a1Panner

It's 64-bit only?

Yes, but an update is coming soon that will include 32-bit for Windows and Universal Binary for Mac. I will post here when it is released.

Thank you.

The plugin has been updated now to work for 32-bit Windows and UB on Mac. It is also now available as an AudioUnit on Mac.

There must be something wrong with the VST version for OS X, upon loading the plugin, it only passes audio to the left speaker, to get it balanced, the plugin needs to be set to either the left or right position.

Hello. This is the correct behaviour. The output of the VST is four channels of first-order Ambisonics (AmbiX format). This is an intermediate format that is not meant to be listened to directly. To listen to the spatialized sound you need a decoder to speakers or headphones (such as the a1Monitor). Think of the output of this plugin as a combination of microphones: the first channel is an omni mic (same signal level independent of panning position), and the 3 others are figure-of-8 mics on the Y, Z and X axes respectively. This is why the second channel (Y) has signal when the source is to the left or right.

Here is a short example of how to get started with Ambisonics and the basics you'll need: https://www.ssa-plugins.com/gettin-started-with-ambisonics-tutorial/

If you have more question, let me know :)