Accounting for the Bangor Hum and can there be any useful generalisations made which would assist Hum studies Countrywide.


By Dr Chris Barnes, Bangor Scientific Consultants   e-mail

Homepage for all my interdisciplinary research



 Additional measurements are made of the Hum in the Bangor area using magnetic field, acoustic spectra, magnetic spectra, and Wall voltage spectra. It is apparent there are several different modes of the Hum i.e all of which produce a Hum like perception in the two subjects of the investigation. It would seem at least in the author’s residence some of these modes may be associated with instability of the   electrical power grid and with the possibility of parametric conversion.   




The author and his wife moved to their present address some eighth years ago. The previous house had a very noisy night-time environment there was an industrial compressor near by and hospital air ambulances working most nights so it is unlikely either of us would have heard the Hum.  The present house was initially single glazed and again quite noisy at night living near to student accommodation.  After double glazing was installed the author’s wife complained of a buzzing noise at night which the author was unable to hear. However, after a further two years the author started to hear the noise.  Mutual agreement was reached on the detail and quasi –periodicity of the sound perceived and research commenced which led us to believe we were hearing what is commonly described the world over as the ‘Hum.’


The author has since published extensive works on the Internet on the subject of the Hum. The author concludes, by both personal experience and by his studies of the anecdotal reports of others, that generally and World wide there may be more than one type of Hum with more than one cause.    In brief these are believed to be;


1.      Natural infrasound e.g. Volcanoes (

2.      Anthropogenic infrasound and LFN

3.      UHF/ Microwave radiation (microwave hearing with or without dielectric resonance effects)

4.      Low frequency magnetic often associated with comb spectra (quantum biological detection)  

5.      1 and 2 sensitising the auditory apparatus for 3 or 4 or vice versa

6.      Some combination of 1-5above not excluding the possibility of Bragg Matching and/or coherent detection


The author has experienced 2, 3 and 4 personally and has reported on 3 and 4 elsewhere (refs). 4 will also be reported on briefly here below.  However, on this occasion we are restricting discussions mainly to the Bangor Hum (as perceived at the author’s residence) and since on most occasions this hum can be reduced or stopped using ear plugs the rest of this paper will be restricted to discussions of 2 above. Regarding the likely source(s) of the Hum information can be gleaned by looking at the available spectra, which have been recorded at the author’s residence.   What is most striking is that in the author’s home the infrasonic and LFN spectra almost mirror the magnetic spectra that in turn almost mirror the ‘wall voltage spectra’   where the wall voltage is defined elsewhere (refs).


Properties of the Bangor Hum


1.      Is intermittent

2.      Has a vertical component

3.      Has horizontal components from more than one direction

4.      Is sometimes manifest when there is FM on 50 Hz and pulsed harmonics on mains 

5.      Is often associated with appearance of inter-harmonics on mains

6.      Infrasonic and LFN spectra almost mirror the magnetic spectra which in turn almost mirror the ‘wall voltage spectra’ in range 0-300 Hz.


In more detail the Hum as perceived by the author and his wife can often be heard to switch on and off. It very commonly switches on at circa 2300 hours. Sometimes in the dead of night the switching on and off of the Hum is accompanied by a seismic jolt, in which parts of the fabric of the house appear to creak, personal experience. 


The author conducted a simple experiment using an incinerator lid as a directional acoustic antenna and established at least one component of Hum directivity (ref).   The Hum must have some coherent components as it can be deadened by blowing winds or incoherent sources of selected speeds (ref). Indeed a previous publication by the author (ref) shows that the Hum can have components related to power line harmonics and/or infrasonic components, the latter at first sight thought not to be related (ref) but we should keep an open mind on this!  Vehicles moving along the road also deaden the Hum for a few seconds.  This could happen by disturbing a surface wave or a ground propagating wave or simply producing a competing signal for the ear with a longer latency period.  From the above there is a strong suspicion that the Bangor Hum is somehow and sometimes associated with the electricity generation and supply industry.

Indeed infrasound has been recorded at the author’s residence which seemed to turn on and off according to the use of different combinations of motor-generator sets at Dinorwig hydroelectric plant (refs).


