Here’s a simple scientific experiment. Please listen to this audio file* and answer the question below. The file (all 56mb of it) contains three versions of the same 1’15″ excerpt of Mozart’s Piano Concerto K.491. One is the original uncompressed CD-quality audio, the other two are compressed, like you’d download from iTunes or Amazon. Can you tell which is which?
EDIT: Did you get it right? Did anybody else? The results are now in.
* The sample is from this album, which I heartily recommend. I picked it because it contains all the things that typically encode badly: piano and strings, loud and soft. It’s a big file. It has to be, because the whole thing’s gotta be at CD quality for the science to work. I’m sorry if it takes a while to download. This is what music would be like on the Internet without compression, because CD quality audio is quite a bit bigger than the stuff you’re used to downloading. There are formats that make CD-quality audio a bit smaller, but they don’t work on many of the popular players.
Is there a glaring hole in my methodology? Use the comments. I’ll close the poll and post the answers (and results) when we’ve got enough votes.