THE HUM FAQS (Frequently Asked Questions) by DR CHRIS BARNES GW4BZD


For Hum Science and much more.

  Pic  below show some Hum locations

1.    What is the HUM?

 The Hum is highly geo-sporadic and is also temporal sporadic

It is an anomalous sound heard or ‘perceived’  by  an estimated  2-11% of the population mainly at night, mainly indoors and in mainly industrialised countries, although a similar thing has been heard due to volcanic action in Hawaii.  Hearing maximises in the 50-60 yr old  age groups but the author is aware of people as young as 24 and as old as 78 who presently hear the HUM.  A striking feature of the Hum is that it can rarely be audio recorded, or at least the sound recorded does not properly mirror the sound heard.  This tends to suggest that some component of the Hum is not acoustic but this does not rule out infrasound or seismic vibration.


2.    What does the HUM sound like?

Any description of a perceived sound or noise has, by definition, to be purely subjective. Those who hear it describe it as like a throbbing diesel engine or a distant fly, bee or wasp trapped in a bottle.  Sometimes the sound is perceived as though it is just behind one ear. Sometimes physical vibrations can be perceived as well, particularly if lying in bed.  Sometimes the pattern heard is more complex and may sound almost like music, Morse code or digital code. Sometimes the patterns speed up and slow down other times they are constant. Sometimes the noise sounds more ‘digital’ like ‘phuts’ of pressure almost punching the ear drums with a very fast rise time. 


3.    What causes the HUM?

     In summary it is believed to be either an infrasonic phenomenon (a type of LFN) or more rarely in some individuals a magneto –acoustic or gravito –acoustic (seismic) phenomenon.    Infrasound can modulate other low frequency sound either in the ear (see Moller and Pederson 2004) or at the vibrating walls or floor of a building ( Dr Barnes private research), people with good low frequency hearing become aware of this in a quiet environment, sometimes referred to as a highly skewed acoustic spectrum (absolute quiet above about  200 Hz) ( see Vasudevan and Gordon)


4. What is the source of the Hum

     The latest conclusion of the present author is that the Hum is associated with renewable energy systems, especially although not exclusively wind energy. This does not mean to say that historic Hums or absolutely al Hums have this origin.

     At least for the Hum in North Wales and that reported on Forums in many places round the World, the Hum seems to show properties of being both natural and anthropogenic. This is not a conflict if the Hum is comprised of two or more signals which may or may not come from the same source but satisfy (3) above.   Neither is it a conflict because natural processes control the flow of both natural and anthropogenic sound through the air or seismic signals through the ground.  


     Thus the Hum could potentially involve modulation together of natural earth sounds, signals and fields with anthropogenic (person made sounds or signal fields) or in that it is intensity modulated or has occurrence times which are due to the propagation routes of the anthropogenic component(s) also depending on natural geo-physics and /or space physics processes.  


The author’s presently held Scientific opinion is that in its simplest form the HUM is caused by certain crucial combinations of infrasonic and acoustic sound and/or ground borne (seismic) vibrations present only at certain locations and/or in certain buildings (for an insight into how this could happen see ( Air–ground interaction in long range propagation of low frequency sound and vibration—field tests and model verification by Madshus et al 2005). Unlike Madshus whose paper deals with  one source the present author’s experience suggests that for the Hum it may be from more than one source* including  wind farms, power lines and gas mains behaving badly and including hydro power stations. Ground vibration in the Hum can be have natural causes or be caused by the same anthropogenic signals or even a.c. electrical ground currents causing seismo-electric mixing.


Wind farm emissions are known to irreversibly sensitise and alter ear physiology but sensitization of the ear to the Hum may only possibly include radio signals of various frequencies, Magnetic# and Electromagnetic fields may also feature but these are NOT usually the direct cause of the Hum but are merely catalysts for it.  Coincidently the Electricity grid could also be modulating the local gravitational field giving rise to infrasound.  Deaf people may hear the Hum through bio-magnetic or bio-gravitational detection. World electricity grids at 50 and 60 Hz may even interact in space to give a form of the Hum!!  

