Hi bill! You can connect your HW-T650 Soundbar to your Samsung TV via HDMI ARC port, as this will allow you to turn your soundbar on and off with your TV. Make sure you also enable the Anynet+ setting on your TV, which controls external devices that are connected to the TV via an HDMI cable, and will turn on/off when you turn the TV on/off.
Go to: Settings > General > External Device Manager > Anynet+ (HDMI-CEC)
^Gina