How can I turn my dual sub box into a single sub box?

Alpine Type X 12" Sub Box Design?

• Ok, so I've asked on here a few times and still havn't solved my problem, I have a single 12" Type X hooked up to an Alpine PDXM12 1200 watt amp. I hit 142.5 db at a competition so I am not complaining or trying to mess with it too much, but here's my settings: Low Pass Filter - 80 Subsonic - 15 Gain - 3/4 of the way Bass Boost On Deck Is Off Subwoofer Setting On Deck Is +5 I ordered a bass knob from Alpine, which hooks in to the amp, and it's almost full I only turn my volume up to 25 max, I believe deck goes to 32 or something I'm 90% sure it's my boxes fault, but I cannot hit low notes for s**t. Every other note feels like an earthquake, but as soon as the bass drops down low in songs like I'm Shinin' by The Pack - it seems like my sub disappeared for some reason The box I have right now is from Alpine and says Type X on the front.. link here http://www.google.ca/imgres?q=alpine+type+x+box&um=1&hl=en&safe=off&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&biw=1920&bih=922&tbm=isch&tbnid=dGmuu59lrGzo2M:&imgrefurl=http://northbay.canadianlisted.com/car-parts/alpine-type-x-sub-box_1148830.html&docid=xQj1_kimxx--TM&imgurl=http://images.canadianlisted.com/nlarge/alpine-type-x-sub-box_5831217.jpg&w=400&h=500&ei=tptnT_r5BoS-0AHZ3NSGCQ&zoom=1&iact=hc&vpx=175&vpy=120&dur=3418&hovh=251&hovw=201&tx=123&ty=160&sig=113069913009782240347&page=1&tbnh=133&tbnw=110&start=0&ndsp=45&ved=1t:429,r:0,s:0 (only one I could find online) but I also have a box that's home-made and is about 3.6 cubic feet and has a 12.5" x 1.75" port which box would be better, because I believe the home-made is too big (I've heard 1.8 cu. feet is best with port for my sub) I really wanna keep the same settings, but be able to hit lows too.. thanks

• Answer:

  you would need to build a new box tuned to a lower frequency... but lower tuning will result in lower SPL numbers at a show... it may meet your sound needs but not the meter... you could have a skilled box builder make an adjustable port box where an interchangeable board in the slot port will change tuning frequency of the box... have done 2 like this with decent resulting change in sound and SPL...