You put a JL into a shitty prefab box or use a shitty amp and it won't sound good. The enclosure design and overall install is key to tapping into the potential of your speaker. Most people think the problem is the sub and not the box, so if it sounds bad and they see the JL logo, they'll think that all JLs sound bad. So you can understand why a manufacturer would not want you to simply throw it in prefab box. Instead, they want you to buy their amps and their boxes, which although are very expensive, are designed specifically to work for their products.