Lance dei Crespusculi is a piece for solo electronics, made up of fixed sounds files, playing continuously from a Reaper 58 channels audio session.
The first 9 channels of the Reaper session feed a vertical “totem” of 9 loudspeakers, while the others 49 channels stream a 6th order HOA soundfile through the permanently installed dome of 89 loudspeakers of the Espace de Projection (ESPRO).
So, in total, the electroacoustic device used for the piece is made up of 98 speakers.

1. Audio and Loudspeaker setup

The acoustic configuration of ESPRO’s periactes is set as overall absorbant, except for those wall panels, closer to the TOTEM, which are hit by direct sounds coming from the TOTEM speakers itself, and that must be set to “diffusant” (see photos below).

2. Patch presentation

The 49 channels track, 6th order HOA 3D, is an encoded only one. The decoding and sending to the 89 speakers of ESPRO’s dome is made sending the audio out of the RME Danteface #1 audio card, to the input of the RME Danteface #2, which is handled by the ESPRO’s Mac Pro running a Max 8 Spat PANORAMIX patch (49 encoded inputs / 89 decoded outputs).

3. Software installation

Concert computer #1

• Download and install REAPER

Concert computer #2

• Download and install Max 8
• Download and install IRCAM SPAT 5 package (https://forum.ircam.fr/projects/detail/spat/)

4. Initialization routine

Concert computer #1

• Launch REAPER
• In reaper Settings panel, set audio device to “RME Danteface #1”
• Sample Rate = 48000 Hz; Block size = 512 samples
• open the file “LdC_CONCERT_58ch_02.RPP”

Concert computer #2

• launch Max 8
• set RME Danteface #2 as I/O audiocard
• set Sample Rate to 48Khz
• quit and relaunch
• open the patch “Panoramix-Ircam.maxpat”
• In Panoramix interface, click on the “load” button, and load the file : “Panoramix-Constellation Nunes_Stroppa.txt”

7. System calibration and tests

Verify the overall balance between the Totem and the HOA, using first a white noise test patch, then playing the Reaper session. Adjust in order to make the Totem as “the soloist”, and the HOA dome as the “accompanying orchestra”, like in a concerto setting.
If needed, do some equalization on the single frontal channels of the Totem (ch 4, 5, 6), cutting highs and compressing the signal a bit, in order to attenuate them a bit, so to avoid hearing discomfort for people sitting in the first ranges of seats.

8. Performance notes