Although we still don’t have access to Pandora here in Canada (it’s coming though; trust me), you’ve probably heard quite a bit about how it works. After entering some personal preferences, the streaming music services creates custom playlists for you drawing from what they call their “music genome project.” A staff of musicologists deconstructs songs into their constituent DNA which allows the algorithm to make intelligent choices about what you might want to hear.
Boing Boing takes a look at how it all works.
Among the algorithms that run our online lives, Pandora’s Music Genome Projectmay not be as critical as Google’s search equations, but the math behind the self-programming Web-radio service seems just as opaque.
Some of that mystery is by design, but Pandora’s been a little more public about how it gathers and grades the more than one million tracks in its collection. And over a long briefing at its Oakland offices and subsequent follow-ups over e-mail, it told me a few more details.
First, humans grade the songs, not computers–and it’s surprising how much effort is involved. Pandora’s 25 or so music analysts have to assign either one-to-five rankings or more quantitative measures (say, beats per minute) for as many as 450 “genome units” per song.
For example, vocals get graded on terms like “Smooth or Silky” (Tom Waits’ “Come On Up to the House” earned a totally unsurprising 1), “Delivery Spoken-to-Sung” and “Child or Child-like.” Music can be broken down by metrics such as “Melodicism Lo-to-Hi” (how easily could you play this back?) and “Melodic Articulation Clean-to-Dirty” (how precisely does the melody hit the beat?).
Each of Pandora’s analysts–many hired from the Bay Area scene via word-of-mouth–can handle four songs an hour, for about 10,000 songs graded a month.
Continue reading. (Thanks to John for the link.)