Posted by J.C. Vanderhave on January 04, 2000 at 17:00:37:
In Reply to: How do I get good stereo sound in my 81 528i? posted by SwampJedi on December 26, 1999 at 14:24:39:
The solution I found was this: I used 2 - 4X6 two ways and used a bandpass subwoofer enclosure. You can get the plans off the web from polk audio. I cut 2 small 2 - 1/2 inch diameter holes in my rear deck. I used a couple of desk cable flanges (the ones that you use when you are running cable through an office desk) to dress up the holes in the deck, and give a stock looking appearance. I then ran two lengths of 2 1/2inch ABS pipe from the bass ports on the enclosure to the flanges.
With only a small 8 inch driver, the bass is very crisp and punchy - not boomy. Plus you don't have to push massive wattage to get decent sound. The bandpass enlosure is small and doesn't take up much room (it's only 20 inches long). I used this set up on my '82 320iS as well as my wifes '77 530i.