Of paramount importance is the observation of the frequency spectra of the wall voltage and magnetic component being almost identical.    To conventional Physicists, Engineers and Lay people this may seem somewhat unusual. Indeed to Dawes (ref) the very notion of his wall voltage has led him to conjure up theories of electro-gravitation in an attempt to explain the Hum.  Such elaborate theories are simply not needed. All we need to do is to look to Geological science for the answer.  It is very instructive to look in Geology the process of electro acoustic logging. Here an electromagnetic source elicits an acoustic response from say a fluid filled borehole.  The paper of Hu et al (JASA 122 (1) PP 135-145, 2007) is most instructive. Next all we need to do is take the electromagnetic field from power lines into the equation and perhaps also Schumann Resonances and hey presto we have the answer. So much so in fact that Hum signals are actually in themselves used for Geophysical Prospecting!

Although the author doubts if the inventor would have been a ‘Hummer’, see US Patent 7,227,362 B2.  In fact since the seismo-electro-acoustic effect is a reciprocal effect alternating pressure waves not associated with the electricity grid can also create voltages in soil, rock, stone, brick or other porous material wherever we have an electrical double layer. Are we not indeed also talking mechanoreceptors of the cochlear and skin for example?      


A very commonly reported facet of the Hum is that it is sometimes just that! Sometimes people report anecdotally they perceive a constant Hum whereas at other times their perception shifts to that of a quasi periodic signal sometimes harsh and disturbing other times quite gentle and almost with the properties of a lullaby. Even the author has had first hand experience of such effect.  The frequencies commonly reported are tone matched by so called ‘hummers’  at 30-80 Hz  (ref) with quasi- periodicity form 0.5 to about 5 Hz.     If the Hum is then associated with the power grid as first suggested by Dawes (ref) and more recently by Cowan (ref) there may well be more than one type of instability which gives rise to different people’s subject experience. Such instabilities have been known at UK hydroelectric power stations in the past, in particular the Dinorwig plant  (Mansoor et al, Control Engineering Practice 8(11) pp 1261-1272, 2000).  


To test our hypothesis we should look for such features with and without the Hum present but we should always bear in mind that at low frequencies the ear is very non-linear (ref) and we should also bear in mind a construct that the ear can make between higher frequencies in a partial harmonic series known as ‘missing fundamental’ (ref).  Finally we should bear in mind that room resonances can amplify beats between apparently very low level narrow band signals. In this respect, many environmental health departments draw a blank in Hum investigations because few have access to narrow band monitoring systems or acoustic spectrum analysis and credit is often not given by the medical establishment that some people can hear at infrasonic frequencies.      


The final question is do we need to restrict ourselves to just earth bound sound and vibration or could Schumann resonance and PC1 pulsations be relevant and power line harmonics travelling into space at kilohertz frequencies.  We can test all of this in spectra obtained magnetically and from the wall voltage and from magnetic and acoustic measurements at fixed locations or in the field.    


A weekend of experimentation


The period of summer 2011 has seen new Hum reports arising in the UK in Woodland Teesside and also Bolton Lancashire (the


The period of 19th-22nd August 2011 saw a tremendous intensification of the Hum in Bangor. It has severely interfered with the sleep of the author and his wife. 


In the ‘fight back’ a brief but intense period of experiential investigation has been conducted.


Experimental methods and apparatus.


Wall voltage spectra, magnetic spectra and acoustic spectra were recorded initially at the author’s residence using an Acer laptop computer and the spectrum analysis program known as Spectrum Lab.   Full details of these techniques have been described elsewhere. Measurements were taken at various times throughout the period at times when the Hum could be perceived and when it could not.




Full frequency spectra plots will be added to this paper in due course but for the convenience of the scientific community and in order to bring sanity to Hum sufferers it is being published initially without i.e. in ‘beta form’.


What is very clear from the results is that there is more than one set of conditions which gives rise to an acoustic/infrasonic form of the Hum even in the author’s residence. There is no reason why this should not apply nationally or even globally. If one ascribes all of these conditions to the electricity grid it ought to be possible to find the same or similar spectra by moving to locations much closer to it.


One thing which has been noted which was not noted in previous studies of the Hum at the author’s residence is that 50 and 100 Hz audio tones appear to come and go at different times of the day.  If either of these beat with nearby acoustic frequencies from whatever source say at +/- 8 to +/-15 Hz away then hum like effects are experienced. Sometimes the 50 Hz tone appears to be accompanied by acoustic frequency tones at circa 42 Hz, 55 Hz or 60 Hz. It is not known if these are inter-harmonics of the electricity grid or from another anthropogenic source or could they be related to Schumann resonance?  Thus further investigation is under way. On other occasions there is rapid FM on the 50 Hz magnetic signals. On other occasions there is pulsation on the higher harmonics.


