The MBox can only handle 2 simultaneous inputs, not 4. The Digi 001 can handle 18 simultaneous inputs through a combination of 8 analog, 8 lightpipe and 2 S/PDIF. So if you want to take 4 tracks in SIMULTANEOUSLY the MBox is out and the Digi 001 is in. There is a way of using the MBox taking 2 tracks in at a time and then lining up the two pairs in the edit window. First, put an audio "mark" across your tape tracks in an unused part of the tape. Maybe 10 seconds before the actual audio starts, or 10 seconds after it ends. The placement is not important as long as you don't damage your desired audio, and the mark is identical across all tracks. (You only really need to mark two tracks, one in each pair, but it's easier to talk about it if I say to mark all tracks.) This mark can be a single "click", a hi-hat, a kick drum. Pretty much anything. Short percussive sounds work best. Now that you have an identical "mark" sound on each track, fly a pair of tracks into the MBox. Now fly the second pair of tracks into the MBox. Your tracks will not be in sync. Now go into the edit window and find your "mark." Grab both of the audio regions from your second pair and slide them until the mark lines up with the mark on the first pair of tracks. It sounds like a hassle, but it's pretty easy once you've done it a couple of times. I do it with ADAT tapes all the time on the 001. Mike