*Please note that ZMF Headphones has changed the name of this headphone from "The Omni" to "Ori".

Omni. From Latin origin it means something like “all, every, of all things, the whole.” To date, The Omni is the whole of ZMF Headphones. It’s the flagship offering; it’s the pinnacle of what Founder Zach Mehrbach’s constant tweaking and dissecting of a headphone in every way can yield.

At ZMF Headphones, every headphone is assembled by hand, tweaked, tuned and sent out by Mehrbach, a painstaking process I’ve been privy to see firsthand on several occasions. In full disclosure, I first met fellow Chicago local Mehrbach some years back as a disappoint ZMF x Vibro owner. I had mentioned some complaints on a popular headphone forum, and, in standard ZMF customer service fashion, Mehrbach was quick to personally message me about my issues and offer a solution. He takes his products seriously, he stands behind them, and he is simply a stand up guy. This has led to a true audio acquaintanceship between us. I’ve seen the inner workings of ZMF Headphones. I’ve been invited to demo and critique countless prototypes. And, I’ve been able to see the culmination of Mehrbach’s work result in some truly fine products that headphone enthusiasts around the world enjoy. So when Mehrbach offered me the opportunity to do a long-term review of The Omni, I was happy to welcome them into my home listening room.

The Omni is the result of years of fiddling, research and design between ZMF Headphones and Vibro Labs. Like the ZMF x Vibro (see my coverage), The Omni is built around the latest generation of Fostex’s T50RP driver and cannibalizes some of its suspension parts. The Omni, however, uses an all-new, semi-open, 100-percent wood cup that’s hand finished in-house. And, true to its name, The Omni aims squarely at doing everything well. ZMF Headphones has always been about customization, so there are eight different woods to choose from—all of which have their own subtle personalities—a couple of headband, slider and emblem options, and various cables to choose from that make each order unique to its prospective owner.

My review unit uses ZMF Headphones’ own angled leather pads (these fit on many headphones, and I highly recommend them), African Blackwood cups, pilot pad headband, and DHC copper litz balanced cable. The African Blackwood did wonders for the ZMF x Vibro. It’s a beautiful and very dense wood that leans to the dark side while still being fast and resolving, so does it do the same for The Omni?

First Listen

Smooth. Powerful. These were the first two words I could think of to describe The Omni when I queued up Moderat’s track “Bad Kingdom” for my first listening test. The sub-bass and overall bass extension is literally some of the best in the business. I’ve owned premium headphones from Audeze, Beyerdynamic, Hifiman, Fostex and Sennheiser, and no other has come close to producing the feeling of the SPLs hitting my ear drums like The Omni. The bass is thick and rich; it oozes like honey, but it’s not slow like molasses. It simply hits hard and fast and leaves its impact on you. If you’re a basshead, The Omni is to die for. The textured bass in “Bad Kingdom” is heavy and complex, it can make or break a headphone for me, and it makes The Omni. 

Despite the bass being the clear dominator in The Omni’s sound signature, there’s no muddiness, it’s not boomy, and somehow it refrains from sounding closed in. You’d think that The Omni’s mostly closed-back (semi-open) design and emphasis would crush its soundstage, but its atmosphere extends surprisingly well to what seems like a few inches beyond the headphone. I’d say The Omni’s dimensional soundstage is somewhat comparable to that of the Fostex TH-600, which I think extends very well for a closed-back headphone, and the Sennheiser HD650, which has a more intimate soundstage despite its fully open-back design. 

Intimate is also what you get as The Omni’s oomphy basslines blend into its smooth midrange. The Omni won’t let you Flea the prominent basslines (get it, get it?) in the Red Hot Chili Peppers’ album title track “The Getaway” or hit “Dark Necessities,” but Anthony Kiedis remains front and center with his smooth vocal tones. Tom Toms and guitars are projected well with full-bodied resonance and twang. For jazz tracks, like Matthew Halsall & The Gondwana Orchestra’s "Ode to the Big Sea," The Omni sings out with a full, sweet sound that’s smooth on the senses. 

The one sense you may feel from time to time is that you’ve lost some sizzle in your sound. The Omni is notably dark compared to many hi-fi headphones. While the treble it has extends well and captures enough resolve, it’s the treble that it doesn’t have that you may miss from time to time. As the treble smoothly drops off, The Omni loses some sense of space and instrument separation as well, but at the same time it works wonders for taming the unruly treble that’s become all too common in modern music. The Omni truly offers a reprieve from the loudness war; it’s a savior of shitty rock recordings that are too sizzle and sibilant happy. 

Sibilance is something you’ll never have to worry about with The Omni. Its relaxed tonal balancing favors those looking for enveloping bass and mids. What The Omni does, it does well. But how does it stack up to some of the competition?

