Assuming your Mac is relatively new, visit System Preferences > Sound > Output and select the entry that matches your TV. If there is no entry for your TV, your Mac may be too old to have audio out through HDMI, in which case you may need to run a separate audio cable.
Thank you very much. Tis is a new MacBook Pro and just learning all the little tricks. This one is priceless as BOTH sound and video now pass to the TV via HDMI after your suggested adjustment in Preferences.Thanka again.