Q Media M2/M3 - Q. How do I control the volume on a Q Acoustics Soundbar/Soundbase with my TV's remote?
Models M3 & M2 use an HDMI connection and as long as you connect it to the HDMI socket on your TV marked ARC, (normally HDMI 1), the TV output is set to PCM stereo and the TV's CEC is enabled (this is labelled differently per manufacturer, i.e. Panasonic call it Viera Link), you should find you are able to control your system via the TV remote. This method offers the highest sound quality along with the added functionality of volume and standby control.
Using the Toslink optical connection or an analogue connection, you'll find that you cannot control the volume through the TV remote.