I've built sub boxes several times for my cars and it's fairly simple when doing a sealed enclosure, for sure. I'm more than willing to look into ported and go that route, but I just don't know enough about how to figure out the tuning part. I need to do some reading I guess. But 5cf might be too large for the space since it's actually in a living room. The 21" cube is a perfect size since the Klipsch is 19 1/2" x 17.5", so it would be near the same size. I can live with that, but I'm not sure wife would like something more than twice the size, lol.
So does anyone have recommendations on subs in that price range?