In terms of their sound, the Clear Mg is identical to the Clear Mg Professional (as the Clear was to the Clear Professional).
Regarding the fuller sound: I do actually hear the Clear Mg as fuller sounding than the Clear. While I tried to explain why in the video, I'm not sure I did as well as I'd have liked, mostly because I'm not sure I know exactly why.
I have a feeling this is similar to the HD800 / H800S comparison -- there are few who'd argue the HD800S sounds more full-bodied than the HD800. Yet depending on which measurements you look at, I've seen some showing a touch more bass with the HD800S, and some showing a touch more with the HD800. Which is true? I think the bass is largely the same, and the measured differences in bass with the HD800 / H800S are likely unit-to-unit variation, measurement-to-measurement variation, etc. The one big difference we can see is in the treble, and it's not altogether massive. Here's a measurement comparing the HD800, HD800S and HD820 I posted some years back:
Fig.1 (above): Sennheiser HD800, HD800S, and HD820 frequency response comparison, measured on the GRAS 45CA (RA0401).
Focusing on just the HD800 and HD800S measurements in Fig.1, you'll see that the main difference between them is from 4k Hz to around 6.5 kHz (peaking at around 5.8 kHz), the HD800 measuring with more energy there. Is that the reason for the perceived difference between them, for the fuller-sounding signature of the HD800S? Maybe, yeah. It's certainly at least part of the explanation. (I strongly prefer the HD800S to the HD800, for whatever that's worth.)
I think that may be analogous to what's happening with the Clear and Clear Mg.
Is that the
only reason for the perceived differences with either the HD800/HD800S comparison or the Clear/Clear Mg comparison -- why the successors in those pairings sound more full than their forebears? I don't think so.
Regarding the measured treble differences between the Clear and Clear Mg, I think they're significant. As with the HD800/HD800S, the smoothing of the treble is happening somewhere many of us are quite sensitive. Also, there's better extension above 10 kHz.
Thank you for the kind words,
@DivineCurrent!
Yes, other than packaging and colorway, the Clear Mg and Clear Mg Professional are the same.