Sound (8.5/10) – As expected, the bass is the dominant aspect of the sound signature of the M8. What is surprising is just how technically competent the low end is. The bass is extremely extended, dropping below 30Hz without significant roll-off and audible well into the low 20Hz range. With the exception of the Hippo VB, the Atrios may have the flattest sub-bass of all the bass-heavy earphones I’ve tried. But it’s not just the excellent extension that gives the Atrios their reputation – the bass is detailed and impeccably textured. The dynamic drivers found in the Atrios can move quite a lot of air and, while the impact isn’t quite as precise as bass produced by BA-based earphones, the Atrios exercise impressive control over their low end. The bass is neither muddy nor bloated and can be an incredibly satisfying underlying element on bass-light tracks. On tracks with dominant basslines, however, the low end of the Atrios can be intense and perhaps even a bit overpowering if your personal preferences lean towards more analytical sound as mine do.
Recessed slightly in comparison to the low end, the midrange is clear and detailed. The clarity lags slightly behind the Sennheiser IE8, Hippo VB, and most armature-based earphones in the price range but still manages to impress for an earphone balanced the way the Atrio is. The mids are smooth, surprisingly uncolored and natural-sounding, and blended well with the bass and treble. Stringed instruments sound especially crisp and pleasant with the Atrios but vocals have good presence as well. The treble is just as smooth and relaxed as the midrange and boasts impressive extension with silicone tips and a slight bit of roll-off with foamies. The top end is quite natural and, though fine detail is not as forthcoming as with some of the more analytical earphones, the edginess present in the treble of earphones such as the Hippo VB and Panasonic HJE900 is nonexistent with the Atrios.
The overall tone of the Atrios is quite dark, especially when using foam tips, but the presentation is quite monitor-like in nature. Soundstaging is good for an IEM but they won’t keep up with a Sennheiser IE8 or Phiaton PS200. Compared to the IE8, the Atrios have noticeably poorer separation and are a bit more tiring as a result. Truth be told, the Atrios sound like an IEM version of the popular M-Audio Q40 monitors – both are quite flat and uncolored aside from the hugely boosted bass, matching also in the little details such as the dark tone and fairly spacious and three-dimensional soundstage. As proper monitors should be, the Atrios are fairly revealing and 128kbps mp3s are a no-no with them. Lower listening volumes are also not ideal for extracting all of the detail the dynamic drivers of the M8s can produce.