 * A classic proven case of this was at Kokomo where separate sources of 10 and 30 Hz were traced.  The laws of physics mean these would only produce the Hum at certain locations. 


# If you want to know if you are magnetically sensitive, try standing underneath high voltage pylons with your fingers poked firmly in your ears to cut off all external sound and see what happens, there should be a direction effect if you are .  Also you are more likely to hear the Hum in a parked car while the interior light is dimming if you are magnetic sensitive.

4.    How come I just started hearing the HUM?


It could be your age. The author’s hypothesis is that as our high frequency hearing sensitivity starts to fall off with age our low frequency sensitivity boosts up to compensate for it .  It could be you just moved house to a location which has the right frequency components for the HUM, SEE 3 ABOVE. It could be you just had double glazing fitted!

    It could be a new wind farm, factory, industry or power plant has opened up added a frequency component needed for the HUM.  Latest research suggests that even people in-between 24-41km from some wind farms may be affected by the Hum.   This may be either by infrasound or seismic vibration or both. There is scientific evidence to support the idea that people’s low frequency hearing threshold will become more acute when exposed to infrasound.  The author has now also shown some that certain radio frequency emissions may also sensitise the ear to the HUM BUT they are facilitators rather than cause.    So it could be a new cell phone mast, TETRA or TV or radio mast has just opened up.  Evidence is that most cases of the HUM are NOT due to radio frequencies alone come from the fact that hearers still hear it in  a Faraday cage.  But remember the magnetic vector potential can enter a Faraday cage


5.    Why do I only hear the HUM at night?


At night it is generally quiet there is less masking noise. There is less vehicular movement to ‘stir up’ the HUM.  Movement is important because if your Hum has more than one component these may each need to arrive ‘coherently’ (this means with their wave crests in phase or at the same time) for you to hear the Hum so moving cars and gale force winds etc. can disrupt this process 


6.    Why do I only hear the HUM indoors?


Your house acts like a giant acoustic sounding box. Double glazing and cavity walls actually make matters worse! Cavity walls may conduct ground borne vibrations such as those from idling trains in sidings and radiate them as infrasound and sound. Double glazing blocks off high frequency sounds but is next to useless with low frequencies below 150Hz. Chimneys and drain pipes may also enhance the Hum by a process known as Helmholtz Resonance ( rather like blowing over a bottle neck).    The floor and walls also act as converters which convert seismic vibration into acoustic sound.  

            Piezo -electricity in brick can also radiate 100/120 Hz mains hum as a very weak acoustic sound.



7.    Why don’t ear plugs work very well?


Ear plugs offer very little attenuation at infrasonic and low sound frequencies.  However, wax offers far more attenuation than foam at low frequency.

Natural masking noises the wind and waves or recordings thereof are much better.   Also in some cases you might find a combination of ear plug and radio frequency screening material even better. 


8.    Why does the HUM seem to vary with the weather?

The weather effects the way sound and infrasound moves through the atmosphere. If any of your HUM components are coming from any distance say 2-1000 km they WILL ALWAYS be changed by the weather especially winds.  The weather also effects ground borne vibrations. The weather affects electrical leakage currents in walls too.   Also the converse is true, weather has been shown to be affected by anthropogenic activity, and so is the Hum. In North West Britain, for example, it is more likely to rain on Tuesdays and Saturdays and strangely the Hum has been shown to peak on these days as well.      Atmosphere and Lithosphere are also linked through tides and space physics processes and control the flow of seismic signals as well.

9.    We had two feet of lying snow and the HUM went!

It sounds like your HUM is carried in a ground borne vibration or surface wave. The weight of the snow damped the vibration.


10.      Our HUM in the USA went after 9/11 when all aircraft were grounded!

This is a more difficult one.  Either your HUM is directly due to sound or infrasound generated by aircraft maybe you live under a corridor?  Alternatively and very importantly for things like wind turbine noise aircraft generate aerosol into the JET stream which changes the way sound travels from other sources.  When the aerosol and contrails went sound was conducted differently.


