Split Input Channels Using SoundFlower and AULab
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 &amp; drop, it makes the connections for you.

Route a source to two different Channels plugins, kill left in one &amp; 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 &amp; the numbers go orange &amp; start to count time.
As a side-effect, launching any specific Hijack preset will launch any apps assigned to it.