Hacking the Mix

by Vincent Olivieri

 A moment from The Laramie Project at UC Irvine, with sound design (even during intermission) by Tim Brown
A moment from The Laramie Project at UC Irvine, with sound design (even during intermission) by Tim Brown
Need to mix unobtrusively? We built an app for that.

For a production of The Laramie Project at the University of California, Irvine, sound designer Tim Brown wanted to create soundscapes for the intermissions that would be loud enough to be noticeable, but not so loud that they overwhelmed the audience. Because ambient volume could never be predicted, the intermission sound would have to be mixed live—but the sound booth was acoustically isolated from the audience chamber. Installing a small mixing console was an unattractive option as even a small desk would draw attention to itself and the mixer. Brown wanted the mixer and the effect to be unobtrusive. When he approached me to brainstorm solutions, we decided to mix via the most ubiquitous object on a college campus: an iPod.

 

An iPod Touch was small enough not to draw attention to itself, and the mixer would look like they were sending text messages on it, not controlling audio. Because it worked on WiFi, our engineer could move about the house easily, adjusting the mix as he went. Finally, the iPod Touch could send Open Sound Control (OSC) messages to the sound playback computer in the booth. OSC was developed at the UC Berkeley Center for New Music and Audio Technology and is a protocol that allows for communication between devices over a modern network.

 A screenshot of the Mrmr interface builder app, showing the simple interface used to mix.
A screenshot of the Mrmr interface builder app, showing the simple interface used to mix.

On the iPod Touch, I used an app called Mrmr to build a simple mixer to control the volume: one button for “up” and one for “down.” Each button would send a different OSC message over a small network we set up.

 

 

 

 

 

 

 

Max (by Cycling 74) converted the OSC data MIDI data.
Max (by Cycling 74) converted the OSC data MIDI data.

After the OSC messages made their way to the sound playback computer, I used Max (by Cycling 74) to convert the OSC data MIDI data. Max Runtime patched the MIDI data into QLab (by Figure 53—what’s up with all these numbers?).

 

 

 

 

Qlab had to be programmed to respond correctly, too.
Qlab had to be programmed to respond correctly, too.

The last step was to program QLab to handle the MIDI data properly. Each piece of audio that played during intermission had two fades associated with it: one was a 3 dB increase in level and the other was a 3 dB decrease in level (both fades were relative and both had counts of five seconds). The 3 dB change over five seconds meant that the changes were small enough to not draw attention to themselves and by making the fade commands in Qlab relative instead of absolute, the engineer could execute multiple fades to make larger changes in level. We programmed each fade to execute whenever it received the appropriate MIDI command.

 

And voila! The system worked flawlessly. The mix engineer could move around the house during intermission and adjust the level of the intermission sound at the press of a button. Brown was pleased with the result: a low-profile way to control intermission sound level for his elegant design for The Laramie Project.