeps the audio graph small and the loop boundary sample-stable; the UI follows the same Web Audio clock for row highlighting. Patch audition remains a short per-note render, so it can be used safely while experimenting with an instrument.

Build Neon Patrol from scratch

Step 1: Set the brief

Make the musical roles explicit before entering notes:

Voice Role Suggested range Why it works
1 Bass and low percussion C-2–A-2 Anchors the harmony and leaves space above.
2 Lead and answer phrase C-4–A-4 Carries the tune where the ear can follow it.
3 Chords, echo, and drums C-3–G-4 Changes jobs over time instead of playing continuously.

Use 125 BPM, Speed 6, PAL, and MOS 6581 as the starting point. Each 32-row pattern is one phrase. The compact starter arrangement uses eight song-order entries across four related patterns, giving the learning cue room to develop; the full demo expands that idea to 46 entries. Rests are intentional: they create contrast and leave room for sound effects.

Step 2: Create and name the tune

  1. Select New tune.
  2. Name it neon-patrol.c64music.json.
  3. Set Tune to Neon Patrol and fill in Author.
  4. Set BPM to 125 and Speed to 6.
  5. Keep Loop enabled while composing.

The default starter arrangement is safe to replace. Its purpose is to show the shape of a three-voice pattern while you learn the controls.

Step 3: Build a plain, readable baseline

Before using SID tricks, make a version that would still work as a conventional three-part song. From a blank tune, press ＋ Instrument three times so you have four patches. Turn every pulse motion, arpeggio, vibrato, wave-program step, sync, ring modulation, and row effect off for now.

Set the patches like this:

Patch Waveform Envelope (A/D/S/R) Gate Other settings
Neon Bass (1) Pulse 0 / 4 / 9 / 2 5 ticks Pulse width $800, no motion, filter off
Neon Lead (2) Saw 2 / 6 / 10 / 4 6 ticks Arpeggio 0, vibrato depth 0, empty Wave program
Neon Chord (3) Triangle 1 / 5 / 8 / 3 5 ticks Static, no filter routing
Plain Drum (4) Noise 0 / 2 / 0 / 1 2 ticks Static noise, no sync or ring modulation

Audition each patch. This is your control recording: save it as Neon Patrol — Plain or simply remember the sound before adding colour. Every later change should be something you can hear against this baseline.

Step 4: Enter the first phrase without effects

Every tracker cell contains a note, an instrument number, and an optional three-character effect. For the baseline, leave the effect field empty and leave unlisted cells as rests (···). Enter these accented rows:

Row   Voice 1                 Voice 2                  Voice 3
00    C-2 · 1                 C-4 · 2                  C-3 · 3
04    G-2 · 1                 E-4 · 2                  G-4 · 3
08    A#2 · 1                 G-4 · 2                  ··· · 4
0C    G-2 · 1                 E-4 · 2                  C-4 · 3
10    C-2 · 1                 C-4 · 2                  ··· · 4
14    G-2 · 1                 D-4 · 2                  G-4 · 3
18    A#2 · 1                 G-4 · 2                  ··· · 4
1C    G-2 · 1                 E-4 · 2                  C-4 · 3

Type notes directly: g2 becomes G-2, while g#2 becomes G#2. Keep the rhythm simple. Voice 1 is the bass, voice 2 is the melody, and voice 3 alternates chord and drum jobs. Press Play song, then use the voice checkboxes to hear the bass, lead, and harmony separately. The Volume slider in the transport changes only the browser preview level; it does not change the exported SID player’s chip volume.

Step 5: Turn the phrase into a standard song

Now make the baseline long enough to feel like a real cue before changing its sound:

  1. Rename the first pattern Main riff.
  2. Press Duplicate, rename the copy Neon lift, and move the final lead answer up an octave on rows 18 and 1C.
  3. Press ＋ Pattern, name the new empty pattern Night drive, and enter a lower, sparser bass for its first half. Let the lead carry more of the rhythm.
  4. Press Duplicate on Night drive, rename the copy Finale sparks, and raise the lead one octave for the last four accented rows.
  5. Arrange the Song order as Main riff → Neon lift → Main riff → Night drive → Finale sparks → Neon lift → Night drive → Finale sparks. Select a pattern and use ↑ Up or ↓ Down to move it; the selected pattern stays visible while you reorder the timeline.
  6. Leave the checkbox beside each order entry checked while building the baseline. Uncheck a pattern when you want to audition only selected sections; the order remains intact and you can enable it again later.
  7. Press Play song and listen only for composition: does the intro establish the key, does the middle contrast, and does the finale feel like an arrival? Fix notes, rests, and octaves before touching effects.