11.                  Do some geographies/geologies  favour the HUM more than others?


The HUM seems to be perceived in COASTAL regions and MOUNTAIN regions more than others.   In mountain regions there are natural sources of infrasound which could combine with weak acoustic sounds to produce the HUM.  Also Mountain and Hilly regions often have Hydro-electric power plants which could provide ground vibrations and they might have wind farms as well as the latter being in Coastal regions.


In coastal regions infrasound can also be generated naturally e.g. booming sand dunes but also from oil drilling, seismic exploration, super-tankers and wind farms.  There is often more railway (rail-road) activity too.  Idling diesel engines in sidings are a potential LFN problem in the UK.


12.   I still hear the HUM in an anechoic chamber!!

These are only good down to about 150 Hz. The frequency group which causes   the HUM is much lower than this.  


13.   I stopped hearing the HUM in a deep limestone cavern about 150 metres down.

It sounds like one of your HUM COMPONENTS is a surface acoustic vibration which will not penetrate so deep in the earth.  Also not many radio frequencies can enter here. You might still hear a form of the Hum in caves which have piezo-electric or magneto-stricitive rocks.


14.                 I hear the HUM louder when its night and I look outside!!!

You don’t say whether there are street lights.  This is a very hard question to answer anyhow but could be due to synthesesia  ( the brain handling duelled sensory input).   If your HUM is arriving partly from  atmospheric  c infrasound there will be ‘in- phase’ natural speckle of this in the optical background.  Your eyes sub consciously detect this ands duel it with the signal from your ears.   


If on the other hand you are looking at street lights there may be modulation of the light intensity by ground vibration or mains voltage/frequency fluctuation. If the  HUM you hear is PARTIALLY due to a vibration underground or a Power Generating facility the two might reinforce.    Alternatively again your street lamp might be acting as a plasma receiver for cell phone or Tetra microwaves and generating sound by the Zeeman Effect.


15.    I hear the HUM loudest when it’s a full moon!!


This might be due to more atmospheric speckle as in the answer above or it could be due to the effect on tide and tilt altering your local seismic propagation. (The way ground vibrations move is altered by the moon)

Also infrasound propagation in the Hum seems to depend on planetary cycles suggesting it is formed by a complex interplay of natural and anthropogenic (people made) processes.  For instance wind farms produce OAM under certain wind conditions which may eventually be proven to be linked with planetary cycles.


16.    My HUM gets worse before a big earthquake and goes away for about 24 hours afterwards.

Surface seismic waves ‘propagate’ or move through the earth differently according to how much stress is in the earth’s crust.  Their harmonic content is also different. Waves from hydro-power plants are susceptible to this and travel hundreds or even thousands of kilometres.  Your HUM is being affected by how much of this component you receive. The propagation of any ground borne vibration will be affected by the amount of stress in the earth’s crust.  Earthquakes and their pre-cursors also effect the amount of aerosol in the UTLS which is the region which can cause medium range wind turbine infrasound propagation ( 6-41km).   


17. I still hear the Hum in some caves?

These will be more likely caves containing piezo-electric or magnetic material (rocks or minerals).   

The Hum you hear may well be anthropogenic modulations of the earth’s super weak magnetic field.

If you are magnetic sensitive, external magnetic material will act as a kind of inductive matching system

between your bio- magnetite and the World outside.    


18.                 Can I get relief from the HUM?

You could move house but this sadly this drastic measure doesn’t always work. You could emigrate but as more of the World becomes industrialised particularly using renewable energy systems there are fewer and fewer HUM free locations.  You can use masking noises and relaxation techniques.  For some, long distance car  or airplane journeys induce a temporary deafness to the HUM lasting  48 HOURS or so for a 200 Km journey, the so called ‘holiday effect’ - well worth it, take one  now and again!