Systemwide Equaliser

Parametric EQ that sits between your system audio and your speakers.
macOS doesn't have one built in, so here we are.

Built with LLMs. Public domain. Do whatever you want with it (at your own risk).

Install

You need Homebrew, then:

brew install blackhole-2ch portaudio python@3.13
git clone https://github.com/raaghava-p/SystemwideEQ-MacOS.git
cd SystemwideEQ-MacOS
python3 -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt && pip install -e .
python -m equaliser

One thing — PyQt6 6.8+ is broken on Apple Silicon. The requirements file already pins it to <6.8 so you shouldn't hit this, but if you do: pip install "PyQt6>=6.5,<6.8" "PyQt6-Qt6>=6.5,<6.8".

Route Your Audio

The app needs to intercept system audio. BlackHole makes this possible but you have to wire it up once:

1. Audio MIDI Setup → + → Create Multi-Output Device
2. Check BlackHole 2ch and your speakers/headphones
3. Physical device = master clock, drift correction on for BlackHole
4. System Settings → Sound → Output → select the Multi-Output Device

After that, all system audio goes through BlackHole and the app can process it.

Use It

1. Set BlackHole as input, your speakers as output
2. Match the sample rate to Audio MIDI Setup (48 kHz is usually right)
3. Start audio
4. Add EQ bands — five filter types available: peaking, low shelf, high shelf, high pass, low pass
5. Toggle individual bands on/off with the checkbox column
6. Preamp slider gives you ±12 dB of headroom
7. A/B bypass to compare
8. Import AutoEQ headphone profiles (ParametricEQ.txt)
9. Save presets — last session restores automatically

The spectrum analyzer overlays live frequency content on the EQ curve. Peak hold markers on the meters show recent maximums.

Troubleshooting

Problem	Fix
No sound	System output probably isn't set to the Multi-Output Device
Missing device	Hit Refresh. Might need to brew install blackhole-2ch again.
Pops/latency	Lower buffer size or make sure sample rates match everywhere
Clipping	Turn down band gains or the preamp
cocoa plugin error	PyQt6 too new. Pin to <6.8.
Broken after moving folder	Venv has stale paths. Nuke it: rm -rf .venv and redo setup.
Permission error	Terminal needs mic access — System Settings → Privacy & Security

Build standalone app

pip install -r requirements-dev.txt
python scripts/build_app.py py2app

Gives you dist/Equaliser.app. Drag it to Applications.

Limitations

• Stereo only
• Swap devices = stop and restart the stream

_Unlicense