Personally, I think Alpha 15's have a nostalgic sound, probably due to their their relatively small magnet and their cone shape. Reminds me of what was in console stereos in the fifties. Also, they aren't electrically damped as much as most drivers, and so they are ideal for sound systems that can't provide much electrical damping - such as low power tube amps. They already have very high Qes, so low damping factors are pretty much "water under the bridge."

All-in-all, they're an interesting part and very popular for Eminence. The most popular 15" woofer here is probably the Delta 15, but the nostalgic sound of the Alpha 15 makes them pretty popular too. Just be sure that you use a Zobel with them and don't run them "wide open." For subwoofer use, crossover below 200Hz; As a midwoofer, don't go above 1.6kHz. And when used as a midwoofer, the Zobel becomes extremely important. This is the configuration for the Thermionic Series four and seven π speakers, which when combined with a nice tube amp, will take you right back to the 1950's, just like "American Graffiti."