Over at Disquiet, since the beginning of the year, Marc Weidenbaum has been issuing a challenge each week. Every Thursday night he invites anyone who feels so inclined to record a short composition in accordance with a set of simple instructions, which they must upload to SoundCloud by the following Monday.

The Disquiet Junto is a remarkable project which has so far prompted over 1200 contributions from over 200 individuals, involving the manipulation of live performance, field recordings, computer-generated sounds and pre-existing sound-clips. The results are often astonishing, beautiful, strange or amusing, and always unpredictable, no doubt surprising the creators themselves as much as their listeners. It has given rise to an amazing community of sonic enthusiasts, enterprising, friendly and curious.

I’ve been inspired to throw together a few submissions of my own. And recently, the challenge entitled Sounds from Silence (issued on 26 July) got me thinking of another. Here was the brief:

This week’s project deals with the concept of silence — specifically recorded silence. We will take a segment of audio that is intended to signify silence, and then from it make an original piece of music.

Step 1: Select a segment of recorded sound that would generally be perceived as silent. Examples include: the gap between tracks on a tape cassette or vinyl record, the noise your laptop’s headphone jack emits when nothing is playing, the quietest moment in an MP3, a radio signal when nothing is supposed to be heard.

Step 2: Amplify or otherwise magnify that supposed absence of sound until it makes a perceivable noise.

Step 3: Compose, perform, and record a new original piece of music that takes this sound as its sole source material. You can manipulate the original audio as you see fit, but you can’t add other pre-existing audio elements to it.

As it happened, on the Saturday, the BBC Scottish Symphony Orchestra was also celebrating John Cage’s 100th birthday with a concert at City Halls, Glasgow Had I been more prepared I might have entertained the idea of recording the performance with the intention of reworking some of the ‘silences’ together along the lines suggested.

But I arrived straight from a party in honour of another birthday – that of my younger niece and nephew – and didn’t have time to go home and pick up any equipment. In any case, the custodians of the hall might not have appreciated the finer points of my plan had they caught me in flagrant delicto and I didn’t want to be escorted shamefully from the premises.

Still, it affected the way I listened to the concert, which presented a wide range of works including the Concerto for Prepared Piano (1951) (soloist: John Tilbury), ear for EAR (Antiphonies) (1983), Atlas Eclipticalis (1962), and the (somewhat notorious) Child of Tree (1975) in which conductor Ilan Volkov, alone on stage, plucked and prodded a selection of amplifed cacti with what looked like a cocktail stick.

Although they were composed at very different stages of his career, all the pieces struck me as written sparingly. They were dense in places, but never very loud or busy. The music – like a diaphonous fabric – allowed the ear, as it were, to breathe. It reminded me of the frustrations I felt as a teenage listener of Radio Three’s Music in Our Time in the mid 1970s that seemed to settle into an orthodoxy of delicate, precious, shimmering clusters of notes, harmonics and gilssandi that never really got going, never quite managed to set the body a-tingle. It was all so damned cerebral.

You can imagine, perhaps, my glorious sense of relief when I first heard the jerky cacophony of free improvisers Derek Bailey, Evan Parker and Paul Lytton when they played to an audience of less than a dozen in a small room above the Art Shop in Blackburn, Lancashire. A door opened on other worlds and I thought I would never look back.

This time, there was no frustration. I became fascinated by the way the relatively low volume afforded no cover for the audience’s compelling need to make noises. In the absence of loud passages in which to bury coughs and sneezes or substantial changes of posture, these semi-voluntary spasms and twitches were forced into the open, requiring inventive – but still quite audible – modes of suppression, modulation and camouflage.

A woman behind me couldn’t resist the temptation to zip and unzip her boots – producing an intermittent rasp of metal and squeak of leather. I detected the occasional scratch of nail on fabric and flesh, an intriguing showcase of murmurs, sighs and snorts, air vibrating in nostrils, the inadvertent contact of feet with bags or clothes on the floor. I began to make out the ticking of a watch or two. Now and again, a door behind me winced apologetically. From somewhere high up came the distant squawks of Glasgow’s seagulls.

But the musicians themselves also became part of this army of incidentalists. There is an attractive arbitrariness in the performance of works that rely so much on non-standard sources of sound (the pouring of water, the tearing of paper, the interference of piano strings with metal and rubber) when musicians try hard – as they are trained to do – to make their un-scored movements (replacing drum-sticks on a table, turning pages of music, repositioning chairs) as quietly as possible.

Improvisation III (1980) required the performers to occupy seats in the auditorium and operate portable cassette players. One of them (I recognized him as Nick Fells) was just ahead of me, depressing the play, stop and eject buttons and removing and inserting tapes as unobtrusively as he could, but – my attention focused the way it was – these machine sounds preoccupied me more than the recordings projected by the speakers.

In another context, this kind of listening would have been wilfully perverse. But at a Cage concert it is almost obligatory. I came away rejuvenated but with no clear idea how I might tackle the Junto, and the deadline passed before I could think any more about it.

Then, a week later I found myself with half an hour to spare one evening and decided to try and recreate the ‘silences’ at home, using what materials I had to hand. I set up my digital recorder and stereo microphone and gently placed plastic salad servers on the sideboard, opened doors, moved chairs, tried different kinds of muffled coughs, played with zips, crossed my legs, walked carefully up and down the bare floorboards (but not in knee-length boots), tinkered with my old cassette deck and – last but not at all least – breathed in and out.

Editing the file, I created a dozen samples, and mixed them together crudely, looping some of them, bringing them all one by one into the melting pot and then out again. And here it is. The sonic residue from the concert – its smoke and ash, if you will – not preserved, exactly, but reinterpreted. A cover version of what will almost certainly be carefully excised from the recording of the performance when it is broadcast by the BBC later this year. Headphones essential.