For my new system I was buying 4 15" L7's but I then I thought about the 18" soloX so now I don't know which one would be louder some know?(oh yea I plan to use the rec SPL box from kicker. Any help will greatly be appreciated.
you do realize with wiring alternator or alternators and installation, circuit breakers, distribution blocks, the install alone could be close to $1000
but 4 L7's would be louder you have to remember all that surface area the subs are pushing i mean 1 18 solo x would be monstrous but it would not beat out 4 L7's would not even come close but sense going to need a whole lot of power and have already planned for a lot of space i would go with 2 18 solo x's put all the power you planned to put to the L7's but instead to 2 18 X's and that would definetly be louder