Finally there are cases when the Hum is heard when there is strong infrasound around 17 Hz and 30 Hz. Since these frequencies seem at first sight unrelated to the power grid it is tempting to ascribe them to something else. However further experimentation reveals something unexpected!            




 Experiments near power lines


            In the light of the above it was decided to visit a site where the Hum had been heard very loudly in a car underneath National Grid Single Circuit Super Grid conductors.  The site is located between the villages of Tal y Bont and Llanllechid a few kilometres to the South East of the author’s residence. This is a point wherein the 400 KV super-grid,  a MANWEB 132 KV  circuit and a MANWEB 66 KV circuit all run more or less parallel but separated by a few hundred metres. The 400 KV and 132 KV circuits link Pentir Interconnector to Deeside (ref) and operate close to maximum power flow capacity. There are known transient stability issues within the North Wales Group (


On Sunday 21st August 2011, the first visit was made. At circa 8-40 am the Hum was so loud it could be heard in the open air for several hundred yards between the Supergrid and the 132 KV grid.   The field as measured in the car was 29 milliguass under the Supergrid and varied between 8- 14 mG in the surrounding area.


Since it has been anecdotally reported that some individuals perceive a Hum by non-acoustic bio-detection, the author first made an attempt to see if indeed this was possible bearing in mind there are theories why it ought to work (refs).


The author stood immediately under the super-grid with his fingers firmly blocking his ear canals and he ''listened''. The weather was cloudy and slightly damp but not raining. Corona noise could be heard from a more distant insulator. The author then blocked his ears. Absolutely nothing could be perceived. The same went for the 66KV grid.    However under the 132 KV grid a very weak continuous hum (not quasi-periodic) could be perceived with the axis of the author’s ear canals aligned parallel with the lines, i.e. standing looking in either of the two directions orthogonal to the run of the lines.    The hum disappeared when turned the head or whole body at right angles. The field was 10 mG. There was no corona noise from either of the other sources when listening normally.



On Monday 22ND August further power line experiments were performed, at 8am. Magnetic and acoustic frequency spectra were recorded midway between the super-grid and the 132 KV circuit.  The magnetic spectra revealed a strong 50 Hz component as expected but also a very peculiar pulsating component at 180 Hz!


In the acoustic spectrum a lot of infrasound was present, a signal at 50 Hz and the usual nearby signals described above. 


Acoustic spectra were then recorded immediately underneath each set of power lines in turn.   Each yielded strong dual component infrasound with peaks at approximately 17 Hz and 30 Hz by far the strongest underneath the super-grid conductors.   The weather was dry and sunny with a temperature of approximately 14 Celsius.  No corona noise could be heard.


On the return to Bangor measurements were made at various random locations.  The Hum could be heard at all locations and the two infrasound components were present at variable levels but never less than 5dB or so than directly under the 400 KV circuit.


The Hum persisted until about 8-50 am and  coincident with the disappearance of the Hum an acoustic measurement back at the author’s address at circa 9-30 am showed an almost clear acoustic spectrum and only 50 Hz present on the magnetic spectrum.  



On Wednesday 24th august 2011 at about 3 pm an attempt was made to reproduce the power line experiments of Monday's experiment. A visit was made to the same section of Supergrid network near Llanllechid in Gwynedd and also measurements were obtained under a section of Supergrid at LlanfairPG on Anglesey, connected the the Llanllechid network section via the Pentir Switch Station. On this occasion slightly different and slightly less intense acoustic spectra were recorded. At Llanllechid there were two sub-harmonic frequencies of 16.7 Hz and 25 Hz together with an inter-harmonic frequency of 33.33 Hz.

At Llanfair PG a much more complicated spectrum was found. There was an ill defined band of low frequency infrasound between 5-12 Hz, some audio at the 50 Hz fundamental in addition to the same sub and inter-harmonics noted at Llanllechid. There were also some other weaker acoustic signals at circa 23, 36 and 44 Hz of unknown origin.



Discussion of the results 


It has been shown fairly conclusively that the electricity distribution industry is responsible for the Bangor Hum. Previous publications of the author have speculated a connection with the Dinorwig pumped storage scheme.    The Dinorwig plant is used for frequency control all across Britain and is connected thereto via the power grid investigated so there is a possibility that other current manifestations of the Hum may be related.  Maybe the instability at Dinorwig has returned; see (Mansoor et al, Control Engineering Practice 8(11) pp 1261-1272, 2000).  


