The workaround is to power cycle the USB speakers.
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 in to the console.
If you are not logged in to the console when you plug in a USB audio device, root becomes the owner of the device. However, if you log in to 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 log in 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.