My Philips TV fails to produce any sound when connected to an accessory device with an HDMI to HDMI cable even if the picture quality is good?

The TV's behavior is considered to be normal as some accessory devices have an HDMI audio output setting that requires to be turned on when using an HDMI to HDMI connection

Check the on-screen menu of the accessory device to ensure that the HDMI audio output is set to ON

In some cases, you may need to set the digital out audio stream of the accessory device to PCM

For detailed information, please refer to the user manual of the accessory device