More Important Evidence.
A German Hum researcher was recently given access to two insulated chambers, the first shields acoustic, electrical and magnetic signals.
The EM shielding works excellently for frequencies above 1kHz and the acoustic shielding is very good at all frequencies.
The second chamber was not built with acoustic shielding but does block most ambient noise and it shields all magnetic and electrical fields.
It has the best shielding standards in the world, no chamber has better data, neither the Earth's magnetic field or any EM is detectable within this chamber.
These chambers are most probably the quietest places on Earth and yet the Hum was "heard" in both.
This adds to the mounting evidence that the Hum is neither acoustic or electromagnetic and therefore must have some other cause.