If you're looking for the original Visual Scratch video, you can find it here.
We capture turntable velocity using Ms. Pinky and fader position using an Ecler Nuo 4. The scratching sound is generated in Max/MSP. Then we scale the control data (turntable and fader) to ±1.0, the range of digital audio signals. The control data is saved to one audio file, and scratch audio to another.
With the two sound files as input, the graphics are generated in Processing, using the incredibly helpful Ess, PDF and MovieMaker libraries. The y-axis position reflects the velocity of the turntable, color is based on the frequency content of the scratch audio, and the thickness of the line is based on the volume.
Turntablism is the art of manipulating sounds and creating music using phonograph turntables and an audio mixer.
Check out a history of scratching from Skratchcon 2000, presented by QBert and DJ Flare.
For more, watch Scratch, an excellent film by Doug Pray.
DJ Axel Foley is a Boston-based DJ and record nerd.
...to Wayne Marshall for making introductions.
Like this? Check out the History of Sampling.