The pulse of an electronic rust inhibitor as recorded through a coil pickup microphone.

Trails of sonic activity drift, unheard, around us. Beneath our feet the earth groans in frequencies too low to be discerned. From the trees ultrasonic clicks from insects remain unrecognised. At home electrical pulses radiate from domestic utilities. It is the unheard universe.

Discovering these hidden sounds is one of the joys of field recording. Although contemporary discourse describes the world as getting smaller field recording and the act of listening reveal the planet to be much larger than we think. How satisfying to know that there are still some mysteries to be uncovered!

With the advent of modern recording technology regions of uncharted sound have been made available to us. Contact microphones capture the subtle vibrations of inanimate objects; hydrophones amplify the sound of aquatic life; coil pickups, my new personal favourite, reveal a musicality of tones emanating from everyday electrical appliances. It is in these objects that I have recently found the greatest interest.

Coil pickup microphones detect the electromagnetic signals of motors and microprocessors. It is endlessly fascinating listening to the variety of tones each appliance projects. The timbre, duration and frequency of tones is quite unique, often falling into the region of what is termed microsound. Here short bursts of sound are heard lasting between one tenth of a second and 10 milliseconds.

The effect of these tiny sounds on our approach to listening is immense. They emerge briefly to the foreground forcing the ears to pay attention to the space into which they retreat. Through this process we hear sounds beneath sounds. We notice a polyphony of textures and beats, the complexity of which encourages the mind to lose itself, if only briefly.

When I first started field recording I did so from a concern for the state of the natural environment. Although that concern still exists my interest in recording has moved to a new terrain – that of bringing the inaudible to the acoustic forefront. With the aid of recording equipment we can overcome the limitations of our auditory system, enabling us to listen to a more 3-dimensional version of the world in which we live. We are the richer for it.