I am not hearing anything while sleeping. Is Philips SmartSleep Deep Sleep Headband working?

The product is designed so that the tones are not noticed during sleep. The volume is calibrated so that it should not wake you. To verify that the headband is working, you can view the connection status in your app at any time during use and your Sleep Boost time the next morning. Alternatively, you can also press the power button for one second to hear the connection tone – a “happy tone sequence” and confirm that it is connected correctly.