Key Points of Audio Device Ownership (System Administration Guide: Devices and File Systems)

System Administration Guide: Devices and File Systems

Keep the following key points of audio device ownership in mind when working with audio devices.

When you plug in a USB audio device and you are logged in on the console, the console is the owner of the /dev/* entries. This situation means you can use the audio device as long as you are logged into the console.
If you are not logged into the console when you plug in a USB audio device, root becomes the owner of the device. However, if you log into the console and attempt to access the USB audio device, device ownership changes to the console. For more information, see logindevperm(4).
When you remotely login with the rlogin command and attempt to access the USB audio device, the ownership does not change. This means that, for example, unauthorized users cannot listen to conversations over a microphone owned by someone else.