Hi,
Sorry to resurrect an old thread, but was searching through and came across it.
I am affected by this too and believe the term is Misophonia. I appreciate this may not be exactly correct, but it sure does cover a lot of what I go through - noisy eaters make me want to explode, when too many people talk at once it all turns to a form of white noise and I can't make out anything, noise that is painful - fire alarms, sirens etc. This is, sadly, very common for people on the spectrum. I can only sympathise if you have to use public transport, as I would rather chew off my own foot than do that and I am lucky enough to be able to afford my own transport.
Like others, I resort to noise cancelling earphones (Atomic Floyd Superdarts) and music; I have different artists or genres for different situations. I also have to sleep in wax earplugs to allow me to sleep - the only slight problem is that on occasion I have been woken up by the sound of my own pulse!
Apparently, research suggests that controlled exposure treatments used for Tinnitus can be effective in some cases.