As I understand it, when an object pushes past the sound barrier, a sonic boom doesn't happen just once, but rather, continually (correct me if I'm wrong). So why is it that there seems to be only a confined, cracking bang instead of a gradually crescendoing booooooooo...m sound, building in intensity until the object passes and then gradually decreasing, sounding more like a long continual "tearing" sound?
Conceptually, I'm visualizing it like a boat moving through water, eventually moving fast enough that it pushes beyond its interference rippling, creating a wake behind it, the wake being one continuous wave. Imagining an observer up ahead seeing the boat coming, they would also be able to see the boat's wake coming, increasing in size and intensity, and then diminishing once the boat had passed, until it gradually disappeared.
So why is it that a sonic boom seems to be a digital/discrete/binary occurrence rather than an analog of continuous sound?
Bonus question (can post separately if necessary):
If a sonic boom is relative to the listener, does that mean that there's an infinite number of boom-boom-boom-boom's happening as it moves? E.g., if a supersonic plane flew past and I heard its boom directly above me, wouldn't my friend 100m further up ahead also hear "my" boom, as well, though diminished? Would they not get their own fresh boom when the plane passed over them? How far away would a listener have to be in order to hear their own "fresh" boom (...not an actual question, just conceptual to paint a picture of how I'm currently (mis)understanding it)?