Thanks Tigre, thanks Sebastian.
QUOTE
There's no need to do so for the iRiver devices. Well, at least if you like this "SRS" / "TruBass" processing it can do.
Currently I still have a CD based mp3 portable, without TruBass+SRS options or something similar (although I'm thinking of purchasing a h140). So encoding the effect could be solution for my current equipment.
QUOTE
Anyway this kind of processing should be done online if possible. not before encoding IMHO.
OK, I agree that processing your "untouched / original" music files stay more flexible for the exchange of equipment and for other listeners, but I am usually the only one who uses my portable with my in-ear buds. Also encoding another mp3 version for the portable from my flac files is not the point (lame became quite fast recently

).
As far as I understand, working with the correct HRTF data would be something taylormade...
Did you try and compare both versions? Does irivers solution outperforms a "hard encoded" in front effect ? - What sounds better to you?
To be honest, I'm currently not sure if I really want to get the "sound out of my head"

, but I like to play with that option, listen and decide then (Tigre made me curious with a post on "AudioHQ" and I followed several posts until I came to that thread here - thanks tigre).
One more question: does the quality of the effect depend on the input material, i.E. classical, jazz, hard rock, ... or the stereo quality of the source?
What I mean is, can the effect become different or unpleasant with different source files, or is it always a simulation of the same listening place in front of a fixed pair of speakers in the same room.