A one-piece sound port adapter for a microphone assembly includes a body member configured to be fitted over a sound port of the microphone assembly. The body member includes an acoustic channel defined in part by a cavity having a sound inlet and a sound outlet, where the sound outlet is acoustically coupled to the sound port. A wall portion of the body member extends into the cavity and configured to modify an acoustic property of the acoustic channel. When mounted, the one-piece sound port adapter converts the microphone assembly from a top or bottom port microphone assembly to a side-port microphone assembly.