How to set default audio input device

This question has been asked before (e.g. here and here), never receiving a satisfactory answer.

In my case, my MacBook Pro consistently defaults my audio input to the soundbar that I have connected to my dock. This apparently happens because the soundbar has a microphone input, but is a problem because I have no microphone attached to it. In one location I want to use my webcam microphone, in another I have a podcast microphone connected.

The answers to the above links were "try the MIDI settings utility." That is not helpful, as that utility does not give a way to set a default or to order devices in preference order. In fact, when I have manually selected the correct input device, the MIDI settings utility doesn't allow me to do anything as far as making it the input.

It seems like there should be something like the printer options where you can set the default printer and have that be a persistent setting. But I don't see a way to do that for input or output. Does anybody know of one?