Hey Observator,See my post "Crossovers for Delta15 @ 700 Hz, Beta12LT @ 15kHz? " below. There are others as well; just take a look.
I tried Wayne's crossover and the KSN1038 but the piezo didn't seem loud enough to me. I was thinking of trying the more sensitive KSN1177--it's basically two piezos side by side!
You might want to redo the PiAlign calculations with the "new" Beta12LT specs off the eminence site. The data file in the PiAlign program uses the "old" specs.
Good luck,
Jeff