Last.fm is doing another one of their fun (if a bit perplexing) audio visual experiments. This one involves tracking the complexity of a song’s rhythm, harmony, and timber, then translating that variability into a flower-like image. The thicker the respective color petal (green=harmony; red=rhythm; blue=tambor), the more variability.
The image to the left is a representation of the Kool and the Gang tune “Fresh”:
“As you might expect from a classic disco song, Kool & the Gang‘s hit ‘Fresh’ doesn’t have much rhythm variety going on: the red rhythm petal is quite slim,” Last.fm’s Mathias Mauch explains in a blog post.
“This is not to say they don’t groove, it’s just the rhythm pattern does not change much over the course of the piece. There is some melodic and harmonic variety going on on small time scales—the green harmony petal is quite thick close to the origin. Towards the tip the green petal goes very thin though, which indicates that the general tonality does not change much over the whole piece—no cheesy key changes there.”
If you are registered with Last.fm, you can even vote on the relative variety of selected songs, then see how Last.fm visually measures that diversity. To the right below is an image for Motorhead‘s song “Overkill.”
The translucent portions of the image represent a mean average. “When this is bigger it usually means there are very significant, but rare changes going on,” the instructions disclose.
Why are Last.fm’s users being given the ballot in this instance?
“We think this visualisation could be used by other people who’d like to find out about the complexity of music, and that’s why we want to publish the technique at an international scientific conference later this year,” Mauch says.
“But here’s the problem: although we’re quite happy with our signal processing magic (which automatically guesses the amount of structural change going on in the music), we don’t know yet if human beings like yourself feel the same way as the computers… and we need to know that in order to convince the scientists to publish our results.”