My car sub is 10inch, but i built the perfect ltr ported box to suit, most people buy a 12inch sub, go out and buy a 12inch sub box, but the litre size to the sub is totally off, so it sounds F@#K#D. Mine doesn\'t, i\'ve measured its response and got it just about perfect to teh manufacture\'s figures.
My PC sub is just a 8inch active powered sub, does the job.