Shock wave cannot travel any further upstream and the pressure progressively builds in that region; a high pressure shock wave rapidly forms. Shock waves are not conventional sound waves; a shock wave takes the form of a very sharp change in the gas properties. Shock waves in air are heard as a loud "crack" or "snap" noise. Over longer distances, a shock wave can change from a nonlinear wave into a linear wave, degenerating into a conventional sound wave as it heats the air and loses energy. The sound wave is heard as the familiar "thud" or "thump" of a sonic boom,
Acoustic shock Acoustic shock Acoustic shock is the symptoms a person may experience after hearing an unexpected, loud sound. The loud sound, called an Acoustic Incident, can be caused by feedback oscillation, fax tones, or signalling tones. Telemarketers and call centre employees are thought to be most at risk. During the exposure, most people will experience discomfort and pain. After the exposure, some people might report shock, nausea and anxiety or depression. Headache, fatigue, hypersensitivity to loud noise and tinnitus may continue for days, weeks or indefinitely. It has not been established how such unrelated symptoms might be caused by an acoustic