This is a transcription of this video from Revision 2012.

Requirements for a 64k synth

• small
• flexible
• somewhat usable

The Idea: Runtime Code Generation

• Theory
  • Write synths & effects, hear changes instantly
  • JIT compiler in editor, store compiled data in intro
  • your synth is no longer limited to your own dsp routines
  • host language independently (?)

• Implementation Challenges

  • How to implement this in my synth?
  • How to make this usable for non-coders?
  • Instansing
  • When writing runtime code, you want to contentrate on the good parts

• Implementation: Compiler (bero)

  • designed a language (aulan)
  • supports integer, boolean, float, arrays, structs, functions, procedures, pointers, inline asm
    • translates to assmebler/native code
  • special feature: instance variables
  • language features:
    • mixture of basic, pascal and c
    • newline = end of block statement
  • compile to native code and links during runtime (Editor)
  • in your intro:
    • use generated assembly files
    • use bero's runtime linker code for object files as constant byte arrays etc.
    • use your normal linker if it supports COFF

Lets take a look at synth design

• a (64k) synth has multiple layers
  • Voice layer
    • code that gets executed per active note
    • classic synth: fixed pipeline
    • most timecritical code
  • Channel Layer
    • code that processes the sum of all active notes of a single instrument
  • Global Layer
    • code that processes the output multiple instruments
    • e.g. sendto-effects, mastering chain
    • example: Buzz - generator & effect concept

Fixed Pipeline vs Dynamic Pipeline

• Fixed Pipeline
  • A good fixed pipeline can be very versatile
  • It's small
  • Drawback: you need a good fixed pipeline (ask your musician :-)
  • global hardcoded effect-chain / sendto-effects
• Dynamic pipeline
  • not all "modular" synths provide modularity on each level (like Buzz)
  • if done on voice level:
    • allows more complex synth patches
    • more implementation
      • the more granular, the more complex
  • GUIs for modular synths either require a bit of work or they are slightly challenging to use
  • custom mastering/effect chain for free
• Hybrid / Semi-Dynamic pipeline
  • Some parts static, some parts dynamic

Parameter Automation / Envelopes

• WOBWOBWOBWOBWOBWOBWOBWOBWOBWOBWOBWOB
• very important to make instruments sound "alive"
• Different approaches:
  • Modulation matrix (fixed pipeline)
  • modular: e.g. node based, operator stacking
  • LFO with fixed targets as volume, filter, pitch
• if you implement this wrong:
  • bad performance

The Synth

• What is it?
  • Concept blatantly stolen from buzz
  • You create machines, write code for thm
  • machines can be assigned to a midi channel
  • variables can be exported as parameters
  • parameters can be bound to midi-controllers