Gradient SW-57 subwoofer
There are two kinds of audiophiles: those who own original Quad ESL speakers and those who don't (footnote 1). This review is for the former, although the latter may find it of some interest. The Gradient SW-57 subwoofer attempts to do for the original Quad (footnote 2) what Gradient's SW-63 (footnote 3) does for the Quad ESL-63: supply the bottom octave while relieving the ESLs of the strain of reproducing low bass.