It may be entirely psychological. In one experiment, researchers served people the same wine, but labeled one as being a $100 bottle. Without a miss, people said they enjoyed the $100 bottle more, despite being the exact same wine as the $20 bottle. Not only that, but when examined with an fMRI the region on the brain associated with enjoyment lit up brighter. So they not only believed they enjoyed it more, they may have actually enjoyed it more, despite being no different.
The same thing happens with music and music quality. One study looked at professors within the field. When they were told the person playing was a world-class musician, they rated them far higher, despite the fact they weren't. The opposite was true too, when told the musician was an amateur, they rated them lower, despite the fact they were actually world-class musicians.
You're told you can hear the difference or that one type of music format is better and even if there is no difference your brain believes there is. We're great at lying to ourselves, even if we don't realize it.