On this topic I just finished comparing my pair of Audiopulse Axis 12", 1 was in a sealed 1.4 cu ft and the other was in approx 2.5 cu ft with a Mach 5 18" passive.
They were both driven by QSC PLX amps but the sealed box was fed twice the power. They were both placed in the same exact location and eq'ed with a SMS-1 to be flat and the levels matched.
I ran through the usual tests from Master & Commander to LFDH and a few DTS demo discs.
It should come as no surprise to most that the PR box played lower and louder with less strain. As far as SQ with music and movies they were about the same except when things starting getting really loud, you could then hear the sealed begin to struggle.
I was actually much more impressed with the PR box with the Axis then I was with the same set-up and the 12" TC2K which the box was initially made for. I eventually will make a ported box for the Axis to try out as well, I just need to figure out what would work out best for this driver, any thoughts?
If space is a concern then the Axis 12" in a small box is an excellent performer, you just need to add some boost and a lot of power unless you have a small room. I am actually blown away by the Axis in a small box and I normally run a Mal-X so I am hard to impress.
You can check out some pics of the 2 subs at the thread I started to find some options for a ported alignment.
http://www.hometheatershack.com/for...audiopulse-axis-12-worth-port.html#post180197