View Full Version : dual 15" IDQ IB help please !

06-17-2006, 10:02 PM
Alrite heres the deal, I'm trying to run these sucka's IB in my trunk, my car is a 2000 grand prix, heres a shot of the part that comes down, that panel there also pulls down to be open the the trunk, which is what the front piece on my model will match up to


In this picture, that open area will match around where the middle part of the backseat pulls down


This shows where the subs will be mounted, magnet out , I'm just wondering if there would be any disadvantages to this setup


06-17-2006, 10:17 PM
That model will have a very large peak at a high bass frequency, say somewhere between 150-200hz , you'll need a steep x-over slope (18-24db oct) to make sure you won't hear it, other than that it should work fine.

06-17-2006, 10:56 PM
well I can do 24db/per on my amp, i'd probably cross em at like 70ish hz, if i can smooth out the area between the subs and the front edge, will that help ?

06-17-2006, 11:54 PM
Yea I did a quick rough model and the peak is around 10db at 180hz, so with a 24db slope starting at 70hz the peak will be ~14db down, that combined with the cabin gain you'll get at the lower frequencies should make it more or less unnoticable.

Make the large chamber the 15's fire into as small a volume as possible, the smaller it is the higher in frequency the peak will be and the more it will be rolled off by the x-over. The smaller section acts as a port, make it as large(surface area) and as short as you can, both will increase the frequency of the peak.

06-17-2006, 11:56 PM
Alrite If I fiberglass it I can get the volume really small.