Actually, the math you did calculating the number of bits in a 5-minute song is correct only for mono. It turns out that CDs are actually 16 bits *per channel* per sample; if you wanted to calculate the number of bits for stereo audio, it'd actually be twice as large (423 million instead of 212 million). That said, very few songs actually utilize stereo audio to its full extent, and nearly all songs would be recognizable from their mono versions alone. But very interesting article, and thanks for sharing!