Description of live-electronics

Live-electronics capture in real time audio signals from one actor and four musicians of a classical string quartet - two violins, one viola, one cello - evolving freely on stage, through wireless microphones attached to each protagonist.

The captured sounds, together with some audio samples which are triggered from the control-room, are dynamically treated and spatialized through a 3d audio system made of 16 speakers placed on stage and around the audience.

Additionally, a set of servo-motors, driven from composer’s computer, controls some dedicated scenographical equipment on stage.

The live-electronics are processed using two computers - one computer, held by the composer and called “Electro computer”, mainly processes live sounds with effects, while the second computer, called “Spat computer”, held by the computer-music designer is mainly dedicated to sound spatialization.

Both computers - Apple Macbook Pros - use Ableton Live 9 32bit and Cycling’74 Max 7 32bit, as well as a couple of VST plugins. It is necessary to port/acquire the different programs that were developed to 64bit platforms if one wish to update the setup to more recent versions of both Live and Max.

The different cues during the show are function of the action on stage, and were not written into a dedicated score document when the show was created. Composer performs together with actor and musicians. It is necessary to contact him for further information about the performance and its cues.

Sound diffusion

“Front” speakers 1 to 6 are positioned in a vertical plane on the frame of stage edge:

“Surround” speakers 7 to 10 are positioned in an horizontal plane around the audience:

“Stage” 11 to 14 speakers are positioned in a vertical plane against the upstage wall, facing the audience. Speakers 11 & 12 should be positioned as high and wide possible, speakers 13 & 14 stand on the stage ground. Monitors L & R are positioned at left and right edges of the stage, facing musicians.

This setup provides the possibility of diffusing the sound into different spaces: Front, Surround, Wall, Stage, and all together. For instance, the reverberations used in the piece are diffused through all speakers, providing a global and wide sound space, surrounding both audience and musicians. Subwoofers diffuse a L/R mix of each pair of speakers - therefore delaying the different speakers pairs into the subwoofer channels might be a little tricky, according to their positions in the 3D space.

Microphones

Four DPA microphones with embedded wireless HF emitters/receptors are used to capture the sound of the string quartet. Microphones types should be adapted to each instrument: 2 violins, one viola and one cello.

One DPA microphone with embedded wireless HF emitter/receptor and headset is used for the actor..

Computers & soundboards

Both computers are Apple Mac Book Pros running Live 9 and Max 7 in 32bit mode.

Soundboards for each computer should be able to host the audio signals from each actor and musicians (5 separate inputs).

“Electro” (composer’s) computer must deliver 8 separate audio channels that feed 4 different speaker pairs. “Spat” computer must feed all 16 speakers through separate audio channels.

Additionally, the Electro computer sends 8 stereo channels to the Spat computer for further spatial diffusion of some of the audio material it generates.

Mixing desk

As both sound diffusion and processing are quite complex, it is necessary to use a flexible digital mixing desk such as the Yamaha DM1000 which was used for the creation. The mixing desk should be able to feed 16 full range speakers + 2 subwoofers, send 8 separate signals to both computers, host 5 separate signals from actor and string quartet, host 8 separate signals from Electro computer and 16 separate signals from Spat computers.

MIDI mixing & control

Electro computer’s Live set is controlled through MIDI controller devices that belong to the composer. Spat computer’s Live set is controlled through 2 Beringher BCF2000 MIDI devices: one device enables and mixes different “scenes” using one volume fader per scene on several mixing layers (pages), the second device has one global control over the different reverberation and sound movement effects in one single mixing layer.

Servo-motors control

Electro computer also runs a Max patch which is used to send some serial messages to some dedicated servo-motors on stage. It is necessary to contact the composer for further information about the mechanical system which is driven by the Max patch.Software

Description of the content of the IlSeTrouve.dmg archive available from the IRCAM server page.

“IST-Electro” and “IST-Patches” folders contain the Ableton Live set and Max patch run from the Electro computer. The Live set also needs the “B4 II” VST plugin from Native Instrument to be properly installed and authorized.

The “IST-Spat” folder contains the “IST-Spat-Original.als” Ableton Live set run from the Spat computer (other versions were stored there for archive purpose). The “IrcamVerbStereo51.vst” document from the “To VST Plugins folder” found inside the IST-Spat folder must be copied to the /YourHardDrive/Library/Audio/Plug-Ins/VST folder.

The “IST-BCF2000” folder contains some MIDI sysex sequences to run from any DAW software (Logic, Pro tools) in order to configure the BCF2000 devices used with the Spat computer.

• run the BCF2000-InitAll.syx file on both devices to reset the device to factory defaults

• run the IST-BCF2000-Mix-Backup.syx file on the MIDI device used for global mixing

• run the IST-BCF2000-Scenes-Backup file on the MIDI device used for mixing scenes

Contact

For further information about the piece and the live-electronics, please contact either composer or computer-music designer at:

• benjamin@benjamindupe.com

• manuel.poletti@ircam.fr

Or contact IRCAM’s Production department: https://www.ircam.fr