science4ever Posted July 28, 2013 Posted July 28, 2013 Some most likely say it is imagined and not real. it has gone on for some 50 years or so but seems to come rather randomly which makes it unpredictable. The Hum is a low freqency sound that is most easy to hear inside a quite room and it seems that you have to be past middle age to hear it. Could that indicate it is somethin in our body? Anyway those afflicted are very disturbed by it. Here is a typical Daily Mail retelling of it. It is late here now 10.20PM so I did not feel for finding the most scientific retelling of the story. The conspirators love to suggest wild sources for it. http://www.dailymail.co.uk/sciencetech/article-2380368/Can-hear-The-Hum-How-1-50-world-affected-low-droning-noise-scientists-explain.html So if you are a retired scientist and knows how to set up an acoustic dB meter and love to investigate things close to urban myths then this is the chance to make a different. I don't trust that I have heard it but what I have felt in my body is something very similar not a Hum but a low frequency that is only felt but not heard. Very low period. way below 20Hz I trust it was the plumbing in that house and when I moved to another house they had it too but several houses did never have it or very seldom. it always came at night or very early morning so I wild guessed it is the pumps that regulate the temperatur for the central heating in the house and that when cold water meet warm water the plumbing start to vibrate. so this could be something similar but at a higher frequency that is heard and not felt. So a good dB meter should be able to record it and show level and how it fluktuate.
iNow Posted July 28, 2013 Posted July 28, 2013 Isn't that just tinnitus? Maybe a laptop computer, or just an HVAC system?
science4ever Posted July 29, 2013 Author Posted July 29, 2013 Tinnitus is usually very high freqences way above 3KHz but whow knows some 2% may have an unusual variant with muscletension that couple to the eardrum and they maybe hear a lowfrequent hum then. But having gone on for 50 years i trust they would know if it is Tinnitus because usually one have that constant and this "Hum" comes randomly and last for a while and then is gone. So I agree it can be HVAC or why not a Truck or Lorry at a distance and the room accoustics resonate with that frequency of the motor and if it comes randomly somebody visiting and let the motor running while they eat their Fish and chips or Burger whatever and then drive home. I have heard cars that drive people home from late work and they sit a talk a while before the person step out and when the engine has low tourque? then it sometimes resonate with the room I sleep in and the volume get really high which is disturbing. So maybe that is the best answer.
Enthalpy Posted July 30, 2013 Posted July 30, 2013 Take a microphone, a headset, build an high-gain amplifier. If you hear the hum more loudly in the headset, then the source is not in you. Do you recognize the hum of a transformer? Just go near to one and listen. 50cm from a 1MVA transformer, or 50mm from a 100VA one - plaese don't forget the insulation.
Griffon Posted July 30, 2013 Posted July 30, 2013 (edited) I experience something like this from time to time. It's a bit like there's a big stationary lorry up road with its engine idling. The frequency is just too low to hear. I sort of feel it. Odd. I also hear it intermittently in pubs too. No funny comments please! But I put that down to some kind of pump perhaps. But it tends to go on for sometime, 20 minutes perhaps. Then I'm aware it's stopped. It's quite unpleasant in fact. Almost like my head is being pummelled. Mind you, I'm increasingly getting tinnitus too as I get older. Most of the time I just ignore it. Edited July 30, 2013 by Griffon
science4ever Posted July 30, 2013 Author Posted July 30, 2013 I experience something like this from time to time. It's a bit like there's a big stationary lorry up road with its engine idling. The frequency is just too low to hear. I sort of feel it. Odd. I also hear it intermittently in pubs too. No funny comments please! But I put that down to some kind of pump perhaps. But it tends to go on for sometime, 20 minutes perhaps. Then I'm aware it's stopped. It's quite unpleasant in fact. Almost like my head is being pummelled. Mind you, I'm increasingly getting tinnitus too as I get older. Most of the time I just ignore it. Much appreciated you shared this. My Tinnitues is two or three high pitched noisy "tones" way about what musical instruments play. Higher then the highest note on the Piano. These two or three tones are close to each other so they create a low freq wobble and they change in phase or pace with the heart beat so I wild guess one hear the flow of blood in the ear??? So like you noticed the only way to get "rid of it" is to ignore that it is there. If one are lucky then after some minutes one don't notice it anymore and suddenly get aware of it hours later. But it sure is there all the time. Very hard to wild guess at what internal dB level it is . The volume is rather annoyingly high. could ot be 35 to 65 dB? How can one find out? Thanks also for the suggestions from Enthalpy on eliminating some sounds by using recording way away from the body. Yes I know much about hum from transformers and from fans too. I worked for a few years as a Radio Repair Assistent helping the Master out in a local shop. When the capacitors got old the hum from the power supply got really annoying so they came to us and we desoldered the old and put a new one and it cure it. I don't know if we have the "Hum" in Sweden. But like Griffon point out it sure could be a big Lorry parked well away for the higher overtones to not reach the room but the low frequency below hearing is strong enough to travel hundreds of yards without much attenuation and is felt like a vibration. i've heard that the extreme low freq "Bangs" of the very big airplane from Paris to New York? Concorde? that bang can be seen on good measurements all over Europe so extreme low frequences travel many hundred of miles. Big twirly rivers can give noises that travel far too. So to find the source for the Hum can be challenging? I shared it here more as an amusement to dream of solving once for all. There are so much wild speculation about what it is. Communication to Sub Marin boats? whatever people has wild fantasies.
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