Spl suggestion

[quick65]

I have 15 cubic feet of room for a box.  My goal is low frequency spl.  Im thinking about (2) 18’s in a ported box.  I had X series sundowns and wasnt very impressed.  I only want to use 3-4kw of power.  What do you suggest?  

[Joe X]

Post pics and specs (box specs, amp, electrical, etc) of your previous setup, Sure enough the X subs are for the lows and not SPL but two 18s (if properly setup) should not be so disappointing  unless the box is wrong or the subs are not driven properly.