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...

[FrankSidebottom1]

The meters show audio but I cannot hear anything :(

[devinroth]

BlackHole doesn’t send audio to your speakers. You need to do that yourself either with a daw or multi output. Devin

…

On Jun 3, 2025 at 6:37 PM -0700, FrankSidebottom1 ***@***.***>, wrote: Screenshot.2025-06-03.at.19.36.21.png (view on web) The meters show audio but I cannot hear anything :( — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[FrankSidebottom1]

So if I generate a multi output device in Audio MIDI Setup and set 2 CH BlackHole + UMC4044 (which is my audio interface) as Output should this work?

[devinroth]

Yeah depending on what you’re doing. Devin

…

On Jun 4, 2025 at 3:40 PM -0700, FrankSidebottom1 ***@***.***>, wrote: So if I generate a multi output device in Audio MIDI Setup and set 2 CH BlackHole + UMC4044 (which is my audio interface) as Output should this work? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you commented.Message ID: ***@***.***>

[FrankSidebottom1]

I want to apply an EQ to my systems audio.
The signal flow would be Computer Audio > EQ > Audio Interface (Speakers)
Before I could do it with soundflower and AU Lab but soundflower has no support for my mac mini m2 so I'm taking my chances with Blackhole 2CH but no luck

[paulzaptec]

The above instructions should work.
If you want, you can use Hosting AU instead of Apple's AU Lab. I find this works better; I'm using it to do system-wide EQ on my MacBook Pro M1.

[Headlands7]

Thank you for this! I just can't get it working, have been through every step multiple times. Is this not working on Sonoma, perhaps?

[devinroth]

The usually culprit is mic permissions. Devin

…

On Jun 12, 2025 at 4:16 AM -0700, Headlands7 ***@***.***>, wrote: Thank you for this! I just can't get it working, have been through every step multiple times. Is this not working on Sonoma, perhaps? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you commented.Message ID: ***@***.***>

[Headlands7]

Thank you, I did that for everything (deleted all mic permissions on my mac, then enabled them one-by-one) and still no luck...no audio is getting into AU Lab. About to give up and pay the $45 to get whatever that app is that does it all for you. Any other suggestions to try before I do that?

[pseigo]

Take a look below, @Headlands7

[devinroth]

You can try a DAW instead if AU labs isn’t working. Devin

…

On Jun 13, 2025 at 1:47 AM -0700, Headlands7 ***@***.***>, wrote: Thank you, I did that for everything (deleted all mic permissions to start from scratch, then enabled one-by-one for all) and still no luck...no audio is getting into AU Lab. About to give up and pay the $45 to get whatever that app is that does it all for you. Any other suggestions to try before I do that? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you commented.Message ID: ***@***.***>

[pseigo]

Working for me so far on macOS Sonoma 14.7.

1. Follow this guide. (Guide: system-wide audio EQ using AU Lab #474)
2. Create a "Multi-Output Device" in Audio MIDI Setup: https://github.com/ExistentialAudio/BlackHole/wiki/Multi-Output-Device -- but set BlackHole as your output device.
3. If AU Lab doesn't request Microphone permissions, follow the steps summarized here under issue Trying it out with AU Lab without success #4.

p.s., I get ParametricEQ profiles for my headphones (that I type into a 10-band AUNBandEQ effect) from AutoEq :)