Music and background sounds Almost all political ads use music. It's usually orchestral, stately, designed to sound inspiring to a broad spectrum of listeners. Volume of music is very important. A common approach is have a crescendo of sound at the end an ad. Background music is borrowed from horror movies when the ad attacks an opponent.
Music is often fiercely patriotic-sounding.
Background noises are important and seldom consciously noticed by viewers. Sirens, traffic noise, drumbeats are commonly employed. A good way to pick up use of music and background sounds, of course, is to look away from the screen during the ad. You'll find a lot going on there that you'd otherwise be unlikely to notice. Film editing and camera use Slow-motion is commonly used to increase the salience of an image.