I'd love to hear answers to the same question.
Spent some time seeking to research DRC (digital room correction). One way to go is the additional hardware route, something along the lines of the Lyngdorf, Audyessy-made (now discontinued) stand-alone box, etc. An option, but an option that includes a DAC. If you already have a separate outboard DAC, going from analog to digital and then back to analog again seems, well, silly. And when you get right down to it, if you're coming from a digital computer source already (Mac Mini, in my case) seems silly not to have the software processing in the same box.
For Mac, far as I know, there's no simple answer. First, being that I use Itunes with an ad-on (Bit Perfect), there's no compatibility with plugins. In order to get that working, you need something like Audio Hijack Pro. That grabs the output from Bit Perfect and allows for the addition of plugins (software to run the DRC). From there, the one that had caught my eye is the ARC System from IK Multimedia. This is built around the Audyessy engine, and allows you to run it as a plugin on top of Itunes/Bit Perfect -- provided you first grab the signal with Audio Hijack Pro in order to let you apply plugins.
Far as I know, this daffy patchwork is the only way to make it go under my circumstances. Haven't tried it to see how / how well it may work, but there you go.
Any other or better options, or feedback regarding whether the patchwork is worth the effort, would be super fine. Many thanks.