Any ideas what to do with these? (10" PA Midbass)

[Puggie]

I would like to build a pair of very high quality PA speakers, my criteria are basically high quality, low distortion sound down to about 50-60Hz, they will be mainly used on voice and acoustic guitar. I have got the following midbass drivers (Volt BM251.4) in the 4Ohm version (these specs are for the 8Ohm)

Fs 57Hz
Re 5.2ohms
Qa 2.9
Qe 0.37
Qt 0.33
Vas 38litres
Xmax 2.5mm
Sd 288cm2
Vd 72cm3
Le 0.8mH

I've had a play and come up with about 30l tuned to 55Hz, this should give me a good response down to about 50-60Hz then rapid roll off. My intention is to partner them with something like a Fountec Neo2 ribbon or similar high efficiency large ribbon, porribly slightly waveguide/hornloaded.

can anyone come up with anything better? TL/MLQWT/etc?

thanks.