Sound impressions
If you’ve read my recent impressions, you’ll likely know how enamoured I’ve been with PMG’s Apx ME ultra flagships – a $7,000 set of summit-fi IEMs with an almost perfect tonality for my preferences: powerful, textured bass, rich organic mids, and a smooth, relaxed treble that doesn’t force itself on you and lets you listen for hours without fatigue.
On first listen, Zeta II was giving me serious Apx ME vibes. There were some differences, yes: the treble was slightly more pronounced, but still refreshingly polite, and the midrange wasn’t quite as forward, but still lively and clear. Bass wasn’t quite at the same summit level as ME, but then, I can probably count on one hand the IEMs that come close to that tribrid-driven bass quality.
Still, the similarities were close enough that I felt compelled to make some measurements of the two sets, and they more or less follow the same curve, with slight differences in emphasis along the line.
I’ve been listening to Zeta II almost exclusively for the last few weeks, using a selection of my usual test tracks – favouring slower, more melodic singer-songwriter and indie pop female vocalists with a splattering of faster-paced modern pop, classic rock, and the occasional classical score.
Most of my listening was done with HiBy’s RS8 II, and indeed, I find the synergy between these two both impressive and versatile. I don’t need to use any of the RS8 II’s many sound shaping tools to get Zeta II where I want it.
Tonality
I hear Zeta II’s tuning as somewhat U-shaped, but mostly balanced. It has a smooth, natural, organic sound with good amounts of clarity and almost zero harshness anywhere in the frequency range.
Bass is dynamic, powerful and reaches fairly deep. Take Lana Del Rey’s Young and Beautiful – that sub-bass rumble underneath her ethereal vocals has real physical presence that belies the rather modest size of the 8mm dynamic driver by today’s standards. It’s not overly elevated, nor is it the last word in texture retrieval, but it’s got some real body to it, with a nice balance between sub- and midbass that doesn’t creep into the lower midrange or muddy the vocals in any way.
I’ve come to appreciate sets like these that don’t overcook the bass quantity, blending it smartly with the other frequencies so that it’s there when needed and not when not. Mind you, where there’s big bass in a track, you’ll hear it. Switch to Missy Elliott’s Work It and crank your volume beyond whisper quiet – you’ll get proper thumping energy down low without any bloat.
Moving up to the midrange, you’ll hear vocals as neither recessed nor overly forward. This is one area where Zeta II differs from the aforementioned Apx ME, with a gentler, more restrained midrange presentation that’s still solid enough, detailed enough, and organic enough to sound very natural without pushing instruments and vocals too close to your ears.
On Brandi Carlile’s The Story, her powerful voice sits comfortably in the mix rather than jumping out at you. You may not get the same level of vocal intimacy as you would with some vocal-forward sets, but instead get a more even-keeled presentation that some may find less exciting but also more forgiving.
There’s a touch more presence in the lower-to-mid midrange than there is in the upper mids, so you never have to worry about anything sounding too sharp or shouty. But if you prefer some extra bite and detail in guitars and female vocals, you might find these lacking slightly, at least compared to other sets.
Last but not least, the treble. HiBy seems to have joined the microplanar party with Zeta II, including said driver for the treble frequencies. Thankfully they’ve implemented it without the planar ‘sizzle’ you may have heard with other IEMs using these drivers. Incidentally, this is another trait that Zeta II shares with Apx ME, which likewise uses a planar tweeter for treble extension without sizzling up the lower treble.
While I consider the treble polite, it’s not without substance. The four EST drivers add plenty of air up top. On Flower Face’s Heat Waves, the delicate cymbal work has a pleasant shimmer without coming off hard or edgy, and treble notes have some decent body to them too, so they don’t come off thin and shrill. Again, this is not going to be the last word in detail, but there’s more than enough here to keep all but the most ardent detail-head happy.
Technical performance
As with its tone, Zeta II’s technical performance leads from the back. In other words, you’re not going to get a bold, uber-spacious detail monster with this IEM, but rather a gentle unveiling of sound that’s both pleasant and precise in equal measure.
Given its price point, I’d say Zeta II resolves more than admirably. Even compared to some much higher-priced flagships, I’m not really missing any detail, even on complex tracks.
Dire Straits’ Sultans of Swing – with its intricate guitar work and layered instrumentation – comes through with impressive clarity and separation. There’s also plenty of pace in these drivers, and one advantage of a smaller dynamic bass driver, especially one with a diamond-like carbon diaphragm, is its ability to keep up with pacier music without smearing.
Another commendable technical metric is staging, which is big enough to be notable but not so big that it comes off as unnatural. There’s lots of width here, with sounds projecting outward almost beyond my ears, but also enough depth to keep the stage dimensional and not flat.
The live version of the Eagles’ Hotel California really showcases this well – you can almost feel the space of the venue, with the crowd noise sitting distinctly behind the band. If there’s one thing that usually separates more advanced IEMs from the rest, it’s spaciousness, and Zeta II is nothing if not spacious.
Imaging and separation aren’t far off the pace of far more expensive counterparts either, and it’s a testament to how far IEM technology has come, and how good modern drivers have become, that this level of sound shaping is attainable without having to spend significantly more.
It’s been a while since I last listened to original Zeta, but I can say for sure the first attempt leaned far more coloured, with a boisterous, boomy midbass and lack of refinement in the upper registers even when compared to entry-level IEMs today. Zeta II is a notable upgrade, not only in refinement but also composure, tonal balance and technical performance.
On its own merits, this is an IEM that can stand assuredly with any other in this tier, and is easily a class leader when it comes to build, style and overall performance. In fact, I’d grade it far closer to the $2,000 IEMs in my stable, and even higher than some more expensive IEMs that didn’t have Zeta II’s gentle touch, even-handed tone, and overall sense of musicality.
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