An acoustic module with a transducer and a solid waveguide. The transducer and waveguide may be curved to focus the acoustic energy along a focal line. The transducer, the top surface of the waveguide and the bottom surface of the waveguide may extend along coaxial curves. The waveguide may include a recess closely receiving the transducer. The waveguide may include an integral skirt that provides a thermal mass. The acoustic module may include a space to accommodate thermal management options. For example, the acoustic module may include a heatsink, an active ventilation system and/or a phase change material. The ultrasound device may include a controller configured to perform a uniformity scan sweep during supply of operating power to the transducer. The uniformity scan sweep can extend through a frequency range that includes the operating point of the acoustic module and does not exceed an acceptable efficiency loss.