"During this period of concentration, I created, around 1947--1948, a 'monotone' symphony whose theme expresses what I wished my life to be.
This symphony of forty minutes duration (although that is of no importance, as one will see) consisted of one unique continuous 'sound,' drawn out and deprived of its beginning and of its end, creating a feeling of vertigo and of aspiration outside of time. Thus, even in its presence, this symphony does not exist. It exists outside of the phenomenology of time because it is neither born nor will it die. However, in the world of our possibilities of conscious perception, it is silence -- audible presence."
[Yves Klein, Overcoming the problematics of art]
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"My old Monotone Symphony of 1949, which was performed under my direction, by a small orchestra on March 9, 1960, was destined to create an 'after-silence' after all sounds had ended in each of us who were present at that manifestation.
Silence... This is really my symphony and not the sounds during its performance. This silence is so marvelous because it grants 'happenstance' and even sometimes the possibility of true happiness, if only for only a moment, for a moment whose duration is immeasurable."