I'm sure they do..but 6x9"s and a subwoofer wont mix. Doubly so if their sharing a box.
Taken from
http://www.caraudioaustralia.com/forums/in...showtopic=58374"Some people choose to use 6x9”s to get “big bass”. 6x9”s are commonly sold relatively cheaply, and are advertised as being able to play “deep bass and crystal high notes”.
Not so. Most 6x9”s, while having large surface area and being able to play low, simply wont sound nearly as clear, go as loud, or quite as low as a subwoofer.
Also, because they are trying to play the entire spectrum of sound, they won’t do it all very well. In regards to bass, it will sound muddy, compared to a dedicated subwoofer, and because they are usually mounted behind you and playing directional frequencies, they will drag the sound backwards, not what you want.
If you use 6x9”s WITH a subwoofer, any frequencies that both speakers make, will interefere with each other. You’ll get cancellation, which means by a trick of physics, you wont even HEAR some bass frequencies. The 6x9”s and the sub will generally interfere with each other, and reduce your overall SQ."
Also, note safety. Apart from the illegal aspect (cutting holes in your parcel shelf without re-inforcing it is technically illegal), a subwoofer will weigh more than the 6x9"s, no doubt....and you dont want it flying through the cabin in a crash. So secure it. Very well.
A small boxed sub in the boot, maybe with ports firing up through holes where the 6x9"S currently sit, is a safer and probably more practical option. If your willing to try fibreglassing in such an awkward space, it will be easier to mount the woofer proper in the boot, safer, too.
Last but not least, yes, there are free-air subs on the market, but the general consensus is that they are inferior to subs designed to run in a box. Even small ones. It makes sense, somewhere your going to need a compromise in a free air sub, its going to need to waste energy dampening the cone (through stiffer suspension or whatnot) whereas this would be have been done by the trapped air in a box normally. Logic suggests.
Consider a removable sub-box also. Any sub-box hanging off the parcel shelf is going to take up a bit of room...i can think of ways you can have a sub-box in the boot, firing up through the ports, still leaving plenty of room in the boot. If you car's a CE, i have the same as you, and have been considering similair possibilities.