We're gonna need a bigger speaker.
Speakers, actually.
Then we'll just amp up loud enough to shatter said rods with the dulcet-questionable rendition of Slim Whitman's "Indian Love Call".
Or just use the Alaskan HARP.
None of those will reach the Ort Cloud where the attack will come from.
But if you need rally big speakers and a group to play the noise, then I suggest Disaster Area the loudest band in the Galaxy and the loudest noised of any sort.
“The Hitch Hikers Guide to the Galaxy notes that Disaster Area, a plutonium rock band from the Gagrakacka Mind Zones, are generally held to be not only the loudest rock band in the Galaxy, but in fact the loudest noise of any kind at all.
“Regular concert-goers judge that the best sound balance is usually to be heard from within large concrete bunkers some thirty-seven miles from the stage, whilst the musicians themselves play their instruments by remote control from within a heavily insulated spaceship which stays in orbit around the planet - or more frequently around a completely different planet.”