Creating endless sounds

Vesa Välimäki, Jussi Rämö, Fabian Esqueda Flores

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

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This paper proposes signal processing methods to extend a stationary part of an audio signal endlessly. A frequent occasion is that there is not enough audio material to build a synthesizer, but an example sound must be extended or modified for more variability. Filtering of a white noise signal with a filter designed based on high-order linear prediction or concatenation of the example signal can produce convincing arbitrarily long sounds, such as ambient noise or musical tones, and can be interpreted as a spectral freeze technique without looping. It is shown that the random input signal will pump energy to the narrow resonances of the filter so that lively and realistic variations in the sound are generated. For realtime implementation, this paper proposes to replace white noise with velvet noise, as this reduces the number of operations by 90% or more, with respect to standard convolution, without affecting the sound quality, or by FFT convolution, which can be simplified to the randomization of spectral phase and only taking the inverse FFT. Examples of producing endless airplane cabin noise and piano tones based on a short example recording are studied. The proposed methods lead to a new way to generate audio material for music, films, and gamin32g.
Original languageEnglish
Title of host publicationProceedings of the 21th International Conference on Digital Audio Effects
PublisherUniversity of Aveiro
Number of pages8
Publication statusPublished - 4 Sept 2018
MoE publication typeA4 Conference publication
EventInternational Conference on Digital Audio Effects - University of Aveiro, Aveiro, Portugal
Duration: 4 Sept 20188 Sept 2018
Conference number: 21

Publication series

NameProceedings of the International Conference on Digital Audio Effects
ISSN (Print)2413-6700
ISSN (Electronic)2413-6689


ConferenceInternational Conference on Digital Audio Effects
Abbreviated titleDAFX
Internet address


  • Audio systems
  • digital filtering
  • Digital signal processing
  • Music technology


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