Whatever the cause, there is some exceptionally interesting science at work here. The grid either locally or globally appears to be behaving as a parametric frequency and acousto-electric energy converter.


For instance the result of August 22nd at a magnetic frequency of 180 Hz – 3x 50 Hz = 30 Hz (yet observed as sound rather than electromagnetism)


50 –3 =approx 17 Hz again observed as sound!

The involvement of 180 HZ is interesting. Could we have coupling with the US power grid via ionosphere pumping?  Certainly higher order power line harmonics have been detected in space (refs) and 60 Hz US power grid is thought to excite a Schumann resonance independently of world thunderstorms! (Ref)



Or if conversion runs the other way i.e. acoustic to electric (AE) and the grid is behaving non-linearly.   To do this we may need to borrow theories from geological prospecting to account for this (refs).



We could have 17 AE x 3 = 51 (electromagnetic)

And 50x 3  = 150 +30 AE = 180  (electromagnetic)



This might serve to explain cases of apparent rapid FM on the 50 Hz signal and offer an alternative explanation as to the source of the 180 Hz pulsating magnetic signal.

 The results of August 24th can be similarly analyzed.

We have 25 AE X 2 = 50 EM, 16.7 AE X 3 = 50 EM and 33.33 AE X 3 = 50 X 2 EM

Again we have parametric relationships.

Indeed since it is understood from geological science that the AE effect is reciprocal, then the whole grid or sections of it could act a quasi-stable infrasound parametric amplifier depending on ground moisture, and stress in the underlying rock strata! One resident in the village of Woodland, Teeside has recently spoken to the author and explained how she only commenced hearing the Hum after a 24 foot hole appeared in the road at the end of the village. Clearly this has changed the underlying strata and allowed a new coherence formerly not present.     Indeed United States Patent 5757177 ‘Infrasonic frequency resonant circuit and method for use thereof’ considers use of the power grid as an infrasound receiver.  


The fact that 50 Hz and 100 Hz sound comes and goes at the author’s location means there is also a mechanism for this but a far simpler mechanism for 100 Hz generation exists in sub-stations. 


There is one word of caution.  There is a high-pressure gas pipeline crossing some distance away at Tal y Bont.  Such pipelines have been associated with infrasound production but this does not account for why it should maximise under the 400 KV lines unless we have a resonance phenomenon?  Alternatively does the infrasound really arise from either? Could the infrasound arise from vibrations of the motor-generator sets and by coupled back into the grid via a quasi –stable feedback path involving seismo-electric coupling? Seismologists have recorded similar but lower frequency turbine vibrations which are sub –harmonics of synchronous machines huge distances from hydro plants (refs), either way ground borne seismic signals in combination with airborne infrasound has the potential to yield all the observed properties of the Bangor Hum including coherence and atmospheric reflectivity effects of the sort reported elsewhere (refs).   




·         There is an extremely strong likelihood that, at least on some occasions, the Bangor Hum as perceived by the two sensitive individuals in this present study has its origins in the electricity grid and or pumped storage frequency control equipment connected thereto.  

·         There seem to be several unstable modes of the electricity grid which involving different frequency pairs which facilitate  perception of the Hum

·         This would account why some individuals perceive the Hum and why others don’t, e.g. Depending, for example, on the lower frequency thresholds of their hearing lining up with a particular set of incoming frequency pairs and perhaps further the ability of building structures and room resonances to enhance this (refs).  

·         Of particular interest is the generation by the power grid of wide area two or even multi- tone infra sound which may involve parametric conversion and amplification. Parametric oscillations in power systems have been known but it is believed this is the first time acoustic conversion has been observed.

·         A clear source of the infra sound for other instances of the Hum remains unidentified. It could be the motor-generator sets at Dinorwig, these synchronous machines and the hydraulic equipment attached are known to radiate ground borne vibrations in the 2-12 Hz range (refs) or it could be another external source such as the gas grid (refs) or water or sewage pumping or it could even arise from ionosphere lithosphere coupling modes. In these respects further research is being made.    



When fully complete these findings will be communicated to the administrators of the National Grid. They are unlikely to respond to the aid of a few ‘hummers’ who many regard a crazy anyway but when they realise how much energy they are potentially wasting we may get some relief! In this latter respect the author has already filed a UK patent.


Dr Chris Barnes

Bangor Scientific Consultants August 2011.