For those of you that have been waiting for my write-up of the ZMFxVibro, I do apologize for the delays. I know I’ve dropped a few bits of info on them here and there, so you might already know I’m pretty happy with how these sound. As a disclaimer, I have been talking and working with Zach quite a bit over the past few weeks to help him refine the headphone, so there’s bound to be some inherent bias in my opinion. Anyway, let’s get to it. (Clarification: This review is based on the latest tuning as of mid-September, a fairly new and likely final revision.)

Looks, Comfort, Build Quality, Presentation, Misc.

I have to say, I think these are a good looking set of headphones. On this tour unit, the blue finish and particular type of wood makes for an interesting and, in my opinion, beautiful look. You’ll recognize the classic headband, and the metal railings can be re-finished as well. There is a nice set of finish options, both wood and railings, to choose from.

The variable port configuration works fairly well and does what it is supposed to. While I prefer the implementation that allows you to finely tune the Alpha Dog, the ZxV’s venting options is much more convenient to utilize despite being less granular. I found I preferred having one port open per channel on the ZxV, as having them all closed made them a bit too weak sounding, and any more made them too bass heavy for my tastes (can be fun, though). To be fair, Zach was targeting a headphone that could be rather bass-heavy and lush sounding. My impressions were done with my preferred configuration. One downside to this setup, however, is that it’s pretty easy to lose the plugs.

Thanks to the alpha pads and padded headband, the ZxV is a fairly comfortable headphone. I still think the Alpha Dog itself is a bit more comfortable and fits better on and around the head with the suspension-like comfort strap, as the ZxV’s wood cups and overall method of construction make for a more rigid headband and fit. Good thing the T50RP headband can be bent without much worry.

Overall, the Alpha Dog feels like a more premium, well put together product, and the ZxV has a distinctly hand-built look and feel to it. Still, the ZxV does have its aspects of beauty and is certainly more than functional, so it really just comes down to the sound in the end. Oh, and the ZxV comes with a hard, padded carrying case, I believe (the tour unit does, at least).

Sound

I think the ZxV is a very enjoyable headphone to listen to. They are a bit on the bass-heavy, slightly dark side, but generally have a good sense of balance to them. Mids are not scooped, and treble detail doesn’t appear to be missing. At times, the bass can be a bit disconnected sounding, but the sound does tend to be rather cohesive. I thought the bass sounded fairly clean and offered good pitch and detail. With one port open, sometimes I wish it was still just a bit lower, but I often like the tasteful bump.

Subjectively, something about the upper-mids and treble can be a bit edgy sounding, not unlike how the HD600 can be at times. The ZxV also can be a touch harsh or, perhaps better put, hashy sounding, but this never really bothered me or got in the way of enjoyment for long listening sessions. It’s probably just my ears given how slight it is.

That said, I do think the ZxV offers a good sense of clarity and blackness, more so than the Alpha Dog. The ZxV might also be a faster and more resolving headphone than the AD. If anything, despite being less neutral above the bass, darker, and lusher than the AD, it has bit more of a “hi-fi” sound to it. The AD noticeably excels when it comes to soundstage over the ZxV, as the ZxV is more on the closed sounding or intimate side, but the ZxV does seem to do well with separation regardless (and that extra sense of clarity helps). I found the Zx V to be a fairly organic sounding headphone when compared to the other headphones I have on hand, which is something I prefer over the AD’s presentation. I might even find it more organic sounding than the HD600/650, but it’s hard to say and depends on my listening mood. I think the ZxV has pretty good tone to it. I wrote a note saying it can be a bit nasally at times. I guess that is true, but very minor and no worse than niggling issues I’ve heard from about any headphone.

The ZxV does appear to have a tiny bit of channel imbalance, but this is largely fixed if you fiddle with the fit and placement. Really, it doesn’t get in the way and usually isn’t noticeable. The AD suffers from this too. I think unless you are meticulously trying to match channels, there are some inherent limitations with the T50RP drivers.

Compared to the PM-2…I dunno, I think I just like the ZxV more in most regards. It makes the PM-2 sound boring and lacking something. Hell, I might even prefer it over the Sennheisers in back-to-back listening tests. Hard to say. Overall, despite them not being perfect, these are one of the more enjoyable headphones I’ve tested recently, and I did find myself gravitating towards them during my back-to-back tests.

Measurements

Frequency response measurements do show an overall slightly dark tilt, but the midrange is pretty good and even. There are some channel imbalances evident below the treble area, but I didn’t ever find this really detrimental. Bass is a bit elevated, but sounds tasteful to me. The treble is a bit uneven and depressed in some spots, but that doesn’t seem to contribute to anything sounding particularly weird. Still looks better than the PM-2 to me, and quite a few other headphones.

Zach and I have had some discussions about internal damping and reasons for this pair’s channel imbalances, and he is pretty confident current production pairs should match a bit more closely than this. Based on what I know about this pair and some advice I gave Zach from that, I’m inclined to think he is probably right, and it’s not anything that will affect the overall sound.

Distortion results overall look pretty good. Arguably smoother than the AD’s results, which might contribute to the subjectively more “hi-fi” sound and clarity. There is a bit of a rise in bass distortion, but nothing major. The distortion spikes in the left channel didn’t seem to impart any negative subjective characteristics, and, again, based on what Zach and I have discussed about the internals on this particular pair, this should be ironed out in current production pairs (the B-stock pair I tested earlier looked good, results not published). Even if the channel imbalances and harmonic distortion oddities were to not be further ironed out, I don’t think it’s worth worrying about.

CSDs look pretty clean, which isn’t unexpected for a T50RP mod like this. The extra bit of decay around the 2-3KHz area might factor into the edginess I was hearing, but even that is pretty minimal. I don’t think most will have issues or even notice what I was talking about.

Conclusion

They might not have the perfect build or looks of the Alpha Dog or PM-2, but I simply really like how the ZxV sounds. The original, B-stock pair I heard was a bit uneven and too harsh in the treble, and I think Zach did a good job targeting the sound he was looking for in the end with this pair. The ZxV now employs some front damping to help smooth out the sound, and I think the materials produce good results. Perhaps there is still room for improvement with other front damping materials and configuration, but I’m pretty satisfied with this.

I’m going to restart the Changstar ABS tour with this pair (if you don't know what I'm talking about, perhaps some day you will), and I encourage you to try them out if you are intereste d! Maybe you’ll enjoy them as much as I do, maybe not. Either way, thanks to Zach for loaning out this pair! I’ll try to get some pictures of it up soon as well.