maybe I am missing something here- I probably am- but when I 1st got sonar i was quite stumped and dismayed at being unable to record the audio I was hearing whilst tweaking Zeta+2- just the midi stuff. I found asio4all mentioned on other threads here and elsewhere and used the virtual line in on a bus to go back to an audio track that I recorded which then audio out to the master. So I managed to build up layering different tracks thus. I got an akai eie pro too to use the loopback- but I have blue screen issues cropping up and worry about hdd damage caused by hard crashes.
Bottom line is it (asio4all) seems to have done the job for me- but isn't this what you pros and veterans have been doing but using better hardware to record audio from either hard instrument or loopback soft synth ?
Sorry, but this thread got me feeling pretty confused about things right now
(I got Scott G.s X2 and X3 Power books to guide me in the beginning, but ashamedly I have to admit I find it is more fun to make noise than reading how to). Hope no one is offended.