I can add a “mono mixer” function node directly to a Metasound file via blueprint, but I’m not sure how to add one via the MetaSound Builder Subsystem - it looks like I’ve only got options for Graph Input/Output, and Metasound Nodes.
You do that using the ‘add metasound node by classname’ option, to find the class name of the mixer copy it to your clipboard and then paste it in some text document, in the resulting string you can find the classname for the given node.
Thank you!