This is a answer that has been tried and it solves my problem. Hopefully it will be an useful reference for other. The answer originate from here.
Open a terminal window via cntrl/alt/F!
log in with your normal userid and normal password - the password is not echoed to the screen
sudo cp grub grub-original < press enter > This creates a copy of the file before you modify it
sudo gedit grub < press enter>
This will start up the editor and open the grub file for editing. You want to look for a line like this:
and change it to look like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1"
Then click on save, wait for it to save, then exit the editor to return back to the terminal window.
sudo update-grub < press enter >
sudo shutdown -r now < press enter >
These last 2 steps will regenerate a file used at boot time, then shutdown with a reboot (-r) so your PC will reboot.
After reboot, click on the sound icon on the top bar, click on "Sound Settings", and hopefully you will see the option now for HDMI sound output. You'll have to click on it to make it the default, then just close out of it.
Try something now to see if the sound is active via HDMI now.