You probably know this but just in case and just a suggestion: check with the driver manufacturer’s specs on the cabinet’s internal volume?
I bought 4 subwoofers and I'm absolutely not doing a DBA! Hah!
I just received shipments of 4 subwoofer drivers and they will not be going into a distributed bass array.
I'm replacing my left and right speaker stands with powering subwoofers with 2 subwoofer drivers each. I call them powering because they will be powering the 2-way monitors that will sit on top. Here's a beauty shot of the insides.
The amp has all the DSP power I could need to produce perfect speaker measurements. I wonder if JA at Stereophile would wax poetically if I priced them high enough?? 