See I had it tuned low once upon a time, it didnt have any punch to it. So I decided to cut the port length down and it tuned it a little higher. I love it but when some rap songs are low and its like its not even there.
I have tuned 3 of my enclosures at 28Hz and one at 29Hz. They were all "punchy" and hit the lows nicely. Subs were: 12VQ, W10GTi, (3) GTO804's (29hz tuning), SE10. All hit the lows nicely. THe GTO804's don't go very low which I knew when I bought them I just wanted to try something new but they hit the 30's nicely. Flattest response I've had so far.
there are a few 15" avalanches available in the classifieds for around 200 each, one of the greatest sql subs made. will get crazy loud and low off the right wattage.