Two-channel sound (6)
I believe the answer is:
stereo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">two-channel sound</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stereo that I've seen before include "One might play record" , "Audio system, hi-fi" , "Of sound equipment, having two speakers" , "Sound transmission from two sources through two channels" , "With twin audio channels" .)