Been listening for 1-2 hours since received this morning.....
Pretty remarkable IEM. The first words out of my mouth to describe would be incredibly detailed, transparent, balanced and natural sounding.
It is a different animal in that it has this airiness where all the harmonics just float throughout your head. It is very pleasureable and almost intoxicating. While I wouldn't necessarily say it has a huge soundstage, this airy space around all of the instruments creates plenty of "room". GR8 has it too and it seems unique to the Grado's and I have not heard it from any Ety, Westone or Shure product. It would seem quite obvious Grado was seeking out this kind of sound and certainly achieved it.
This GR10 is the most naturally sounding detailed IEM I have ever heard. It does indeed have a good 15-20% more treble detail than the GR8 and is also amazingly transparent. You really "see into" the music. Because of this it will pick up flaws in a recording but this hyper-detail does not seem harsh or grainy much at all....it is very smooth. I have not heard the REO's or e-Q7 but it is certainly Ety level detail in every regard but sounds much better due to the airiness of the harmonics and a bit more bass. It is not cold or sterile as some use to describe Ety's. Quite the opposite.
As far as efficiency, while the ohms changed from 120 to 32 (from GR8), I would only consider the GR10 slightly more efficient that GR8. I'm sure an amp would make it sound even better but it does not require one. Also, I am only detecting slightly more bass than GR8 (5-10%?). I think Grado was consciously careful of this not to create too much bass to throw the balance off and I think most IEM's out there are aiming for a funner sound which usually includes more bass, perhaps too much to claim balanced perfection no matter how many drivers. It would not be a stretch to say GR10 is approaching harmonic perfection in an IEM. The biggest change from GR8 seems to be more treble, a slightly fuller sound and more overall clarity. Again, to have such transparency and detail while still retaining such smoothness is remarkable IMHO.
In summary, If you liked GR8 you will certainly like GR10. Is it worth $400? On one hand I would say not because of lack of accesories, case, etc. On the other hand, I think it is a very different beast and this Grado (what seems to be becoming an IEM trademark with them) airiness and loft to the harmonics seems unique among all IEM's. It is no copycat of anything so in that regard, they can charge what they want. I would guess Grado knows exactly what they have with this product. Knows it won't sell a ton of them because so many want a BIGGER sound, but they also know they accomplished the precise sound they wanted. The GR10 is almost a reminder of what music should sound like or use to sound like from the analog days. It sounds as good as any other $400 IEM I have heard, just different (and unique). It could be the most naturally balanced among any IEM out there. I think a good percentage of listeners out there prefer a larger robust sort of sound presentation and those people may not think all that much of GR10 (at $400). But for those that are seeking harmonic perfection, loads of detail but balanced and natural...there may not be another IEM out there that does it as well.
I can't really say if I prefer it over SE535 and W3 yet because it is such a different beast and it is too new. I will try to judge that after many more days of listening and will provide more thoughts in general on the GR10.
