With a sensitivity rating of 124dB, the HEM8 is the most sensitive in the series. It hisses mildly when plugged into a Lynx HILO and a little less when plugged into a COS Engineering H1. It doesn’t hiss when plugged into an iPhone SE or an AK240/380, and only minimally when plugged into an AK70. I reckon that the HEM6’s sensibility of 113dB or less is the sweet spot for portable earphones. I’d very much like if all earphones hissed as little as the HEM6 and HEM2.
The HEM4 and the HEM8 have in common high frequency extension. It is meted out differently in both earphones. While both ride highs way into the rafters, neither agitates sibilance like an Audio Technica CK10, or an Etymotic ER4 might. The HEM8 isn’t quite as energetically voiced as the HEM4. Its treble fades to black a bit faster, but not before lighting up chimes, high vocals, and percussion. It’s also got what the HEM4 really doesn’t: bass. It’s got the god-like bass of the HEM6, but with more even sound pressure and speed against the mids. And even early on those mids are brighter.
On a darkness scale, the HEM2 wins it. It is followed by the HEM6. And because the HEM8’s bass is deep, and in some ways, dark, the HEM8 is next. The HEM4 really is the oddest one of the bunch, and even after weeks with the HEM8, which I really like, I’ve got to say that I prefer the HEM4’s even Stephen voicing.
Here is the why: the HEM8 has a bit of echo to the lower mids, which can cause low-voiced male vocals to throb a bit more than natural, whereas the HEM4 is completely natural. And the HEM2, while darker than every HEM, transitions smoother though frequencies than the HEM8. Part of the reason may be that it is warm throughout, with no troughs or peaks to distract. Everything falls into place after it; this comes at no cost.
The HEM8’s bass is noticeably more layered than the HEM2’s, and it positions audible elements more precisely than the HEM6. This goes for high-frequencies, too. Decay speed is good, but masked slightly by the slight echo in lower mids. Now, let’s get to the HEM8’s mild V-curve and mild post-vocal suckout. It reminds me of the Ultrasone IQ, which for many years, was my favourite earphone. This suckout really works to liberally paint live recordings with the light patina of a monitored ad-hoc studio production.
The HEM8 is the most dynamic of the line, and it is bound to polarise. It nails pop and even trance, though that mild lower midrange echo might catch up super fast, super bassy music. Its stage is the most developed, with pretty deep Z-axis positional detail in lows and highs, but pretty flat field in the middle. In other words, its stage is a direct upward iteration on the HEM6’s. It is also the most intricate of the series, obviously blending two disparate voices: V-shaped impact and neutral mids.
I’m a HEM4 guy, though the HEM2 remains my pick against other-brand price rivals. It nails warm without sacrificing immersion. The HEM8 is up against a lot of V-shaped earphones in and above its price range, some of which output deeper Z-axes, or smoother bass-to-mid transitions. It fits really nicely, has one of the nicest accessory kits I’ve encountered, and is wonderfully marketed. But that is the case with every HEM earphone.
Through testing the HEM series, I’ve become a fan of Nuforce’s marketing and array of choices. I think this series has something for everyone. And unlike a lot of earphone series, whose flagships mop the floor with the entry level, the HEM series is brilliant from the start. Where you go from there: to the neutral-leaning HEM4, or the dark-but-sparkly HEM6, or the HEM6 with layers (HEM8), is up to you.