The generation of panning laws for irregular speaker arrays using heuristic methods

Currently, the ITU standard surround sound speaker arrangement is based on an irregular 5 speaker array. However, this may change to an irregular 7 speaker array (as is now the standard on computer hardware) or more in the future. The Ambisonic system, pioneered by Micheal Gerzon, among others, in the late 1960’s, is very well suited to situations where the end system speaker configuration is not fixed in terms of number or position while also offering a simple way (via energy and velocity vector analysis) of quantifying the performance of such systems. However, while the derivation of the decoders is well documented for regular speaker arrangements [1], optimising the decoders for irregular layouts is not a simple task, where optimisation requires the solution of a set of non linear simultaneous equations, complicated further by the fact that multiple solutions are possible [2]. Craven [3] extended the system to use higher order circular harmonics and presented a 4th order Ambisonic decoder (9 input channels), although the derivation method used was not presented. In this paper a semi-automated decoder optimisation system using heuristic methods will be presented that will be shown to be robust enough to generate higher order Ambisonic decoders based on the energy and velocity vector parameters. This method is then analytically compared to Craven’s decoder using both energy/velocity vector and head related transfer function based methods.EPSR

Has Ambisonics come of age?

Ambisonics was developed in the 1970’s as a flexible, psycho-acoustically aware system1. Developed at the same time as Quadraphonics2, Ambisonics is an often mis-understood system that was far ahead of it’s time. Due to the ubiquity of surround sound equipment in modern computers and interest in live surround events becoming more widespread, is the time, finally, right for Ambisonics to come into its’ own? In this paper, the definition of what makes a system Ambisonic is clarified with reference made to the traditional energy and velocity vector theory, higher order systems and use in both the live and domestic environment. More recent developments by the author are discussed with respect to irregular Ambisonic decoder design (such as for the ITU 5.1 speaker array) and analysis using Head Related Transfer Function data showing the extra insight this can give into the performance of one, seemingly similar, decoder design over another. The freely available suite of VST plug-ins (comprising of decoders, panners and an Ambisonic reverb) created using this technology are also presented, with case studies of their use in student projects at the University of Derby

GASP: Guitars with ambisonic spatial performance

‘Guitars with Ambisonic Spatial Performance’ (GASP) is an ongoing project where our expertise in surround sound algorithmic research is combined with off-the-shelf hardware and bespoke software to create a spatial multichannel surround guitar performance system. This poster was funded through the ‘Undergraduate Research Scholarship Scheme’ (URSS) and presented at the University of Derby Buxton Campus 10th Annual Learning & Teaching conference on Wednesday 1st July 2015. The theme being ‘Students as Partners: Linking Teaching, Research and Enterprise’. The poster was also utilised as a contribution to the Creative Technologies Research Group (CTRG) ‘Sounds in Space’ symposium held at the University of Derby in June 2015, at which three pieces of multichannel guitar recordings were demonstrated.‘Undergraduate Research Scholarship Scheme’ (URSS) University of Derb

Hearing Without Ears

We report on on-going work investigating the feasibility of using tissue conduction to evince auditory spatial perception. Early results indicate that it is possible to coherently control externalization, range, directionality (including elevation), movement and some sense of spaciousness without presenting acoustic signals to the outer ear. Signal control techniques so far have utilised discrete signal feeds, stereo and 1st order ambisonic hierarchies. Some deficiencies in frontal externalization have been observed. We conclude that, whilst the putative components of the head related transfer function are absent, empirical tests indicate that coherent equivalents are perceptually utilisable. Some implications for perceptual theory and technological implementations are discussed along with potential practical applications and future lines of enquiry