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Higher-order Spatial Impulse Response Rendering (HO-SIRR)
Higher-order Spatial Impulse Response Rendering (HO-SIRR) is a rendering method, which can synthesise output loudspeaker array room impulse responses (RIRs) using input spherical harmonic (Ambisonic/B-Format) RIRs of arbitrary order [1,2]. The method makes assumptions regarding the composition of the sound-field and extracts spatial parameters over time, which allows it to map the input to the output in an adaptive and more informed manner; when compared to purely linear methods such as Ambisonics.
The idea is that you then convolve a monophonic source with this loudspeaker array RIR, and it will be reproduced and exhibit much of the spatial characteristics of the captured space. Note that the HO-SIRR algorithm is an extention of the original first-order SIRR formulation, first proposed back in 2005 [3,4], by employing the higher-order analysis principles described in .
Note that we are currently in the process of fine-tuning the implementation. Therefore, if you find any bugs in the MATLAB/plug-in code, encounter a particulary poor rendering with a certain Ambisonic RIR, or have any general suggestions for improvements/new features; then please get in touch :-)
The Plug-in / Standalone App (Beta)
The suggested workflow is:
Listening test results at a glance
The perceptual performance of HO-SIRR was evaluated based on formal listening tests in , where it was compared to Mode-Matching Ambisonics decoding. It was found that if the mono signal is quite stationary (such as a trombone recording), then first-order SIRR renderings can sound almost equivalent to 5th order Ambisonics. However, if the mono signal is more transient (such as a kick drum or speech sample), then the benefits of the higher-order SIRR renderings are revealed. For an in-depth description of the listening test and a discussion of the results, see: .
About the authors
 McCormack, L., Pulkki, V., Politis, A., Scheuregger, O. and Marschall, M. (2020). Higher-Order Spatial Impulse Response Rendering: Investigating the Perceived Effects of Spherical Order, Dedicated Diffuse Rendering, and Frequency Resolution.
 McCormack, L., Politis, A., Scheuregger, O., and Pulkki, V. (2019). Higher-order processing of spatial impulse responses.
Updated on Wednesday 21st of April, 2021