Abstract: A sound source capable of generating high energy acoustic pulses is lowered into a well borehole. A chamber of high pressure air in the source provides the energy for the pulses. A firing mechanism in the source is armed using increased pressure on the drilling mud in the well borehole. The pressurized mud is stored in a chamber in the source having closable ports. When the firing mechanism is operated, the ports are open, forcing the mud from the source into the borehole mud column and causing a cavitation zone in the mud at the ports. When the cavitation zone collapses, an acoustic energy pulse is formed. Pulses may be formed in this manner at the same depth or a number of depths in the well bore during a single run of the source in the well.