Are there any free (or inexpensive) tools for converting multi-channel surround to 2-channel binaural ?

I’m experimenting with Sound Particles and would like to try and convert the surround output to binaural. The tool right now does not offer this feature although I added it to their list as a feature request. Until then, looking for ideas.


[Edit: Just to clarify – I’m looking for a tool that will convert files and render out a new binaural audio file. Some solutions appear to be geared for monitoring only]