I use 2 VMPS Larger Subwoofers with my La Scalas. the results are excellent. With a 70 Hz crossover and properly adjusted level, you cannot tell there are subs in the system. I am doubtful "speed" has application with subwoofers, but in any case, the VMPS blend naturally with my La Scalas. They are more than "fast" enough to match and with 2 plus 450 wpc, loud enough. At first I had one and it was enough, when placed in a corner, for all but the loudest rock and roll sessions.