I have an IA 20.1 on order and am thinking of going with two Mag D2 15s for it.

I designed a box that is 7 @ 30hz w/ 90in^2 vent area.

I was wondering if you guys had tried that type box yet and just how does it do? Does it start to dip after 50hz? I am sure it wil probably ring my bell from 30 - 50hz. I am just worried it won't do much afterwards. About where would you said my 3dB down point would be?

Also, I have a goal of a 146+ new TL with this setup Legal on music. 98 explorer....think that is too lofty of a goal??

Thanks :-D

-Alex

Not a lofty goal at all - you should be able to get that no problem. The drivers will do fine above 50 also, inductance is decent so the 80 Hz extension is very obtatinable.

I designed my box man, check it out and tell me what you think.

41.5 wide (wheel well to wheel well)

14.75 high (well under the window line :-D)

31 deep (6" of firing room for the port)

16 x 5.75 port (92in^2)

I figured it up to be right at 7.2 or so ft^3 net. I also calculated that a 21" long port will put me somewhere from 30 - 33hz.

Does that look good to you bro? Enough port area? Port length correct?

Another question.

If I tuned this box down to like 28hz, so I could really shake some chit -- would I then start to have trouble over 50hz?

I really want something that will rumble like hell.

Tuning lower doesn't mean the high frequency extension will suffer more. You're not making a bandpass enclosure so your upper frequency limit is based more on inductance than anything else.

Don't forget about tranfer function. I don't know how your Explorer will react, but my buddy's camaro has a black hole starting about 48Hz unless you have the sub up front. There was nothing I could do in that vehicle other than an up front placement to get any useful output out of the sub system above 50Hz. Some vehicles just have major cancellation issues that you will have to address at installation time. OF course, many applications will vary.

IMO, you shouldn't be using the sub above 50Hz anyways. Midbass is the key here. Once you have a strong midbass foundation, you'll never have the desire to run the sub any higher.