Ambisonic guidance

important information about ambisonics tools and their formats

1 AFormat

  • aFormat is a 4 channel file format, it’s particular to specific microphones and needs careful decoding with calibration software
  • before it can be used by most ambisonics plugins, it needs to be converted to bFormat
  • The Sennheiser Ambeo mic spews out aFormat signal and this needs to be converted to bFormat with their plugin en-uk.sennheiser.com/ambeo-blueprints-downloads
  • The type of bFormat that comes from this plugin can be set to either ambiX or FuMa, but you’ve got to be careful to note, in the filename which type the bFormat is in, it can be hard to tell otherwise.

2 BFormat

  • bFormat is an encoded 4 channel signal made up of WXYZ channels
  • W is a virtual omni microphone
  • X Y and Z are virtual figure of 8 microphones
  • This format (either derived from Aformat or recorded/made up directly in software) can store spatial information in sound recordings or virtualisations
  • NOTE this is an encoded format and must be decoded. You need to know if it was encoded with the ambiX or FuMa method in order to use DAW plugins correctly.

3 Ambisonics toolkit

  • This can be downloaded here: www.ambisonictoolkit.net/. It integrates beautifully with REAPER and id pretty full featured.
  • The ambisonics toolkit requires bformat signals to work properly
  • These bformat signals must be in FuMa
  • The ATK offers an ambiX to FuMa converter and vice versa

4 Facebook 360 and Google

  • Both use the more modern ambiX format

5 ICST toolkit

cycling74.com/tools/icst-ambisonics-tools

  • These are superb ambisonics encoding and decoding tools for MaxMSP
  • They can be set to work in ambiX or FuMa mode, but you need to be consistent.
  • This can be set using the type message followed by an integer. Type 0 is the default FuMa, Type 1 is N3D, and Type 2 is SN3D. Unless you’re going for very high orders of spatial resolution, best to stick with FuMa.

6 suggestions for a file naming procedure

Whatever your file naming procedure, you need to be consistent with it and apply it carefully.

  • initials_ file name _type _format extension

e.g mp_blockOfRacket_FuMa_bFormat.wavWh