This is the “plain” version of Neon Patrol. Save it now so you can return to it after experimenting.

Step 6: Compare the plain song

Make one listening pass with all three voices enabled, then repeat with each voice muted. The purpose is to hear the musical structure without relying on timbral tricks. Check that:

If the plain version does not work, stop here and rewrite the notes. Effects should reveal a good song, not conceal a weak one.

Step 7: Add one SID technique at a time

Duplicate your saved plain project or keep it open as the reference. After each change, press Play song, then compare the result with the plain version:

  1. Fast chord illusion: on Neon lift, set Instrument 2's Arpeggio to 0, 4, 7. Replay voice 2 alone, then the full mix. The single oscillator now implies a major chord.
  2. Row arpeggio override: put A47 on voice 2 row 08 of Night drive. Compare that one entrance with the same row in Main riff.
  3. Delayed vibrato: set Instrument 2 vibrato depth to 12¢, speed 6 Hz, delay 3. Compare a held lead note before and after; the attack should stay clear while the tail moves.
  4. Pitch punctuation: put U18 on the final bass entrance of Neon lift, then D12 on the answer in Night drive. These should sound like pickups and replies, not permanent bends.
  5. Pulse-width motion: set Instrument 1 Pulse motion to 180 at 1.5 Hz. Toggle it back to 0 and listen for the change in width and brightness.
  6. Programmed waveform: on Instrument 3, add Wave program steps at tick 0 = noise, tick 1 = pulse, and tick 4 = triangle. Replace one chord stab with this patch and compare the transient/body/tail shape with Plain Drum.
  7. Filter movement: enable Route through filter on the bass, choose low-pass, and place F5A on the first voice-3 entrance of the finale. Compare the closed, plain entrance with the opening filter colour.
  8. Voice time-sharing: replace a voice-3 chord stab with Instrument 4 on one row, then restore the chord on the next. Mute voice 3 to verify that the rest of the song still works, then enable it again to hear the extra percussion.
  9. Chip character: audition the result on MOS 6581 and MOS 8580. If a trick only works at one extreme setting, reduce it until the musical idea survives both models.

Keep a note of which changes are improvements. The goal is not to use every effect everywhere; it is to make the same notes tell a more expressive story than the plain recording.

Step 8: Lock in the finished arrangement

Once the comparisons are complete, turn the experiment into a deliberate final arrangement:

  1. Keep the plain song open as your reference and decide which effects earned a place. A single arpeggio, bend, or filter entrance is often stronger than the same effect on every note.
  2. Play Main riff by itself. It should establish the key and rhythm with no sudden effect that sounds like an accident.
  3. Play Neon lift next. Check that the higher answer, brighter filter event, and faster movement feel like a lift rather than a new unrelated song.
  4. Play the Main riff reprise. If it feels too static after the lift, add one small variation—an octave change, a passing note, or a different voice-3 hand-off—not a full rewrite.
  5. Play Night drive with voice 3 muted, then enabled. Its bass and lead should work alone; voice 3 should add colour, not be required to explain the harmony.
  6. Play Finale sparks and listen to the last four accented rows. Use a rising Uxx, falling Dxx, or filter opening only if it makes the arrival clearer. Remove anything that makes the ending feel unfinished.
  7. Use ↑ Up and ↓ Down to verify the final eight-entry order: Main riff → Neon lift → Main riff → Night drive → Finale sparks → Neon lift → Night drive → Finale sparks. Rename any copy that still says copy.
  8. Check only the sections you want included in the final playback. An unchecked pattern is skipped by Play song and by the generated player, but it is not deleted and can be restored with one click.
  9. Save the finished tune, replay it from the beginning, and only then export the .cbi. Keep Loop enabled while editing; turn it off for a one-shot cue so the generated player stops at the end.

