Just got mines today and I'm absolutrely wow'ed by the sound of them. ALMOST (and I said ALMOST) as good as the triple driver, 3 way, UM3X and better than the SM3 on my opinion. Vocals are lush and sweet, forward and natural like the UM3X/SM3, with outstanding definition and texture, bass is as good as the UM3X in definition (a bit better than the SM3). UM3X have more quantity (especially sub-bass). UM3X/SM3 have better treble definition and the UM3X don't congest on tracks with many layers of instruments (instrument separation), but GR-07's clarity is as good as the UM3X and much better than the SM3 which are way too dark for my taste. I have just noticed them congesting on Metal compared to the UM3X, but this is a track where even the UM3X have to do a hard work to render all layers (Silent Out Loud - Gronholm). They sound more 2D whereas the triple drivers give you a more 3dimensional sensation and emotion (which I personally love). Imaging is just different due to the 3 way crossover and driver placement. One can have a more emotional/involving listening experience with the triple drivers, others don't. It's up to personal preference.
The GR-07's deliver LOTS of details, amazing clarity, high-end midrange and great bass and fairly good instrument separation for the price range. Definitely the best dynamic IEM I have ever heard period. Have had Sony EX1000 and the likes and the GR-07 are better on my opinion. They sound full bodied (unlike the EX1000's that are too lean), mids are top notch, bass is good and they deliver punchy, well defined sub-bass as well. Treble needs improvement, but it's not bad at all, just not at the same level of the triple drivers that cost 3x as much. Will see if it improves with burn-in. Will give them some 200 hours or so to settle down. Timber is a bit more realistic on the GR-07. The most noticeable difference for the triple drivers is the 2D imaging vs 3D imaging, instrument separation and treble *quality*. Bass and mids sound pretty much like the same IEM which is very interesting for a 150 EURO single driver IEM. The same for clarity/detail. Simply amazing at this price range.
At this price (around 150 EUR shipped), they are a no-brainer and from my experience including high-end universal IEMs, you won't find any better. Totally forget Panasonic HJE900, IE8, Monster Turbine, DBA-02, etc (and even the 2 driver j-phonic K2 SP), they can't compare.
Of course this is just my opinion, your mileage may vary. |Joker| for example, gave the j-phonic K2 SP a 9.4 and 9.1 to the GR-07, where I would definitely lower the j-phonic K2 SP rate below 9. The same for the SM3, I would give them a 9.1, would give 9.4 to the UM3X and 9.2 to the GR-07, so this is very subjective.
Edited by miow - 2/3/12 at 7:46am