Air duct as tuning mechanism and engine cover

摘要

A tuning device may include a tubular portion having a hollow cross section and a flat body portion covering an engine. The body portion may have a chamber disposed therein and a throat providing fluid communication between the chamber and the tubular portion. Air flowing through the tubular portion causes the chamber to produce interfering sound waves having a predetermined frequency. The interfering sound waves manipulate sound waves produced by the engine.