I just recently got a Mac computer and so am trying out Audirvana. I found the instrument separation to be so intense that I felt the kind of fatigue you can get with too much stereo separation on headphones. After a bit of searching, I found a super simple crossfeed audio unit component that you simply put in the library/audio/plugins/component folder. It has just a few settings after you activate it in the Audirvana preferences for feed level and for low pass frequency. It is based on the Boris Mikhaylov's Bauer stereophonic-to-binaural DSP library.
With the crossfeed turned all of the way up, it makes the soundstage much more natural and cohesive. It truly is a relief as it takes the edge off of the hyper-real separation of the Audirvana software by itself.
Here is the link for the free download: http://larsggu.me/crossfeedcomponent/
Just download the Crossfeed.component.zip and then unzip the file before putting it in the component folder. Then select it under Audio Units in Audirvana's preferences and configure it as you wish.
Best of all, it is free!
Edited by Nirmalanow - 7/13/14 at 8:51am