On October 25th at 7pm, Opera of the Future Group at the MIT Media Lab will screen an HD recording of the premiere of Death and the Powers, Tod Machover’s new opera, as part of the Media Lab’s 25th Anniversary celebrations. The audio for the premiere was recorded directly from a Studer Vista 5SR live mixing console using Digital Performer 7 and will be mixed for the screening in 3rd Order Ambisonics using a Media Lab custom DSP engine.
The system will feature three Bowers & Wilkins 800D speakers for left, center and right channels, five satellite B&W 805s speakers for surround fill and an ASW855 sub for SLF.
The production relies on a sonic transformation as well as visual transformations to locate Simon Powers in the “system.” The audio infrastructure to support him is quite extensive, utilizing two formats of surround sound, realtime performance control and several custom effects engines; all with the goal of achieving a smooth continuum ranging from completely acoustic to completely amplified textures. This is one of the unique characteristics of Powers; while some sections are whisper quiet, some are positively massive. The large dynamic range in the audio system allows even the most basic characteristic of the sound to follow Simon’s emotions very closely.
The heart of the Powers audio system is a DSP engine based on CoreAudio AudioUnits running inside Digital Performer 7. The majority of the system’s 350 audio inputs and 250 audio outputs run through this system, which contains custom plugins to implement Ambisonics Surround Sound: an abstracted, permitter-based spatialization algorithm; and WFS (Wave Front Synthesis), a system for constructing a wave field to allow very precise localization inside the boundaries of the ambisonic system. Because surround sound is an essential part of the performance, it is critical for everyone in the audience to experience it. Each of the VIP boxes and balconies contains its own “mini” surround sound system; a superb application of the inherent scaling capability of ambisonics. This was especially useful in HSH Prince Albert’s box, which was ornate, but acoustically disconnected from the rest of his opera house because of several very heavy curtains.
All told, the system contains 143 separate speaker outputs which have their own DSP. These are intelligently managed by the DSP engine and controlled live using Apple iPads running TouchOSC. Finally each of the Duran Audio Axys loudspeakers in the main Left-Center-Right audio system runs additional DSP to manage internal crossovers and system-wide equalization.