Maghister thing is dithering typically means introduction of random patterns as a way to simulate greater detail.You know much than me about dithering i will not contest that at all...
Schumann as I understand it is a resonance...not a random pattern.
So the two would seem to be totally different.
But is the imprecise varying frequencies of the cheap S.G. around a theorical 7.83 Hz but being more an oscillating device around 4 hertz and ten hertz with their harmonics dont mimic a random pattern effect on the homogenuous noise level of the house?
I ask the question?