Ok so i have a 96 mazda b2300 reg cab and im trying to figure out what to do as far as subs with it. A blow through is not an option right now. Im thinking maybe a few L7 10s becuase I know theres no room for my 15 L7. What to do?

How much depth are you looking to give up. L7-10's are a good option. A single 12" ported would be another good option as well IMO.

ideally as little as possible. I might swap out seats in my truck to get more room. I also thought about putting it behind the passenger seat

I am overly impressed with Fi SSD's. SSD 12's are 6.5" deep, taking into consideration room for the pole vent and using 3/4" MDF you would need a total depth of just under 1'. Give it 1.5cuft tuned to 33Hz and put it on the passenger side with the sub firing forward and have an external port firing towards the drivers side (20sqin slot port or a 4" aero port will work fine). If you can feed it 7-800w it should get decently loud. A similar configuration with an L7 or other 12 would work great too. Remember that a 12'' has almost as much cone area as 2 10's, generally requires less air space, and speing strictly about motor efficnecy between the two sizes with the same motor (and not driver efficency) is twice as efficent.

Cone SA can be calculated, cone depth being the only unknown. Warning - math to follow: SA Cone = 2pi(avg(r))(h) where h represents cone depth avg(r) in this situation is half the radius, or one quarter the diameter Define x and y as cone depth for the 10" and 12", respectively. Setup for one twelve equals two tens 2pi(3)(y) = (2)2pi(2.5)(x) y = 5/3x So, you're saying a 12" speaker has 5/3 times the cone depth of a 10"? Seems unlikely. *Let's use an assumption* that cone depth is proportional to radius, or y/6 = x/5, solve to y=6x/5. SA 2x10": (2)2pi(2.5)x SA 12": 2pi(3)(6x/5) We'll look at a comparison of SA by dividing the 2x10" eq by the 12" eq. The actual values of the cone depths become irrevalent. (SA 2x10") / (SA 1x12") = 5/(18/5) = 1.39 Operating under this assumption, two tens give a helluva lot more SA than a single 12". Either I'm missing some critical piece of knowledge here or the rule of thumb is BS.

I beleive he's saying the 12" is more efficient than two 10"s. I diddn't do all the math on this one but a quick thinkthrough leads me to believe he's correct.