Csound Instruments

A collection of standalone audio synthesis instruments built with Csound, demonstrating various sound design techniques and DSP concepts using high-level audio programming.

Overview

This repository contains self-contained Csound-based synthesizers and sound generators. Each instrument is a complete audio synthesis system with its own documentation, demonstrating different approaches to sound design - from noise-based textures to modeled instruments.

What is Csound?

Csound is a powerful, domain-specific audio programming language for sound synthesis and composition. It combines signal generators, filters, effects, and control structures in a text-based format, making it ideal for both artistic sound design and educational DSP exploration.

Instruments

Wind Synthesizer

Location: wind_synth/

A noise-based synthesizer that creates realistic wind and breath-like sounds using state variable filters and dynamic envelope shaping.

Features:

• Two instruments: evolving textures with LFO panning, and steady drones
• Stereo noise generation for natural spatial width
• SVF filters with resonance control for tonal shaping
• Independent filter and amplitude envelopes

Quick start:

cd wind_synth
csound wind_synth.csd                    # Render to WAV file
csound -o dac wind_synth.csd             # Real-time playback

Read full documentation →

---

More instruments coming soon...

Quick Start

Prerequisites

Install Csound:

Windows (MINGW64):

• Download from https://csound.com/download.html

macOS:

brew install csound

Linux:

sudo apt-get install csound

Verify installation:

csound --version

Running an Instrument

Navigate to any instrument directory and run its .csd file:

cd wind_synth
csound wind_synth.csd              # Creates wind_synth.wav

Common options:

csound -o dac instrument.csd       # Real-time audio output
csound -o custom.wav instrument.csd # Custom output filename
csound --sample-rate=96000 ...     # Override sample rate
csound -d -o dac ...               # Enable debug messages

Repository Structure

csound_instruments/
├── wind_synth/              # Wind/breath synthesizer
│   ├── wind_synth.csd       # Csound synthesis definition
│   ├── README.md            # Instrument documentation
│   └── CLAUDE.md            # AI assistant guidance
├── CLAUDE.md                # Repository-level AI guidance
├── LICENSE                  # MIT License
└── README.md                # This file

Each instrument is self-contained with:

• .csd file - Complete Csound synthesis code
• README.md - Usage guide, parameters, and sound design tips
• CLAUDE.md - Technical architecture notes for AI assistants

Csound File Format

All instruments use the .csd (Csound Document) format, which combines three sections:

<CsoundSynthesizer>
<CsOptions>
  <!-- Command-line flags: output file, bit depth, etc. -->
</CsOptions>
<CsInstruments>
  <!-- Synthesis code: instruments, signal flow, DSP -->
</CsInstruments>
<CsScore>
  <!-- Musical events: note triggers, timing, parameters -->
</CsScore>
</CsoundSynthesizer>

Creating New Instruments

To add a new instrument to this collection:

1. Create directory:

   mkdir my_instrument
   cd my_instrument

2. Create .csd file with synthesis code

   • Define global settings (sr, ksmps, nchnls)
   • Implement instruments (instr 1, instr 2, etc.)
   • Add score events (i1 0 2.0 ...)

3. Add README.md documenting:

   • What the instrument does
   • Parameter descriptions and ranges
   • Example usage and presets
   • Sound design techniques

4. Test thoroughly:

   csound --syntax-check-only my_instrument.csd
   csound -o dac my_instrument.csd

5. Optional: Add CLAUDE.md for complex instruments

   • Architecture details
   • Signal flow diagrams
   • Implementation notes

Sound Design Philosophy

Each instrument in this repository demonstrates specific DSP concepts:

• Subtractive synthesis - Filtering rich sources (noise, sawtooth) to shape timbre
• Envelope control - Dynamic parameter modulation over time
• Stereo imaging - Spatial positioning and width techniques
• Modulation - LFOs, envelopes, and parameter automation

The goal is to create musically useful and educationally clear instruments that showcase both artistic sound design and technical DSP implementation.

Resources

Csound Documentation

• Csound Manual - Complete opcode reference
• Csound FLOSS Manual - Tutorials and best practices
• Csound Community - Forums and discussions

Learning Csound

• Start with simple instruments (oscillators, filters)
• Understand rate types: i-rate, k-rate, a-rate
• Study signal flow: source → processing → output
• Experiment with parameter ranges and combinations

Contributing

Contributions are welcome! When adding new instruments:

• Keep each instrument self-contained
• Document parameters and usage clearly
• Include example scores demonstrating the instrument's capabilities
• Follow existing naming conventions and structure
• Test on multiple platforms if possible

License

MIT License - See LICENSE file for details.

Acknowledgments

Built with Csound, developed by Barry Vercoe and maintained by an active open-source community.