After much forum-exploration, I’ve found that many people have had either a similar problem as me and solved it, or the same exact one and not solved it:

For audio, I use HDMI out -> converter (to optic) -> receiver -> speakers.  Just recently (for no obvious reason) my laptop stopped recognizing the HDMI cable plugged into it. All of my drivers are up to date, and if I unplug the HDMI cable, my laptop makes a sound letting me know that something’s been unplugged.

I’ve tested the receiver, multiple cables, the converter –everything– but no dice (it must be my computer, eh?). I’ve tried “Show Disabled Devices,” checking the Device Manager, and every other solution that the internet has offered, but I don’t know what’s up. This is my Sound settings with the HDMI cable plugged in:

When the problem first occurred I was using Windows 8.1, and the general consensus I had received on upgrading to ’10 was “If it ain’t broke, don’t fix it.” Now something was awry, so I tried solving the issue by upgrading to 10. That didn’t work, and I now have Windows 10 and the same exact issues. Anyone have any idea of what’s going on here? 

From your issue description, I understand that you are not getting sound using HDMI cables.

In order to help you better, please provide us with the following information.

• What is the make and model of the computer?
• Did you try connecting different HDMI port and check if it works?
• Which application are you using to stream movies on the computer?
• Are you able to hear the audio from the computer (without the HDMI)?
• Does this issue occur for a specific file?
• Do you get any error messages/codes?
• Did you make any changes to the computer prior to this issue?

HDMI cables do support audio signals, but not all HDMI-enabled video cards support audio. If your HDTV has an audio input, you might be able to connect a separate audio cable from your computer’s sound card directly to the TV. Otherwise, you’ll need to connect the audio signal to a different output device, such as external computer speakers or your home stereo system. Follow these methods and check if it helps:

Method 1: By default Windows does not route sound over the HDMI output. To change this they need to change the settings in control panel.

Note: This will turn off sound from the speakers or normal audio output on the laptop. To get that back you will have to reverse this process.

a) Press Windows key + X
b) Click on “Control Panel“
c) With the Control Panel in “Control Panel Home” view please click on “Hardware and Sound”
d) Where it says “Sound” in green letters there are three options below that are in blue click on “Manage Audio Devices“
e) This will bring up a window labeled “Sound”
f) On the “Playback” tab there is listed the sound options available to you. One should read “Digital Output Device (HDMI)” Click on that.
g) There should now be a check mark on that option, make HDMI sound output as default .
h) The Sound should then play through your HDMI hookups to the TV.

Method 2: Update the Sound driver

a) Press Windows key + X key when you are at desktop.
b) Select Device Manager.
c) Double-click Sound driver from the left panel to Update.
d) Right-click the device, and click Update driver Software
e) Windows will prompt you to confirm the device’s removal. Click OK to remove the driver.

Please reboot your computer

You may also refer to: Fix sound problems