I’m just starting the work and fun of reading/writing/thinking/rereading/rethinking/rewriting my way through Jonathan Sterne‘s wonderful new book, MP3: The Meaning of a Format (introduction here). For those unfamiliar with his work, here’s a representative quote from the beginning:
Because it uses both kinds of compression [redundant data compression and perceptual coding], the MP3 carries within it practical and philosophical understandings of what it means to communicate, what it means to listen or speak, how the mind’s ear works, and what it means to make music. Encoded in every MP3 are whole worlds of possible and impossible sound. (p. 2)
When I explore lossy and lossless formats with my students, I 
often use a visualization of MP3 files, which allows us to learn from looking at representations of sound (one of my interests). It is clear how the bit rate lops off the upper frequencies drastically, with 56kbps very audibly different even with laptop speakers (of course, Sterne’s book takes this much more seriously and challenges the notion that compression is a bad thing, but this visualization presents some of the ideas that can be explored). In honor of the conversations that will be stimulated by Sterne’s book, here’s the PDF file with embedded audio. [Note: since YouTube and many sharing sites compress uploaded video and audio, I’ve released this as a PDF that has embedded audio, which is best heard using Adobe Reader. This way, I’m confident that when you click each format, you’re hearing that format and not a re-compressed version.]
Matthew Thibeault 