Despite all of the strategic mistakes Microsoft has made in the digital media space, some of their underlying technology is pretty remarkable. In particular, the Windows Media Audio (WMA) codecs occasionally surprise and impress me.
In this context, a codec is a computer algorithm used to reduce the file size of digital media files for easier transmission over a digital network. In very basic terms, this is done by removing extraneous information from the signal–for example, bits that represent very high or low tones that most listeners cannot hear. The trick is removing the right stuff–sometimes, seemingly inaudible portions of the signal, when summed up, contribute to a particular instrument or voice’s character–remove too much, and the cymbals sound tinny, or the guitar sounds flat, or the singer’s voice sounds thin.
But more sriking to me was a recent personal example. Diminished Men, for whom I’ve been playing bass, recently finished recording an album. It was done onto 2-inch analog tape, then moved into ProTools (the industry-standard digital mixing tool) for mixing. The tracks have been mixed, but not mastered. Mixing is where you listen to each individual track (bass, guitar, each drum), decide which tracks to use where (for example, we did lots of guitar takes with different tones), equalize the tracks you’re going to use, blend them together at a certain relative volume, re-equalize, re-blend, and so on. Once that’s done, you master each song, which means equalizing the whole song, compressing it, increasing the volume, and so on. This is done to bring out parts that are hidden, add power, and so on. (Mastering is also where you decide song sequence, how much space between tracks, and so on.) There’s a lot of complicated voodoo (and opinion) involved in both parts–for example, an unmastered mix might sound like crap to an untrained ear, but will sound better once the engineer has equalized certain parts up and down or compressed the whole thing.
Anyway…when I converted those mixes from full CD to 320kbps WMA files for my Zune, it actually ended up sounding like a good master. My guess is it eliminated a lot of low-level noise in the midrange (this is an instrumental surf band with lots of guitars and drums with big reverb), bringing out the low and high a bit and making the overall thing sound cleaner and crisper, while still preserving the slightly chaotic tone.