I’ve released a set of Ambisonics plugins over on my main website that you might want to check out: https://spatialaudio.xyz
The set includes first-, third- and seventh-order versions of the following plugins:
- aXPanner – Ambisonics encoder
- aXRotate – Ambisonics sound field rotation
- aXMonitor – Ambisonics decoder to binaural and stereo
- aXCompressor – A compressor that preserves the delicate spatial relationship in the Ambisonics signals.
- aXGate – A noise gate and downwards expander that preserves the delicate spatial relationship in the Ambisonics signals.
- aXEqualizer – An EQ that preserves the delicate spatial relationship in the Ambisonics signals.
- aXDelay – A delay plugin with 5 modules that lets you place the delayed signals wherever you want in the 3D sound field.
There are EDU and bulk discounts available if you get in touch!
Last month the last paper from work done during my thesis was published in the Journal of the Audio Engineering Society. We tested localisation for off-centre listeners with third order Ambisonics for two different noise signals: transient and non-transient. We found, in line with Precedence Effect literature, that the transient signal produced sound images pulled more towards the nearer loudspeakers than the non-transient signal.
We also tested different localisation models. All of them were relatively good at predicting the perceptual results. The best results were obtained by an extended version of Gerzon’s energy vector that includes elements of localisation dominances and the precedence effect (See here for an overview and here for the paper).
P. Stitt, S. Bertet, and M. van Walstijn, “Off-Centre Listening with Third-Order Ambisonics: Dependence of Perceived Source Direction on Signal Type,” J. Audio Eng. Soc., vol. 65, no. 3, pp. 118–197, 2017.
Links: DOI – ResearchGate
Last month we had a paper published in the Journal of the Acoustical Society of America (JASA) on the influence of large head movements with head-tracked binaural when using non-individual HRTFs. In brief, we found that large head movements helped improve localisation for frontal and rear sources, had little impact on lateral sources and that micro head movements didn’t seem to produce increased externalisation. You can get a lot more detail (even individual subject results) from the paper itself!
The work was lead by Etienne Hendrickx and was a collaboration as part of the BiLi Project. In this case the partners were LIMSI-CNRS (during my post-doc) and the Conservatoire de Paris (CNSMdP).
E. Hendrickx, P. Stitt, J.-C. Messonnier, J.-M. Lyzwa, B. F. Katz, and C. de Boishéraud, “Influence of head tracking on the externalization of speech stimuli for non-individualized binaural synthesis,” J. Acoust. Soc. Am., vol. 141, no. 3, pp. 2011–2023, 2017.
Links: DOI – ResearchGate
The Audio Engineering Society has put up the papers for the upcoming 140th AES Convention in Paris. You can download my paper here.
The paper was done in collaboration with the Conservatoire national supérieur de musique et de danse de Paris, who will also have some very interesting demos on a stand at the Convention.
It’s a study comparing perception of sound source stability between 1- and 5-source sound scenes for different levels of latency. I’ll be presenting it on the last day of the convention in the Immersive Audio section.
I’ve had a paper accepted to the Journal of the Audio Engineering Society based on some of the work from my thesis. It was published last week.
The title is “Extended Energy Vector Prediction of Ambisonically Reproduced Image Direction at Off-Centre Listening Positions“. It presents an extension to the energy vector (rE) of Gerzon used in the Ambisonics literature. The extension allows for better prediction of localisation for listeners who aren’t equidistant from all loudspeakers.
It basically adds elements of the precedence effect (or “Law of the First Wavefront”) to the energy vector. This means it can now be used to predict time-delay panning, in addition to amplitude panning.
You can download the paper in the AES e-Library:
- P. Stitt, S. Bertet, and M. van Walstijn, “Extended energy vector prediction of ambisonically reproduced image direction at off-center listening positions,” J. Audio Eng. Soc., vol. 64, no. 5, pp. 299–310, 2016. DOI: http://dx.doi.org/10.17743/jaes.2016.0008
I’ll be posting some supplementary data and tools in the near future. There’ll be some examples of the usage and some listening area localisation maps.
Check back soon!
I’ve neglected this blog a bit in the last year, but there should be a few more things coming soon. And I think I’ll try my hand at making a VST plugin using Matlab (a new feature that looks exciting).
Anyway, I’ll be presenting a paper at AES Paris this year. It is about the influence of head tracking for different scene types with binaural audio and was written with colleagues on Project BiLi at CNSMdP and LIMSI. The conference takes place 4-7th June. Please get in touch, I’d be happy to meet plenty of new people!
The paper is:
P. Stitt, E. Hendrickx, J.-C. Messonnier, and B. F. G. Katz, “The influence of head tracking latency on binaural rendering in simple and complex sound scenes,” in Audio Engineering Society Convention 140, 2016, pp. 1–8.
So my thesis is all signed off and I should hopefully upload it (probably to ResearchGate) some time soon. As a teaser, here are some of the main points covered:
- A review of spatial hearing, plus reviews of some important binaural and vector models for prediction.
- A review of Ambisonics and Higher Order Ambisonics (HOA).
- Results of three perceptual experiments for Ambisonics and HOA at off-centre positions.
- Comparison of the binaural models and Gerzon’s energy vector to the perceptual results.
- An extension to Gerzon’s energy vector to include elements of the precedence effect for more accurate predictions at off-centre positions.