Development of a novel surround sound format and associated microphone techniques

The most common surround sound format (often known as 5.1) does not enable accurate positioning of sounds to the side or the rear. Based on a detailed analysis of the binaural hearing cues used by humans, a new surround sound loudspeaker format has been developed using 8 loudspeakers arranged in a regular octagon. Listening tests have been conducted to demonstrate the superiority of this setup compared to 5.1 in terms of accurate sound positioning around a listener. In order to enable development of microphone techniques to capture soundfields for this reproduction system, localisation curves needed to be derived that map the relationship between a range of interchannel time and levels differences of signals (ICTDs and ICLDs respectively) and the perceived sound location. Various signals with a range of ICLDs and ICTDs were produced between pairs of adjacent loudspeakers, and listeners were asked to evaluate the perceived sound's direction and its locatedness. The results showed that the curves for the side pairs of adjacent loudspeakers are significantly different to the front and rear pairs. The resulting curves have been used to derive suitable microphone techniques for this loudspeaker setup.