Bigger drivers don't translate to a better sound, as my experience with KZ ED4 has proven. You would expect a massive bass from these drivers, but you only get a standard one. The vocals and highs are so loud and harsh that it makes you want to take these earphones off and throw them away.
There's another issue which seem to be plaguing many KZ earphones: they use extremely weak glue. That plastic nozzle part broke off as soon as I tried to take the ear tip off and I had to glue it back myself with a more decent glue.
Althought these earphones' sound signature is suspiciously similar to KZ GR's sound signature, the ED4 seem to improve quite a bit in terms of clarity.
A pretty nice bass response, but pretty standard.
A robust and nice looking housing and inline remote.
The vocals are shrieky and sibilant and the highs are sharp and painfully loud.
The plastic nozzle part is poorly glued, it broke off as soon as I tried to take the ear tip off. Had to glue it back myself.
The same gut-like cable KZ uses for their products.
The splitter is way lower than chest-level and makes the cable wiggly and hard to control.
Package & Accessories
Ear Tips - Single-Flange:
S+M+L, black (translucent), ?4mm bores
Build & Materials
Metal + plastic (glossy), ?5mm nozzles, soft strain reliefs
TPE, soft strain reliefs
Silicone (grippy), 119cm, soft, straight
TPE, 90° angled, short, soft strain relief
The low score is due to the use of a very weak glue. The nozzle easily breaks off of the housings.
Comfort & Fit
I got a good seal with the pre-applied M-size tips. No problems at all. Still, the generic tips aren't the best at keeping the earphones inside.
Lows / Bass
The bass is pretty deep and precise, and even has some sub-bass, but it struggles with it, almost as if it's about to crack.
Mids / Vocals
Very audible sibilance in the vocals make the whole listening experience fatiguing.
Highs / Treble
Excessively harsh highs. They are so loud that listening to these earphones just for a few minutes can induce a headache.