I have an external, USB Microphone (YetiX) that is not being recognized by the Operating System (Catalina 10.15.4)
I have tried most of the solutions that are often proposed, including an SMC reset, a PRAM reset, using a powered USB hub... interestingly, the System Report *does* identify the microphone as being plugged into the USB port (as a USB 2.0 device, which it is) -- but the Operating System does NOT recognize it as an audio input device.
MacBook Pro 15", macOS 10.13