What is the Hum and why is it so random and geo-sporadic?  By Dr Chris Barnes Bangor Scientific Consultants www.drchrisbarnes.co.uk   email scienceconsultants@yahoo.co.uk





The nature of the Hum is briefly reviewed. A strong hypothesis for the Hum (type 3) as a magneto-acoustic effect is advanced.  Only by using such a hypothesis in conjunction with one in which allows the generation of the Hum signal to be due to a combination of natural and anthropogenic processes can one even begin to explain how the Hum is perceived and what has been even more perplexing for others that is its  very geo-sporadic nature.




The Hum (type 3) (ref) is a highly subjective, geo-sporadic, magneto-acoustic phenomenon which afflicts an estimated 2-11% (ref) of the adult population. Those afflicted mainly but not exclusively describe hearing a noise like a distant possibly misfiring diesel engine. Their experience is usually, but not exclusively, worse in the dead of night. Reasons for this are explained elsewhere (refs).  The Hum (type 3) is more than just a simple noise and cannot readily be audio recorded (refs).  It is possible however, that   those who are sensitive to Hum type  3 may also be sensitive to infrasound and low frequency noise separately manifest ( Hums type 1 and 2) (refs). For most afflicted people the Hum appears to be significantly amplified by buildings (refs) but these must be complete i.e. have roofs and be connected to the utility services (ref).   Most people afflicted by the Hum are aged between 50-60 years but the author has a son who began hearing the Hum aged 24 and has had personal communication with three female subjects in their 30’s who also perceive the Hum. Personal experimentation of the author tends to suggest that modern pulsed electromagnetic technologies may be sensitising people to the Hum i.e. they are a possible pre-cursor but not the cause.   Another interesting facet of Hum sensitisation is that the majority of people interviewed by the author who experience the Hum had also survived earthquakes a few years previous.   


Magneto-acoustic hypothesis

Some studies in the USA and Germany claim that certain ‘Hummers’ ( the colloquial for people who hear or perceive the Hum) are  able to hear the Hum inside anechoic chambers and Faraday cages(refs) .   Much has been made of this in some pseudo-science quarters with claims that the Hum is somehow associated with a supernatural force field.   However, a little critical thinking leads to a much more down to earth hypothesis.    Anechoic chambers are only good down to about 150 Hz so short of sealing people inside a vacuum chamber once cannot preclude an LFN or infrasound component to the Hum no matter how subliminal. A Faraday cage will screen out high frequency electromagnetic waves but cannot block static or slowly varying magnetic fields.


It is possibly reasonable then to assume that those afflicted by the Hum in general (all three types) are sensitive to LFN, infrasound and/or magnetic fields.   


If the majority of Hum cases were simply due to LFN then it is the present author’s opinion that far more such cases would be readily solved by environmental health investigators.  In fact this turns out not to be the case.  As far as the author is aware only three such cases Worldwide have had such simple explanations.  These include the Hawaii volcanic Hum, the Kokomo Hum and a case documented in the journal Noise and Health (refs).


Both the author and his wife are Hummers and they together with a lady subject afflicted by the Hum in South Wales describe and anomalous Hum-like perception whilst sitting in a motor vehicle after parking and switching off the engine which is accentuated by opening and closing doors and seems to persist for the duration of dimming off the vehicle’s interior light. It is not known if all Hummers experience this effect but since this is fairly crucial to supporting the present hypothesis any feedback and comment would be most welcomed.  The Hum like effect experience is similar to but not the same as the Hum in houses per se.   The fundamental difference is that the motor vehicle hum has a regular beat whereas the Hum in houses has a quasi-periodicity.  The hypothesis for the vehicle is that somehow the vehicle ECU and PWM control circuits generate a periodic magneto-acoustic signal. Both very weak acoustic and significant magnetic comb spectra have been recorded inside vehicles under these conditions with fundamental frequencies of a few Hz and these results have been published elsewhere (refs). Inside the vehicle the magnetic field fluctuates between about 2 and 8 milli-Guass, maximising near the ECU and vanity light.  It is postulated that this manifests a form of Hum type 3 wherein the acoustic and magnetic signals have a distinct phase relationship with each other and that Hummers can somehow detect this by a synergistic combination of the senses.         


So magnetically sensitive is the author that he can even perceive the 100 Hz magnetic field from high tension power grid conductors usually at a potential of 132 KV or 400 KV and at magnetic field strengths between 3-12 mG.  The experiment is simply to walk immediately under power lines and force ones fingers in ones ears to the point where all background noise is totally screened out. One then aligns oneself ear to ear looking forward with a gaze orthogonal to the run of the conductors and listens very carefully. One then rotates through 90 degrees. In the first instance a magnetically sensitive individual will perceive a very weak 100Hz Hum which will vanish upon rotation.  


