In the oil industry, the acoustic sounding method is a well-known technique for taking the depth measurements of particular attributes of an oil well or borehole. The method involves sending a short, sharp, clear, loud bang sound down a borehole and recording the echoes generated. One device for generating the sound needed in the acoustic sounding method is an air or gas pressurized chamber which is discharged at or near the wellhead. The sound being generated by this device, commonly known as an acoustic generator, comes from the energy released by the equilibration of the different gas pressures. The current invention is an acoustic generator and its control unit that uses several new and novel features to improve the quality of the sound generated and echoes detected in the acoustic sounding method including a unique and novel design and configuration of the portal between the pressurized chamber and the borehole.