I posted earlier about a blown 10" in my Ampeg SVT-1510HE cab.. I called Ampeg for a replacement speaker recommendation for this. I had asked about an Eminence BETA 10B, a 16ohm 250wRMS speaker. The tech said my cab has a "crossover" and that all power is not going to get to the 10", so a high powered speaker is not necessary. This cab has a 15" and a tweeter as well. What is this crossover doing? How do you calculate the power?