Third-octave and Bark graphic-equalizer design with symmetric band filters

Jussi Rämö*, Juho Liski, Vesa Välimäki

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)
32 Downloads (Pure)

Abstract

This work proposes graphic equalizer designs with third-octave and Bark frequency divisions using symmetric band filters with a prescribed Nyquist gain to reduce approximation errors. Both designs utilize an iterative weighted least-squares method to optimize the filter gains, accounting for the interaction between the different band filters, to ensure excellent accuracy. A third-octave graphic equalizer with a maximum magnitude-response error of 0.81 dB is obtained, which outperforms the previous state-of-the-art design. The corresponding error for the Bark equalizer, which is the first of its kind, is 1.26 dB. This paper also applies a recently proposed neural gain control in which the filter gains are predicted with a multilayer perceptron having two hidden layers. After the training, the resulting network quickly and accurately calculates the filter gains for third-order and Bark graphic equalizers with maximum errors of 0.86 dB and 1.32 dB, respectively, which are not much more than those of the corresponding weighted least-squares designs. Computing the filter gains is about 100 times faster with the neural network than with the original optimization method. The proposed designs are easy to apply and may thus lead to widespread use of accurate auditory graphic equalizers.

Original languageEnglish
Article number1222
JournalApplied Sciences (Switzerland)
Volume10
Issue number4
DOIs
Publication statusPublished - 1 Feb 2020
MoE publication typeA1 Journal article-refereed

Keywords

  • Audio signal processing
  • Digital filters
  • Equalizers
  • Hearing
  • IIR filters
  • Supervised learning

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  • Projects

    NordicSMC Aalto

    Liski, J., Välimäki, V., Pulkki, V., Wright, A., Fierro, L., Wirler, S. & Alary, B.

    01/01/201831/12/2023

    Project: Other external funding: Other foreign funding

    NordicSMC: Nordic Sound and Music Computing Network

    Prawda, K., Välimäki, V. & McCrea, M.

    01/01/201831/12/2023

    Project: Other external funding: Other foreign funding

    Equipment

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