How does the A2+, HD3, HD4, A5+ Wireless and HD6 switch between audio sources/ manage multiple inputs?

-Both analog (3.5mm mini-jack and RCA) inputs are "open" or active, so you can leave 2 audio sources plugged in at the same time.

-The USB (Optical for HD6) and the Bluetooth module share the same DAC (Digital to Analog Converter) If connected to both, the Bluetooth connection will take precedence. If you're using USB (Optical for HD6) for example, and start using Bluetooth, USB (Optical for HD6) will mute and Bluetooth will take over. If you pause or disconnect from Bluetooth the speakers will automatically switch back to USB (Optical for HD6) after a few seconds.

*Please note, if you have a digital (Bluetooth, USB or Optical) and or multiple analog sources connected and streaming you are able to hear the input sources if they play simultaneously.