How Pandora Radio Works

Assembling the Pandora Playlist

So here's what happened behind the scenes when we created our Ben Folds Radio station: Pandora located a song by Ben Folds and pulled up the Genome analysis for that song. It then ran an algorithm that compared every song in the Genome database to the genetic makeup of that song in order to identify songs that have similar traits. The algorithm looks for matches across 400 parameters. Here's just a handful of the traits and concepts it looks at (definitions excerpted from the Virginia Tech Multimedia Music Dictionary):

  • arrangement - the selection and adaptation of a composition or parts of a composition to instruments for which it was not originally designed
  • beat - the regular pulse of music
  • form - the structure of a composition, the frame upon which it is constructed; based upon repetition, contrast, and variation
  • harmony - the concordant (or consonant) combination of notes sounded simultaneously to produce chords
  • lyrics - the words of a song
  • melody - a succession of tones comprised of mode, rhythm, and pitches so arranged as to achieve musical shape
  • orchestration - the art of arranging a composition for performance by an instrumental ensemble
  • rhythm - the subdivision of a space of time into a defined, repeated pattern
  • syncopation - deliberate upsetting of the meter or pulse of a composition by means of a temporary shifting of the accent to a weak beat or an off-beat
  • tempo - the speed of the rhythm of a composition
  • vamping - to extemporize the accompaniment to a solo voice or instrument
  • voice - the production of sound from the vocal chords, often used in music; falls into six basic categories defined by pitch, ranging, from bottom to top, Bass, Baritone, Tenor, Contralto, Mezzo Soprano, and Soprano

Keep in mind here that every song's traits are determined "by hand." There was an actual human being who identified the characteristic voice types, beats, structures and tempos for each of the 400,000 songs in the Genome database. It's a profound undertaking that will probably continue for as long as Pandora Media has the money to pay its experts to listen to music all day.

We'll take a look at some concerns with Pandora in the next section.