Ok, looked at the sub last night. Interesting design. Ported sub w/ 2 small drivers in a composite enclosure. It's a neat little package... cute. Too bad their budget and space constraints squeezed them into designing something that leaves so much to be desired.
Here are the approximate measurements I got of the enclosure:
Top cover diameter - ~17"
Bottom diameter - ~14"
Height - ~7"
I guess this is the space we can work with if we are to keep the spare. So using the smaller diameter (bottom), we can probably fit a 9.5" X 9.5" X 7" box (lol!!). Which works out to about a 0.3 cu foot enclosure WITHOUT accounting for the woofer's volume. I'd say it's pretty much next to impossible to go with sealed boxes and larger drivers while keeping the spare.
Only solution to get a true subwoofer in there is to use a cylinder shaped enclosure with a diameter of 14" or a conical shaped cylinder using the top & bottom dimeters which would probably push the enclosure volume to atleast ~0.5-0.6cu ft. In any case, I think it's very difficult (and expensive) to get something like that fabricated. Using a sonotube may be an option (for a straight cylinder).
So I'm back to square one.
Options are with spare:
- Free air sub
- Replace woofers in existing Blose with better quality drivers
- Dual 6x9 woofers mounted on a custom round mdf plate on top of the spare maybe? - I need to think this through. :x
Get rid of the spare, then it's a whole new ball game. You can probaly squeeze 2 12's in there if ya wanted to.