I was recently reading an issue of "Truckin'"

[LiquidClen]

And this guy in there had 4 Boston Acoustics subs, and 4 Passive Radiators. Has anybody tried PR's? How do they sound in comparison to a real sub? I'm curious. How do you set them up so that they work properly and effiecently?

[touringcamry]

You need the sub and the passive radiator to work together. I think the PR allows the sub to go lower and louder than it normally would with a sealed enclosure. I guess it's almost like putting a sub in a ported enclosure except the enclosure is much smaller.

I think you can find those Boston Acoustics sub and PR on crutchfield. http://www.crutchfield.com/S-sHAWv5o...520&I=065GTR12

I almost bought an Infinity Basslink subwoofer a while back. 10" sub w/ passive radiator
http://www.crutchfield.com/S-sHAWv5o...0&I=108BASSLIN
For its size and power, it doesn't work well in sedans, but works well in hatches, suvs and pickups where the sound isn't muffled.