I would buy the biggest power amp I could afford, position my stereo speakers in an optimal location, cue up the Starland Vocal Band's Afternoon Delight and blast it on a continuous loop. My roommate might have some tips for you. When we had construction outside our place, it was driving him completely insane (he worked nights). So he took my guitar amp and hooked it up to his computer and various of my keyboards and put on the most irritating noise he could possibly generate at full blast, aimed out the window at them. He actually got them to leave early one time, but most of the time he just felt satisfied in knowing that they couldn't get anything done or discuss anything without yelling at the top of their lungs. I highly suggest this. You can put the amp at an open window and then put a mattress or a bunch of pillows behind it so you don't have to hear it yourself.