Effects you can write in a row

Effects are three hexadecimal characters. The first letter selects the operation; x and y are hexadecimal parameters.

Code Meaning Example
Axy Arpeggio: root, +x, +y semitones A47 = major-colour triad.
Vxy Vibrato depth and speed override V26 = gentle delayed movement.
Uxx Slide pitch upward over ticks U18 = rising bend.
Dxx Slide pitch downward over ticks D12 = falling bend.
Fxx Set filter cutoff from the row F5A = a darker-to-brighter transition.

Use effects as punctuation. A bend on every row stops sounding like a bend; a single filter event at the start of a phrase makes the next entrance feel intentional.

Shape the SID chip

Open the SID chip tab after the notes are working.

6581 versus 8580

Audition both models before committing to a narrow filter setting. If the musical idea only works on one exact cutoff, simplify the patch or leave more headroom.

Clock and global filter

Choose PAL · 985248 Hz or NTSC · 1022727 Hz to match the machine you will target. The Workshop stores musical notes and derives the correct frequency words for the selected clock.

Start with low-pass mode, cutoff 1180, resonance 7, and master volume 13–15. A voice only reaches the filter when its instrument has Route through filter enabled. The live register view shows the selected voice's frequency, pulse, control, ADSR, and the shared filter registers at $D415–$D418.

Use filter movement as colour: open it for a chorus, close it for an intro, and avoid maximum resonance unless the result is deliberately unstable.

Listen and revise like a player programmer

Press Play song and make one kind of change at a time:

  1. Mute or remove the lead mentally. Does the bass still imply the harmony?
  2. Listen to the lead alone. Is its rhythm memorable without the chord stabs?
  3. Listen for clashes between voice 3 and the game's future sound effects.
  4. Change one patch parameter, audition it, and decide whether the change survives the full arrangement.
  5. Play the same phrase on both chip models and at the target clock.

The Craft tab's cards are reminders of the same approach: time-share voices, use fast arpeggios, program the note after gate-on, compose in three lines, and treat chip variation as part of the design.

Save the project

Choose Save tune. In a desktop project this writes a .c64music.json file under music/ and updates the .crusty manifest's assets.music list. The file preserves:

Use Open tune to load a saved JSON project. The Workshop normalises invalid or missing values to safe defaults so an older hand-edited file can still be opened.

Export the player include

Choose Export .cbi to download the generated include. The generated source flattens the ordered patterns into arrays and includes a player routine.

@INCLUDE "neon-patrol.cbi"

PROC MAIN
    SIDM_INIT
    WHILE 1 = 1
        FRAME_WAIT
        SIDM_TICK
    ENDWHILE
ENDPROC

The generated .cbi file includes this same example, with the actual .cbi file name filled in. If the include is beside main.cbs in src/, paste the shown @INCLUDE line as-is; change the path only when you store the include in a subfolder.

Call SIDM_INIT once. Call SIDM_TICK at the display refresh cadence named in the generated file: 50 Hz for PAL or 60 Hz for NTSC. The player updates SID.FREQ, SID.ADSR, SID.CTRL, SID.PULSE_WIDTH, gate state, filter state, and master volume. Your game loop owns scheduling, pausing, and deciding how music shares time with sound effects.

If Loop is off, the generated player clears its playing flag and calls SID.ALL_OFF at the end. If you need a title-screen loop and a gameplay loop, export separate tune files or add a second player state in your game code.

Historical method, used responsibly

The Workshop's design follows documented SID practice rather than a particular commercial score. Rob Hubbard's 1986 interview describes programmable patches and software that flips between them; Martin Galway's released Wizball source shows compact stream interpreters, patch changes, arpeggio data, pitch movement, pulse-width movement, and filter programs. The Commodore reference manual explains the underlying SID registers and envelope controls.

Read the originals for technique and hardware context, not for copying melodies or copyrighted game data:

Neon Patrol, the Workshop starter arrangement, and the generated data in this project are original examples.

Final checklist