Resynthesis Of Spatial Room Impulse Response Tails With Anisotropic Multi-Slope Decays


Spatial room impulse responses (SRIRs) allow for the capture of a room’s acoustics with directional information. This directional component expands the uses for both analysis and reproduction. Anisotropic reverberation decays with multiple decay slopes may occur in coupled rooms and rooms with non-uniform absorption distribution. However, noisy measurements with low signal-to-noise ratio pose issues in analysis and reproduction in practice. This paper presents a method for resynthesis of the late decay of anisotropic SRIRs, which accounts for both multi-slope decays and directional reverberation. A spatial filter bank is used to extract directionally constrained signals, which are then analysed and parameterised in terms of multiple exponential decays and a noise floor. The late reverberation that is predominantly covered in the noise floor is then resynthesised from the estimated parameters using modal synthesis. The SRIR with the restored late reverberation tail is reconstructed as Ambisonic signals. Evaluation of the algorithm shows that signal-to-noise ratios of as low as 40~dB can be reconstructed with low error.

Submitted to Journal AES Special Issue