A sonic boom is many sound pulses arriving simultaneously

Evidence

At Mach 1.0, the object is traveling at the speed of sound, and a shock wave piles up in front of it. This was one reason that flight was thought to be difficult at or beyond Mach 1.0, before the sound barrier was ever broken. At Mach 2.0 and 4.0, a cone-shaped shock wave is produced, the envelope of many adjacent waves adding up. The observer at R hears silence and then a loud bang, the accumulation of many pulses arriving at the same time. It is easy to show that the angle α between the path of the object and the shock wave is given by sin(α) = c/υ, where c is the speed of sound, and υ is the speed of the object (see figure 7.32). — Eric J. Heller, Why You Hear What You Hear- An…, 637

Categorization

• DEFINE: Disambiguates the sonic boom: not a single blast but the coincident arrival of accumulated wavefronts, with a compact formula for the shock cone angle.