eq

A system-wide equalizer for macOS with no icon, no window and no menu.

Ten bands, 32 Hz to 16 kHz. A curve per output device: the laptop speakers keep theirs, the Bluetooth speakers theirs, the headphones theirs, and the right one is in effect the moment macOS switches. A daemon does the work; a command edits the numbers.

$ eq
MacBook Pro Speakers (own profile)   preamp: +0.0 dB
  32Hz  64Hz 125Hz 250Hz 500Hz  1kHz  2kHz  4kHz  8kHz 16kHz
  +4.8  +4.0  +4.2  +2.3  +0.0  -3.1  +0.0  +0.0  +3.1  +2.4

Install

brew install --cask servitola/tap/eq

The first eq registers the daemon as a login item named EQ. Its first start asks once for System Audio Recording: grant it to EQ, and eq status says running. No config file is needed; the first change writes ~/.config/eq/eq.json. Login items, a hand-made LaunchAgent, uninstalling: docs/install.md.

Use

Command
eq	the curve in effect on the current output
eq set 64hz +4 1khz -3	change bands; --device JBL for another output
eq import "WH-1000XM4"	apply an AutoEq or OPRA correction by headphone name, file or URL
eq preset save|use <name>	keep a curve, put it on any device
eq tui	the live meter and every setting, from the keyboard; ? lists the keys

eq off and eq on bypass it, eq undo steps back, eq doctor checks the setup. eq device silence "Mac Studio Speakers" keeps an output silent whatever the volume. Every command takes --json; every change takes --dry-run. All of them: docs/commands.md.

Driver mode

eq mode driver plays through a virtual output device, "BE-RCA · EQ", named after the real one, instead of tapping system audio: no permission, no Privacy indicator, and the device reports its whole latency, so video keeps lip sync. Installing the driver asks once for an administrator password and restarts coreaudiod. Experimental; eq mode tap goes back. docs/driver-mode.md.

Documentation

• Commands: every command, presets, undo, terminal colours
• Shaping the curve: app rules, parametric filters, bass, treble, tilt, compression and colour
• The terminal UI: looks, views, keys, instruments
• Import and export: AutoEq, OPRA, Equalizer APO, REW, eqMac, Poweramp, EasyEffects, Peace, CamillaDSP
• Events, hooks and the meter socket
• Driver mode, and recovery
• How it works: the signal path, latency, footprint
• Development
• Changelog

Limits

• macOS 14.4 or newer, Apple Silicon. Tested on macOS 26.6.
• Ten graphic bands plus up to 32 parametric filters, imported or added by hand.
• One curve per device, applied to everything on that device. An app rule swaps the whole system's curve while that app plays; it does not give two apps two curves at once.
• A DAW that needs zero latency: eq off while you work.

Licence

MIT © servitola. The vendored engine and the driver's base keep their Unlicense. OPRA data, fetched at run time and in the test fixture, is CC BY-SA 4.0: see OPRA.