'Roger Scruton (another rare example of a philosopher paying attention to the problem of the audible) radicalised the view of sounds as events by proposing the term secondary objects for auditory phenomena - analogous to Locke's secondary qualities. Sounds are not qualities of objects, but phenomena free from their sources. And the properties of secondary objects, to which Scruton includes, along with sound, for example, rainbows, are their ways of detecting themselves'
Anatoly Ryasov, 'Barely audible hum. An Introduction to the Philosophy of Sound' (translated from Russian).