Fi has a specific model IB3 for infinite baffle.
Fi Q may perform ok, but won't last long in infinite baffle setup because it is not designed for it and the sound quality will be lower than IB3 or other specific infinite baffle subwoofers.
I have a 1.5c sealed box crying for a fi q12, or aa havoc. This are my 2 choices for now. My last two subwoofers were image dynamics idmax ''12, best subs there is but won't last on 800w+ amp. I was fast enough to sell my first one when it almost ran out of juice, and the second one just died on me.
Give me a call or e-mail so we can discuss the payment and shipping