Discovered this brilliant app today.

Blue Note Records is an American jazz label, established in 1939. The name comes from the "blue notes" of jazz and the blues.

It’s quite likely your ears know who Blue Note Records are, even if you’ve never heard the name before, as their tunes have been sampled in many well known hip-hop tunes. Check out the Blue Break Beats tab for side by side examples of some of the most sampled tunes.

http://www.spotify.com/us/blog/archives/2012/09/12/blue-note/