...I've been able to get the mic to work with Oculus link using a USB headphone and mic. Here's what I did: 1. Opened Sound Settings. 2. clicked on Manage sound devices. 3. Disabled Headset Microphone "Oculus Virtual Audio Device". 4. Make sure that you choose the USB mic that you have plugged in for both "Output" and "Input". Using this technique I'm able to get the mic to work in Altspace using the Oculus Link.