What Was That?

I Can’t Hear You

Ahh, the sweet sound of silence. A joy I’ll never experience again. In fact, I haven’t heard true silence for over 35 years. That was when the tinnitus kicked in full time, 24‑7. Subsequent hearing tests confirmed 20‑30 percent loss and in went the ear plugs.

After several years as a mad keen punter, out 4‑5 nights a week, often drunk, and always up the front, I started working R’n’R already regularly exposed to seriously dangerous noise levels. I’d also done a lot of heavy construction work, often using loud tools without aural protection.

Inevitably, something had to give. After a year or two mixing, it was my hearing. Audio engineers have a lot of tricks, but a crucial component is being able to hear! Fortunately, I enjoyed lighting even more and walked that path instead.

The damage had been done though. Foam plugs and earmuffs saved me from much more degradation, but permanent ringing has been an unavoidable fact of life for the decades since. Many people lose their mind over this, but I accepted early on that I should learn to live with it. In the constant background hum of city life, it blended into the auditory blur of daily existence. Moving to the country brought the ringing back into focus. Here, when the winds don’t blow, the ears scream.

Nowadays, the white noise of a hard surfaced cafe can be deafening, to the point of being quite painful. One of the most agonising noises are cicadas. Thankfully, this is only for a few weeks each year but, being surrounded by gum trees, we are also surrounded by these cacophonous tymbal smashing louts.

The noise that these little beasties make en masse is excruciating. I clocked them at 105dB‑A this summer, but the worst of it only lasted a day.

Some years, I’ve had to don ear protection for several days during the din. I didn’t measure those, but they sounded well north of 110dB. Reportedly, the species Cyclochila Australasiae (Greengrocer) can reach 120dB. Ouch.

The other unavoidable noise pollution out here comes from the Sulphur Crested Cockatoos. We have them in huge flocks, often numbering a hundred or more. Given that each one can screech at 110dB, the cacophony when they are all going off together is overwhelming torture. Thank goodness for double glazing and thick sound absorbent walls.

Fortunately, the cockies are only at their worst twice a day. At dawn, they stretch the vocal cords, but not much more loudly than the kookaburras or currawongs. Dusk can be another thing altogether. Not only does the volume level increase seemingly exponentially, they go slightly mad in their flying antics, darting at impossible angles even drones would struggle with. The vocal theatrics that accompany the aerial circus are equally random and unhinged. Suitably ear‑goggled, it is often a hilariously entertaining spectacle.

Not so jolly are the constant rumbles from Puckapunyal, about 60km from here. With world events as they are, it is perhaps appropriate that our soldiers are practicing a bit of bomb chucking.

Tinnitus and harmonic sound waves

A constant 4kHz ringing is a fact of life for me. I tried masking and that didn’t work well enough to bother continuing. For context, I was simultaneously working loud live gigs, drinking caffeine and alcohol daily, consuming nicotine and other stimulants ‑ these are all known to increase tinnitus. So, ‘suck it up and get on with things’ became the default approach. If I cannot change it, I have to live with it. Not a bad way to approach most problems, but particularly with permanent or chronic ailments like these.

The other intriguing aural anomaly is a recurrent night‑time hum. It kicks in around 10 pm and can continue either constantly or sporadically until after 2 am. The sound seems to start at about 100Hz as a continuous tone. This sometimes goes for up to an hour before changing pitch slightly to about 130Hz, then cycling between the two. It is also quite intermittent ‑ I can go weeks without hearing it, and then it recurs. Sometimes, a once-off, sometimes for a month straight.

Where does this noise come from? I suspect some sort of machinery that is also a fair distance away. A pump or a compressor is the most likely suspect. Without the high background noise floor of the city, and with the long waveform of lower frequencies travelling great distances, it’s little surprise that I can hear it. That others cannot doesn’t exclude it from my lived reality.

Whether I’m hearing the exact frequency that is being generated, or a higher harmonic, is irrelevant. Unless it is some kind of psychological artifact, or a physiological symptom, I still ‘hear’ it. Mercifully, this doesn’t bother me, and I often even use it to construct doof loops in my head as the hum oscillates. Small things amusing small minds etc…

Sandy and the mysterious AC compressor

There is precedence for this kind of oddity within the family. Not blood related, but my father’s second partner (of 35 years) complained of regular hums so loud and consistent that she was becoming quite disturbed and cranky. Given that acerbic and sarcastic were default modes for my stepmother, adding the other traits was less than desirable.

Dad and Sandy went through innumerable doctors, audiologists and other related specialists. All to no avail. Insultingly, a fair few told her she was ‘making it up’. Any women ever heard this contemptuous rubbish from the medical fraternity before?

They were both tenacious buggers though. The old man started taking environmental audio recordings and trying to analyse what was going on. Early efforts revealed little of use. We talked at length about what might be occurring and what the options were to prove it. He ended up trialling increasingly specialist (and expensive) microphones, testing at multiple locations. First, around the house, but later in other nearby sites.

Eventually, he started to find some low frequencies regularly showing up. I don’t recall exactly which ones. Using the locational data, he triangulated the source to a multi‑story medical complex approximately 10km away and approached them formally to see if they knew of the source. And, if not, whether he could access the site to run further tests.

Management denied everything at first and refused any site inspections. They forgot about the insane focus of an autistic engineer in retirement. Doubling down with multiple recordings spread over time and distance, a ridiculous array of spreadsheets plotting every mouse fart within 30km, and a fortunate conversation with the site maintenance officer, eventually got him access to test all over the building.

And there he found the hum ‑ emanating from a rooftop mounted AC compressor whose runtime corresponded exactly with Sandy’s noise complaints. Some acoustic experts finally got involved and designed a baffle that stopped the offending frequencies getting more than a few metres. Problem solved.

The reason that no‑one else could hear this noise was its subsonic nature. Infrasound is outside of the human hearing range. Scientifically, Sandy couldn’t hear the noise directly but was either picking up on either a harmonic of its frequency or could feel the fundamenal in her body. No‑one else they polled in the area felt it enough to notice, even when it was proven demonstrably to exist.

Infrasound has always been part of the natural world. But human endeavours are adding to the subsonic noise. Machinery causes hums, industrial scale machinery amplifies these. Wind turbines have been the target of ongoing debate on what, how much, and how harmful is the infrasound produced. A recent brace of unsettling subsonic noises are being attributed to data centres in the US. The answers to these quandaries are well beyond my rudimentary understanding.

All the above should be couched in the fact that, as an audio operator, I make a great LD. Humility aside, I understand enough of how audio basics work to pull an adequate mix on analog gear. But I know that many of you will have far deeper knowledge on these topics and would welcome (verbal!) feedback on any points I have raised.

I can hear clearly now (that the noise has gone)…

As part of annual eye checks, I get a free hearing test. Recently, I was pleasantly surprised that my ears tested ‘perfect for my age’. Further, my peripheral and locational perception recorded above average. So, to the constant ringing, weird night‑time hums, functional deafness in loud environments, and audible pain from surrounding critters: youse can all get stuffed. According to Specsavers, I hear perfectly.

If my vision were sharper, I’d be able to see where I put the noise cancelling headphones.