Joe:
It sounds like we might be looking for the same thing....bass frequencies NOT covered by the LITTLE speakers in their stock locations. Oh, and I also have NO interest in mega bass.
I'd be totally happy finding a location to fit some 6.5" drivers giving me bass only down to around 50-60Hz.
The little 4" drivers in the 4 stock locations prolly are only good for about 120Hz at their LOW end. This high of a top end roll off really makes the sound unpleasant.
The thing is, just having a subwoofer that's good for 30-85Hz isn't going to work here. I'll have a huge gap from 85-120Hz that will be very audible and may actually sound worse than the current situation. Plus, this would require putting a sub box in the trunk all the time which I'd rather not have to do.
This was originally the reason for the 8" sub. An 8" driver has the ability to fairly accurately deliver frequencies as high as 150Hz. But, once again,an 8" driver is would be in a cabinet...hence, my thoughts on using a free-air 8" sub in the rear deck compartment. This would take car of the cabinet issue.
But, from the feedback I've gotten, the sound I'd get would be totally unpredictable due to the free-air nature of the driver and trunk response issues.
Maybe I'll inquire about just building some really shallow cabinets that are ONLY just big enough to fit in the two rear deck compartemnts and then fit some shallow 6.5" drivers in them. If this were possible, I wouldn't have to do any cutting back there which would be a HUGE plus with me.
Only question is whether a box of adequate volume (roughly .5ft^3 I would guess) can be built that would fit flush into those rear deck compartments. I'll have to start taking some measurements and run the numbers.
Other advantage to this is that the 6.5" drivers would be fairly cheap and would fill the gap under the little 4" drivers perfectly while giving me totally adequate bass response DIRECTLY into the cabin of the car.
