From the BF website:
Mix and match 12XN rigs
All the 12XN550 Barefaced cabs will work well together. However the best pairings are either with identical cabs or with matching 1x12" and 2x12" variants (i.e. BB2 with BT2, SC with ST). The other particularly good pairing is the Super Midget with the Super Compact.
Thanks Chris, very helpful. Sounds like an SC
will work well with a BB2, and quite well with an SM. Alex does
not say that an SC is not a good pairing with a BB2
; it is not recommended that you should avoid this avoid this, particularly, as I had said it perhaps was in my last post. It is still not the "best" combination though, it would seem.
Best pairings are still identical cabs or ones that are matched variants (i.e, horn with horn, no horn with no horn.) Except for SM+ SC which, for some reason, is "the other particularly good pairing".
The only thing I think would be weird about a SC + BB2 is that the BB2 is the larger box and therefore the better "base" for the stack, but I'd rather have the horn on the higher cabinet, rather than the lower one. I'd still rather have the SM, rather than an SC, stacked on my BB2 (as I do often) since the higher cab, SM, has a horn. The quoted text you provide doesn't mention BB2 + SM specifically, but he has indicated via email that this is a good pairing (as the "matched variants" implies should be the case).
Not fully relevant but I will share it anyway since it is peripherally relevant... I had asked Alex this: Since the SM is smaller, it's more stable (IMO) if it is not pushed all the way to the front vertical face of the stack, but rather somewhat back, a bit more centered, since it's front heavy if you have it right to the front edge. Does setting the SM further back cause any phase issues, dispersion effects, etc since the 12" drivers are not vertically aligned in that case, and the horns do not align horizontally when the SM is centered side-to-side on top. Apparently, it is NOT an issue for either phase or horn dispersion. The only difference, IIRC from his remarks, is that setting it back will cause the top SM cab to project its sound a bit more upward (not a bad thing and possibly a good thing). Perhaps Alex can correct me if I am not remembering this accurately. He said just experiment with it, put it where you want, and enjoy. Maybe this info is useful for anyone using stacked cabs that are not identical.