Dynamic Higher-Order Stereophony

Higher-Order Stereophony is a new spatial audio approach which extends classic stereo to higher order soundfield reproduction and generalised loudspeaker arrays, in a similar manner to Higher-Order Ambisonics. Higher-Order Stereophony reproduces the soundfield accurately across a line only, which must be orientated to align with the listener's interaural axis. This work introduces Dynamic Higher-Order Stereophony, which expands the technique to include listener tracking using dynamic amplitude panning. This means the soundfield is reproduced across a dynamically moving line dependent on the listener's orientation, to ensure correct reproduction of a desired set of binaural signals. A number of classic stereo approaches are shown to be special cases of first order Stereophony, and decoders to reproduce Higher-Order Ambisonics content using the new technique presented. A listening test comparing Higher-Order Stereophony and Ambisonics reproduction, low-passed at 4 kHz to reduce spatial aliasing artefacts, shows that the former technique can perform equally well as Ambisonics to the same truncation order with respect to positional properties of a virtual sound source, while using a smaller number of loudspeakers. The approach can also produce rear virtual sources using only loudspeakers positioned in the front of the listener, however with the requirement of listener tracking.