Secondary speaker outlets are on the underside of the chassis, towards the front edge where the chassis tapers, so they're not muffled by the desktop. (zdnet.com)
The Mate 9 comes with a dual stereo speaker setup with a single speaker found on the bottom and a secondary speaker built into the earpiece above the display. (androidauthority.com)
The secondary speaker is tucked into the earpiece, and the overall sound that comes out of the dual speakers is noticeably louder and clearer than last year. (androidcentral.com)