So, HE400 vs HD650, FLAC through a Fuze LOD and an O2, trying to put as many objective relative comments and as few ambiguous words in there as this arena allows.
I found that what the 400 does, it does very well, and that's clarity, detail and separation. When you have a lot of brass and deep strings going on in an orchestral piece, the HD650 tended to let them blur out the finer-bodied instruments like flutes, clarinets and smaller strings, very slightly. Their timbre could still be heard, but had to be concentrated on somewhat. The HE400 on the other hand, was super-clear, with the texture of the finer instruments immediately apparent. Unfortunately the body of the deeper instruments just wasn't there; the bass was, and it was very clear, but there was something missing (the same something that resulted in the very slight blurring with the HD650).
An example of this is the guitar in the background of this song at 1:20. It's there on every decent 'phone I have, but it's so immediately apparent on the HE400s. Whether or not this is a good thing will depend on whether your listening style requires it or whether having detail thrust at you will cause you to focus on it at the expense of everything else.
When it comes to air and clarity , I think they were improved by the fact that the HE400s are more open than the 650s; the HE400 drivers (not pads) seem to cause less isolation of outside noise, which I think decreases the distinction between sound that's coming from the drivers and ambient sound. This was the case both with music playing, and with the headphones silent.
When it came to less populated tracks and tracks without many deep instruments, I felt that the 650 outshone the 400. The 400's emphasis on treble gave the impression of detail and texture, but that detail/texture was still present through the 650s, just not thrown in your face. The smooth texture of the mids (and I hesitate to use terms like bass, mids and treble anymore because I realise I don't know exactly what falls where) was so valuable in my enjoyment of these pieces and were exactly what I was hoping for in a headphone, coming from the UM3X. The flute at :40 in the video below is a prime example of something that was euphoric through the HD650s and relatively empty through the HE400s. The same was true for female vocal, with a great example being the harmonising at 2:28 in the video above (which gets butchered by youtube's compression anyway, but even so)
My bass/I-don't-give-a-crap-about-timbre tracks were from Avenged Sevenfold's "City of Evil" and The Prodigy's "Invaders Must Die". While the 400 has better extension down low, I didn't miss it while listening to the 650s, and I did miss a bit of impact that I felt was lost in the mid-bass when listening to the HE400s. Additionally, these songs are filled with crashing symbals and other reasonably harsh sounds. I can barely listen to them at moderate to high listening volumes with the 400s, let alone enjoy them. I found the 650s to smooth out the harshness without dulling them.
Tracks incorporating a bit of both (textured acoustic instruments and synths/heavy bass)from artists like Shpongle and Infected Mushroom were more enjoyable on the HD650. The airiness, clarity and minute details aren't worth much, because of the recording and style of music.
A few random things
- Build quality. The HiFiMans look and feel like a top-of-the-line 'phone that's lacking a bit of polish and budget. Funny, because that's pretty much what they are. The HD650s are light and plasticky and feel like a peripheral, rather than a piece of equipment in their own right. They don't look very durable (when it comes to abuse, not longevity) and the fit/finish is slightly below what I'd have expected from a ~$400 phone, given what I've seen of HiFiMan and Shure's offerings at this price point.
- Price. I don't know what the going rate is for HD650s in the rest of the world, but in Australia I'm looking at $350 online and $480 local, which is the maximum I could justify on a headphone. Coming from my UM3Xs, it's not a matter of which costs less, but whether the HE400 has anything to offer over what I currently own. While it has fantastic qualities for 20% of my music library, the sound sig is unusable for most of it, so it doesn't. The HD650 does, and doesn't give a huge lot up when looking at the HE400s qualities in isolation, either.
- Weight. As I said a bit earlier, the HE400 gives the impression of quality in the same way a 1911 does compared to a Glock (for the shooters amongst use). That is to say, it is not just solid and inflexible, but also heavy, which may or may not be a bad thing for you.
Hopefully that helps anyone who's considering the 400s and knows what sound they like.
Edited by Dragunov-21 - 11/9/12 at 11:13pm