Acoustic waves and Ultrasound are both sound waves. However, the waveforms and frequencies are different.  Ultrasound has a periodic oscillating wave with a narrow bandwidth and low-frequency range of 0.75-3 MHz. An acoustic wave is characterized by the rapid rise in higher with a mostly positive wave followed by a short tensile wave (negative tension). Ultrasound also has a thermal effect (heat); whereas, acoustic wave therapy does not.