ZMF Eikon (Cherry) Review

Thanks to Zach from ZMF and Will and Linear Tube Audio/Urban Hifi for making it possible for me to audition and review this headphone.  I really appreciate the opportunity to spend some time with these headphones prior to their release so that I may share my opinions.



ZMF has taken an interesting path to becoming a premium headphone manufacturer.  Originally starting with selling modified Fostex T50RP headphones, a line which has quite a few fans, he has now moved away from Foster (though he still maintains his product line of modified T50RPs), and has begun to produce two new dynamic driver based headphones, the Eikon and the Atticus.  The Eikon is the more premium model of the two, utilizing a custom biocellulose driver.  One of the more interesting features of this driver is its impedance, at 300ohm it’s the highest impedance biocellulose driver that I know of in a production headphone currently.  Historically, companies like Fostex, known for their biocellulose drivers in their TH-line of headphones, have always focused on using biocellulose driver diaphragms in drivers with very low impedance voice coils, focusing on making them more sensitive and easier to drive without needing a powerful amplifier.  Biocellulose drivers, being extremely stiff and lightweight, make it easier to pull this off.  While the headphones are sensitive, in listening to them they tend to have a very powerful, sometimes overpowering low end, and very uneven mids and treble.  My theory is that this may be caused by the extremely high flux density of the magnetic circuit combined with a low impedance voice coil that can make the sound seem sloppy and uncontrolled.  Zach claims that using a higher impedance voice coil in a biocellulose driver mitigates some of these issues.

In looking at these headphones, it’s immediately clear to me that some inspiration was taken from the famous Sony MDR-R10 in the design of the cups and especially in the design of the headband.  This is a very attractive looking headphone that blends ZMF’s signature style and wood choices with lines and curves obviously inspired by that classic Sony.  One of the things that Zach seems to have emphasized in this headphone is the use of wood in the design and construction.  The acoustic chambers in the headphone including the cups and driver baffle are made entirely out of wood.

Fit and Comfort

Fit and comfort on this headphone is excellent for me.  I am using lambskin pads on the Eikon, which use very soft leather wrapped around relatively thick but pliant pieces of foam.  The headband feels like a thin piece of spring steel or something similar, wrapped in leather and also includes a suspension leather strap to evenly distribute the weight of the headphone on your head.  The cup adjusters are metal friction sliders that are still quite stiff for me, and may take some working in to make easier to adjust.  I prefer it stiffer like it is now because it’s much more difficult for the headphone adjustments to change when hanging or otherwise not in use.  While the headphone is a bit heavy, it’s perfectly comfortable for me.  I am used to heavier sets of headphones so your mileage may vary on weight tolerance.  Clamp is pretty tight on this headphone, but like any, I’m sure it would break in with use, the pads being so large and soft also helps spread the pressure evenly and easily maintain a good seal.

Sound Impressions

I think Zach’s overall tuning of this headphone really hits all my major preferences and in some ways is a bit reminiscent of the Hifiman HE-500, a headphone that I believe Zach has mentioned was an inspiration for the tuning here.  I think if that was his goal, he has done a more than admirable job of not just achieving with the Eikon, but improving upon in it.  The headphone seems to have a relatively even and very slightly downward sloping signature, with a dip in the upper-mids and low treble area ending in a mid treble spike somewhere in the 9k to 10k region for sparkle.  I think bass, mids and treble are very well balanced, the sound is cohesive and very smooth.  I think it shares some commonalities with the HE-500 that I really enjoy in all the headphones I own: being flat or slightly slanted to about 1k-1.5k, dipping to 2k, remaining flat to about 8k and then having a small spike somewhere between 8k-10k.  

Bass on the Eikon seem quite flat, not demonstrating any mid-bass emphasis and maintaining very good sub-bass extension.  The bass region does seem slightly emphasized as compared to the mids here, but not in a way or with a quantity that interferes with the overall tonality.  The bass is quite smooth and maybe helps me with my understanding of the “liquid bass” description some people like to use.  The initial attack of bass notes is present, but not emphasized in any way, and while they are felt, the attack isn’t felt especially sharply versus the sustain and decay of the note (this I’m told may be a characteristic of the Cherry vs Padauk cups).  The overall impact of the bass is extremely smooth and has impact without being especially “hard”.  While I generally prefer the harder and more defined impact of bass, I also enjoy the softer and smoother presentation of bass here.  Despite not having the same initial impact, overall the palpability of bass on this headphone is very good.  Extension does not seem to be a problem here except for the absolute lowest notes, I estimate that this headphone begins to roll off under 30Hz, but presents sub-bass very well without obvious emphasis and with a satisfying linearity.  Bass texture is smooth and very clean, revealing good detail and texture while also being very palpable in its impact.

Mids on this headphone are also smooth. I don’t find that the bass bleeds into the mids or interferes with them at all.  I do find male vocals and the lower end of female vocals just slightly forward, which could suggest a bump in the 1k-1.5k region.  I do find that the overall balance of the mids is to my preference, which also suggests that the mids begin to dip as they approach 2k.  This allows the mids to be forward without necessarily being shouty in a bothersome way.  The mids and their transition to the lower treble isn’t not marked by any emphasis to me and maintains the headphone’s overall very slightly downward slope.  The mids keep a balance that I generally find natural sounding.  The smoothness of the mids does not give way to any sort of grain or grit, vocals are presented very smoothly with great detail, and again the initial attack of notes seems dampened here, lending less texture/palpability but still remaining able to present nuances in the sound like breathiness and lip smacking with ease.  

The treble on this headphone seems very smooth and extended with good sparkle due to a peak somewhere in the mid-treble.  In general I don’t have any issues here, though depending on your taste, you may find the treble a bit bright.  I actually find the treble to have a good balance and fitting with my preferences , having the mid-treble peak for sparkle/impact but otherwise maintaining a smooth, clean and well extended sound.  The balance of the treble and the mid-treble spike in particular remind me of the HE-500, however it seems that the rise to that spike starts sooner and is lower and a bit more gradual than the HE-500 lending the sense of sparkle and impact without being quite as harsh.

Overall I find that the staging, imaging and separation remind me a lot of the Denon AH-D2000, helped by a better treble balance.  The staging is somewhat small, but seems accurate when listening for the spatial relation of instruments and it is pretty easy to place individual elements of the music within the stage.  The headphone seems very fast and smooth, doing a very good job reproducing transients and the sustain of instruments.  Because of the ported rather than fully sealed design of this headphone, isolation is only ok, and there is definitely leakage of the sound outward as well, but less so than a fully open headphone.  


I think Zach was right on in choosing to create a high impedance biocellulose driver, and the results are clear to hear.  Everything sounds well extended, smooth and controlled, lending excellent clarity and texture with great balance.  I am a very big fan of Denon’s AH-D2000 which shares a sort of similar configuration and tuning, but I’ve always felt that one thing that was lacking was the definition and clarity of sub-bass on that headphone.  I see the Eikon really picking up where Denon left off and further refining the sound, making a more impactful, smooth and clear headphone with excellent balance and imaging. With the excellent exterior build quality, ability remove/replace cables and the much-refined sound, the Eikon has left me in a predicament about what to do with my Denons.  I think Zach has succeeded in creating and tuning an excellent semi-closed headphone with great technicalities and tone that manages to avoid the pitfalls present in many attempts by much bigger companies to create a really exceptional headphone using a similar formula.