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.

This work introduces a new theory for spatial audio recording and reproduction named Higher Order Stereophony. Through the use of the Taylor expansion, the technique accurately reproduces a sound field across a line that is orientated as the interaural axis of a listener, to attempt to recreate a set of desired binaural signals. The technique utilises loudspeaker amplitude panning, and is shown to encompass in its framework traditional Stereophony approaches such as the stereo sine law. Therefore, the technique expands Stereophony to higher orders and more loudspeakers, leading to a greater frequency range of accurate reproduction, in a similar manner to Higher Order Ambisonics. Higher Order Stereophony is shown to exhibit many similarities to Higher Order Ambisonics, and decoders to transition between the different sound field representations are derived. Higher Order Stereophony is also re-derived through a mode matching approach using a subset of spherical harmonics, those with degree index equal to zero only. The theoretical results are then validated through experimental measurements using various microphone arrays, considering the reproduced sound field across a single line and the reproduced spherical harmonic coefficients of the sound field.