S3A Decorrelation Toolbox

The s3a decorrelation toolbox is an open-source set of tools for decorrelating audio. It includes the s3a decorrelator, an upmix algorithm written in python. The algorithm can also be used to upmix any audio source to any number of channels. The algorithm is blind and the resultant upmix remains mono compatible.

It was designed to maximise envelopment for diffuse sound objects such as ambience, applause and reverberation but can be used for any source material.

  • Generate multichannel audio from mono or stereo. In fact generate any number of outputs from any number of inputs.
  • Upmix existing content to surround sound.
  • Choose between maximising envelopment for materials such as rain. Or just upmix the ambience of legacy recordings.
  • Have complete control over the processing and positioning of transients, harmonic content and noise content.
  • Use the advanced settings to choose different decorrelation methods and filters.
  • Written in python, the toolbox is easy to modify or extend with different decorrelation filters.

The source code is available this link to our github repository.


Coming soon. See the README on the source page to get started.


The S3A Decorrelation Toolbox is available under the
GNU General Public License
. The licence is included in the source.

S3A is funded by the Engineering and Physical Sciences Research Council (EPSRC).
Programme Grant Scheme – Grant Ref: EP/L000539/1
© Copyright 2018 S3A