A respiratory therapy device including a housing, a flow diverter structure, a high frequency pressure port (HF port), and an entrainment port. The housing defines a primary passageway having a patient interface side. The flow diverter structure is in fluid communication with the primary passageway and is characterized by the absence of a venturi tube. The HF port is configured for fluid connection to a source of oscillatory gas flow, and is fluidly associated with the flow diverter structure. The entrainment port is openable to ambient air, and is fluidly associated with the flow diverter structure. With this construction, the device is configured such that flow characteristics of gas flow from an external source are altered upon interacting with the flow diverter structure to create a pressure drop for drawing in ambient air through the entrainment port in delivering a percussive pressure therapy to the patient side.
