Just FYI if you do a cone area displacement comparison between multiple smaller woofers vs 1 larger woofer and box volume requirements you'll see that multiple smaller drivers win every time.
Example - 3 10" vs 1 18" - 235.5 sq in for the 10's vs 254.34 and box volume would be approximately 3 cuft (and smaller) for 3 10's vs 9 cuft (and larger) for 1 18" woofer. You get a 3db coupling effect from having multiple drivers next to each other and with proper enclosure building they'll hit the same low notes due to secondary harmonics.
BTW I was on Team Streamline Audio when we built Alma Gates 164.9 DB Bronco with 46 10" woofers and 23 1400 watt amps. [img]smile.gif[/img]
The main reason why I'm drawn to a single 18 is the fact that bigger drivers generally reproduce lower frequencies better. I love subsonic bass... the kind you can't hear but can really feel. I haven't been able to get much of it with 2 12s.
Trust me build a nice 7th order bandpass porting through the back deck of the trunk with 4 10's and you'll be in heaven. to make it perfect make the seal between the trunk and the interior cabin air tight and it will make a huge difference.
I had 6 15" woofers through the rear deck the car isobarically mounted when I took 6th place in the Expert class 1995 IASCA world finals in my 92 Caprice. I only did the 15's for the WOW factor that the MTX Thundercast series gave you when you saw the 3 baskets coming up through the rear deck.
Highest order I've ever heard of is 6th, and don't those things have to be built perfectly or else they'll sound like crap?
Define "heaven" . Pure SQ with good SPL, or just all-out SPL?
Alright, so I did some research [img]5.gif[/img].
7th-order is just a 6th-order with a tuned port between the two chambers, correct?
Almost everyone on the audio forums seem to think that bandpass boxes sound like crap. I'm going for SQ here as well as SPL... would 7th-order still keep me happy? Trunk space is a big concern too [img]tongue.gif[/img]