JBL GTI Box help

[motoamster13200]

I am buildign a box for my JBL GTI 12. 2.25 Cubes at 30HZ. Why are the ports so much different on the two box designs? Thanks

http://img23.imageshack.us/my.php?image=225cubes31hz3375sqin2bm.png


http://img147.imageshack.us/img147/1372/portoc0.th.jpg (http://img147.imageshack.us/my.php?image=portoc0.jpg)

[motoamster13200]

It seems like the one on JBL would be tuned a lot higher due to the shorter and wider port, but they are both 30 Hz

[motoamster13200]

I figured it out. The JBL recommend box is used with a PVC port.


Now what would you recommend porting my W12GTi Mkll 12 to for both rock and rap? Or should i go sealed? Ill be giving it 1000 RMS