Pros - Above average bass, Not bad treble, Horizontal soundstage with full depth (lots of mid layers)
coming from vsd3/s, i felt the same vsonic signature, not too far. it's soundstage offered slightly more depth to me somehow. vsd3/s are have big sounding mids which makes the soundstage more vertical, they certainly do not totally lack depth like the ostry kc06a but "feel" slightly more vertical. it's just a feel, not a day/night difference and nothing that will affect to a buying choice. i mean they're still superior.
at first gr02 really impressed me because i was expecting something much bad considering the $25 price paid (like xiaomi piston, oh i want to puke when i remember that item). but yes there's some differences which might affect to a buying choice if we compare against vsd3/s, especially with the $35 ordinary price tag. just for $5-10 more you're gonna get bigger mids with more bass acoustic & treble seperation. gr02 is rather a sneak peak to the vsonic products and for the discounted price, it's ok i think. if you're low on money i think you can live with it (i'm only saying this for the discounted $25 price).
i don't know how it'll stand against koss budget products however. i think koss can do some damage on this. koss products have more bass for shure. their mids are bigger than gr/r02 but vsonic still leads on mid layer seperation and their highs are more bright. i'll make my conclusion about koss vs vsonic when i get some ruk30/plug into my body again (i'll get a ruk30 again soon). same goes for the brainwavz r1, it's also something comparable to vsonic (with the discounted $20-$35 price especially) but i liked koss/vsonic more to r1, due to ease of driving & stable frequency balance, add build quality to that. r1 also has bigger mids & bass acoustic if i'm remembering right (my 2nd unit of r1 is also coming soon).
g/r02's bass frequencies coming very flat, you need more amplification on 30hz deep bass (strong bass frequencies like 125hz also comes unamped but not as much as deep bass) than most of bassy models out there. be sure to feed it right to get more bass.
Build quality: 4.5/5
Thin wire, but further more everything looks tight.
Sound quality: 4/5
It’s personal but this is my opinion: this IEM comes short on all fronts except bass and soundstage, from which the last is an obvious result of the use of ventilation holes in the back of the housings. The bass might even be overpresent for some (it is the Bass edition though), but the key fact for me personally is that this IEM lacks clarity in mids and highs (dull) and seems to lack a good sub bass (might be due to the ventilation, non closed means it's harder for an IEM to produce the pressure needed for sub bass). Some people may find and call the dull sounding highs and mids “warm”. But again, that’s personal, I find the sound dull.
The wide soundstage as a result of the use of ventilation holes also has a downside: less isolation. But it’s still pretty good for a ventilated IEM.
What can I say? The IEM has a more or less standard design for a sub € 50,- model. It’s pretty big which makes the housing come in contact with the ear shell and will eventually cause irritation (for me within 2 hours). Besides that the Bi Flange is terrible, and a real downer for me personally as I expected more of it. The seal is too tight which causes a pressure change in the ear. If you pull the ear shelf up and back to straighten the ear canal and push the IEM with Bi Flange in as deep as possible and as far as is it’s comfortable, and then let go of the housing, it then pulls a bit back sucking the air in the ear canal and so the eardrum. You then hardly hear any sound at all. Even if by some miracle you get a good seal, the isolation isn’t that much better than with the use of single flange tips. Also the Bi Flange is a pretty big tip, which isn’t comfortable for people with smaller ear canals in general.
If you like a dull or "warm" sound with enough bass than this is your IEM. Beware that for long use the available tips might not suffice. I recommend to get comply T(X)400 tips with this IEM (Shure olives do not fit as the nozzle is too wide).
I personally prefer Shure olives over comply tips due to the durability, and have succeeded in modding the tips. You can do so by taking a metal stick (I used a screw driver) from which the diameter is a little bit wider than the diameter of the nozzle. Stick it in the Olive with a bit of force (I stuck it in all the way through the mesh) and heat up the metal (for example by using a cigarette lighter). Let it sit for a while (about 10-15 mins) and voilá. You can now place it on the nozzles.
Tip: take small sized Shure Olives if your a medium user. The wide nozzle pushes out the foam filling up the ear canal more than normal.
Pros - Clear mids, not too bright, controlled bass, great isolation, good soundstage
Cons - Earbuds are not really comfortable.
The GR02 is certainly an amazing IEM for 40 dollars. It took me a while to get used with it, but it is great sounding. Soundstaging is pretty good, as I tried with a few live jazz and classical recordings. The bass is very controlled. Initially, the bass might be a little soft, but after messing around with the equalizer, I got the best bass I could get from the GR02. The bass might go over the other parts at times, but it depends on your music and how they were mastered.
I daresay the GR02 is actually a great all rounder IEM. It sounds good out of the box. Hook it up to your player and you'll be amazed.