An ultrasound apparatus capable of mixing and/or atomizing fluids is disclosed. The apparatus includes a horn having an internal chamber through which fluids to be atomized and/or mixed flow. Connected to the horn's proximal end, a transducer powered by a generator induces ultrasonic vibrations within the horn. Traveling down the horn from the transducer, the ultrasonic vibrations induce the release of ultrasonic energy into the fluids to be atomized and/or mixed as they travel through the horn's internal chamber. As the ultrasonic vibrations travel through the chamber, the fluids within the chamber are agitated and/or begin to cavitate, thereby mixing the fluids. Upon reaching the front wall of the chamber, the ultrasonic vibrations are reflected back into the chamber, like an echo. The ultrasonic vibrations echoing off the front wall pass through the fluids within the chamber a second time, further mixing the fluids.