sonic surrounds

Today is the first day of my third ICAD in Montréal (program available here), after Sydney 2004 (as audience only) and Limerick, Ireland, 2005 (when I presented at the student thinktank). This morning I presented my paper, “Mitigation of Binaural Front Back Confusions by Body Motion in Audio Augmented Reality”, on one of my perceptual experiments characterizing mobile augmented reality (AR) performance - a part of my PhD research.

Being preoccupied with final preparations, I missed the details of early presentations, though it was impressive to see the sea of wireless headphone-clad ICAD audience listening to binaural examples. Below are some memorable observations of the day.

One notable idea that I’m surprised not to have come across before was a process to capture 128 simultaneous Head Related Impulse Responses (HRIRs) from a single subject in a matter of seconds, using the reciprocity technique, where 128 microphones mounted on a very sci-fi polyhedral head cage capture signals emitted by tiny ear-mounted loudspeakers - a reversal of the usual microphones-in-ears technique. This idea and the below image are from the paper “PERCEIVED NATURALNESS OF SPEECH SOUNDS PRESENTED USING PERSONALIZED VERSUS NON-PERSONALIZED HRTFS” by John Usher and William L. Martens.

Another noteworthy paper was titled “SPATIAL AUDIO QUALITY EVALUATION: COMPARING TRANSAURAL, AMBISONICS AND STEREO” by Catherine Guastavino, Véronique Larcher, Guillaume Catusseau and Patrick Boussard. The paper described two experiments evaluating subjective spatial quality and localization errors for the two multichannel spatial audio presentation methods on a 6 speaker array vs 2 and 4 speaker transaural, and showed that Ambisonics provides best sense of immersion, while pairwise amplitude panning provides best llocalization errors.

ICAD afternoon 1 presented a series of sound-art and music tape/(actually, hard disk) performances, including various performances by Pauline Oliveros (presented in person), with comments on the acoustic and artificial spatial environments as co-performer. The day finished with a networked performance by Tintinnabulate Ensemble, involving Oliveros, Jonas Braash, and others on several acoustic instruments and computers, with video and audio link between two internet-joined sites, multichannel speaker array diffusion and simultaneous binaural headphone channels involving binaural signals captured via dummy head in the first row of the theatre… a swagful of technology and complication that reached some interesting moments, but also some limitations of the delayed interaction and tendency towards continual playing by all musicians… nevertheless an interesting musical / technological experiment in line with the expansive mindset of the conference. Now to leave the wifi and get out before day two arrives.

here’s a sketch of an improv performance I’m posting as a reminder to resume this particular experiment when I have more free time after finishing the thesis.

this piece is done in Pd, using field recordings of a street cleaner machine; also some granulation controlled by a particle swarm simulation, providing some great organic bass sounds in the later stages (and mids earlier on); a glitch/pop generator run through a loop catcher; and an inertial-physical-model-controlled drone providing some slowly descending glue tones, though occasionally damaged by very slight dropouts serving as a reminder to use Pd with Jack for better reliability.

as i said, a sketch only, but with elements well worth a revisit. the swarm-granular-bass might be an interesting anchor for some warped dsp dubstep hybrid (!?).

 

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