Try this site they have a listing for the SP15A's but not the B's, which should be pretty close, I think the A's were for guitars and the B's were for bass guitar. The only difference between the EVM15L's and the EVM15B's were the L's had 3 or 4 extra ribs on the cone to make it stiffer, where as the B's didn't have those extra ribs, which only varied the Qms and Vas of the speaker if I remember right.