Just wondering if walling my civic hatch with two 15" woofers instead of a single 18" sub would it be better.Im sure two 15's will be louder than one 18 but who knows. I have the space for two 18's but i would have to make a really custom box and im not up for that right now with it being winter and cold. What do you guys think? Two 15's walled or a single 18? Power will be depending on what the woofers can take but i have 8k or so for power at the moment. Maybe only 7k in the future. I have an 18' Custom built RD 18" heavyweight but im looking at two 15" t3 audio tsns', or two 15" shocker sigs. Let me know your input, any is good.