You would use "around" in this situation, as it implies a direction and not a shape. "He went AROUND the corner." However, in some situations, you may round a corner. For example, a baserunner in...
Sound waves have a longer wavelength which allows them to bend around corners more than light waves.
Because sound waves bounce off walls and light only travels in straight lines unless it is hitting a reflective surface.
Because there is a blockage when you try to see around it but nothing blocks sound unless there is not an opening.
The reason why is cause light can only travel in straight lines, it can not travel in bends or curves!