In Auto on/off mode, it will power on by the first active source and that will stay active until signal timeout or disconnect. What does this mean?
For analogue signals (Balanced and RCA)
When the soundbar/conferencing bar have powered on via the activating analogue input source (Balanced or RCA), it will be kept as the active source for as long as there is a signal. When the signal is removed, the sound bar/conferencing bar will be kept on for an additional 20 minutes before automatically powering off again. And the wake-on-signal function will start over again sensing for an active signal.
For digital signals (HDMI-ARC and USB Audio)
For the digital signals, it detects either on the USB 5V signal if a source is connected or disconnected, or on HDMI-ARC it uses HDMI-CEC to determine the power state.
Here's an example some may experience. A TV with HDMI-ARC is connected to the soundbar. At the same time, a Laptop is also connected to the soundbar via USB Audio.
In this example, the TV is turned on initially and hence HDMI-ARC is the current active source on the sound bar. The user now wishes to change source to USB Audio and looks for the sound bar as a source on his Laptop audio output.
It will however not show up as a source on the laptop until the TV is switched off, and the USB source will get chosen as the active source on the sound bar instead, via signal sense (Auto on/off).
Likewise, if the USB source was activated first then the TV will not detect the Sound Bar on HDMI-ARC before the USB is disconnected from the Laptop.