I'm at about 40+ hours of burn-in and the harshness in the upper mid/lower treble is starting to grate on me. I am pretty sensitive to sibilance and harshness, so I'm hoping some more burn-in will help.
I will give my impressions versus a few other iem I have for any interested.
I have the Monster Turbines (non-pro) and the Panny 900 that I listen too most.
Lets start with a few words about my taste in music/sound signature. I am a certified basshead. I love bass...both in pure volume and in clarity. That being said I listen to a fair amount of different genres from classical to country to hip-hop to dub-step. Not much I don't like. One thing is for certain, if it can't bring the bass, don't bother applying.
Now, onto the Atrio. A bit more balanced that I thought according to other reviews. The bass does not seem overbearing at all, actually the bass seems downright tame for my tastes. The phones do have a really impressive ability to highlight the bass when the music calls for it though, and not just in quantity...the bass seems very well controlled and organic. Definitely a step up from my turbines in quality. Quantity wise maybe a tad more sub-bass, but a little thinner in the upper bass. I would say the bass seems as fast as the pannys but much more prominent. Then again, I think of the panny's as bass-light.
To my surprise the treble is really a standout. Very detailed and very present. Lots of sparkle and clarity. Way better than the turbines and I would say a little better than the pannys. A little lower in volume that the pannys.
The mids are where a little problem lies. So far they sound a little thin and dry, with a rather large hump in the upper midrange that gets highlighted on some vocals, cymbals and is very noticeable in classic electric guitars. To my ears it sounds a bit like some lower end horn loaded speakers, with a sort of upper mid-range "honk".
Some musical selections for an example:
Seal-Seal - whole album. A nicely recorded album with good dynamics and a fairly layered sound. Seal's voice is a difficult one to convey well as it spans a fairly large range and will sound "off" if the speakers are not up to the challenge. My take-good, not great. A bit stuffy sounding. More natural timber and just the right amount of natural sibilance compared to the turbines and pannys but just missing was a bit of the lower end thickness of both the other phones. The good is that the natural sibilance of Seal's voice is clear and crisp without the ear piercing sound.
Bruno Coulais - Coraline OST - End Credits. Another nicely layered album with lots of natural and organic sounds and a difficult voice to reproduce. This is a standout to me for the Atrios. The treble is very detailed and well represented. The low end is also very well represented and fantastically textured. On this recording the mid-range does not seem as recessed and the upper mid "honk" is not as apparent. The French singers voice is very sibilant, and I experienced nothing irritating about how the Atrios portrayed it. On the contrary the panny 300s are like nails on a chalkboard for this song and the turbines just don't resolve enough detail.
Cookie Monster - Optimus Prime. Nice bass...no really, nice bass. Unfortunately this recording is a bit harsh and the Atrios show it in spades. A bit hard to listen to as the "honk" is very apparent and pretty much kept me from enjoying the music. But the bass is killer.
Avenged Sevenfold - Nightmare. Another album that is hard to listen too with the Atrios. The guitars are not downtuned as in much of the heaver music, so the range is really problematic. Very "honky" and painful for my ears. Seriously, I felt like I was listening to a DJ play music with cheap PA speakers because of the upper midrange.
Bottom line-only good for certain music. Very revealing, nicely textured and much quicker than I expected. More balanced on the whole than I expected. The upper midrange is a killer for me...I think I am really sensitive to it, and it makes some of my music hard to listen to.
Like my Panasonic 300s I imagine lots of burn in won't cure this hump. I will try to eq it out, but haven't gotten too much of a chance to play with the eq yet.