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Appl. Sci. 2017, 7(5), 483;

Late Reverberation Synthesis Using Filtered Velvet Noise

Acoustics Lab, Department of Signal Processing and Acoustics, Aalto University, 02150 Espoo, Finland
This paper is a revised and extended version of a paper published in the International Conference on Digital Audio Effects (DAFX), Maynooth, Ireland, 2–5 September 2013.
Current addresses: Bo Holm-Rasmussen—The Royal Danish Academy of Fine Arts, Laboratory for Sound, 1050 Copenhagen, Denmark. Heidi-Maria Lehtonen—Dolby Sweden, 11330 Stockholm, Sweden.
Author to whom correspondence should be addressed.
Academic Editors: Woon-Seng Gan and Jung-Woo Choi
Received: 15 March 2017 / Revised: 2 May 2017 / Accepted: 3 May 2017 / Published: 6 May 2017
(This article belongs to the Special Issue Spatial Audio)
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This paper discusses the modeling of the late part of a room impulse response by dividing it into short segments and approximating each one as a filtered random sequence. The filters and their associated gain account for the spectral shape and decay of the overall response. The noise segments are realized with velvet noise, which is sparse pseudo-random noise. The proposed approach leads to a parametric representation and computationally efficient artificial reverberation, since convolution with velvet noise reduces to a multiplication-free sparse sum. Cascading of the differential coloration filters is proposed to further reduce the computational cost. A subjective test shows that the resulting approximation of the late reverberation often leads to a noticeable difference in comparison to the original impulse response, especially with transient sounds, but the difference is minor. The proposed method is very efficient in terms of real-time computational cost and memory storage. The proposed method will be useful for spatial audio applications. View Full-Text
Keywords: audio systems; digital filters; digital signal processing; room acoustics audio systems; digital filters; digital signal processing; room acoustics

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Välimäki, V.; Holm-Rasmussen, B.; Alary, B.; Lehtonen, H.-M. Late Reverberation Synthesis Using Filtered Velvet Noise. Appl. Sci. 2017, 7, 483.

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