Exactly. Human ear is focused to mid range there the human voice is. And those 12k+ Hz (harmonic reverberation ultrasound) noises you can't distinctly hear, but they make the environment feeling in your head.   Vinyls sounds better, because recording process on vinyl doesn't have dynamic...

High frequency response + THD. Clearer response  = wider "soundstage". This is so because of anatomy of our hearing.

MD username: joe.cool   High-end DAPs and Amps

  Give a try to 80e, if you find. They sounds exactly the same, but more detailed with better bass control against 80i. Anyway, 80i are just great headphones.

Thanks for update.  But I got an issue in latest fw: USB DAC does not work in ubuntu (14.04 LTS). When I connect x3 in DAC mode to my pc, audio devices in settings disappearing and I have to hard shut down pc. FW 3.3 - DAC works.

Yeah. Maybe that is only my personal experience. But I had 4 Portas, for the last one which I use  I replaced wires from cheap skullcandy iem. I think maybe not only cold air, but something else make wires like sticks.  I always wear it on streets.

And PortaPro's wires like peace of frozen plastic, which never get soft again..

I did this with my SR60i with 2 holes, I've got more low-end, but not controlled like in new E generation . If u want heavier or darker sound - u should try. Btw, new SR80e come already vented with 2 holes.

With new fw I've got a mess with icons in category menu

Sennheiser IE4

Pure matte black!  

Yeah. EQ is great upgrade for X3.

Same experience with Grado SR80e, better treble response, and bass drive with 1 (bass gain). SQ become even better with EQ on (3.22 fw), doesn't matter if it flat or tuned, because it slightly reduce audio volume in LO remain the same current.

This logo appears only on 3.21 and 3.22 fw. FYI

Yeah, that's works, but partially. I've changed all the pics in this folder, but custom bootanimation appears after red fiio boot logo. I want to know is it possible to remove that logo.