On Ligeti

There we are, a short clip of Berliner Philharmonic on Ligeti's Atmospheres.

It is quite amazing how the clusters don't sound out of tune actually. In some way, the vibration caused by the clusters creates the "atmosphere".

Which brings forth the thoughts about tuning properly according to the pythagorean ratio. Is it relevant here?

Much of the music involves the timbre produced by the cluster of notes played by a group of instruments together(the different families), with plenty of extreme crescendos and decrescendos, i.e. from almost silence to very much "in your face" loud.

I wonder if we take the first instance the music starts, could we find every single chromatic note? That would make it a 12-note pitch set? and complement of it is.... erm... silence?