You do not need a "serial key" to install the app. Installation is free. Here is the correct path:
DTS Sound Unbound is a cutting-edge audio technology that revolutionizes the way we experience sound. By installing DTS Sound Unbound with a valid serial key, users can unlock a world of immersive audio, elevating their entertainment experience to new heights. In this article, we'll walk you through the installation process and provide you with a comprehensive guide on how to install DTS Sound Unbound using a serial key. dts sound unbound serial key install
Go to the Microsoft Redeem page, sign in, and enter your code. You do not need a "serial key" to install the app