The quality of the sound of my 2 EP-400s for 'music only' is simply outstanding; however, I've never used them for the high demands of HT. Four undoubtedly will have enough horsepower for the rigors of HT as was demonstrated here in 2007:
http://www.audioholics.com/subwoofer-reviews/axiom-audio-ep400-subwooferThe EP-400 has been significantly tweeked since this article in 2007. Mine are the latest version that continue to impress me with their exemplary performance. Get your out wallet if you purchase four though, ha!
Personally, I would go for 2 X EP500s for HT - way cheaper too...
TAM
Thank You
taken right from the article
According to Ian Colquhoun (President of Axiom Audio), the EP400 was produced to fill a specific need: to pack real subwoofer performance into the smallest possible enclosure. Ian and crew demonstrated that four subs are better than one at our 9th Annual State of the CE Union Event on October 6th, 2007. In a reasonably sized room such as the demo room they utilized (roughly 400ft^2), they were able to utilize 4 EP400's strategically located equidistant from the listening area against the midpoint locations of the 4 walls. Using a switching device to switch between 4 EP400s and 4 EP600s located in similar areas, it was nearly impossible to hear or detect a difference. The EP400s were playing just as low and loudly into their demo room validating their claim that the EP400 has similar extension of the EP600s when played at similar volume levels in a moderately sized room. For those wondering how they can cram 4 giant boxed sized subs into their theater room to take advantage of even bass response in all listening positions, the EP400 may just be the answer to your problems. We look forward to examining this new little GIANT in the near future via a formal product review.
