psu would just restart the computer or freeze it hard-core, not allow it to continue displaying data that's changing (like the blinking memtest icon) or really output anything - like the audio. that makes me think that it's a mobo issue. if the hdd was dumping bits along the way, too, that might cause an issue similar to this as well. plus, if a mobo got stuck on something, it'd just hang on that audio sample that was playing and continue hammering it out.
bad power is only an issue if your psu doesn't have active pfc, which most corsair models do have. if your psu doesn't have a switch on the back to switch between 110 and 220v for power intake, it's got active pfc, and as a result can take anything from 100-240 from the wall without any issue. i had a similar problem with an old pos computer with passive pfc at my wife's house in the basement, which is over a hundred years old and has poor wiring.