Yemin Oh | Quartet for Colors | Fall 2010
- Footage from the LoL Performance at the Manship Theatre – April 4th, 2011
“Quartet for Colors” is a piece for four laptops and eight objects that have different colors on each. Main conception of this piece is to combine the visual aspect and sonic aspect together within musical way in ensemble. A color of each object is associated with fragment of certain sounds. Most of part of piece is improvisation, using color objects in musical form decided by the composer. So, audience not only enjoys aesthetic of music but also experiences visual elements that are mixture of movements of performers’ objects.
- Personal Motivation
Motion Tracking using video camera irresistibly fascinates many people from several fields. I am also fascinated by video tracking system and I made a video-interactive piece for four laptops.
- Detail of Setting
As you can see at picture 1, mainly, we prepared four hemisphere speakers, four audio interfaces, five laptops, one Ethernet hub, One projector, wires, cables and LED balls(or fluorescent band). We made five stations; four audio stations and one video station. Each audio stations consists of laptop, audio interface, and speaker, and Video station connected to projector. All the stations are connected to the hub.
Before the performance, we setup local IP address on laptops, and dimming of stage light. The reason we setup the level of stage lighting is because the webcam of laptop does not recognize the color of LED balls if brightness of stage is too dark or bright. Also the projector needs certain level of brightness of stage.
- Computer Processing
Granular synthesis and reverberation are used as primary sound processing. I used system sound files of OSX and Max/MSP sound files as source sound of synthesis.
After color tracking, webcam sends signals to audio processor, and the signals trigger
sound files that are about one or two seconds long. The signals are decided by X-axis(Left-Right), Y-axis(Up-Down), and Z-axis(proximity) of movement of LED ball. X-axis affects a pitch of the sound, Y-axis controls length of grains of granular synthesis, and Z-axis is loudness of sound. Eventually, gesture of LED balls determines not only shape and timber of synthesis sound, but also brightness of video processing which is triggered by amplitude of the sound.
There are two main video processing. First one is a color tracking, and the other is a color filtering.
After the camera captures a color that is previously set by a performer, computer will track X, Y, Z, axis of the color. The position of the LED ball on each axis affects different parameters of audio processing. (Each section of the piece has different value of parameters to be controlled). At the same time, the computer filters out all the other colors of video except the color of the LED ball, and amplitude of sound will affect brightness of the filtered video that only includes color of LED ball.
Each laptop of audio station sends video data to the laptop of video station through Hub. The video laptop collects the data, and adds them together to the screen.
- Compositional Outcome
There are three sections (A-B-A’) in the piece. In A-Section, appearances of color into camera angle make a sound; play the sound file. So, in this section, introduces timbre of sound of each color in unexpected rhythm, and it also shows to audience that the each colors of video are associated with each sound. In B-Section, granular synthesis sound, which merges into the sound of A-Section, builds a development of the A-Section. At the climax of the entire piece, granular sound and sound of A-section make a musical peak of the piece. And then, comes back to original sound as A prime. Performers improvise a sound with LED ball as their instrument in musical form. Since it is mostly based on improvisation of performers, audience enjoys aesthetic of randomness in musical way. Not only do they experience a stochastic music, but also do they enjoy aesthetics of randomness of visual art.
Evaluation of multi-discipline is not easy to be done, because criteria of the evaluation cannot be decided clearly. However, since my profession is based on music field, it would be easier to evaluate it from musician’s viewpoint.
First of all, lighting issue is the one that must be solved. During the performance, they should be careful about misdetection of color tracking, because color of performer’s skin is easily recognized as LED ball by computer (We used florescent band or LED light ball in performance). Also, angle of camera should be away from video of background screen. One more important issue is color setting in dark. Because the camera does not recognize a color in dark light, set a reflected color on hands after hold the LED ball.
Second, in terms of aesthetic viewpoint, degree of completion of the piece is not highly achieved. Performers need many practices to learn the way to control the color object, and rehearsal several times for an interaction between performers. If algorithmic composition method should be added, degree of completion will be elevated more. Because of organic unity of timbre, I used a few sound files that has similar timbre, but it lead to lack of sound variety. If it includes more sound timbres, aesthetically it can be achieved.