Sound Enhancement is one of the four basic features of Lenovo Nerve Sense, which lets you enhance the sound output to your headphones / speakers. When turned on, this feature maintains volume levels, prevents distortion and creates a surround sound experience.
The feature significantly enhances the immersion while gaming. While this feature can be a great addition while you're playing racing games, first person action games or while listening to music, competitive players might want to leave the feature turned off as its making footsteps (or other, very subtle sounds) in competitive games slightly more difficult to hear (Counter-Strike, Battlefield, ect.).