I heard about this on the news on the way into work this morning. It struck a chord with me as I have been hearing a low frequency hum at night for the last couple of years.
I live in a rural area and have thought that I have either been hearing nocturnal farm traffic or the noise of a generator from a nearby (half a mile) battery farm. The common denominator seems to be that it happens on quiet nights when there is no wind or weather generated background noise. Once it starts, it keeps me awake unless I block the noise by listening to my itouch. The hum I hear is exactly as described in the article - the sound of a diesel engine on tickover, with phasing effects as if it is changing distance or location.
My wife is totally oblivious to the noise but having heard the news article too, now understands that I am not just going nuts - I have oversensitive hearing!
The HumCan anyone else hear the hum?
B
Posted on: 19 May 2009 by gone
I think 'the Hum' covers many possible background noises in the environment, as well as physiological symptoms, so it's difficult to generalise.
I had a low frequency noise problem years ago, which only appeared in the evening and the morning and was only audible in the house, and not outside, so we assumed it was something in the house.
After a lot of measurement, we found the noise outside too (it was only being amplified in the house by a room mode, but it was still only ~25dB at 37Hz) but we also found that it switched on and off fairly regularly, implying something man-made.
A long story, but we finally tracked it down to a boiler flue a couple of houses down, where a hole had rusted through the pipe, and created quite a nice organ pipe, which only fired up when the boiler was on (controlled by the thermostat). Easy to fix.
But I think we were the only people in the street who heard it. The local authority thought we were mad.
A simple example, I know, but there are so many possible sources, that I think it is impossible to generalise. For example, there are a lot of diesel generator sets sitting all over the country powering mobile phone masts, often in rural areas. But such noises are measurable, albeit with difficulty sometimes.
The unfortunate thing is that such things quickly become associated with other issues, such as 'noisy' windfarms, which really complicates the problem.
It's the ones you can't measure which must point to something physiological
Cheers
John
Posted on: 24 May 2009 by pjl
A fascinating article. I heard the hum back in the 70's when I lived with my parents in Birmingham. It was audible to me only at a specific point on the upstairs landing of the house. I agree with Nero in that I believe that their are many different explanations. In this case I believe it is possible that low frequency noise from a main road about a mile or so away somehow became focussed at that particular point in the house. It can often be extremely difficult to trace the source of such noise at it is able to travel for miles in the right conditions. So there may well be no obvious local source. As an illustration of this I well remember one Saturday evening at my parents' house when we were plagued with a very low frequency but clearly audible "thumping" sound. We searched the house and looked from all the windows in an effort to pin-point the source - but to no avail. We remained puzzled until on Monday a local news broadcast featured an article on an outdoor rock concert which was staged the other side of the city to where my parents lived, on Saturday evening. This had clearly been the source of the "thumping" sound, yet the location was about 10 miles away! Similarly, I have sat in my parents' garden in the past on a very still and quiet summers afternoon and have heard the sound of cattle mooing in the distance. They lived in the suburbs of Birmingham and the nearest countryside, just visible from my bedroom window on the horizon, was about 4 miles away. All this illustrates the capacity for sound to travel a considerable distance in favourable conditions. So if you do experience "the hum" be prepared to look anywhere within say a 10 mile radius to locate a likely source.
Peter
