Skrillex uses Ableton Live. Mainly because of it’s flexibility and the unique ability to play live.
Almost anything you want can be done seamlessly in Ableton Live.
Even Deadmau5 uses Ableton Live.
You can eread more about it here - Skrillex DAW and Gear!
A Filter/Equalizer which analyses the whole Spectrum, and higher Frequencies 2k- 10k a "hiss" can be removed by turning the "hiss" frequencies some db down.
In Vocal Production for example you have to find the "z", "s", "ch", "f" etc. frequencies as these are the "hissing" sounds, removing ...