Lemon64: How does one learn SID sound design these days? (2020)

A returning C64 user with an Ultimate64 has found sid-wizard ("reminds me of ScreamTreacker/ImpulseTracker in terms of composition") but cannot turn what he knows about subtractive synthesis into instrument values — the SID "_seems_ like any other subtractive synth, but doesn't behave as I expect when I twiddle parameters". The thread answers with a reading list, three analysis tools and a learning order, then drifts into whether ring modulation and sync matter.

Key claims#

• Reading list (MeneerJansen, Tobias): the chip is "described quite well in the 'official manual'" — a "[SID 6582] PDF" download (the scout note that led to this thread identifies the host as sid.kubarth.com; the link itself is not preserved in the raw text) — see s-mos-6581-datasheet; "work through the examples in the C64 manual" (c64-programmers-reference-guide) "and the numbers in those trackers start making sense"; witchmaster's free book on SID-Wizard (s-witchmaster-creating-chiptunes-with-sid-wizard) and "a tutorial by someboy else" (link not preserved); MeneerJansen's own "quick 'n dirty" register notes (pastebin MZvuRWw5). Prerequisite: know "what is an oscillator, filter, ADSR, etc." Caveat: C64 synth programs mix the chip's hardware features with software additions ("more than 1 LFO"), which makes them "not very straight forward". SID-Wizard 1.8 "might be one of the most complicated [programs] for the C64 I've ever seen. It's like a DAW."
• Analysis tools: lasse-oorni — "Long time ago I used to play back songs slowed down so that I understood how drum sounds (e.g. Hubbard) were pieced together from frames of noise, triangle, pulse etc." — and today siddump (CSDb release 192079), which "shows the values the tune is writing to the SID registers per each frame". wizball6502 — SIDViz by tamat (tamats.com/apps/sid) shows live "what channel used what waveform or ADSR settings to produce the sound you hear", and chordian's comparison of SID editors (chordian.net/c64editors.htm) lists "the CPU time in rasterlines that each player requires" (sid-player-routine).
• How much is going on: wizball6502 — Hubbard & co. work "out of the 29 parameters available", with "a lot happening and consistenly changing every 50th of a second"; NM156's counterpoint — "There isn't really that much to it, there are only 4 waveforms, and typically waveforms only change a couple of times per instrument (if at all) It's in the overall composition."
• Ring mod and sync: commodorejohn — the datasheet describes them poorly; ring modulation "effectively only works between the triangle output of the channel with the ring-mod bit set and the square output of the previous channel"; the two effects "effectively require two out of three channels", but give "some less conventional timbres than the basic oscillator waveforms (or even the combined-noise ones)"; examples: the "bell" tone of the main tune of The Lord of the Rings (ring mod), the Crazy Comets theme (sync, "more on the wild effects side"). NM156: "Not many" tunes use them, "mostly … for effects"; his own tune for International Karate Ultimate Competition has "a couple of examples"; "The most well known tune that does it I guess is the Sanxion loader (also one of the first that did it)". malcontent: ring mod gives "a metallic ringing quality", with "some interesting distortion … at lower frequencies" (he wonders whether that is how some people get louder bass — unconfirmed by anyone in the thread). Tobias: "for making 'regular' sounds for sid tunes, you will most likely never use either ringmod nor sync. don't even bother with those unless you understand everything else."
• Lasse's starter recipe and learning order: "An easy way to get started with using sync is to have the bassline voice as the sync source, and turn on the sync bit in the lead voice. This adds a distortion or 'screaming' quality, somewhat like an electric guitar." But basics first: "Basic waveforms, ADSR, pulse width + modulating it, vibrato and pitch slides, 'wavetable' programming (can get started for example by adding a frame of noise waveform into the beginning of notes to get a bit more rhythm to them)".

Practical takeaways#

Read the datasheet and the PRG's examples, then dissect real tunes — slowed down, live in SIDViz, or frame by frame with siddump. Learn in Lasse's order (waveforms → ADSR → pulse width and PWM → vibrato and slides → wave tables, starting with one frame of noise on note starts); leave ring/sync for later, and when you get there, sync the lead voice to the bass voice.

Notable quotes#

Lasse: "I used to play back songs slowed down so that I understood how drum sounds (e.g. Hubbard) were pieced together from frames of noise, triangle, pulse etc."

NM156: "there are only 4 waveforms … It's in the overall composition."

Relevance#

The wiki's SID learning path (tracking-workflow) had no "how to study existing tunes" advice beyond the book; this thread supplies it with named tools. It also gives ring-modulation-and-sync its first practical usage advice and sourced "heard in" examples (forum claims, attributed as such) and siddump its first mention.

Pages touched#

tracking-workflow · ring-modulation-and-sync · wavetable-programming · instrument-design · siddump · lasse-oorni · sid-wizard · sid · sid-player-routine · commodore-64 · chordian · c64-programmers-reference-guide