New Active Crossover... Bryston 10B, JL audio CR1, Pass Labs XVR1 or First Watt B5?

By "So is the B4", I meant discontinued, not designed for OB's.

I looked into the Pass, but it's over my card limit ;-). The Bryston is too limited in flexibility (slopes, frequencies, etc.). The First Watt B5 is designed specifically for OB loudspeakers and subs, and at any rate is discontinued. So is the B4, which is the x/o you may want (it is VERY flexible: 1st/2nd/3rd/4th-order filters in 25Hz increments from 25Hz to over 6k!). I did, and found myself a used one. It too is, unfortunately, out-of-production. Call Reno Hi-Fi---a major Pass/First Watt retailer: he may know of an available one.