No Applications in THX Spatial Audio in Synapse

It sounds like you're not able to see any applications listed under the THX Spatial Audio section in the Audio Mixer, despite having turned it on.

It's great that you've already tried opening various applications and games, as well as uninstalling and reinstalling the Synapse 3 software. One thing you could try is making sure that the applications you're testing are actually producing audio output - sometimes applications may appear to be running but are not actually producing sound.

Additionally, you could try checking for any available updates to the Synapse 3 software, as well as ensuring that your Nari Ultimates are running on the latest firmware. It's also worth checking if there are any specific settings or configurations for the THX Spatial Audio feature that may need to be adjusted.

If these steps don't seem to resolve the issue, you may want to consider reaching out to Razer's customer support team for further assistance. They may be able to provide additional troubleshooting steps or potentially even replace the hardware if necessary.

I had the same issues when I first set mine up.  I can’t find it now, but I went down a rabbit hole on, I think, Reddit.  I removed THX Spatial for Dolby Atmos (I already had a lifetime subscription to Dolby anyway).  Oh my what a revelation that was!  Anyway, if you do use THX, remember, it is for gaming, not music, movies and the like.  It removes the wonderous, thunderous explosions and chest thumping gunfire in favor of hearing footsteps.  This actually baffled me with THX being known to exaggerate these things, not diminish them.  Hopefully there’s an update in the future with a choice.

As far as your situation goes, three things might help…

1. If you haven’t done it yet, try updating your audio drivers.  And
2. How to use the THX Spatial
3. How to use the THX Spatial as a Playback device

I hope something helped.

i found thee fix here,