What's at play is the sampling theorem. Using instantaneous shutter, considering the speed of sound is very high*, every part of the image is resonating essenti

What's at play is the sampling theorem. Using instantaneous shutter, considering the speed of sound is very high*, every part of the image is resonating essentially the same sound; the sampling theorem says you can only perfectly reconstruct up to F/2 hertz if you sample at F frames per second. The rolling shutter introduces regular variations at at much higher frequency, allowing much better sampling. - Actually, doing a quick calculation shows that at 1khz a 1/2 wavelength is just 17cm. I wonder how precise spatial scene/source information has to be to allow this diversity to contribute significantly to the sampling. If you had a planar source and precisely spaced two objects it shouldn't be too hard to increase spectral resolution. The complementary possibilities are also be interesting -- with precisely laid out N objects and a good spectral resolution for each afforded by the shutter you could perhaps resolve the sound into N distinct sources, allowing to determine the origin of the sound; with precisely known source locations you may be able to extract some object location information.