To get to the soundstage level you really have to push the boat out with patience, cash, and careful audio route planning. It's not all about the headphone. If things were only that simple.
First of all, the musical detail has to be present in the music track that would allow for a realistic soundstage. Don't expect anything from mp3. FLAC, WAV, APE are the kind of formats you need to look at.
..This isn't convincing. Because there is no discussion of what this information might be or of the large difference between a 320 lame and 64 old-skool mp3. Even worse, there's no discussion of the fact that no one can tell (i.e. in a blind test rather than in their imagination) the difference between 320 aac/mp3/ogg and cd/wav/flac. If soundstage was so different wouldn't this in fact be very easy?
Next you need a DAC that can dig down to the soundstage bit level and reproduce it without any artefacts that could misalign the soundstage.
A bit is a bit; all DACs look at all the bits - and their behaviour at this level is determined entirely by $1-$5 chips that provide all their core functionality.
Edited by scuttle - 3/4/13 at 1:03pm