Comb-Filter Free Audio Mixing Using STFT Magnitude Spectra And Phase Estimation

Presented at the 11th International Conference of Digital Audio Effects (DAFx-08), September 1-4, 2008, Espoo, Finland.

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This paper presents a new audio mixing algorithm which avoids comb-filter distortions when mixing an input signal with time-delayed versions of itself. Instead of a simple signal addition in the time domain, the proposed method calculates the short-time Fourier magnitude spectra of the input signals and adds them. The sum determines the output magnitude on the time-frequency plane, whereas a modified RTISI algorithm estimates the missing phase information. An evaluation using PEAQ shows that the proposed method yields much better results than temporal mixing for nonzero delays up to 10 ms.





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Sound Examples

All sound examples are stored in the FLAC format (Free Lossless Audio Coding). Details and decoding software can be found here.

See the presentation slides for more details

Example Reference Additive Mix STFT without phase estimation STFT with phase estimation
Chatanooga-choo-choo FLAC FLAC FLAC FLAC
English horn + Glockenspiel FLAC FLAC FLAC