This work is the electronic part of Sentinelle nord by Florent Caron-Darras, written for 21 musicians and electronic setup. It was produced on the basis of an original patch by Tom Mays, in the electroacoustic studios of the Conservatoire National Supérieur de Musique et de Danse de Paris during 2017, concurrently with the composition of the score. The work was premiered on September 26, 2017 at the CNSMDP, Rémy Pflimlin Hall, as part of the Composition Prize concert, performed by the Conservatoire Laureates Orchestra conducted by David Reiland. Required equipment: A Macintosh computer running macOS 10.10 equipped with Max/MSP 7.3.5 1 audio interface of the RME UFX type MIDI master keyboard controller + program change pedal 1 mixing console Diffusion over a ring of 8 loudspeakers (+ front loudspeakers) Computer environment: MacBook Pro Retina running macOS 10.10 Software configuration: Max 7.5.3 (Cycling ’74) Additional software components: This Max patch uses external objects from IRCAM’s Spat library developed for the Max environment. These can be found in the “externals” subfolder of the directory Sentinelle_Nord-F_Caron_Darras-cnsmdp26092017-48kHz. Electroacoustic setup: 8 loudspeakers arranged around the audience and a stereo front system for orchestral amplification Inputs/Outputs: 2 inputs / 8 outputs Program startup procedure: Unzip the archive and copy the folder to the desktop of the computer (or any location of your choice). Open Max 7 and specify the access path to this folder in the Options / File Preferences menu so that Max can locate the dependencies required for the piece. Close Max. Reopen Max and launch the master patch of the piece “---FCDSENTINELLENORD-64bits-CNSMDP12052020.maxpat”. Turn audio on. Working sample rate: 48 kHz Program functions: The electronics consist of 119 synthesized sound files spatialised over 8 loudspeakers. A real-time effect is triggered at the very end of the piece, bar 239: a stereo freeze generated from the stereo mix of the full orchestra. This patch allows sounds to be triggered using a MIDI keyboard (MIDI note no. 72) placed on stage and operated by the ensemble’s second pianist. The performer also triggers the freeze using MIDI note no. 41. The spatialisation of the freeze, as specified in the score, is triggered from the control room using a button on a BCF2000 controller (controller no. 0). The level of each sound file can be programmed within the trigger message for each sound (EVENT subpatch). Real-time monitoring of sound file levels and the freeze level is possible via two faders on the BCF2000. A BCF initialisation is provided in the patch (the relevant BCF2000 buttons must be configured beforehand as continuous controllers). It is possible to simulate the freeze using the sound file freeze-simul-1 located in the “freeze-simul” subpatch. Play this file by switching the freeze input to simul (drop-down menu) and trigger the freeze using the freeze capture button. The “freeze-simul” subpatch also contains a recording of the full instrumental ensemble without electronics for the entire piece.