I've had an opportunity to do a side by side comparison of the LS50 and CM8 (s1) at home for a while. These are popular speakers so I thought I'd share my thoughts
It may seem odd comparing a 3-way floorstander with a 2 -way monitor, but they actually have a lot in common. They both have an unusually high -3db point, followed by an especially gradual roll off in bass to the -6db point. They're both very clear and precise speakers with solid cabinets, and are reputed for reproducing vocal music. And actually they sound unexpectedly similar. Switching between them it was surprisingly possible to forget which pair was playing.
Equipment was a rotel ra-11 being fed digitally over AirPlay. A combination of 256kb/s AAC and 1411kb/s ALAC. I have a subwoofer but I'm not using it here.
Here's how I would describe the differences (slight as they were):
CM8: clear and precise, yet warmer and fuller, more bass extension, more laid back, slightly more relaxed in the treble. Wider sound stage.
LS50: very clear and precise. Amazingly sharp imaging. More revealing. More analytical and less "colour". More restrained but also more detailed bass. More emphasised treble. Forward, fast and at times harsher or more fatiguing (especially with string instruments). A fraction less sensitive/loud.
I'm also tempted to say that the ALAC files sounded great on both pairs, while the lower bitrate AAC were very slightly less enjoyable on the LS50, but I need more listening time to be certain of this point.
I actually bought the ls50 for late night bedroom listening while i go to sleep, but they're so forward and revealing it's not the most relaxing speaker to listen to, and the cm8 might be better for this purpose. On the other hand floor standing speakers look quite odd in the bedroom.
It's possible a more powerful amp might address the occasional harshness in the ls50 compared to the cm8. Or perhaps this is simply an inherent difference in the speakers?