Sometimes, trusting Head-Fi can be misleading
As soon as I bought my S400, I immediately made a "phat pad mode" with rolled paper tissues under the pads. And the headphone was somewhat sibilant, vocals a bit distant. Good sound, but... I expected a little more.
Some time later, I removed the paper rolls.
Wow.
The sibilance is gone. What I have now is textured, impactful bass. Good vocals (not on the same level as Audio Technica's, but good). An overall balanced sound. Yeah, I'd like a touch more treble to make music more lively, more sparkly, and vocals more intimate and romantic. But I spent 40 Euro for this. It's better than the 70€ AKG K518DJ. I cant' complain. In fact, I'm enjoying the S400 a lot. Unmodded. What do you know.
Clamping force is also much less than with the AKG, and the S400 is much more portable. The way it folds is genius. And I can flip one earpiece outside when I want to listen to something while remaining aware of my surroundings.
Isolation could definitely be better, but if it must come with headaches from the clamping force, then I'll do with less isolation. I couldn't wear the AKG for more than an hour, and that was stretching it. With the S400, I can comfortably listen for at least a couple of hours straight.
I find myself using the S400 more than my full-size cans. It's just so easy to pick up and go. It also sounds acceptable out of my laptop, because it isn't too revealing.
I'm still curious about the portable wooden Audio Technicas, but I'm very satisfied with the S400 as a portable. Excellent value for the money. I just don't feel I need more.