vmps' are good *and* cheap. :>) i've heard the top-line welodynes, & the mid-line rels in one-sub set-ups - they never sounded right, the bass always sounded like it was coning from the sub, never blended into the soundstage, and was boomy one-note *thump*. perhaps set-up was poor. the *only* time i ever heard a single sub set-up sound ok was a hsu powered sub - one of the older models that, while round, wasn't as tall as the latest iterations. it was placed in the near-field, like a coffee-table, right in front of ya. the soundstaging was wery natural...
doug s.