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.
I 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: