Kinect manipulation — sound synthesis (Project 2)

For my and Dan’s project, we wanted to do something with the Kinect. In particular, we wanted to be able to play a video game with sensor data from the Kinect. However, when we ran into issues with this, we decided we would create an instrument that used Kinect sensor data.

My contribution was the sound synthesis element.

Our setup was as follows– a Kinect connected to a Windows machine with a license for dp.kinect2 sends sensor data through OSC. We use multiple ports for efficiency and simplicity. On my personal laptop, I read this sensor data and perform sound synthesis.

The first step in my sound synthesis was list parsing. For each body part I read (head, left hand, right hand, left foot, right foot), I am given a list representing X, Y, Z, and certainty. I wanted to use the distances between the body parts to create my instrument, so then I made a subpatch to calculate that euclidian distance.

Once I did that, we had to do some manual testing to see the range of distance values that were possible (i.e. standing in front of the Kinect and doing a starfish pose, to get the widest distance between the body parts). Once we did that, we could scale the potential distances (0 to X, X being the max) into usable numbers for sound synthesis.

I wanted the distance from the hand to feet to correspond to pitches of two separate oscillators (left and right), and the distance from the hands to the head to correspond to the loudness of each oscillator. To make the patch more usable, I have the oscillators round to the nearest fifth, instead of just sliding up and down continuously. To do this, I created integers of multiples of 7 (the number of half steps to a fifth).

Jesse also helped me get it so that the motion speed controlled a lowpass filter. To do this, we used the “t” object to store a float. This allows us to compare it to the previous value and subtract the difference. This speed controls the cutoff frequency of the lowpass filter. I then use the distance from the hands to the head to control the resonance of the filter, keeping it between .3 and .8.

I then compress the result and add reverb, cuz why not?

We also decided that the potential pitches for the right hand/leg oscillator should be the same pitches as the left. We considered at one point having each side have different ranges of pitches to allow for more playability, but decided that ease of use and understanding was more important.

If we had more time, it would have been nice to implement some way for the contour of the oscillator to change with some other variable. However, I’m pretty proud of the work we did– our tool is interesting and usable.

The patch: