O1A Decoder - Headphones

O1A Decoder - Headphones

Host Support

Host TypeSupport


Output2Binaural Stereo


This plugin takes a first order ambisonics (O1A) mix and decodes it to 3D stereo suitable for use with headphones. The results are similar to a binaural recording and can be used to place sounds behind, around, above and below the listener.

This plugin uses Blue Ripple Sound's ground-breaking "Amber" HRTF technology.

The plugin is available in the O1A Decoding plugin library.

Technical Notes

The Blue Ripple Sound Amber HRTF uses data from the IRCAM LISTEN HRTF data set, available at http://recherche.ircam.fr/equipes/salles/listen/index.html.

The HRTF data for each head in the data set is cleaned and converted into a suitable parameterised model. The parameter space is explored to find an "average" head model which works on a wide range of heads. This is then used to build a higher order ambisonics (HOA) decoder.

This results in smooth HRTF-based decoders which work on a wide range of heads and do not suffer from the high frequency phasing artefacts common with some other headphone decoders and binaural panners, particularly when sounds are moving. The decoder is able to synthesise ITD (inter-aural time difference) cues at low frequencies and ILD (inter-aural level differences) throughout the frequency range. This plugin uses the first order (O1A) version of the decoder.