Ever since I first had access to the internet, one of the great pleasures that it’s had to offer me, is the ability to accidentally stumble upon utterly fascinating discoveries that you never knew you were interested in. Despite the seemingly unstoppable rise of the algorithms that seek to give us ever more ‘accurate’ search results, it remains possible make these strange discoveries and fallen fascinating tangents. Like most things in life, sometimes you want to keep to the beaten track and other times you want to grab a map, a head-torch, and go spelunking.
When I was a student wiki-walking was a known phenomenon (XKCD have an illustrative strip on this) and a colleague of mine will often start watching a technology demo on youtube and fall down a rabbit hole that could end up with him watching the latest discoveries from NASA’s probes or learning how to make ASMR videos. Another friend of mine calls it falling down a hole in the internet. (And now we’re back to spelunking.) Personally, I tend to find myself listening to oral histories recorded in the middle of the Navajo dessert in the 1960s or reading up on how to build my own hydrophone. It wouldn’t be the first time I’ve fallen asleep listening to location recordings from Sri Lanka or had to give myself a stern talking to about how much I don’t need an Otamatone.
Some discoveries prove to be only passing distractions, but others I come back to over and over again. Hydrophones, are definitely one of the latter.
My real interest in hydrophones, started in a somewhat unexpected location. It was a bright, brisk September day in which I was attempting to finally fulfil and completely different notion. Several years previously I’d read an interesting article on repurposed lighthouses and developed a hankering to go to the top of one. The quest seemingly growing in significance and importance – as these things tend to – the more I was thwarted in my attempts to carry it out. On the day in question, I’d spotted a chance to finally succeed – Cromarty Lighthouse was included in that year’s Doors Open Day events. Cromarty Lighthouse, is actually a retired lighthouse – and is now properly known as the Lighthouse Field Station, a part of Aberdeen University’s School of Biology.
The lighthouse itself is of the short squat kind that mark harbours rather the tall sentinel variety that mark lonely outcrops, which in practical terms means that only a limited number of people can climb its tower at any one time, so they had an exhibition in the base of the tower for those of us waiting. As part of their research, floating in the Moray Firth are a small number of hydrophones, recording the sounds – both natural and industrial – of the Firth for the purpose of passive acoustics analysis. (Some of the research station’s specialisms include the impact of marine noise pollution – from oil drilling, to marine renewables to ferries – on marine wildlife.) They had a variety of recordings and a kid-friendly game set up where you matched the recordings to their sources.
It turns out that there’s a world of difference between knowing, logically, that sound travels differently through water, so the underwater soundscape will inevitably be completely different, and putting on the giant headphones and immersing yourself in that other world while standing on dry land. Even better, they’d not long since had an artist in residence in working with some of the recordings which in turn lead down it’s own strange and wonderful rabbit hole.
I suspect I love hydrophones for the same reason that I love contact microphones, because they open up a whole other dimension in sound. Listening to the world through either of these type of microphones makes it explicit and undeniable how rich and complex the soundscape of our world truly is, and how much of it we ignore in day to day life.