I've always liked the Celestion HF 1300/ Coles 4001G combination, works so well in many designs, e.g. B&W DM1, DM2, DM2a, DM4, the DM3 uses the Celestion HF1400 (1300 with bigger magnet) and the Coles 4001G.
Some say that the midrange of the BC1 is better than the SP1. I have never owned SP1.
I do have all the B&W above and BC1 and BC2.

