The optical out port on the PC is a bit of a mystery to a lot of people. It sits in the back of your PC, emitting a permanent red laser glow whether or not something is plugged into it. It almost looks like you’re meant to plug something into it, but what? The answer is, logically, an optical audio cable, and here we’ll show you how to get it working, with the caveat that it’s become rather clunky to properly utilize on Windows 10 in recent years.
How to Enable Optical (S/PDIF) Audio on PC
First of all, there’s the obvious matter of making sure that both your speakers and your PC have the optical (S/PDIF) port. With that off the list, simply plug your PC into your speakers using an optical cable.
As with any cable format, companies will try to claim that their cable is better than others due to gold plating, “High Quality,” or other marketing jargon, but ignore all that. Buying a cheap optical cable should be absolutely fine unless you plan to tie it up in knots. Optical cables work in a similar way to HDMI in that they send digital signals that aren’t really subject to degradation. The main difference is that audio data uses less bandwidth than HDMI, so even if the quality of a cable isn’t great, you’re not likely to be affected.
Once the optical cable is plugged in, click the speaker icon at the bottom-right corner of your Windows taskbar, then click the speaker name above the volume slider to see if an “Optical” or “Digital” sound output has shown up. If it has, just click to enable it.
If the speaker doesn’t show up there, then right-click the speaker icon in the taskbar, click Sounds, and then the Playback tab.
Right-click anywhere in the Playback tab list, then click “Show Disabled Devices.”
At this point a device called something like “digital output” or “optical output” should show up. Right-click it and click “Enable” to switch it on. Once you’ve done that, right-click it again and click “Set as default device.” You should now have optical audio enabled.
How to Enable Optical 5.1 Surround Sound on PC
The real benefits of an optical become apparent when you look to use surround sound, but there are quite a few criteria your PC will have to meet. Also, as a general rule, if your receiver/speakers have an HDMI port, you should use that instead, as it offers much better 5.1 compatibility with Windows 10 drivers.
First of all, is your motherboard capable of outputting 5.1 surround sound? Just because there’s an optical out port doesn’t guarantee that you’ll get surround sound across all your games, movies and so on. Your optical port on your motherboard should support 5.1 sound, though this will vary greatly depending on what Windows version you’re on, whether it registers as a Dolby-compatible output, and so on.
You can check to see if your setup supports one of the Dolby 5.1 formats by going to the Sound window -> Playback. Right-click your device, click Properties, and then the Advanced tab. Simply click the drop-down menu, select “DTS Interactive” or whichever 5.1 surround setup you want to use, then click OK. (If your PC doesn’t detect Dolby Digital, then you may have some work to do, and we’ve offered links to some workarounds in the conclusion.)
You should also click the “Supported Formats” tab to make sure that the formats your receiver is capable of handling are ticked.
That should give you the basics of using an optical cable on Windows 10. The thing is, there is much nuance to it and many variables where things could go wrong. It’s not just your sound card and speakers that need to support it – it’s also the individual media you’re using, as well as the fact that recent Windows versions have made optical out support rather buggy. (You can no longer use the ‘Configure’ button in the Sound window, for example, to enable 5.1 speakers.)
If you do run into optical audio problems, you can find numerous workarounds on internet forums, such as this, this and this, though some of these involve driver modification, replacing DLLs and so on, so try them at your own risk.