Audio Limiter (Windows)

Small WASAPI loopback utility that applies a peak limiter to the audio from any render endpoint you select.

Build

# Release build
.\build.ps1

# Debug build with verbose logging
.\build.ps1 -Configuration Debug -Verbose

The script requires Zig on your PATH and the Windows 10 SDK installed under C:\Program Files (x86)\Windows Kits\10.

Quick Start

# Show available render endpoints and their indexes
.\bin\audio_limit.exe --list-devices

.\bin\audio_limit.exe --threshold -7 --render-index 0

# Capture default system output, limit peaks at -10 dBFS, play back to default device
.\bin\audio_limit.exe --threshold -10 --attack 3 --release 80 --makeup 0

# Capture from device index 2 (e.g. HDMI output), render to device index 0 (speakers)
.\bin\audio_limit.exe --capture-index 2 --render-index 0 --threshold -12 --attack 4 --release 120

Without a Virtual Cable (tested on Windows 11 with unused output device)

Route the game (or per-app output via Windows "App volume and device preferences") to an unused physical endpoint, such as HDMI or secondary speakers. Run the limiter with that endpoint as --capture-index and your real headphones as --render-index. Avoid capturing and rendering on the same device unless the original stream is muted to prevent doubling.

With a Virtual Cable

Install a virtual audio driver (VB-Cable, VoiceMeeter VAIO, Virtual Audio Cable, etc.). Set the game or Windows default output to the virtual device. Start the limiter with --capture-index <virtual> and --render-index <headset>. The limiter then processes everything before it reaches your ears.

Limiter Parameters

• --threshold <dB>: Ceiling in dBFS; more negative values clamp peaks harder (default -6).
• --attack <ms>: Attack time; shorter reacts faster to transients (default 5).
• --release <ms>: Release time; longer reduces pumping artifacts (default 50).
• --makeup <dB>: Post-limiter gain; keep 0 when you only want to reduce volume.

Restart the program after changing parameters; settings are read at launch.

Notes

• Capture and render devices must share channel count and sample rate.
• Press Ctrl+C in the console to stop.
• Keep Windows set to 48 kHz for best latency when possible.