Every room is different, but what I said about placement - It ONLY applies in stereo. In mono, there is no reason to use two. I haven't been in a situation that afforded me a 20 foot span in a looooong time. That was part of the draw to the L1 in the first place. I still believe that in most applications, 2 is detrimental to the coverage. This of course, is affected by exact placement, angle, volume, room acoustics etc. There's no one right way, but in almost every case I've encountered - the Bose is better in mono.