I just finished my hack for Music Hack Day SF. It is called Bipolar Radio. It is your standard Pandora-style artist radio but with a twist. Type in an artist, and you’ll get an endless stream of music by similar artists. When you need to hear a high energy song, just click on the yellow happy face and you’ll instantly hear a high energy song by the currently playing artist. Similarly, if you’d like to chill out, just click on the green face and you’ll instantly hear a low energy song that should help you relax a bit.
The hack uses the Echo Nest song data to help find the high and low energy songs. I use a combination of loudness, energy, danceability, and tempo to sort and filter the songs by an artist into the high and low energy buckets. I’m taking advantage of the new Rdio / Echo Nest integration to get Rdio IDs so I can play them in Rdio’s nifty player.
Give it a whirl and let me know what you think: Bipolar Radio
Music Machinery 
#1 by kasper on May 11, 2011 - 6:13 am
ah, great idea. can’t get it to work though, it just goes into a crazy spin of records and songs, but plays none…
#2 by Paul on May 11, 2011 - 6:14 am
Kasper – Rdio is currently a US only service. I think that is why you get this behavior. Sorry. If Spotify makes a similar API, I’ll make a Spotify version for all of the Eurpoeans.