@homeontheland, this is great - a fine analogy to the perceptual aspects Op Art in an auditory sense.
I remember a similar exercise from my first or second year of Music Technology at the University of Adelaide, where our lecturer conducted a similar exercise. We weren’t told what was going to happen and he simply checked in with us beforehand to make sure we were feeling alright. He then shut the curtains to our large studio space and started the playback of a loop of him saying ‘experiment’ infinitum for the 15-20 minutes. Afterwards we were then asked to write down what we heard on a whiteboard. All kinds of things came about: ‘eggsperm’, ‘errumdrum’, ‘humdrum’, excrement’, etc.
I remember the process and outcome had a huge impression on me - it was definitely one of those inspiring WTF moments of my Uni days that would go on to influence my practice.