Oversampling for Nonlinear Waveshaping: Choosing the Right Filters

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Oversampling for Nonlinear Waveshaping: Choosing the Right Filters. / Kahles, Julen; Esqueda Flores, Fabian; Välimäki, Vesa.

In: Journal of the Audio Engineering Society, Vol. 67, No. 6, 06.2019, p. 440–449.

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Kahles, Julen ; Esqueda Flores, Fabian ; Välimäki, Vesa. / Oversampling for Nonlinear Waveshaping: Choosing the Right Filters. In: Journal of the Audio Engineering Society. 2019 ; Vol. 67, No. 6. pp. 440–449.

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@article{a6a076c47569485f9bc9368d5ab029c1,
title = "Oversampling for Nonlinear Waveshaping: Choosing the Right Filters",
abstract = "An assessment of filters for classic oversampled audio waveshaping schemes is carried out, pursuing aliasing reduction. For this purpose, the quality measure of the A-weighted noise-to-mask ratio is computed for test tones covering the frequency range from 27.5 Hz to 4.186 kHz, sampled at 44.1 kHz, and processed at eight-times oversampling. All filters are designed to have their passband contained within a ±1 dB range and to exhibit a minimum stopband attenuation value of 40 dB. Waveshaping of sinusoids via hard clipping is investigated—spectral enrichment due to the discontinuities introduced by its nonlinear transfer function maximizes aliasing distortion. The obtained results suggest that linear interpolation equalized with a high shelving filter is a sufficiently good method for upsampling. Concerning decimation, the interpolated FIR, elliptic, and cascaded integrator-comb filters all improve the results with respect to the trivial case. The cascaded integrator-comb filter is the only tested decimation filter that achieves perceptually sufficient aliasing suppression for the entire frequency range when combined with the linear interpolator.",
author = "Julen Kahles and {Esqueda Flores}, Fabian and Vesa V{\"a}lim{\"a}ki",
year = "2019",
month = "6",
doi = "10.17743/jaes.2019.0012",
language = "English",
volume = "67",
pages = "440–449",
journal = "Journal of the Audio Engineering Society",
issn = "1549-4950",
number = "6",

}

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TY - JOUR

T1 - Oversampling for Nonlinear Waveshaping: Choosing the Right Filters

AU - Kahles, Julen

AU - Esqueda Flores, Fabian

AU - Välimäki, Vesa

PY - 2019/6

Y1 - 2019/6

N2 - An assessment of filters for classic oversampled audio waveshaping schemes is carried out, pursuing aliasing reduction. For this purpose, the quality measure of the A-weighted noise-to-mask ratio is computed for test tones covering the frequency range from 27.5 Hz to 4.186 kHz, sampled at 44.1 kHz, and processed at eight-times oversampling. All filters are designed to have their passband contained within a ±1 dB range and to exhibit a minimum stopband attenuation value of 40 dB. Waveshaping of sinusoids via hard clipping is investigated—spectral enrichment due to the discontinuities introduced by its nonlinear transfer function maximizes aliasing distortion. The obtained results suggest that linear interpolation equalized with a high shelving filter is a sufficiently good method for upsampling. Concerning decimation, the interpolated FIR, elliptic, and cascaded integrator-comb filters all improve the results with respect to the trivial case. The cascaded integrator-comb filter is the only tested decimation filter that achieves perceptually sufficient aliasing suppression for the entire frequency range when combined with the linear interpolator.

AB - An assessment of filters for classic oversampled audio waveshaping schemes is carried out, pursuing aliasing reduction. For this purpose, the quality measure of the A-weighted noise-to-mask ratio is computed for test tones covering the frequency range from 27.5 Hz to 4.186 kHz, sampled at 44.1 kHz, and processed at eight-times oversampling. All filters are designed to have their passband contained within a ±1 dB range and to exhibit a minimum stopband attenuation value of 40 dB. Waveshaping of sinusoids via hard clipping is investigated—spectral enrichment due to the discontinuities introduced by its nonlinear transfer function maximizes aliasing distortion. The obtained results suggest that linear interpolation equalized with a high shelving filter is a sufficiently good method for upsampling. Concerning decimation, the interpolated FIR, elliptic, and cascaded integrator-comb filters all improve the results with respect to the trivial case. The cascaded integrator-comb filter is the only tested decimation filter that achieves perceptually sufficient aliasing suppression for the entire frequency range when combined with the linear interpolator.

U2 - 10.17743/jaes.2019.0012

DO - 10.17743/jaes.2019.0012

M3 - Article

VL - 67

SP - 440

EP - 449

JO - Journal of the Audio Engineering Society

JF - Journal of the Audio Engineering Society

SN - 1549-4950

IS - 6

ER -

ID: 34665792