Today's Poor Almanack

For a while I've had the idea to do a cartoon about that sound that's used in political attack ads to describe how unsuitable the Other Guy is for elective office. You know, that deep, dark chord like somebody putting both arms down on a piano keyboard, only it's enhanced and overtoned and uglified until it sounds utterly depraved. The TV screen ges darker, the announcer's voice gets ominous, they show a photo of the Other Guy, and you hear this BWRRAANNNGG. And if you're susceptible you don't vote for the other guy.
They've been using that sound for a while, years and years I'd guess. And I've never really heard any comment on it anywhere. So I did this cartoon, which only says part of what I wanted to say, or only says it badly. What I really needed was some kind of chip to actually make the noise, or a better onomatopoetic spelling, or just a better idea to start with.