Good for you, zazex.. glad you're giving them another shot.
Mine arrived earlier today. There's been some speculation about different versions which I tended to agree with.. especially about the initial pairs from when they were released.. my pair (which I got late in 2011) didn't sound anywhere near as bad as the early versions seemed to measure. If they did, I would've been hard pressed to give them another shot. The 8400 I received today had a clear cover and a while plastic shell which housed the headphones. I ordered from the same Amazon place/vendor zazex did (I ordered when there were three in stock).
As expected, they were less than impressive ootb: a bit shrill & fatiguing in the treble.. thin through the midrange.. and loose & flat in the bass region. Despite that, they were still quite surprisingly still quite listenable.. and enjoyable. After a good five to six hours of burn in, they're starting to show their true potential. The 8400 sound every bit as lovely as I remember them from the first time I owned them. Most all my listening with the 8400 has been with an iPhone (streaming 320Kpbs music from my MOG app) & the UHA-6S MKII & Objective 2 amp. A few things I'm really diggin' so far:
-The soundstage is really impressive for a closed phone. They don't feel "closed in" or claustrophobic in the least. Impressive width & fantastic depth. The fact these phones are very easy to listen to for extended period of time (both in tuning and comfort) gives your ears ample time to adjust to the soundstage & you'll come to appreciate the fact it's really well proportioned.
I've heard many phones that have great depth, but no width.. and vice versa. The most enjoyable phones are ones that always have a hefty amount of depth and enough width to balance it out. I've never felt the need to have a massively wide soundstage as imaging tends to suffer from an artificially wide stage when location queues feel excessively distant or unnatural. I get none of that with the 8400.
-The 8400 has fantastic extension. I was surprised by how deep the bass extended.. and how effortlessly it did so. When amped, I was able to make out individual notes in the the sub bass region with ease. The 8400 never lost control of or muddied those seemingly subterranean frequencies. It was definitely some of the most impressive clarity and extension I've heard from any phone actually. The bass also had a nice punch to it. Certainly not basshead-satisfying.. but when looking at what this phone aims to achieve in the grand scheme of things.. the bass presentation fits in very well.
At the other end of the spectrum.. the treble shimmered, sparkled, and shined so effortlessly.. and extended with just as much as ease as it did with the bass. I'll refrain from talking about the treble more cause there isn't much for me to add (to what's already been said by others) aside from the fact.. it's stunning, vivid, clean, clear, and showstealing. To my ears, the -upper-midrange through treble- presentation mirrors that of the famed RE272. I'm looking forward to doing more A/bing between the RE272 & 8400.. particularly in this frequency region, causes there's a frightening degree of similarity (especially in the all too crucial upper midrange). In fact, I think this phone is a great match for those RE272 lovers that want to get that sound in a full sized, closed headphone. It offers a very similar midrange-treble signature with a bit more heft and warmth through the lower midrange/bass (where the RE272 sound a little too fast and thin, at times).
-I love the midrange clarity, neutrality, and depth. Timbre is exquisitely balanced: not too wet or dry.. thick or thin.. warm or cool. Simply neutral, accurate, and very dynamic. Here's where you begin to hear that delicate, 'ethereal' warmth I mentioned a few posts back. It becomes more audible as the phones burn in.. you'll sense a faint, lovely touch of warmth which seemingly hugs the very edges of notes. It gives everything in the mids (through the treble) a delicious touch of smoothness & liquidity. There's an immersive, almost cinematic quality to the midrange presentation that's making it very difficult to put these phones down. Sorry if it's tough to explain.. but once you hear it, you'll understand. Other points..imaging is superb. Due to the excellent space around individual instruments and balanced note weight, picking out the spatial aspects of sounds and instruments is easy and precise. The decay of notes feels so very natural, too. Everything simply sounds like it would in real life. There's a rounded texture to it all that makes for a live feel.
For all the love the treble gets, I'm realizing that the midrange is the "darkhorse gem" of this phone. It's not as apparent when you're playing less than ideally (well) recorded material.. but feed the 8400 some great classical, jazz, flamenco, bossa nova, or soul music.. and you'll be left picking your jaw off the floor marveling at the pristine vocal reproduction, swirling instrumentation, and excellent dynamics. The Objective 2 seems to offers a lot of synergy that shows off the 8400's spectacular midrange flair.
-Amp comparison: I'll get into this more in depth later on, perhaps, but briefly.. both the UHA & Objective 2 pair BEAUTIFULLY with the 8400. I mean beautifully. Both amps are quite similar in 'sound' (or lack thereof, right?) as they are both highly resolving, and transparent in nature while feature very low distortion. These characteristics synergize with the 8400 extremely well to 'show off' the its incredible clarity, resolving ability, neutrality, and extension. Some might want to 'jazz up' the 8400's neutrality with tubes or a more colored solid state amp.. but I want to hear that unique, KRK monitor-inspired neutral liquidity in all it's naked glory. The UHA & O2 deliver that in spades.
I find the UHA to be the more technically proficient amp.. With the 8400, it seems to offer better control, more precise imaging, and a blacker background. The O2 presents an absolutely epic (wide) soundstage. It's quite something with the 8400. Though it lacks some of the refinement as far as control and imaging accuracy the UHA seemed to excel at. Personally, I enjoy both amps with the 8400.. but find myself preferring the O2 with the 8400 when I'm in the mood to throw technicalities out the window & just get lost in the expansive sound. The O2 will show you just how impressive the 8400's soundstage width is, too.
-I can't stress this enough: feed your sourced & amped 8400 rig music that's well recorded material.. it doesn't necessarily have to be very high bitrate/lossless stuff (I find 320Kbps more than enough), but more importantly.. try to ensure the music is mixed and mastered well. You'll be floored by how these phones will sing with such material. Most of my test tracks were from one of my favorite jazz groups, Acoustic Alchemy.. and listening to their music with the just the iPhone/O2 or UHA/8400 was immensely enjoyable. As noted by many others, the 8400 can go to town on acoustic guitars and percussion.. and there's plenty of both from AA. I can't recommend their music enough.. not only cause it's beautiful music.. but it's also great test material to see how your phones handle complexity, dynamics, detail, cotnrol, accuracy, and separation.
Next up.. the ODAC & then my desktop rig. I'm looking forward to hearing how it sounds with through TubeDAC-11's tube output.
