I too believed it to likely be of an acoustic nature, that is until I had an acute episode of it that was so instantaneous and so loud as to, in my mind, convince me that an acoustic cause could not explain what I experienced while sitting in my home of several years, with the windows closed, with no traffic on the street. I never heard the HUM with any intensity at this location before, only became beset with symptoms after they installed a Cell Phone Tower down the street from here. I have a degree in electronics, what I experienced sounded like something one would expect from a modulated source, very deep, very loud, and warbling up and down at a rapid rate. Nothing I can think of in nature or in my experience with motors and the like would explain what I heard.
Even though people claimed to have recorded it, and I cite the Tom Moir Hum Recording (supposedly an actual recording) as being closest to the sound that I hear in the country, it does not explain what I hear in the city.
And for the audio, what is the source? I hear the HUM in the country when it is quiet, yet when I am around items that one may attribute to causing the HUM, such as Fans and the like, I don't hear it. I think it's unlikely that the source will be a simple audio created by modern devices. Plate Tectonics perhaps, gravity waves, but not simple noise from fans and motors. (In my humble opinion).
I have tried, in the country, to equate distant fans as the source, but, unlike the HUM, I can always find the general direction of the source of the sound. The HUM seems to be ubiquitous. It sounds the same near our country home as it does 60 miles away in an adjacent state.
I think that as HUM hearers, we must always remain open to other possibilities for the HUM, and the possibility that what some people may perceive as the HUM may not be perceivable to other HUM hearers. Looking for a "one size fits all" solution may delay important discoveries concerning the HUM.
--- In email@example.com, Tobypaws2002@... wrote:
> In a message dated 13/11/2008 09:38:35 GMT Standard Time,
> resonantworks@... writes:
> it is unlikely to be of an audio nature.
> Well I have recorded 'my' Hum easily,
> on analogue and digital recorders.
> I compared 'no hum' with 'high hum', and the difference is unmistakeable.
> I conclude that different people may be hearing different things.
> We cannot say that it is one thing or the other, without visiting each hearer
> and measuring what is there......
> It's very difficult to compare sounds on just what people describe.
> Maybe some people can hear radio waves, I don't think so,
> but naturally no-one really knows what may be possible.....
> I am convinced that MOST hums WILL turn out to be audio....
> this is from my contact with hundreds of hearers....
> Best Wishes,
> LFNS Helpline, England.