I'm still in my listening/burning-in phase. The only other pair of quality headphones I own is the M-80 and I've been doing some A/B-ing and testing with my phone and laptop, both amped and umamped and don't feel I've spent enough time to really nail down what I'm hearing and how to describe it.
My initial thoughts echo the characteristics that others have already noted:
- Wider soundstage than the M-80.
- Much deeper, extended bass response (mine purrs from my phone[Wolfson DAC] with or without an amp).
- Sparkly, crisp treble is present and actually changes some of the songs I've listened to dozens of times with the M-80.
- Sounds fantastic plugged directly into my phone or laptop, and even better with an amp(cMoyBB v2.03), but it's not a crazy difference where I couldn't live without the amp. I will note that if you have an amp with bass boost, like the cMoy does, you're in for a treat. While the amp affects the M-80 slightly, but not in anyway that justifies buying an amp for it, the M-100s absolutely take whatever you decide to run through it and literally has a blast. Bass boost switch on cMoy + M-100 + Dubstep = Eargasm! Purr? Try roar!
- Mids are more recessed than M-80. Actually, the bass seems a bit recessed, too. Because of the wider soundstage on the M-100, your position in relation to where the music is coming is set a bit further back, whereas the M-80s have a more in-your-face, sitting next to the speakers kind of feel. I remember someone saying that it seemed like the M-80s had a stronger bass impact, and, depending on your source or whether or you not you have an amp, it does sound that way. I made the same observation when I first A/B'ed them and actually preferred the sound of the M-80 over the M-100. Once I played around with my cMoy and the bass boost switch, I realized that the M-100s bass is miles ahead of the M-80s and requires that you feed it the proper juice.
- Last thing. On the M-80, a particularly drafty day will lead to a wind tunnel effect on the headphones replacing your New Found Glory cover of Rocketman with a horrible whooshing sound. Not so with the M-100. Maybe that's the purpose of the felt cloth adhered to the vents beneath our V-MODA crests. The M-80s lack this piece of felt.
I'll have a more detailed review when I spend another week or two with them.