Guide: system-wide audio EQ using AU Lab

[clanger9]

I made a guide for doing system-wide audio EQ using AU Lab. It includes the necessary steps to stop it clicking.
All errors and omissions are mine. I hope this is useful for someone. Feel free to reuse/republish.

Download

1. BlackHole 2ch (free, email required): https://existential.audio/blackhole/
2. Additional Tools for Xcode 13 (includes AU Lab v2.3, free Apple developer registration required): https://download.developer.apple.com/Developer_Tools/Additional_Tools_for_Xcode_13/Additional_Tools_for_Xcode_13.dmg

Install

Install BlackHole
Copy AU Lab app to Applications

Configure

From the macOS menu bar, select BlackHole 2ch as your speaker

Open Audio Midi Setup app
Click + Create Aggregate Device
Under Use, check both BlackHole 2ch and your speaker device
Under Drift Correction, check both BlackHole 2ch and your speaker device <- this is important to stop it clicking & crackling after a few minutes
Click on Aggregate Device and rename it to "Desktop Audio Correction"

Click on your speaker device name and set channel volume of your speakers to -10dB

Open AU Lab app

AU Lab -> Preferences -> Devices
Select Desktop Audio Correction
Set Frames to 1024
Under Expert Settings, set CPU Usage to 10%

File -> New
Select Stereo In/Stereo Out and Desktop Audio Correction as both Input and Output Device
Click Create Document

Add EQ & room corrections under Output 1 - Effects .

• For the usual graphic equaliser, select "AUGraphicEQ"
• For room corrections, "AUNBandEQ" is probably the plugin you want…

File -> Save as "Desktop audio correction"

AU Lab -> Preferences -> Document
Check Open a specific document:, select the file you saved above
Check Use Preferred Audio Device… and select Desktop Audio Correction

Window -> Minimise
Right-click on AU Lab icon in the dock, check Options -> Open at Login

In System Preferences -> Users & Groups -> Login Options, look for the AU Lab line and check Hide

If you don't get any sound via AU Lab, it may be that it hasn't got permission to receive audio. Check under System Preferences -> Security & Privacy -> Microphone

[porg]

Hi @clanger9, thanks for providing this guide!

• Before going deeper and trying this out: Is it possible to apply this equalizer (EQ) only on one speaker (e.g. left speaker only) ?
  • My left MacBookPro speaker starts to fail slowly (resonates at certain frequency range)
  • As a temporary measure (until repair/replacement) I 'd like to cut off the annoying frequencies, but only on the left channel.

[clanger9]

Hi @pog I can't see an obvious way to do this on a single channel.
Since writing this guide I have switched to using Hosting AU (rather than AU Lab), which seems to be more reliable.

[porg]

• Thanks for the info that one channel EQ is not possible in AU Lab.
• Would it be in Hosting AU?

[clanger9]

Hosting AU seems to have a similar limitation. It might be possible to create an aggregate device in Audio MIDI Setup to route the EQ to one channel only. Just a thought...