While that's kind of true, it's not 100% spot on. For the most part, you're not hurting much with a perfectly square sealed enclosure for a sub. There are, however, upper order harmonics of the fundamental frequencies the sub is playing that could have ill effects on the sound the sub is putting out. These may be noticed in the higher bass frequencies. With these upper order harmonics having a much smaller wavelength, the enclosure does not need to be the size of a bus to get standing waves or other nasty sounds coming from the cone.i'm with the two that said it doesn't matter for subs....
the only time it would matter for a sub is if the box was soooo large (school bus size and up) that the waves would actually have a chance to cancel each other inside of it. since low end freq. has such a long wave, you would need a HUGE box to notice the difference.