OSAMC 3/2017

What is it?

• 3 channel digital controlled synth in a single chip
• One chip in each C64 (1982)
• 10 - 17 million units sold
• used heavily for games, intros, demos

How does it sound?

• Because Nils doesn't like theoretical talks
• Youtube link:Katakis soundtrack (originally shown with jsSID)

Features

• 4 Waveforms types: Triangle, Sawtooth, Square, Noise
• a ADSR waveform envelope generator for each channel
• 1 filter for all channels
• Ring modulation of channels possible
• playing 4 bit samples is possible through tricks but cpu-time-consuming

Hardware

• Multiple Revisions MOS 6581/6582/8580
• First version sound different due to different filter design
• Designed by Robert Yannes, who later build the Ensoniq SQ1

Registers

• 29 8bit registers
• 7 registers per voice: frequency, pulse width, control, ADSR
• 4 global registers: filter cutoff, resonance, filter mode, volume
• Read-only registers for A/D conversion

Block diagram

Composing restrictions

• 3 channels
• Memory
• register control time to set the registers - depending on context as low as 63 cpu cycles (one raster line)
• Tooling requires technical knowledge (eg. hex numbers, layout and function of SID registers)

3 channels?

• Youtube link:Last Ninja 2: Central park rendered as oscilloscope

Free software for composing

• most editors have a tracker style interface
• SIDRip - a C64 SID-Editor - usable on emulators
• Cheesecutter - multi platform GPL editor
• GoatTracker - another multiplatform GPL editor. newer versions can handle midi input.
• + lots of native editors with various licenses
• demo time (in the talk we did a small dive into goattracker, basically following this tutorial to produce modulated square wave as shown in : this tutorial)

Sound collections

• High Voltage Sid Collection:
• Current version: 94.4 MB, 48943 PSID files
• Song files between 1kb and 60kb (if using samples)

Players

• libsidplay + sidplay2 Library + player for psid files
• resid library for accurate emulation of various sid models and realtime support
• sidplayer
• Javascript implementation of a player
• + lots of commercial and shareware options (playsid started as dos shareware). There is even an app for that - look in your favourite app store.

Remixes

• remix.kwed.org/ - largest and still active remixing community
• Youtube - lots of SID-related content

Ongoing DIY efforts

• http://www.ucapps.de/midibox_sid.html
  
• http://www.keytarcentral.com/2012/09/commodore-64-keytar/#more-12204

Ongoing DIY efforts

• lots of projects to provide two SIDs for stereo modes
• + deprecated projects for interfacing to isa/pci
• Problem: sound chips are getting rare and get destroyed quickly, because of CMOS technology
• Therefore projects to provide pin compatible replacements using ATMega/Arduino/etc

Commercial hardware

• MSSIAH - Cartridge to turn your c64 into a midi synth
• Elektron Sidstation - honorable mention, because it was the first instrument sold to mainstream musicians

Bonus

• Youtube link: Oscilloscope view of Arkanoid: 4th voice using the broken volume register for FX and drums