@Dave Bell, Re: MP3 compression
You might have a look at
where you can hear what MP3 (the MPEG1 Layer III audio codec, as defined in ISO 11172-3) discards by opening one of the links in the table with dBA values. It is pretty horrible.
My impression is that MP3 leaves the sound intact, but compromises the emotional impact. May be a boffin with access to an fMRI scanner can do some research on this.