Audio peak reduction using a synced allpass filter

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Peak reduction is a common step used in audio playback chains to increase the loudness of a sound. The distortion introduced by a conventional nonlinear compressor can be avoided with the use of an allpass filter, which provides peak reduction by acting on the signal phase. This way, the signal energy around a waveform peak can be smeared while maintaining the total energy of the signal. In this paper, a new technique for linear peak amplitude reduction is proposed based on a Schroeder allpass filter, whose delay line and gain parameters are synced to match peaks of the signal's autocorrelation function. The proposed method is compared with a previous search method and is shown to be often superior. An evaluation conducted over a variety of test signals indicates that the achieved peak reduction spans from 0 to 5 dB depending on the input waveform. The proposed method is widely applicable to real-time sound reproduction with a minimal computational processing budget.

Original languageEnglish
Title of host publicationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2022
Place of PublicationSingapore
Number of pages5
ISBN (Electronic)978-1-6654-0540-9
Publication statusPublished - 2022
MoE publication typeA4 Conference publication
EventIEEE International Conference on Acoustics, Speech, and Signal Processing - Singapore, Singapore
Duration: 23 May 202227 May 2022

Publication series

NameIEEE International Conference on Acoustics, Speech and Signal Processing
ISSN (Print)1520-6149


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


  • Audio systems
  • digital filters
  • music
  • optimization
  • sound enhancement


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