And about that 15" again that says it should go in a 4.2ft3 box tuned at 22hz. That box should be fine right? Why would parts express be wrong?\n\n\nYour problem is that you are not only ignorant, but also belligerent. That is not a winning combination.\n\nI have 66 years speaker design experience now, and I have done my very best to help you.\n\nThe last model I sent you fits your requirements perfectly.\n\nYou want a ported sub, nothing wrong with that.\n\nYou want it to reach the last octave. It does. It is 3db down at 24 Hz, so that is only four cycles away, and the loss of output from 24 to 20 Hz is negligible. Room gain will more then obliterate that loss anyway.\n\nThe design specifies a driver that is specifically designed for ported application. Your driver is not. This is important as in creating a design, bass quality is even more important than extension.\n\nThe design I shared with you I can be certain will provide very high quality bass. If you look at the included graphs, and no how to understand, you can see that sub has outstanding specs. If you had looked properly, you would see that sub will produce 107 db at 20Hz with only 150 watts of power.\n\nThe design is also cost effective and relatively easy to build. It is cheap enough you can afford to build two if you want.\n\nThat design fulfils everything you are trying tp achieve.\n\nThat is all I have to say on the matter. You asked for help, you have got it free and gratis, now get on with it.