The Comparisons

The Omni’s place in the market falls somewhere between the likes of Audeze’s LCD line and the ever-popular Sennheiser HD650. In comparison to the Audeze LCD-X, which has been my reference headphone for quite a while now, The Omni makes the LCD-X sound bright. This was a startling surprise for me. In general, Audeze LCD headphones are lush and dark, even the more balanced X. While The Omni and LCD-X share similar traits in being bass and midrange masters, I feel that The Omni has far greater bass emphasis. It hits harder and deeper, but feels less controlled. Throughout the mids, the X seems to pull out more details and textures, especially on jazz tracks where it easily bests The Omni in instrument separation, placement and clarity. The highs are where these two headphones diverge even further. Both have notably rolled off treble, but The Omni sounds even more rolled back because of its strong bass emphasis, as if it completely glances over the treble. Here the X pulls ahead again, offering better detail retrieval and more edginess on cymbals, strings and horns. It’s important to note that these are observations while switching back and forth on single tracks. While listening to one or the other for an extended time, your ears become accustomed to the sonic signature, so the differences become less apparent and you can simply enjoy the music. And I assure you that both of these recreate music very well. While both are heavy headphones, I’d say they’re about equal in comfort. I think the ZMF pads are actually plusher than Audeze’s, but I don’t get the same hotspot on the top of my head while wearing the X. Your results may vary. Both share the same cable terminations, so if you have an LCD model, you can use your cable on The Omni, which is nice if you have custom cables.

I feel like Sennheiser HD650 or Fostex TH-600 owners may look to The Omni as their next step in the pursuit of Audio Nirvana. The biggest consideration among these three is the sonic signature that you favor. The HD650 is a classic—it has a very analog and intimate sound with an enhanced upper bass and midrange that is often described as being “romantic.” The HD650 and The Omni flat out sound very different. The Omni across the board is far smoother, exhibiting none of the grain or edge that the HD650 has. The Omni’s bass is deeper, smoother and more impactful. Like the HD650, The Omni offers rich mids, but they are tonally different. Here again, The Omni is smooth and effortless whereas the HD650 pushes vocalists right into your face. As for the treble, the HD650 has some grit to it, it can be sibilant at times, and it doesn’t tame poor recordings. Well, The Omni, as you know, is the opposite of all of that. With either headphone you will experience an intimate and enjoyable performance. The Omni does everything better to my ears, but the presentation is also very different. The HD650 is supremely comfortable and is easier to amp in my experience. But if you have an amp that will drive The Omni well, it’s definitely worth giving your Sennheisers a run for their money.

I mention the Fostex TH-600 because it’s a staple for bassheads and Massdrop’s collaboration models have expanded its popularity. Without question, The Omni hits harder, deeper, cleaner and more controlled. The TH-600 is very U-shaped in its sonic signature, meaning there’s bass and treble and the mids get left behind. The Omni excels at transitioning from bass to mids and delivering all of their lushness to your ears. You’ll gain a lot of musical body by upgrading to The Omni without sacrificing the bass you love. You’ll simply get better bass, better mids and, oh yeah, better treble. The TH-600 has sibilant and grainy treble. The Omni knows better. I listen to a lot of electronic, downtempo and EDM music; the TH-600 was a fav of mine here, but The Omni takes the cake now. Again the TH-600 is a very comfortable and lightweight headphone compared to The Omni, but the sonic improvements are worth experiencing. The Omni and TH-600 have similar reach and dimensionality in the soundstage to my ears, but still The Omni edges out the TH-600 in the end. 

The Caveats

Power and pleasure. What I mean by that is that The Omni craves power and, depending on your penchant for heavy headphones, may or may not be a pleasure to wear. 

The Omni isn’t quite as current-craving as the notable Hifiman HE-6, but it most definitely needs power to perform best. On my Eddie Current Balancing Act, I typically listen to my Audeze LCD-X and Sennheiser HD650 around the 10 o’clock mark on the volume dial; The Omni had me cranking it up to about Noon-thirty or one o’clock to make them sing. I also have the powerful Hifiman EF-6 class-A solid state headphone amp, and The Omni required the dial to reach about 11 o’clock for comfortable listening. In my experience, both The Omni and ZMF x Vibro mate best with tube amps. There’s just something about the synergy there that takes the performance to a more holographic level. 

About that pleasure factor. The Omni and its plush leather pads wrap your ears and smother them like a warm blanket—in other words, very comfy. They do a great job at supporting these beauties that weigh in at 568 grams. In comparison, the HD650 weighs a mere 263 grams and the clunky LCD-X weighs 618 grams. My one issue is really with the headband; even with the pilot pad I get a large hotspot on the top of my head. It’s worth mentioning that my small head may not be best for weight distribution, and the headband can be bent into different positions (carefully), but I simply made due. Of course, the leather suspension strapped headband is also an option to consider. 

These two caveats aside, The Omni has little else to detract from it.

Final Word

It goes without saying that The Omni in African Blackwood is a dark headphone, and dark is beautiful to my ears. The Omni delivers on its promise to be dense and resolving. The bass is tight and powerful. The mids are smooth, lush and intimate. The treble, while relaxed remains resolving to a hi-fi degree. The Omni will not be all things to all people as its namesake implies. But, in all, The Omni makes you privy to a sweet, full-bodied powerful performance time and time again. Figure that one out.

For more information, visit ZMF Headphones and take a behind-the-scenes look at building The Omni below.