The 7X has everything I was worried I wouldn't get from a BA configuration, having spent my recent time with single dynamic drivers. The notes have weight, presence, thickness, and the bass drivers (one big woofer, one dual-driver) can actually move air. When I was told the 7X would be very capable in the low-end, I translated that as meaning "for BA's."
The bass is just straight up capable. It punches, it sustains, it moves air. It does so in a way that I think could be described as audiophile-style bass emphasis. I can't imagine being disappointed when listening to tracks that shine on those sort of headphones. I love listening to electronic stuff on the 7X (e.g. I'm listening to new-school stuff like Grimes, Emika, TRUST, Austra, Chromatics, etc. a lot.)
The mids are forward and thick, if you ask me. That said, there's really no air or grain to speak of in the mid presentation, and that's one thing I found myself missing from the GR07. They're liquid smooth. Also, very recording-dependent. I think that's just a part of them being high-end -- basically all high-end audio equipment isn't forgiving of ****ty recording/engineering/mastering. But, in a good recording, with vocals front and center without too much mid-bass, the 7X shines.
Highs are where I could use some more. I'd like more detail there, more sparkle. Simply more presence. They're not absent, however. It's just that the focus of the 7X's sound isn't the treble, so it shouldn't be your focus if you're considering it. That said, if you're agnostic on those frequencies, I can't imagine being disappointed.
Summary: I think if you're looking for tasteful bass emphasis, the 7X is a smart choice. It can deliver on the full spectrum, isn't some cheap, v-shaped presentation, and for most any recordings across any genre, it sounds terrific.
The bass is strong and deep, and a tad boosted which lends to overall warmer sound. However, I'm really floored at the dynamic capability. Reading reviews of ciems, I continuously see people mentioning how they can adjust based on what the track demands. So if it calls for hard hitting, tight, punchy bass, it's there. And the opposite with thinner tracks. Notes are on the thicker side of neutral, but decay still sounds natural and accurately portrayed.The mids are so so sweet. A little forward, but vocals still sound natural, like you're standing up on stage next to the singer. Which may not be the most natural presentation, but I love my vocals and mids, so this is a plus for me. Detail is there, but it's not an Ety ER4 in this department. Enough to satisfy and just get lost in the music, without overanalyzing microdetails (that's why I ordered the V6). **after I said that, I tried out some more technical songs like Rodrigo y Gabriela's Hanuman and the 7X handled it with ease. It's like they're super detailed, but it's not the cold/analytical detailed that I'm used to from my experiences with Etymotic, and Heir 4.Ai to some extent. It's just warm and enjoyable.Highs are never sibilant, rolling off before they get too hot. Never harsh or fatiguing. I don't find myself yearning for more, nor cringing from too much.Soundstage isn't massive, but I feel like a better source will open them up. I've only listened out of my Clip+ and NFB12 so far, and the NFB 12 opened them up quite a bit. So I can't wait til I get a better player. It seems to me like Heir 8.A and ES5 had a love child (based on what i've read of the two here)