The following is only if you want to build a 'premium' level of subwoofer with outstanding performance.
If you really want the most output from a tiny sub, are willing to spend more, will use a little bit bigger box(to accommodate the slot port) and want another level of performance, it will be difficult to impossible to beat the JL W7 8". In 1 cubic foot + appropriate folded slot port of 7" wide x 2" high x 44" long. Combine with O Audio 500 Watt BASH amplifier. A weaker amp is not recommend for this driver. Also, the subsonic filter is important on the O Audio for the safety of any ported sub used for HT purposes. You will achieve ground plane 2 M output, realistically, around 105dB at 28Hz, 107db by 40Hz. This is accounting for some thermal compression and port compression. The modeled SPL is actually quite a bit more
, but I try to give more realistic performance numbers based on real world factors. Realize, the W7 will have less thermal compression and more linear excursion when compared to most anything else. I tried to select the smallest possible port for compact size, and some compression is occurring as a result.
BTW, the factory specs for 8W7 are way off on VAS. I have tested 2 different pairs from two different production runs and they are consistent, both with VAS nearly 1/2 of what factory spec indicates.
The 8W7 is about $250 from online discount sellers. The only comparable 8" I know of is the now unavailable TC Sounds built one sold by Sound Splinter. However, as was said earlier, it may not be suited to such a small volume. The driver can safely operate at high SPL to about 20Hz in a 1.5 volume ported cabinet! It is a rather amazing 8" driver with extreme thermal capability and incredible linear excursion. I can say that in my use in sealed applications, the one way 19mm xmax is a conservative rating I suspect. Photo
of 8W7 from rear.
Here are the actual T/S parameters measured from an 8W7 for modeling purposes:
VAS: 0.326 ft^3
Le: 1.34 mH
Xmax: 19 mm
Pe: 500 W