I’ve had both and the C7 sound is a bit warmer, more bass extension and lovely treble, a perfectly balanced speaker for detail mixed with easy on the ear, a speaker you can very happily live with and not feel you’re missing anything. For me, and these things are personal, I didn’t get on with the M30.2 XD. I found them bass light, a bit ‘hard’ sounding, not so musically involving.
C7’s all day long for me.
C7’s all day long for me.