^^what he said..except I have no experience with the icons, but they are well regarded on these boards. GTi's are among the best sounding high output subs ever made, they may be rated for 750 watts rms, but they can handle a hell of a lot more and get brutally loud while staying very clean..as said they have the dual 3 ohm coils, and they are very tall for mounting.

 

thanks. i already heard 4 wgti 12"s and it was amazing how it soundend.
it wasnt loud (like earringing) but it hit in the stomach like nothing ^^ plus it sounded good doing it!

but i wondered if the orion hcca would beat the gti in the low end.(?)

 

If you tune it the same, yeah, it's +1250W RMS. I've had subs with resonant frequencies of 32 and 45 and the 45 had deeper more forcefull lows, everything else the same.

 

i also could run 2 15 l7 in a big sealed box rather than the single 15" jbl ported. (2 gtis is too expensive...)
who wins in sq/spl?

 

IMO, There is NO SQ in L7's....

 

I would suggest an American Bass Xfl series sub... 1000 watts RMS and much cheaper than the other models shown.
where are you located?

 

get an 18'' (look in the for sale section)

 

mach 5 15s they sound great hell even there 10s dig deep and are still accurate

 

has anyone heard the power series of jbl?

 

^^yes, they are nice sounding subs, and a good choice for the 500 watt range.