This one really has me scratching my head.
Another taper and I recently recorded a Greensky Bluegrass show @ The Historic Blairstown Theater.
I had access to the SBD and grabbed a patch. 1/4">1/8">M-10. I also ran my AUD rig FOB mk41>kc5>cmc6>SD 722. The venue is a tiny theater and the show was sold out which made it very inconvenient to stop/start both decks so I just let the M-10 run for both sets knowing I had ample battery power and card space.
I was able to successfully do a matrix-in-post of my source (mk41>kc5>cmc6>SD 722). Results are here:
http://archive.org/details/gsbg2013-08-02.mk41.mtx.flac16. Not my first time doing a matrix using 2 different sources from 2 different decks that are not jammed to the same clock. I've gotten pretty good at it and have been pretty satisfied with the results. Enough so that I can't yet justify purchasing a 4 track for the ~15-20% of shows where I have SBD access (even though my inner gear-slut tells me otherwise).
I use Sony Vegas and my matrix-in-post methodology is pretty simple and logical, IMHO. I knock down peak values of each recording to -6 to -9dB to avoid clipping once the two are mixed down. I import both as stereo files in Vegas. I pan the AUD hard left and the SBD hard right and use headphones to shift the events and "rough in" the delay at the beginning of the recording. I've found snare hits and/or stage banter are great for this, BTW. I then pan each to center and listen for "the echo/delay" and shift them by 2 or 3 or 4 thousandths of a second to get them properly aligned and eliminate the "reverb". Then I snap to the end of the recording and use the same methodology using the "shrink" recording function in Vegas. Has alway served me well....
So anyhow, I offered to do a matrix-in-post of my buddy's Neumann source (I was clamped to his stand). He sent me his raw, unedited source which is KM-184>V3>SD 722. I used above-mentioned method, and set 1 turned out great (same sample rate/bit depth etc.). Set 2 is a complete disaster. When I try to align the 2nd set opener I get a 1 minute discrepancy within the first 10 minutes, which is crazy big. Both are in pitch as near as I can tell...
I'm about to abandon this project.....