Read the manual :)

It says it’s already activated and available through Synapse software.

No need of installing external THX Spatial app. Uninstall it and use synapse.

Synapse 3?

Yes. Synapse 3 in Audio → Mixer tab.

Hello, after updating razer synapse, I lost the THX Spatial audio output device. Now only my Razer Kraken V3 PRO is in the output device. Is this how it should be?

Hello, after updating razer synapse, I lost the THX Spatial audio output device. Now only my Razer Kraken V3 PRO is in the output device. Is this how it should be?

Same Problem here!

Everything is OK. They’ve changed it in some Synapse 3 version: it’s no longer 2 separate devices (Kraken V3 and THX Spatial).

Please I got a razer card try to scratch it and then scratch a few number away what can I do now??

Hello

Got the same issue although my Headset is Razer Blackshark V2 Pro 2023 and it happends with newly installed Synapse 4.
 

I get a Pop-Up Window that says THX Spatial Audio “15 days trial or activate” and if I click on activate it asks me for a serial number.
 

This is still a thing in 2025 , one year after the original post, please help!

As above - read the manual for your headset.

You don’t need external THX Spatial, because THX is already available through Synapse.

7.1 Surround Sound and THX Audio are 2 different App.

Do a product registration and you should be able to get the 7.1 surround sound code. 

He mentions Blackshark V2, so it’s not 7.1 surround compatible, he won’t receive the code.

can i use my 7.1 sorround sound code with thx audio or do i have to buy a code?

No.

Please read: 

Headphones Razer Kraken V4 Pro, how to set up THX or how to enable surround sound, when connected to synapse 4 there is no surround sound, like stereo, the sound only becomes quieter. How to fix this? How to enter the advanced sound settings? Or do I need to buy a separate program???

I think everyone has the same problem, but after purchasing THX-AUDIO activation, I heard that it was combined with THX Soft and Snaps 3, so I told them to use it, but it seems that the person who purchased THX-AUDIO wants to use external software. However, if you want to reinstall the software you received after purchasing it, it is blocked, so it cannot be installed. I bought the original one, but I don't know why it was blocked.