Improved approaches to providing a sealed acoustic chamber (e.g., a back volume) for an acoustic component (e.g., speaker) resident in a compact portable electronic device are disclosed. In one embodiment, a compact portable electronic device includes an internal module (or housing), such as an optical camera module that includes optical components, which contains a module volume. The module volume can be provided with a port (e.g., opening) but is otherwise a substantially enclosed (e.g., at least substantially sealed) volume. By acoustically coupling the acoustic component to the port, the module volume can be used as some or all of the back volume for the acoustic component. Advantageously, a compact portable electronic can provide quality acoustic audio output while requiring only a limited amount of dedicated space.