i'm about to purchase an htd level four set...is there any advantage to having the same brand of subwoofer with the rest of the speakers or would a sonosub blend in just as well? i have a feeling i'll be compelled to build one anyways, even if i already have a sub. as far as the speaker in the sonosub, i have some laying around that i could use...2 10" adire brahma's and 1 15" adire brahma. i'm not sure if these subs are recommended for a sonosub or not. it would most likely be a passive sonosub.