How to make a Universal Ambisonic (*.ua) file

Universal Ambisonic (UA) files use a lossless audio compression technology called Wavpack. The first step is to download and install Wavpack version 4.60. Once installed, you must make a multi-channel wav file that respects the Universal Ambisonic specification. Here is a summary of the specification:

Orders: 1st, 2nd, 3rd, 4th
Normalisation Scheme: N3D
Component Sequence: Gerzon ambisonic
Mixed Orders: Only full periphonic and full horizontal are allowed.


For horizontal only files all component channels must be supplied but only the horizontal-only channels need contain data.


Producers are strongly recommended to work in full-periphonic 3rd order (16 channels) as a standard.



Converting from *.amb files

When converting 3 or 4 channel b-format *.amb files, please note that UA uses a different normalisation scheme (N3D). To convert b-format to N3D please consult the UA Specification. When converting from b-format, only the W channel needs to be modified. When converting from FuMa extra gains need to be included to make sure that the higher order N3D channels don't get clipped.

Command syntax

Use this syntax with the wavpack command: 

wavpack -hh -x --channel-order=... -w "UniversalAmbisonic=1" myInputFile.wav -o myOutputFile.ua
If you would like to specify how your ambisonic file will be decoded to stereo (see the spec for more details), you can set further tags like this: 
wavpack -hh -x --channel-order=... -w "UniversalAmbisonic=1" -w "ResonsePattern=100" -w "Angle=90" -w "Azimuth=10" -w "Elevation=5" myInputFile.wav -o myOutputFile.ua

Extra tags

You may also set all of the following tags:

WARNING: NOT YET IMPLEMENTED: Once you have submitted the file to SoundOfSpace.com, these tags (if empty) will be populated with the fields filled in from the web form.