For six speakers, a measurement microphone, and a performer.
A fairly simple system is presented; six small speakers emit an impulse in succession while a microphone listens for their impulse. If the microphone hears the speaker's impulse, an impulse is played immediately on the next speaker; if no impulse is heard, the system "times out" before attempting the same process on the next speaker.
The primary parameters of the piece are the speakers' orientation, their distance from the microphone, and presence of objects blocking the speakers.
In the first iteration, an impulse takes 43 milliseconds to be processed by the system when the speaker and microphone are 1 meter apart. With the speed of sound being approximately 343 meters per second, it should only take around 3 milliseconds for sound to cover 1 meter. So while rhythmic and tonal changes occur due to the proximity of the speakers to the microphone, these changes are subtle due to the characteristics of the system slowing the process down.
The quality of the microphone and speaker cables, the quality of the sound card and DAC used, the quality of the speakers and microphone themselves, and the acoustics of the space all contribute to how fast the system reacts. This initial version uses a Focusrite Scarlett 18i, Boss 4" car stereo speakers, Lepy 24W two channel amplifiers, an iSEMcon EMX-7150 measurement microphone, and a 2015 Macbook Pro.
I've been on the lookout for a better DAC to use for the next performance, hopefully that'll be sometime soon.
I'm slated for a performance at a show being put on by
the wulf. (Dec 30, 2017 @ Coaxial 8PM).
I've upgraded from a USB to a Thunderbolt audio interface, which should lower the latency of the system considerably (a Thunderbolt connection hooks straight into the CPU, as opposed to a USB connection which has to run through a series of buffers). This change should account for the biggest bottleneck in my system. With this drop in latency, I'll be able to reliably create a crude type of wavetable-like "impulse" synthesis with the speakers and microphone.
The piece is also being expanded to be around 25-30 minutes, which might require some patience on my part. I'll have to allow more time for the audience to figure out the system. A lot of my favorite pieces of an extended duration require me to "learn the language" of the work before I can begin to understand it; it's usually an organic process. If I can hold my horses and let each section just sit (right up until the point of boredom), the system should become more clear (and hopefully make the work more successful as a whole). Will update after a few rehearsals.