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!
I’ve just released a new first-order Ambisonic panner over on my new website. It’s absolutely free and you can read more about it here.
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
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!
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.
The proceedings of the joint Ambisonics and Auralization symposium has been published as a book today. You can get it here. It’s definitely worth checking out because there were lots of interesting works presented.
Ten of the papers are missing (including my own) because they’ll be out in the autumn in a special issue of the journal ‘Acta Acustica united with Acustica’.
I’ll be at the Ambisonics Symposium (joint with the Auralization symposium) in Berlin this week (3rd-5th April). The program is here and it looks like it’ll be really interesting.
I’ll be presenting a paper titled “Off-Centre Localisation Performance of Ambisonics and HOA for Large and Small Loudspeaker Array Radii” on the 5th. I’ll post a link to the paper once it’s up on the TU Berlin website, which should hopefully be in the next couple of days.
If you happen to be going then please get in touch because I’d love to chat.