Terugblik Project 143:

Ruimtelijke audio - hoe is het mogelijk?

door Josep Rodenas en Rinus Boone(©2001)

Technical Presentations

The meeting took place at the High-Tech Campus of Philips in Eindhoven last 23rd October evening.  All the participants were directed to the Philips Research Laboratories where a reception coffee was waiting at the main hall at 19h30. The topic of the evening was: "Spatial Audio - How is it possible?" Two interesting presentations were given by Armin Kohlrausch (Philips Research/TUE) and Daniel Schobben (Philips Research).

First Armin Kohlrausch started with his presentation entitled: "Psychoacoustical Principles for Spatial Sound Perception". In his talk, the psychoaocustic principles underlying spatial sound perception were presented and their relevance for sound reproduction via headphones and loudspeakers was discussed. Starting from the basic cues, interaural differences in time and level, the concept of the Head Related Transfer Function was explained, as well as the recording techniques using small microphones in the ear canals of a dummy (or real) head. As for the reproduction, it was emphasized that there are clear differences between headphones and (stereo)loudspeakers, the latter allowing for crosstalk between channels, influence of the reproduction room and the inclusion of outer-ear filtering in the reproduction chain, all of which don't occur when listening through headphones. This talk ended with the conclusion that the best spatial listening impression was created by listening through carefully equalized headphones to a recording made through one's own ears.

After some coffee pause and several discussions (and an award presentation, see below), the second presentation entitled: "Spatial Sound Reproduction" by Daniel Schobben started. In his talk, three recent developments that relate to spatial audio reproduction were presented. One application was the conversion of stereo material to 5.1 channel material. The second application was the reproduction of 5.1 channel material using only two loudspeakers. And finally the sound reproduction of 5.1 channel material over headphones was presented. Two nice listening demonstrations followed this talk where people could experience the advance of spatial audio reproduction.

Josep Rodenas

Award of Appreciation

Na de pauze werd eerst de aandacht gevraagd voor een speciale gebeurtenis, namelijk de uitreiking van een Award of Appreciation aan Ron Geluk. Deze Award hadden wij al eerder willen uitreiken tijdens de slotbijeenkomst op 6 juni j.l., maar wegens verhindering van Ron hadden wij het moeten uitstellen. Ron ontving zijn Award wegens zijn verdiensten op het gebied van de ontwikkeling van een speciaal microfoonsysteem voor het maken van geluidopnames waarbij laagfrequente richtinggevoeligheid vereist is. Hij werd toegesproken door ondergetekende en ontving zijn Award uit handen van onze voorzitter Cees Wagenaar.

Rinus Boone