A further short comment on the Hum, truly a multi-infrastructure problem, water not off the hook! By Dr Chris Barnes, Bangor Scientific and Educational Consultants, November 2013. By Dr Chris Barnes, Bangor Scientific Educational Consultants, November 2013. e-mail doctor.barnes@univ.bangor.ac.uk


The Hum is briefly defined and reviewed. The minimum requirement for the Hum is re-iterated. Experiments with water pressure suggest that, at least in Bangor on some occasions, water pumping frequencies could potentially provide a requisite infrasonic component of the Hum and water leak frequencies may even contribute to the acoustic component. Because the water pressure results are not readily reproducible thus suggests either a highly random system or as is more likely from past evidence a more predictable alternative infrasonic source dominates on most occasions.


The Hum is a geo-sporadic, often nocturnal; menace which it appears may be perceived by some individuals by a combination of senses in addition to normal audition. It can cause general annoyance and sleep disturbance and is even reputed to have caused a few suicides. Some people who perceive the Hum have very acute hearing especially at the infrasound end of the acoustic spectrum. It is quite possible there may be a genetic factor in this and in Hum perception in general. Since the number of Hum cases World-wide appear to be on the increase ideas are that increased LFN and increased pulsed radio emissions somehow sensitise the ears/body to the Hum frequencies.

It is reckoned that between 2-11% of individuals hear/perceive the Hum depending on age group. The peak age for hearing appears to be in middle age but the author is personally aware of individuals as young as 28 and as old as 82 who perceive the Hum. Those afflicted describe hearing a noise rather like a distant irregular idling engine or a large bee trapped in a bottle. Being a subjective phenomenon based on human experience descriptions are naturally bound to vary somewhat. Musically inclined ‘hummers’ people who hear or perceive the Hum tend to tone match it as between 30-80 Hz yet having quasi periodic modulations in both amplitude and frequency. Of late there are more descriptions of the Hum sounding more ‘impulsive’. Geo-spatially modern Hums seem to tie in with the distribution of renewable energy systems.

There was a Hum like phenomenon reported in Victorian times known as the ‘Hummadruz’ but this was reportedly like the continuous sound a swarm of bees at dusk and sustainably different from the contemporary Hum and probably was due to sound form newly established steam powered factories.

The first sporadic reports of the contemporary Hum began in Britain in the 1950’s. However, it did not become well known in the UK until the 1970’s and in the USA until the 1990’s. Because the so called Taos Hum in the USA could not be audio recorded, the Hum took on an almost supernatural guise. There were also those who stated that the Hum was most likely due to Motorways and High Pressure Gas Mains. Both of these are sources of infrasound and in many respects descriptions of the Hum are very like descriptions of the perception of and effects of infrasound. The former Soviet Union had these but in the 1990’s had no renewable energy. Since there was then no Hum in the then USSR or China there were those who dismissed the gas mains idea and instead reached the conclusion that its time and position in space most likely seemed to correspond with operation of western military communication aircraft known as TCAMO, which, incidentally, newer versions of still fly today. However, since the Hum has now become a virtually world-wide phenomenon the time is perhaps nigh to seek alternative explanations. It is undeniable from mapping meta-analysis that geo-spatially modern Hums seem to tie in with the distribution of renewable energy systems.

Anecdotal reports of the Hum suggest it to be far more than just a noise. Reports of the Hum being sometimes difficult to screen with earplugs, depending on head orientation and being perceived in certain types of underground cavern but not other’s together with its maximisation in the presence of low frequency magnetic comb spectra suggest it to be a magneto-acoustic or gravito-acoustic phenomenon also requiring the presence of infrasound and acoustic sound. Interaction of power systems with the earth and near space environment, particularly those rich in harmonic sub-harmonic can provide such signals, being more prevalent in the case of renewable energy.

From an environmental Health perspective, a hum is The Hum when it simply cannot be traced. This is indicative of signals arriving from a distance from one source via multiple paths or from multiple sources or of one distant signal and one local signal which only combine internally, say for example by cochlear mechanics or similar to produce Hum-Like effects.

