The Xiaomi Black Shark 2 Pro was one of the first phones to be launched with the Snapdragon 855+. While it offers impressive performance, it would appear that the company cut corners on its audio hardware, with the phone posting terrible scores on DxOMark's audio tests.
https://www.notebookcheck.net/Xiaomi-Black-Shark-2-Pro-A-gaming-phone-with-abysmal-multimedia.451299.0.html