Inside ZMF Headphones and the x Vibro

February 08, 2015

Tucked away in a corner room, in a non-descript Chicago apartment, the barefooted and bearded Zach Mehrbach works away with scissors and soldering irons, spools of hook up wires and stacks of t50rp drivers, and a host of other tools of his trade. He is the main man behind ZMF Headphones, an easy-going guy that simply loves good sound.

Hand assembled and made to order, Zach prides himself on being a “small shop” headphone builder that caters to his clients’ auditory demands (within reason of course). With the world of high-end headphones seemingly growing every day, Zach is setting himself apart by focusing his attention solely on creating custom orthodynamic headphones based around the ever-popular Fostex t50rp driver and enclosure. While that sounds simple enough, he has spent years extensively researching, testing, tweaking and retuning his modifications to nail down what he considers to be a truly naturalistic audiophile-grade sound that’s “musical, engaging, and above all addictive.”

Originally just a hi-fi enthusiast and headphone modder like many of us, Zach officially took things to the next level when he formed ZMF Headphones in early 2013. Although a relative newcomer to the market, Zach has worked through some early growing pains to rapidly establish a solid following in the audiophile/head-fi world, trusted reviewers sing praise for his creations, and he himself is increasingly making the tradeshow rounds, further building his brand and reinforcing the reputation his personality and customer service have already earned him. 

ZMF Headphones now has four models: The Classic, Master Model, and tunable wood-cupped x Vibro and flagship Blackwood. They span a variety of price points and offer a staggering variety of custom looks, fits and tuning options that allows for a truly unique headphone to be created.

Regardless of the headphone model chosen, ZMF Headphones’ house sound is resolute on being smooth, articulate, punchy and never sibilant.

In this sense, ZMF Headphones aims at offering a closed-back alternative—or companion—to the many open-back orthodynamic headphones on the market, but with a unique touch of course. Zach’s design is intended to blend the benefits of both dynamic drivers and orthos. As he says, “I have set out to tune ZMF headphones with the engaging qualities of dynamic drivers, yet with the encompassing precision, accuracy and timbre that is often associated with planar magnetic headphones. [By] providing an above average soundstage, a perfect engaging mid-range, life-like bass and smooth highs, users get a headphone that can be listened to for hours on end.”

Some may find that too good to be true, but part of the ZMF Headphones value proposition is that if you don’t like the sound, you can send your headphones back for a free retune based on your wants or needs. This is actually how I ended up spending part of my weekend hanging out in Zach’s apartment and ZMF Headphones headquarters.

The ZMF x Vibro

Having read many good things about the ZMF x Vibro, I decided to give it a try for myself, picking up a used pair off of They arrived with walnut wood cups, Alpha Pads, buffalo leather headband and Zach’s OCC copper/silver hybrid balanced cable. I popped them on and ran them through some laps on my Woo Audio WA6-SE, ALO Audio Island and Pan Am, Sudgen Headmaster and Yulong DA8. While the x Vibro had plenty of nice characteristics, I ultimately felt that I was left wanting for more; they just seemed a bit too dark, laid back, and even a touch thin at times to my ears, especially when coming from the Sennheiser HD650 that synergizes so well with the WA6-SE, the main amp in my setup. When I posted this statement on a Head-Fi thread, Zach spotted it, messaged me directly, and set out to deliver some top notch customer service.

As Zach explained in his message, the pair that I had purchased was actually one of his early builds. Since then, he has further refined his design, materials and tuning, meaning the pair I had wasn’t quite up to snuff with his current offerings. The cure: Zach had me over (we live within a short drive of each other) to “update” my used x Vibro, something he’s been trying to do to the few older production models still floating around whenever he spots them.

So while I hung out, Zach worked away and then kindly presented me with my “new” x Vibro. Using his measurement software and testing devices, he showed me how his changes improved the frequency response and left the drivers matched to within roughly 1 db of each other. “The better the left and right channels are matched in a headphone, the better it will sound,” he explained. “All ZMF headphones go through rigorous burn in and testing before being sent to the end user.”

So how does a current spec x Vibro sound? Much better and pretty darn good. When Zach writes his product descriptions, he pretty much tells it like it is. I suppose this is part of his craft; he can’t really afford to sensationalize or be misleading when he’s so actively involved and accessible in the headphone community. 

But to get on with it, the x Vibro is a smooth operator. Coming from a Beyerdynamic, Grado or Sennheiser headphone to these, you’ll likely be thrown off by the very different tone and response, but as your ears settle into the ZMF sound, you’ll start to notice just how resolving it can be.

Throughout the entire frequency range I detect no harshness, no grit, just free-flowing music. The tonal balance is what I personally consider to still be on the darkish side, with a boost in the mid-bass, descending treble response and a mellow mannerism overall that saves your ears from fatigue while still delivering a sufficient amount of clarity. 

Of the headphones I’ve had in my collection, I liken the x Vibro most to the HiFiMan HE-500 when it comes to tone, although, from memory (I sold my HE-500), I think the x Vibro may actually have more engaging mids (more present vocals) and a touch smoother presentation overall. Separation is quite nice with these. The damping and tuning seems to allow you to really pick out each instrument and focus on it, and there’s a nice layering to the sound, especially with high-resolution recordings. For being a closed-back headphone, the soundstaging of the x Vibro is surprisingly good. While the x Vibro has three bass ports on each cup that can be plugged or left open, Zach recommended leaving them open and that is how I also ended up enjoying the x Vibro the most. Plugged, I found the bass could come off a touch cool, but unplugged, the sub- and mid-bass bleeds into the prominent midrange to give these a lusher, more fulfilling sound. 

What I personally find most challenging about the x Vibro is how dependent it is on having strong synergy with the amp it is paired to. An amp that pumps out a strong current into a 50 ohm load is definitely desirable. For example, the x Vibro paired with the Woo Audio WA6-SE is underwhelming for me. With my ALO Pan Am switched to high gain it sounds pretty good. On the ALO Island it’s decent… certainly good enough for at the office. With the Sugden Headmaster, the x Vibro begins to show some real meat. But when matched with the Decware Zen Taboo, purposely designed for planar headphones, the x Vibro absolutely sings; it’s like a completely different headphone. My point here is that amp matching is critical if you want to get the most out of the x Vibro, otherwise you likely stand to be disappointed. This isn't necessarily a bad thing, but it is a valid point to consider before making a purchase.

All in all, Zach is a standup guy crafting some pretty nice custom headphones under the ZMF Headphones label. He truly stands behind his products, so if you haven’t already, check out ZMF Headphones.

Now here’s a look behind the scenes….

ZMF Headphones headquarters

Zach making upgrades to my x Vibro

Drivers being matched for a large order

Carbon enclosures in different stages of assembly

Custom colors for the ZMF Classic

Zach in his listening chair

ZMF x Vibro in Cherry

ZMF Classic

ZMF x Vibro in Walnut

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  5. Very cool read. I hope you're still updating? If not and need content, let me know...I can write about screwing up DIY projects and DeOxiting Goodwill and Craigslist finds.

  6. I enjoyed reading your article :) PLease continue publishing helpful topics like this. Regards, from Let's get gadgets.





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