Guild Wars 2

1) Audio suddenly drops entirely and is replaced with a pulsating, very loud sine wave. Said noise continues even if I mute the game or alt-tab. Closing the program entirely fixes it. Has happened once in WvW and once fighting the swamp boss in Queensdale.

1a) Less severe audio issue: sounds will simply not play sometimes. For a period of time none of my skills will have audio effects. This resolves spontaneously.

1b) I will randomly hear loud voice clips with no apparent source.

2) Game freezes at random. Has happened once when fighting the above boss. Happened about 20 seconds after the audio broke. Only solution was to ctrl alt del and kill the process.

3) Game cuts to black and stops responding. Happened just now when trying to discover a new recipe (level 20 healing pistol). When I clicked, the screen turned black, but the music kept playing. No buttons did anything, though I could alt-tab and exit the game that way.

SLI GTX 560, newest beta drivers, SLI disabled
i5 2500k
8 GB RAM
Windows 7 64-bit with SP1
Everything on my computer is updated as much as it can be

Just had the sine wave problem myself in the middle of a battle with Jormag
twice, exited and started again, 3 minutes in happened again, never happened
until this latest patch (18th sept).

Strangely enough only in the left channel.

i just now had the very loud pulsing noise in the wvw as well. could not figure out where it was coming from until i closed out of Guild Wars and it stopped. Fairly annoying as i was in the middle of a fight and it was so loud that i could not bare it. Not sure what is causing it.

I had all ambient noise drop while fighting some mobs a little while ago.