I might have used neutrality right in the title, but when it comes to sound, I cannot dub HM5 a truly neutral pair. I can see how you could be tricked into believing that, but the more I listened to, and especially, the more I compared it side by side to other cans, the more I saw how it missed its neutrality. It touches it at times, and it sits very close to it, but it doesn't always hit the right spot.
That doesn't mean I dislike them, quite the contrary, but I thought I should mention that before delving into details.
Overall, the signature is fantastic. HM5 features an almost neutral (close but no cigar) sound, with a bass that doesn't have any bloat or blead, a clean mid-range and a bright treble that doesn't become too harsh.
The bass is exceptionally flat, but not necessarily neutral, it actually feels under-represented at times. I'm not necessarily a bass-head looking for that head-shaking oomph like BrainWavz's HM9, and I am not always enthusiastic about Audio-Technica M50X powerful-type-o punch, but HM5 feels like its lacking a proper kick. What is present though has the right texture, is exceptionally tight and will keep up even with the fastest beat.
The mid-range is exceptionally focused, slightly bright (but in a good way) and offers a great deal of detail and clarity. The sound is akin to the HD600, just that it lacks a bit of clarity, and is actually slightly sharper. Male vocals are enjoayble, without sounding too rough, and instruments still retain their musicality, though piano for example can sometimes end up sounding a bit too cold at times.
HM5 has the right-kind of treble, with good extension, and just a twinge of sharpness. They're brighter than HD600 and Audio Technica's M50X, but they didn't become fatiguing for me (which is quite strange since I am quite sensitive to treble). Cymbals are great, but compared to the HD600, the bells and whistles just don't match up. Clarity is also not on the same level as Sennheiser's open back, but it sounds a lot the M50X, standing closer to HP150, though it doesn't match those in detail retrieval.
Soundstage & Imaging
There have been only a handful of closed-back headphones that have managed to impress me when it came to soundstage. BrainWavz HM5 is not one of them. Don't get me wrong, what it gets right, it gets spot one, but there's still room for improvement. The soundstage is nicely centered with a decent width and depth. The imaging is also impressive with precise instrumental and vocal positioning, though at times, I felt like the stage got a little crowded, especially with more cluttered songs.
Separation and Clarity
Overall, separation and Clarity is good enough, but it doesn't seem impressive. It handles simple tracks well, but when it comes to more complex tracks, it starts to struggle. You see, I picked up Brian Coulais' excellent soundtrack particularly for detail and instrumental separation. The second half of Chris Mooney's Aisling song lost a great deal of detail that was apparent on the HD600.