According to CBC, University Of Virginia PhD student Ryan Maguire created the project The Ghost In The MP3 to demonstrate the sounds lost when music is compressed to the file format.

Using Suzanne Vega’s 1987 single “Tom Diner“—the first song ever compressed to MP3—Maguire created the song “moDernisT,” which is made from the leftover sounds lost in the MP3 conversion process.

Maguire writes, “The MP3 is not always the most appropriate format for a given task, and a critical evaluation of the technology and its limitations is warranted. Many listeners today listen exclusively to MP3 files, even in settings where the gains from a higher fidelity format would be clearly perceptible. This [lousy] compression codec has thus come to dominate unanticipated listening spaces.”

Here's the original song:

And here are the lost sounds from the conversion:

moDernisT_v1 from Ryan Maguire on Vimeo.