Regarding Hum type 3 in houses this simply needs extension of the above hypothesis.  Weak acoustic components must be conducted into the house through its fabric and they must have some sort of pre-determined phase relationship with the magnetic fields present.   There are numerous avenues for the condition of both fields which have been discussed by the author and others elsewhere (refs).  


  Explaining the Hum’s geo-sporadic nature.


There has been massive debate over recent decades on the origins of the Hum. Is it a natural or an anthropogenic phenomenon?  The author has published data which shows at least for the Bangor Hum this must be an anthropogenic phenomenon because it varies with day of the week (REF).

Similarly if one plots the aggregated number of unsolved Hum cases reported in the press in the UK and Eire over the past four decades it would seem to be increasing in accordance with the amount of energy production ( unpublished data of the present author) this again strongly supports an anthropogenic cause.   


However, one can equally produce statistical evidence which to some extent, if not completely, supports a natural cause for the Hum.



























Table 1


For example, table 1, above, shows the number of most highly disturbing Hum events in Bangor on a monthly basis over the last 7 years.   If the Hum were due to a natural process such as seismicity this is known to peak around the equinoxes (ref).  There is indeed a peak at the equinoxes but there is also an unexplained peak in July.   The author (refs) and others (John Dawes (refs) and Vic Nixon (refs)) speculate that the Hum is due to power systems. Certainly in the UK there would be expected to be less demand for electricity in July and possibly therefore more surplus radiations to space and ground  and/or more available for Pumped Storage (HEP) generation, also cited by the present author as having direct involvement in the Bangor Hum.    


Natural seismicity creates both seismic and acoustic vibration and electromagnetic signals in the earth and rocks.               One would have thought however those humans would have adjusted to these signals over evolutionary epochs and would not be unnaturally sensitive to them, except perhaps just before an earthquake. There are documented cases of animals showing such sensitivity.   However,   if these signals are disturbed or modulated by power flows from other sources and if such power flows themselves contain implicitly linked magnetic and acoustic components   then we have the Hum type 3!    


Keeping this complex web of interaction in mind, it now becomes possible to explain the geo-sporadic nature of the Hum.  For example virtually anything which interferes with either natural geo-seismic power flows and/or their modulating anthropogenic signals has the potential to initiate, modify or terminate the Hum in one particular locality.      


Apart from natural planetary cycles geo-seismic power flows will be influenced by space physics processes due to earth-atmosphere-lithosphere coupling (refs). At ground level such processes will be influenced by rainfall and the depth of the water table.  So for instance person made changes to the flow of a water course or underground water course may be sufficient to instigate the Hum or terminate it for that matter.  Similarly, tunnelling or the filling in of old tunnels may have effect.  It has also recently been shown that changes in the electrical resistivity of the earth’s crust exhibit a synchronised periodicity with seismicity (ref).


As for the modulating anthropogenic signals themselves, the World’s power grids and generating stations remain the strongest source of magneto-acoustic signals but ships at sea (refs) and aircraft (refs) should also not be ruled out.  Particularly with respect to power systems anything which affects or alters ground currents in a locality may be sufficient to bring about, reduce, enhance or terminate the above described modulation interaction from which arise  Hum type 3. Such actions, and the list is by no means exhaustive, might be abnormally increasing or decreasing   load on a section of power grid, increased provision of wind power or solar PV power, or PLT, all three notorious for DC injection, pulse injection  and phase imbalanced ground currents, and finally changes to other infrastructure along which induced currents flow or which alter the electromagnetic field distribution in the earth can have effect; for example changes to water or gas mains changes to railway infrastructure etc. etc.   Such changes can potentially even be perceived as being as subtle as changing a section of iron pipe for one of plastic or vice versa!  It should not be forgotten that many of the changes described above that effect ground currents also change acoustic power flow and in the earth and rocks the two are virtually inseparable due to the Tolman-Stewart effect (refs).




A strong hypothesis for the Hum (type 3) as a magneto-acoustic effect has once again been advanced.  Only by using such a hypothesis in conjunction with one in which allows the generation of the Hum signal to be due to a combination of natural and anthropogenic processes can one even begin to explain how the Hum is perceived and what has been even more perplexing for others that is its  very geo-sporadic nature.


Sadly the Hum is indeed a facet of modern living.  The only main hope for sufferers is perhaps to explore the biology of magneto-sensitivity in man. In the meantime sufferers are advised to use ferrite loaded wax earplugs and sleep in mu –metal enclosure. Sadly neither of these are very practical.