Check which mode the VoiceBuds are set to In Mode 1 (quiet room - Omni directional microphone), you will hear sounds from all directions. This often results in you hearing low-volume echos as sound bounces of walls in the room -- resulting in a sort of "tinny" sound. 

By switching to Mode 2 or Mode 3 (using the smartphone app or by pushing-and-holding the rocker switch on the VoiceBud) you can make the "tinny sound effect" go away.