Graphic Delay Equalizer

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Research units


A graphic delay equalizer based on a high-order nonparametric allpass filter design is proposed. Command points at the centers of octave frequency bands are connected with polynomial interpolation to form a continuous target group-delay curve as function of frequency. The required number of all-pass sections depends on the area under the target curve. The group-delay area at low audio frequencies is small due to the linear frequency scale, so only a few allpass sections can be assigned there, which reduces the accuracy. Design accuracy can be improved by adding a constant delay to the target curve, which increases the area. Two use cases are presented: the group-delay equalization of a multi-way loudspeaker and the linearization of the phase response of a regular magnitude-only graphic equalizer. The graphic delay equalizer can be used to enhance the perceptual quality of audio systems or to produce audio effects.


Original languageEnglish
Title of host publicationICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)
Publication statusPublished - 1 May 2019
MoE publication typeA4 Article in a conference publication
EventIEEE International Conference on Acoustics, Speech, and Signal Processing - Brighton, United Kingdom
Duration: 12 May 201917 May 2019
Conference number: 44

Publication series

NameProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing
ISSN (Print)1520-6149
ISSN (Electronic)2379-190X


ConferenceIEEE International Conference on Acoustics, Speech, and Signal Processing
Abbreviated titleICASSP
CountryUnited Kingdom

    Research areas

  • Delays, Equalizers, Graphics, Loudspeakers, Acoustics, Interpolation, Audio systems, delay systems, equalizers, phase distortion, psychoacoustics.

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