The HEM6’s 37Ω, combined with an efficiency of 113dB make it just slightly less sensitive than the HEM2. Nasty hiss from old iPods, the original AK100, and the otherwise-brilliant Astell&Kern XB10, is minimal. Naturally, this has me driving the volume up a few notches. Another nice side effect of the HEM6’s low sensitivity is that it is easier to drive along impedance curves. Even poor players with high z-outs suffer very little linear artifacts in frequency response. It’s a trade off I wish more manufacturers would make.
Audiophile tropes describing higher-end earphones of a series as more refined than their entry-level comrades, are tired. Sometimes, however, they are totally spot on. So, by all means yawn and nod to the the following: the HEM6 is, in all cases, cut from the same cloth as the HEM2. In most cases, it is more refined.
The HEM2’s bass lines tended toward soft details which are buttressed by warm, heavy, and soft leading edges. The HEM6’s bass still is warm. But it is faster, tighter, and more finely graduated. It ensures a sizable out-of-head feel that is a cut above the average, but which truly plays off the HEM6’s addictive – and again, warm – mid and high ranges.
Part of what makes the HEM6’s bass sound more detailed is that it rides a lower sound pressure vector than the HEM2. If you’re a traditional bass-head with bolder rumble on the brain, the HEM2 may float your boat. The HEM6’s bass cleaves closer, but not in full accordance to, so-called reference signatures.
Transitions to mid are smooth and phase coherent, but from middle mids on up, the HEM6 warms up. Vocal sound pressure is good, casting voices fore, but the midrange is dreamier than it is clear. Small details jump to the fore, but with blurred edges, and a slight ring. Still, stereo width and positioning are spot on. Separation between instruments is most meagre in the high midrange. Usually this resolves in close stage presentations. Contrariwise, the HEM6 manages decent-to-good stereo width, and a deep, if somewhat crowded, z-axis. The HEM2’s stark wall of sound resolves in the HEM6 into a fluid, fluttering gauze whose peaks and troughs writhe over a space about a metre deep. Upper midrange percussion, chimes, and guitars hover above the shoulders and just outside the ears.
Highs are very slightly more detailed than the HEM2’s. Stereo details push further afield. Like the HEM2, sibilance isn’t a thing to bother about. The converse is that, the HEM6’s highs aren’t all that energetic. Because they pop up high around the ears and out slightly from there, with very little to muffle them, they are less muffled than their sound pressure hints at. High frequency texture detail is meager, but thanks to jumping forward into the sound stage, they appear more energetic than they are.
This presentation, and the HEM6’s general penchant for speedy percussion decay, make it an interesting, though far from perfect companion to trance music. They line even today’s most uplifting melodies with warm overtones. Honestly, it’s the sort of presentation that works as often as it does not. But it almost completely detracts the high-range anchored dance-hall trance feel. And, since Depeche Mode were heavily involved in the founding of modern electronic dance pop, this style just fits.
Darker tones richen up everything. They soften up harsh edges. They pull together loose compositions. They make a celebration out of what done wrong, becomes a veiled mess.
The HEM series is strapped to one of the worst pack-in cables in the audiophile world. I’ve ripped apart every one Nuforce graciously supplied. And I’m no He-Man. Fortunately, it comes with a sturdier, mic’d friend. I find few to no audible differences between the two. At first blush, there are few differences between the HEM2 and HEM6. But given a few hours, differences practically fall over themselves. The HEM6’s tighter decay pushes forward a greater sense of speed. Low frequency detail and stereo involvement propel detail through the entire range.
Rich warmth supplants darkness. This is a brilliant-sounding warm earphone.