InnerFidelity

Sound Quality
Generally speaking the ZMF Eikon has a smooth, warm sound overall. Bass is slightly emphasized and well extended. I wouldn't say the bass bleeds into the mids so much as there is just an overall mild warm tilt on this headphone overall making them a relaxed listen. Bass has a slightly gruff distorted sound and doesn't hit quite as hard as the best headphones, but remains a solid performer and a pleasant listening experience. Response bass through mids is quite even, though the presence region is a little more relaxed than the rest of the spectrum giving the headphones a slightly distant sound.

Response continues its warm tilt into the treble where is becomes slightly more uneven than in the lower areas of response. In particular, there's a small peak at 6kHz that can on occasion be a just a bit troublesome, and there's a notch at around 7-9kHz that tends to remove the some of the shimmer from cymbals. Combined with the slightly laid-back or veiled presence region, I heard the treble as quite polite, lacking in some detail, but otherwise wonderfully free of any harshness, stridence, or annoying missbehaviour. Here's the EQ I ended up dialing in. I liked the warm tilt so I just tweaked the presence and treble notch up a bit to liven the cans.

Imaging is not as deep as a good open headphone as it's slightly relaxed and not in your face in the presence are, giving it a comfortable, if veiled, perceived distance. Image stability and specificity are quite good for a sealed headphone; the image has good width and definition.

The last thing to know about the Eikon is that it's a 300 Ohm headphone and particularly well suited to tube amps, especially of the OTL flavor. Knowing this I did break out my Bottlehead Crack—the only OTL amp I have in permanent residence here. Not surprisingly I heard the bass as a little looser and less impactive, but surprisingly the treble seemed to gain a little more liveliness and liquid smoothness. It's pretty clear to me that finding just the right OTL tube amp to mate with these can will pay some real benefits.

Comparisons
It's rather unfair, but I pulled out my Focal Utopias to get a sense of how far off "world class" the Eikons are. The difference, in terms of an open, resolving sound, was immediate. Clearly the Utopia had much better resolution and clarity. On the other hand I was taken aback by the cooler sound with less bass emphasis more presence emphasis; the Focal seemed to shout in your face by comparison. While I would consider the Focal closer to neutral and much more resolving, I find myself more attracted to the Eikon for a relaxing listening session, especially if were talking about music of mixed recording quality where the Eikon will be more forgiving.

Unfair in the other direction is a comparison with the Oppo PM3. With the exception of being somewhat rolled-off in the top two octaves or so, the PM3 is a superb headphone. I heard the PM3 as quite a bit more neutral through about 4kHz; and overall it sounded more even and smooth, it's presence region more inline. Unfortunately, the rolled-off top end seemed a bigger flaw to my ears than the slightly uneven response of the Eikon. I'd characterize neither can as lively, but would say the Eikon is the livelier of the two, and more easy for me to accomodate over time.

The acid test is against the similarly priced MrSpeakers Ether C and Ether C Flow sealed headphones. I find the C to be smoother and more coherent but lacking some bass relative to the slightly warmer but more uneven and less refined sounding C Flow. Against the Eikon I found both to be more neutral, especially in a more appropriately strong presence region and in evenness of response above 5kHz.

Here's the thing that's hard to write: There's just something to listening to the Eikon that's organic and pleasing to my inner human. Some high performance headphones can be somewhat impersonal in their sound—the HD 800 comes to mind...you have to meet it on its own terms. The Eikon comes to you and just snuggles in for the duration. Or maybe I'm just biased and forgiving of the slightly muffled sound knowing Zach has spent lot of time damping these headphones just right...for his ears. Whatever the case, while I don't consider the Eikons to be reference grade due to a lack of nuanced resolve, I do consider them a wonderfully pleasant listen.

Summary
On the other end of the spectrum from the super technical and sophisticated builds from the big makers, is the hand-made character and radiant artisanal craftsmanship of the ZMF Eikon—a headphone enthusiasts headphone. This significantly heavy sealed headphone with its lambskin pads, headband, and well designed adjustments is surprisingly comfortable. Styling is purely form over function, but done with a craftsman's sensibilities; I think headphone enthusiasts will love the look.

Sound quality is warm and polite with a slightly too withdrawn presence region and notch 6-9kHz that tends to veil the headphones some. Imaging is nicely wide, specific, and stable, but not particularly deep. Dynamics are good but not great. The Eikon is an all-around good performer and sums up significantly greater than its parts to become a very pleasing headphone for listening to all manner of recordings of differing quality. But it does not perform on a reference level, in my opinion, due to a lack of nuanced resolve. Its 300 Ohm impedance lends itself particularly well to OTL tube amps, and responds well to upstream changes and improvements.

I'll heartily recommend this headphone to any enthusiast in the process of developing a rich collection. Though sound quality is slightly too veiled and warm to be considered neutral, there are plenty of listeners that will easily accomodate and find great pleasure in the Eikon's relaxed presentation. And enthusiasts may also be drawn to the beauty of a truly hand-made headphone built with the loving care of an experienced craftsman.

Video

Resources
ZMF Headphones home page and Eikon product page.
Super Best Audio Friends threads here and here.
Head-Fi reviews and thread.