I was thinking of putting four 12"s into a Mazda 3 trunk, and firing them into the cabin with the trunk sealed off.
Is it possible to have them fire upwards, and then have more MDF around it as the poorly drawn picture shows? There is not enough room on the face of the box to have more then 2 (maybe 3) firing directly into the cabin, so firing up and then against another MDF chamber is the only way I can see it fit.
I was thinking sealed box as I don't have enough volume to go ported, nor enough for bandpass either.
How tall should the opening be? Just a tad more then the subs maximum excursion so the woofers don't hit it, or does it need to be much more?