Is there really Surround Sound on PC? (Now solved) Spoiler - Yes there is!

In my PC I have an Asus Xonar D2x sound card which has no problems with Dolby Digital and DTS surround sound from any source - Other than Forza.
This is output to my Denon/Kef home theatre system via Digital Optical cable (S/PDIF).

I see the option for Home Theatre and have set it to this yet I can only get stereo.
I get more spacial awareness via my stereo headset - somehow.
Any help appreciated as my kit is being wasted here. Dolby Digital always worked from the Xbox One to the same system.

Anybody? Please?

I’m guessing that unlike on console, the PC version doesn’t output a Dolby Digital / DTS signal?
If that’s the case just what does the home theatre option do? Is it just their way of saying “amplified stereo speakers?” That’s what I suspect.

I have two items to contribute:\

  1. I’m unable to play FH5 with my Realtek ALC1220 codec-based onboard sound card and the native drivers that support Dolby Digital and DTS. The game will crash every time loading into freeroam if that driver is installed. If I uninstall the driver and use the Microsoft HCL driver, that only does stereo, the game works. I should note that if the native driver is installed the game will crash whether I’m using the onboard sound, outputting via HDMI on my Nvidia 30-series card, or using my Astro TR Mixamp. I’ve asked others with Realtek ALC1220 codec-based onboard sound card that support Dolby Digital and DTS if they’re having the issue as well and some have reported they are and others are not. Not sure why that is.

  2. When I do use my Astro TR Mixamp and the HCL driver for my onboard sound is used everything works fine, including Dolby Atmos for Headphones. So some form of surround sound does work

For anyone with my same problem that lands here looking for answers - I have it solved! At least in my case.
It turns out that Forza Horizon 5 does indeed output a DTS surround signal on PC. It just wasn’t for me.

The reason was that I was using my Xbox controller and sometimes the stereo headset for parties via Xbox Game Bar.
In the game bar’s audio settings it had chosen one of 3 or 4 of the sound card’s output options, but not the correct one.
Cycling through these suddenly stepped it up to 5.1 DTS.
Having previously been through all the settings and properties I could find relating to the sound itself I’d almost given up.
It was the game bar all along.

Then I was thinking that I’d have to change this every time I switched from headset to speakers, but it was fine.
Headset worked in stereo and DTS selected on unplugging the headset.

The latest patch (released 11/17/2021) has addressed my issues with the Realtek ALC1220 codec-based onboard sound card that support Dolby Digital and DTS on optical out.