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.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.

<I>Stereophile</I>'s "Products of the Year," now in its 13th year, recognizes those rare components that prove capable of giving musical pleasure beyond the formal review period. These are the components that can be recommended with no ifs or buts, that will grace any system in which they are used.