Originally Posted by Kamakahah
comfort: KC06A. It's feather light. The 850 is comfortable for me, just heavier.
Isolation: haven't tested in depth. Neither was particularly bad.
Build quality: FX850 hands down. KC06A Feels very cheap and plasticy.
Still to early to be certain about the spectrum on the KC06A; However, I'll share a little.
It didn't pair so well from the HP out of the X3. The line out to a separate amp gave it an overall better balance. *(PRE-BURN-IN)*
The bass was very strong, punchy, great extension and rumble with a significant midbass hump that emphasizes the bass in the sound signature.
The Mids were smooth, warm and detailed but felt like they lack dynamic energy. They also sounded a step back from the lows and highs.
Highs: Forward, detailed, sparkly without sibilance. Lacks extension and has an emphasis (or peak) in the 2-5k range that has been rubbing me the wrong way.
Going line-out to a separate amp brought the Mids a little more forward and seemed to benefit the whole spectrum in small ways, but the overall characteristics remain the same.
Finding good synergy with the source chain is going to be key with these.
They are a solid buy, but their biggest fault is soundstage. To me, it's like a wall of sound. The FX850 is a stark contrast. Right now, with my usual rig, the FX850 outshines the KC06A in the majority of categories. More importantly, it fits my preferences better.
The FX850 is like a sweet, warm and loving embrace that leaves you fulfilled. The KC06A is like an intense one night stand that rocks your world but leaves you feeling sore but with a smile.
Both are currently burning in. We'll see how things change with different setups, tip rolling, etc.