Debris found came from missing Titan sub, says friend of passengers
The most likely first failure is the window. At that instant a rapid turbulent fill event would occur. The outside pressure and the hole diameter will provide a calculable interval for the internal volume to fill. At 12,000 feet = 800 atmospheres, this would be on the order of 1&#x2F;20th of a second, with intense crush&#x2F;shear forces = instant death as perceived. That interval can be related to the speed of sound and wavelength to make a variable frequency &#x27;chirp&#x27; that would be of low to higher frequency. The low frequency would be in the low hertz as an estimate. At the same time inner pressure and temperature would rise to 800 atmospheres and a temperature a little above ambient. The density of water is around 800 times that of air = 800 times the weight of water would enter compared to the weight of the air within. Local temperature would prevail, increased a little by the work of compression of that air to higher pressure(quite high in concept, but quenched by 800 x mass of water.
Thus the sound will not be very loud or high in frequency.
A sphere of C4 will make a compression wave at somewhere over 500,000 atmosphere propagating at about 4000 meters&#x2F;second = fourier square wave containing all the odd order harmonics all the way down = heard round the world. Any transient inrush plasma would be swamped and mixed with cold water = transient and of little consequence.
Banging? One would hope nobody would dare bang the window, but it is conceivable they might have banged the hull in desperation if the window did not crack to attract attention? Did the noise cease at some point? or is the noise still hearable = not them?