This is my attempt in creating several audio spatial system with Pure Data (Pd) for live performance (live electronics, acousmatic concert etc.) that will require minimum technical operating knowledge and straightforward to use. Previously, Pd had an advance spatial system library known as VBAP and Ambisonic HOA by V. Pulkki et al., which will be my reference point for the system basis. Comments and suggestions are welcome for improvement.
speaker array and calibration
Firstly, I’ve created a spatial diffusion speaker array volume calibration system with Pure Data (Pd) for front of house (FOH) spatial diffusion up to 32 channels. This patch comes with a set of five standard GUI spatial speaker diffusion array configuration format; stereo, quad, 5(.1), 7(.1), and 8, which from there, user may DIY for more complex GUI spatial speaker diffusion array configuration format.
For working Spatial Diffusion Calibration Pd patch, see https://github.com/anllume/PureData-Spatial.git
This straightforward system uses a test tone burst (either white noise or sine tone) for each speakers (manual or auto surround spatial trigger) and each FOH volume speakers is adjusted with speakers peak volume reading (dB RMS) picked up by an omni-directional microphone (feed into ADC 1 Pd) based on the FOH speakers-venue acoustic feedbacks. The picked up speakers peak volume level set are displayed by a ‘VU’ meter set with test tone peak VU meter reference. Note that, EQ and spectrogram analyser may be added for further FOH acoustic ‘coloration’ fine tunings
Note: In Europe/UK, multiple stereo pairing front to back system (ie. 1-2 front, 3-4 rear, 5-6 back, 7-8 center front-center back) etc.) is applied for the higher order surround such as octophonic ring instead of 1-2-3-4-5-6-7-8 ring sequence.
Hein, F. (30 April 2022) Sound Anthology: Program Notes. Retrieved from Sound Anthology
Pulkki, V. (2001). Spatial sound generation and perception by amplitude panning techniques. Helsinki University of Technology.