Revel Ultima Sub 30 powered subwoofer
It didn't seem like such a big deal. After all, when designer Kevin Voecks added a passive radiator to the bottom of Revel Loudspeakers' powerful <A HREF="http://www.stereophile.com/loudspeakerreviews/90">Ultima Sub 15</A> subwoofer, no one expected that the resulting 6dB increase in bass output below 35Hz would be so audible. However, Revel's sophisticated double-blind listening tests (described in my review of their flagship <A HREF="http://www.stereophile.com/loudspeakerreviews/96">Ultima Salon</A> full-range loudspeaker in the March 1999 <I>Stereophile</I>, revealed that a big change had occurred. With now twice the radiating surface, the modified Sub 15 produced significantly deeper, more powerful bass.