The device comes with a single speaker unit at the back, and while the speaker isn't as large as the grill may suggest, it still sounds pretty good. (androidauthority.com)
Speaking of audio, the single speaker unit on the bottom benefits from a better placement from before, but provides the expected quality. (androidauthority.com)
That has been done just for the sake of symmetry however, with there being only a single bottom - facing speaker unit, along with a microphone being housed in the other grill. (androidauthority.com)