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transcoding ambisonics to binaural

In order to deliver the auralizations in an accessible format for the web, the Ambisonics auralizations were transcoded from their 2nd-order Ambisonics component representation into the binaural format.  Listeners on the web can then access spatial auralizations using only a set of high-quality headphones and a common computer sound card.

The transcoding process effectively performed the following operations:
  1. The 2nd-order components were decoded onto an ideal dodecahedron loudspeaker array in virtual signal space
  2. The decoded loudspeaker components were encoded into binaural using an appropriate HRTF filter pair based on their direction incident on a virtual head at the center listening position of the array
A measured HRTF library of a KEMAR binaural head (from MIT) was used for the encoding process.  The Linux-based BruteFIR convolver was used to create the filter structure and perform the encoding as a batch process.  In order to reduce download times for dial-up users, MP3 versions of the auralizations were created using the LAME MP3 encoder.
This material is based upon work supported by eMPAC at Rensselaer.
 © 2004, Paul Henderson