When changing the system's audio output device (e.g. from speakers to headphones), SyncTERM has to be restarted for that change to take effect; it'll keep sending audio to the original output device that was active at the time that SyncTERM process was started. This is a unique requirement among (Windows) apps.
Anonymous
IIRC, SyncTERM never closes the audio device to avoid clicks and pops, but it also doesn't do anything unique to keep that device the same.