To set your Stealth 700 Gen 2 Xbox headset up for use with an Xbox Series X or Xbox Series S console, please do the following.
First, power the headset on, and make sure the headset and console are paired. The LED on both the headset and console should be lit solid. If the LED on the headset is double-blinking at all, please perform the pairing process detailed here.
Once the headset is paired to the console, configure the Windows Sonic Surround Sound:
1. While in the Home screen, press the Xbox button on the controller. You'll see the following screen:
2. Navigate to the Profile & System Tab, and select "Settings".
3. Go to General >> Volume & Audio Output
4. In the Headset Audio column (right side of the screen), set Headset Format to Windows Sonic For Headphones.