Update: the problem occurs using two different USB audio devices on two different ports with two different cables.
I plug an audio device into a USB port on my 2014 MacBook Pro running High Sierra 10.13.3. If I play a song in iTunes hosted locally on my hard drive, I hear audio for up to about 20 seconds. Then iTunes continues playing, but no audio comes out of the device (the device is active and powered on and makes just enough background hiss that I know it's on). If I play a video on YouTube in Chrome, I get up to a minute or so of audio, and then the video freezes (!). In all of these cases the internal speakers work fine.
If I pull down the menu bar audio icon and select internal speakers and then re-select the USB audio device, the song comes through the USB audio device again. I can't replay the frozen YouTube video.
Where can I begin to troubleshoot this?
I have a Jabra 9470 Pro headset that I've had connected to my MacBook Pro for months if not years now. Everything has been working fine up until a few days ago.
The base is plugged into the computer via its USB jack. A few days ago, if I select the headset as the default audio device, audio sounds in it just fine for about six or seven seconds. Then it goes silent.
The Mac continues to think that the Jabra base is the USB audio device and clearly thinks that it is successfully sending audio to it.
Another USB audio device works fine, so the problem is clearly somewhere in the macOS-to-Jabra-specifically path.
I know that High Sierra has had some issues with USB audio in the past, but I can't understand what might have happened here. Are there any ideas?