I compiled the latest versions of Fons Adriaensens’ Ambisonics Decoder ambdec-0.5.1 (PDF manual) and his Microphone-Processor to convert TetraMic recordings to B-Format tetraproc-0.8.2 (PDF paper) for Mac OS X.
I packed them in easy-to-use installer packages which should run under Mac OS X >=10.6 (Snow Leopard, Lion, Mountain Lion):
Note about ambdec: The manual is outdated! The configuration window is gone. Use a Texteditor to edit .ambdec files!
ambdec-0.5.1-installer.pkg
tetraproc-0.8.2-installer.pkg
Make sure you have JackOSX (http://www.jackosx.com) and X11 (http://xquartz.macosforge.org) installed.
Troubleshooting: Sometimes the installer does not set the file permissions for graphic files correct, try to check if the folder /usr/local/share/ambdec is read/writeable for the user. You can start ambdec from Terminal and check for error messages (just type ambdec in Terminal and hit Return).
Additionally I compiled and packed the LADSPA Ambisonics Plug-In Set (AMB-plugins-0.8.1) for 32/64 bit on Mac 
OS X >= 10.6 to use within Ardour.
AMB-plugins-0.8.1-LADSPA-osx.zip
Homepage of the Software Author Fons Adriaensen and his (mostly Linux) tools:
http://kokkinizita.linuxaudio.org
