10. What's the meaning of the different colors of the Q5's indicator?

A: The different color stands for different input methods or the battery status 
White: USB input,                Green: Line input ,       Purple: Optical input       
Yellow: Coaxial input,          Blue: Bluetooth input 
And when whatever color of light is pulsating, it means the unit is being charged. 

The Red olor is for battery status: 
1. Pulsate - charging when powered off 
2. Flash twice every 5 seconds - low battery 
3. Steadily on - running out of power and will power off shortly
4. Off  -  fully charged when the Q5 is powered off.