See, that's where some of the internet direct companies really come into play. Probably some of the best subs out there right now, IMO, are mostly vented designs. In fact, in the home, sealed creates different issues - in a small volume with cabin gain, sealed subs generally sound good. Stick them in a large volume area with less gain and you now need a TON more power to achieve the same thing that a vented design can do easily. Vented designs aren't quite as "tight" as sealed, but that is one of the trade offs, as are output, tuning and extension. Peaks and dips can be due to the room as well, so even with a relatively flat response designed into the sub, the result will vary depending on the room. Then you can get EQ involved...