Auto-stand-by mode:
1. The auto-stand-by mode is activated by default.
The LED is lit in purple.
2. The speakers turn into stand-by after 1 hour without
receiving a signal.
3. Switch off eco mode by pressing "Eco" once.
The LED is now lit in blue.
4. Switch on eco mode by pressing "Eco" once again.
The LED is now lit in purple.