Last week at the Echo Nest 4 year anniversary party we had two renown DJs keeping the music flowing.  DJ Rupture was the featured act – but opening the night was the Echo Nest’s own DJ API (a.k.a Ben Lacker)  who put together a 30 minute set using the Echo Nest remix.

DJ API at work (Photo by Jason Sundram

I was really quite astounded at the quality of the tracks Ben put together (and all of them apparently done on the afternoon before the gig).  I asked Ben to explain how he created the tracks. Here’s what he said:

1. ‘One Thing’ – featuring Michael Jackson’s (dj api’s rip)

I found a half-dozen a cappella Michael Jackson songs as well as instrumental and a cappella recordings of Amerie’s “One Thing” on YouTube. To get Michael Jackson to sing “One Thing”, I stitched all his a cappella tracks together into a single track, then ran afromb: for each segment in the a cappella version of “One Thing”, I found the segment in the MJ a cappella medley that was closest in pitch, timbre, and loudness. The result sounded pretty convincing, but was heavy on the “uh”s and breath sounds. Using the pitch-shifting methods in modify.py, I shifted an a cappella version of “Ben” to be in the same key as “One Thing”, then ran afromb again. I edited together part of this result and part of the first result, then synced them up with the instrumental version of “One Thing.”

2. One Thing (dj api’s gamelan version)

I used afromb again here, this time resynthesizing the instrumental version of “One Thing” from the segments of a recording of a Balinese Gamelan Orchestra. I synced this with the a cappella version of “One Thing” and added some kick drums for a little extra punch

3. Billie Jean (dj api screwdown)

First I ran summary on an instrumental version of Beyoncé’s “Single Ladies (another YouTube find) to produce a version consisting only of the “ands” (every second eighth note). I then used modify.shiftRate to slow down an a cappella version of “Billie Jean” until its tempo matched that of the summarized “Single Ladies”. I synced the two, and repeated some of the final sections of “Single Ladies” to follow the form of “Billie Jean