Hey all, I managed to get some listening time in with the HE1000 last night and this morning and I wanted to share some initial impressions.
First off, for anybody asking about burn-in: I first listened to it for a while after letting it play for about 30 minutes. Then I listened to it later after music had been playing in it for 6 hours. I then listened to it this morning after letting it burn in over night, by which point the HE1000s had been blaring music for about 15 hours. I'm going to say that I honestly did not really notice much differences in the sound, if at all, during the three times I just mentioned when I listened to it.
However, I'm not sure if this was anybody else's experience, but in my first several minutes or so of listening to the HE1000, I actually wasn't that impressed. I thought, "is this really the same headphone that I listened to before at CES and CanJam?" But after those initial minutes, I started to pick up all the little things that it did better than best headphones that I currently own (HE-400i and HD700), and I really started to become impressed. My point is, I don't believe the HE1000 is a headphone that will wow upon the very first listen, but its strengths quickly become apparent soon after.
These are some things that I noticed while listening to the HE1K:
The bass is really, really good. This is the first thing that I really started to notice about the HE1000. It sounds better than from what I remember before, though this may be due to listening in my own home and with my own music.
@money4me247 is right on the money when he says that the bass on the HE1000 sounds like its coming from a well-controlled subwoofer. It's like the bass is kind of separate entity from the rest of the frequency response range, but yet the overall sound still remains cohesive. I'm not sure if that is the best explanation, so I'm just going to say that I really agree with money's analogy. The HE1000 tends to emphasize the sub-bass while the mid-bass is firmly kept in check. And it sounds very full, with no hint of bloat whatsoever. I would say that the HE1000 makes my HE-400i (itself already very impressive in its presentation of bass) sound like it has some mid-bass bloat, even though I know that really isn't the case.
I also agree with money4me247's observation that the dynamic range is absolutely humongous on this headphone. I noticed slight differences in volume in certain passages of my music that I never heard before quite easily. I think this huge dynamic range also helps the HE1000 to excel in other areas, which I will get to later.
The HE1000 is amazing in making everything clear in a mix. I found myself noticing background elements in a mix very, very easily, much more so than any of my current headphones. And this doesn't only apply to music. When watching movies or TV shows, in scenes where the main emphasis is on dialogue or other elements with music in the background, I found myself being able to clearly distinguish the sound of the background music, much more so than any other headphone that I remember. I don't mean that the background music is drowning out the dialogue or anything like that - the music is still at the lower volume, but its so clear that you don't need to really turn up the volume to really listen to it.
Like HiFiMAN's other headphones, crappily recorded music will still sound decent on the headphone, but excellently recorded music will sound spectacular. However, the HE1000 does make badly recorded music sound much more apparent and somewhat worse than my HE-400i and HD700, while the HE1000 also makes really apparent which are the truly excellent recordings and which are good but on a lower level.
Vocals sound sublime on the HE1000. Not only do vocals come to the life because of the pretty much perfect tonality of them and because of the details that the HE1000 effortlessly presents, but also because of the huge dynamic range. The fact that the HE1000 is able to capture such subtle changes in volume allows one to really be able to listen to the nuances in the singer's voice - when some words are slightly emphasized, what kind of tone the singer adopts to use in certain parts, etc.
Various instruments sound absolutely life-like on the HE1000. You can really hear the air being blown through the bass instruments. Violins actually have that sound where you know it's a bow being pulled across the strings (something that I never really noticed was missing from the sound of my other headphones until I noticed it here).
And it absolutely nails how the piano sounds. This is not only in terms of tonality, but also again because of that huge dynamic range. I myself have been trained in classical piano and have been playing the instrument for over 10 years. When one plays classical, there are lots of nuances one has to take into account - which notes are slightly accented, when do you start to gradually play louder and louder, when do you play the bass (the left hand) to be slightly louder or softer than the treble (the right hand), etc. That huge dynamic range allows me to hear all of those subtle nuances in a good recording and is truly something that can literally transport me to being right next to the piano player like no other headphone that I've ever heard ever has.
If anybody is looking for comparisons, sorry, I don't have them just yet, mainly because I can't get the HE1000 off of my head once I put them on and start putting music through them. Though I can really only compare the HE1000 to my HE-400i and HD700...
I think that's all that I have for now. If you'll excuse me, I gotta get back to listening to them.