I want to split my stereo input channels so I can Eq one of them. They both would then go to the built-in output. I've installed SoundFloser and AU Lab on Mac OS 10.12 Sierra. I've read through the help pages for AU lab. I couldn't find anything specific to my need. With all the options, it looks like it should be possible. I've tried selecting two mono inputs. I get two left channels as input. I didn't see any way to change the source of the mono input, but I could have missed it.
It could be done using Rogue Amoeba's Audio Hijack which is ostensibly an audio recorder but has really comprehensive routing capabilities too.
You build your path just by drag & drop, it makes the connections for you.
Route a source to two different Channels plugins, kill left in one & kill right in the other - that way each will pass only a single side of the stereo pair.
In front of that you put two EQ plugins, then route both to a single output, headphones/speakers etc.
It's fairly expensive for a one-trick pony, but it's extremely useful if you need the trick it can do.
I posted more examples on https://apple.stackexchange.com/a/203009/85275
BTW, remember to switch it on once you've built it ;-) Button bottom left goes white & the numbers go orange & start to count time.
As a side-effect, launching any specific Hijack preset will launch any apps assigned to it.
- Set Soundflower as mac audio output,
- create a new document in AU Lab,
- add another Audio Input… ⇧⌘A,
- double click on first (left) input track, change Input Channels to mono and confirm,
- adjust accordingly second (right) input track, remember to drag the brown bar to the right cell in the compartment labeled Soundflower Input Stream #1,
- turn Panner knobs full left/right on respective input tracks,
- apply the desired effect on the track of your choice,
- configure Output Settings in Studio ⇧⌘I if necessary.
AU Lab with split channels and Equalizer effect applied to the right channel only:
For everyone here not able to make AU Lab run on Catalina:
Just put AU Lab to the Application folder, and manually edit the TCC trust database:
sudo sqlite3 /Users/$USER/Library/Application\ Support/com.apple.TCC/TCC.db "insert into access VALUES('kTCCServiceMicrophone','com.apple.audio.aulab',0,1,1,NULL,NULL,NULL,'UNUSED',NULL,0,1541440109) ;"