Opening Pandora&#8217;s Music box
<p>I&#8217;ve been meaning to experiment with <a href="http://www.pandora.com">Pandora Radio</a> for a while, and finally got to it today.  It&#8217;s based on something called the &#8220;Music Genome Project&#8221; that categorizes music by how it expresses a large number of &#8220;genes&#8221; &mdash; traits that describe features like song structure, instrumentation, genre influences, and so forth.  According to Wikipedia these are used to construct a vector, and similarity between tunes is measured by a simple  distance function.  You give Pandora a seed artist; it then apparently random-walks you through tunes and artists similar to that artist&#8217;s style.</p>
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<p>Dang&#8230;it works pretty well. I seeded it with &#8220;Liquid Tension Experiment&#8221;, a John Petrucci side project that has produced one of my favorite albums of all time, <cite>Liquid Tension II.</cite>  I&#8217;m now on about the twentieth track it&#8217;s chosen for me and it hasn&#8217;t picked a dud yet.   Artists: Jadia, Citriniti, Vinnie Moore, Joe Satriani, Dream Theater, Flower Kings, Arena, Stuart Hamm, Jordan Rudess, Brand X, Annihilator, Derek Sherinian, Crime in Choir, Firewind, Greg Howe, Planet X.  If you&#8217;ve never heard of these groups&#8230;I&#8217;m not a bit surprised.  I only knew of about half of them myself &mdash; which is <em>wonderful</em>.  My tastes are pretty recherch&eacute;; they center in a poorly mapped no-man&#8217;s land between prog-rock, metal, and jazz.  Finding more stuff I really like has not been easy in the past.</p>
<p>But even more interesting is that if you ask Pandora why it chose a track for you, it will list the genes that were critical for its selection.  Here are some that repeatedly show up for me: demanding instrumental part writing, great musicianship, intricate melodic structure, hard rock roots, jazz influences, instrumental arrangement, minor key tonality, variable tempo and time signatures, chromatic harmonic structure, electric guitar solo, mixed electric/acoustic instrumentation.  </p>
<p>Yup, they&#8217;ve got my tastes nailed with pinpoint accuracy.  Which is especially interesting since I&#8217;m not completely at home in any of the genres that border on the stuff I like.  I want more intelligence than metal usually offers, less obsessive self-regard than jazz is prone to, and more adrenal vigor than prog bands usually deliver.  By analyzing music to the level of &#8220;genes&#8221;, much finer-grained than genres, Pandora is able to represent this pretty well.</p>
<p>The only thing missing is that I&#8217;d like to be able to tweak my preference vector directly rather than by approving/disapproving tracks.  I&#8217;d like to be able to tell it that I&#8217;m also interested in world-music influences and anything with polyrhythms in it, and to turn my preferences for &#8220;instrumental arrangement&#8221; and &#8220;demanding instrumental part writing&#8221; up to max.  Oh yeah!</p>
<p>But even without that, I&#8217;m sold. Pandora is a special boon for people like me whose tastes don&#8217;t fit the music industry&#8217;s marketing categories well. I&#8217;ll cheerfully listen to their commercials, because the payoff is that they discover stuff for me very, <em>very</em> effectively.  </p>
