Posted in the HD-650 Impressions thread - cc'ing here:
Well, got in about eight solid hours with the HE-400 spread over two sessions. It was paired with my Bottlehead S.E.X which, unlike my Crack, is completely stock.
Source was SACD/FLAC > Fiio X5 > S.E.X. I won't do a full review here (that would belong in the HE-400 thread) but I'll knock off a comparison for those interested:
First Impressions
These are very different animals. The first thoughts that came to mind were the unique sound of the planar drivers vs the dynamic drivers. While I find the 650 has great vertical soundstage and an okay width, the HE-400's excel here, and it's the driver technology doing it. It's like tower speakers on either side of your head. More on that later.
They feel solid and well-built, very industrial - I have no concerns with the build and I feel less like babying them than with the Senns although I'm sure I have no need to for either. Maybe the 650's are handled more "reverentially" lol. Yes, the HE-400's are waaay heavier, but man up - I had no comfort issues at all over two decent sessions. The headband padding is non-existent, the foam under the velour too hard/dense, and the cups are big and heavy, but at no time did I feel imposed upon. Just nowhere near as comfy as the amazing Senns are. One thing I liked is that the tips of my ears (no, they are not Spock-ears) never touched the driver-covering cloth which can be very annoying. Moving your head too quickly would easily dislodge them, and the bottom of the beer needed tilting, not my head lol. I'd imagine with the pleathers this would be even worse.
The cable is very stiff and gets in the way, especially with the bizarre mini-coaxial connectors extending so far down. You're always aware of them if you turn your head.
Plugging in, I thought there was something wrong. The output seemed far too low for the setting on the dial. The tubes were fully warmed up, and if this was the Senns I would have been at a very nice, medium-listening level. It was amazing how much current these things can eat. The S.E.X. is a 2wpc single-ended transformer amp, designed for lower-impedance cans. That said it handles the 650's very well indeed, just not quite as well as the OTL Crack. The HE-400's sucked back every bit of what this amp brings to the table. I cannot imagine they sound good from a weak source at all - will try later with lesser powered amps but I can't see it.
Bass
On the HE-400 impressions thread, once you get past the first 80 pages or so of honeymoon bliss and new-owner gushing, these cans are described as "dark", "laid-back but bright", "tizzy" and other contradictory labels. They are touted for well-extended sub-bass, with the texture and slam a planar should bring. I didn't really find that. The bass does extend lower than the Senns but only just. The HD-650's are known for their mid-bass hump which, with their glorious mids, bring a lot of depth, warmth and meat to music. I call the HE-400's flatter through this range which should be a good thing, but if you've come to love the rich low-end of the 650 signature you may be disappointed with the overall presentation of the HE-400 bass. Quite opposite to what my expectations were.
Mids
No contest here. The 650 has the sweetest mids of the cans I've tried, and they blend so well into the upper-lows and mid-lows that they more-or-less define the 650 sound. A hard act to follow. The mids on the HE-400, neither forward nor recessed, seem to have many dips in FR across the range. This may well be where the planar design comes into play. Voices sometimes seem nasal and distant, as if the singer were cubby-holed in a phone booth while the band plays outside. Female vocals suffered more. This may be something my brain will adjust to, and I think it's a function of the incredible separation/tracking of the planars. Each instrument voices individually and it's striking but not always beneficial. Rush 2112 (the remastered 24-bit new release) was is some ways magical as Alex Lifeson's guitar became such a distinct track of it's own, but the overall cohesiveness suffered. On the Senns I was focused on the overall synergy this trio manages, on the HE-400's it was like they each mailed in a track without hearing the whole. Tough one - this will boil down to preference, but overall the Senns win here for their amazing mids no matter which "effect" you prefer.
Treble
I am sensitive to fatigue from harsh highs, from the sibilant range right on up. That's one reason I love the 650 sound so much: it never fatigues or makes you wince. It was the area of most concern with the HE-400's and, sure enough, I had to EQ it down from 7K onwards to avoid that fatigue. Sibilance wasn't an issue - that's a bit lower in the FR, but above that did have the "tizzy" sound sometimes ascribed to these cans. Yes, I checked, they are not the recalled Rev. 3 with the sandy-brown drivers. Taking the high-end down a notch helped and hurt: the tizziness was reduced but not eliminated, but some of the "air" and sparkle was lost. And that air and sparkle was really part of the magic of these cans. Perhaps with the S.E.X, which I already find much more spacious and airy than the Crack, adds too much to the highs here. I really would like to try again on a darker amp, but for me these highs are problematic and that's a shame: these cans need that air to stand out.
Soundstage
No winner here - just preferences. I find the 650 quite intimate for an open can. The HE-400 has more soundstage, especially vertically. This might come down to a genre thing: classical on the HE-400, more jazz-hall on the 650. Both are good
Imaging
Finally the HE-400's score a clear win here. Each instrument and voice capture their own space, and your mind can easily shift to following any one at will. I won't say they're all presented well, but there's no question they're well-separated unlike the 650's more cohesive picture.
PRaT
Not something I'd normally call out, but I do because the two cans are very distinct here. Pace, rthym and timing are much better on the HE-400, as they should be on a planar. The speed of the driver is one of the touted advantages of planer transducers, and here it shows. On very fast-paced, textured percussion (think Yello, world music, a Neil Peart skin-bash) there is a level of definition not only on percussion hits, but the decay between even fast-paced hits that's staggering. This coupled with detail (next) is these cans' strong-point.
Detail
Yep, again the HE-400. To a fault if you love the warm, forgiving sig of the Senns. Listening to well-ripped vinyl the pops and crackles turn from an old friend to a bad distraction, and wow-and-flutter that the Senns graciously hid become a droning track of it's own. The flip-side is you capture all the good details just as well. Details lost in the Senns warm blanket come to the fore, good bad or ugly. With great recordings you'll be impressed at what they retrieve. Poor rips or compression artifacts will stand out in a way the Senns forgive. The classic double-edged sword here, but partnered with the speed, imaging and PRat of these cans it can lead to some magical moments.
All-in-all I'm impressed, but with a few caveats. These are specialists, not the all-rounders the Senns are. With a good recording, a powerful amp and the right genre these things will kick the Senns to bits with their detail, imaging and speed. You will go "wow". And then you'll listen to the other 90% of your music and wonder how you put up with those harsh, uncompromising and un-cohesive tanks. I think the Senns fix so much and elevate the whole, but lose some of what a detail-junkie seeks and don't keep pace as well with fast recordings. But for 90% of listening they best the HE-400 with a beautiful, warm, lush and never-fatiguing signature that's hard to beat.
Win to the HD-650's.