Possible need for a nearby TV and AM Radio Transmitter

The majority of sites throughout the world which regularly also report the Hum are less than 20km from both TV and FM and AM radio transmitters. These might play a part in either Hum sensitisation or Hum perception. Radio transmissions of various frequencies might also take part in a form of Bragg matching with certain acoustic frequencies in the Hum and even an additional method of perception. Because radio frequencies are now a very ubiquitous part of infrastructure it is virtually impossible to decouple their part in the Hum.

Minimum requirement for the Hums

As evidenced by the author’s own experimentation, the perception of Hum like effects in humans can be produced in the acoustics laboratory but not by infrasound alone. There has to be a harmonically related combination of acoustic sound around 50 Hz and infrasound sub-harmonic (s). This condition would be similar to the Kokomo Hum where people would be exposed to 10 Hz, 30 Hz and ubiquitous 60 Hz (both acoustic and magnetic component).

As further evidenced by the present author’s own research frequency or amplitude pulsations in weak acoustic and/or magnetic fields at 50/100/150 Hz in the presence of infrasound between 7-10Hz or 12-19 Hz appear to be present as the minimum requirement for any kind of Hum perception. Whereas renewable energy infrastructure can provide all of these frequencies in particular by means of pumped storage systems, high pressure gas mains have also been implicated in providing infrasound.

How can water be implicated?

Precise measurements of all frequencies associated with source feeds and sink cable/pipe services for all the utilities have previously been recorded in Bangor and Llanfair PG, both areas where the Hum has been perceived. In Bangor a frequency of approximately 14 Hz was found associated with the mains water.

The Bangor Hum has previously been blamed on the Dinorwig Pumped Storage System and indeed its timings could often be correlated with the operating times of specific motor- generator pairs. It also maximises when wind power elsewhere in the grid is at a maximum. However, on some odd occasions a similar Hum has still been audible later in the morning and at times when Dinorwig was neither generating nor pumping. On these occasions infrasound in the region of 14 Hz was present in the affected bedroom.


The experiment which implicated the water main as a possible source of infrasound for the Hum was stumbled on almost by accident. Some months ago, the author was sitting alone at night in his lounge. His wife and son had retired. His son visited the upstairs toilet and flushed it. The Hum momentarily disappeared. Nothing was read into this as it was assumed that the disappearance was just a competing noise effect. However, very recently indeed, Sunday 17th November 2013 the author was awake in bed when his wife was running a kitchen tap and the same diminishing effect on the Hum was noticed. A little later the Hum appeared to cease altogether. Inspection through the bedroom window showed the author’s wife to be using a hose pipe outside.

The author arose and dressed and explained what had happened. A test was conducted with the outside tap switched off and the Hum returned. The tap was switched on again and the Hum lowered in amplitude, only to disappear completely when the hose pressure was on maximum.

That evening when the Hum came on, the author attempted to repeat the experiment but without success.

Conclusion and Discussion

The Hum is sometimes but not always associated with water supply. In Bangor the frequency of 14 Hz is associated with water supply, possibly private pumping. 850 RPM is a popular water pump speed which equates with 14.3 Hz. This supports the notion that relieving water pressure may have reduced this frequency component and stopped/lessened the Hum. The fact that the experiment is not readily reproducible suggests that at other times a different source is providing the infrasound component for the Hum.

Leaking plastic water mains can also provide acoustic sound in the range approximately 50-400Hz (ref).

Nothing in this work detracts from the previous findings of the author but the findings go to prove that the Hum is truly a multi-infrastructure problem and that at least on some occasions and in some locations, water is certainly not off the hook.

It must be stressed that the Hum in the ‘water experiment’ behaved in essence exactly the same as the Dinorwig Hum with respect to moving vehicles passing outside the house. It is strongly suspected thus that at least one component of both Hums enters the house as a Rayleigh wave from the road outside bearing the user service mains and is not been generated by piping inside the house as with, for instance, pipe vibration or water hammer. It is further explained that this was early Sunday morning and the water in the main may have been static or almost static until we ran off water.

Additional movement in the main might not only disturb self –generated frequency components but might also disrupt propagating Rayleigh waves from other sources. It would seem that the Hum, is truly a multi-infrastructure problem, and water is not off completely of the hook!