There is actually something like "brain burn-in" involved.
It is a fact that our brain processes the sound and somehow "equalizes" it, so that our perception matches what we expect to hear.
After I re-discovered many great songs with my present equipment, I found I could hear many of the newly discovered details in the music even when playing through my car-audio kit
What my brain could not make up for was dynamics, though. Listening "Bohemian Rhapsody" on the radio few weeks ago was a nightmare, just as an example. I have also now my whole cd collection on a hard disk (extracted with EAC, stored in flac), and playing through the sound card shows a lot of compression as compared to the original, or when played in my Iaudio X5L.
Regards,
Alberto