There are two trucks that emit loud noises in Amman:
1) the gas truck, which plays music that made me think initially that it was an ice cream truck, and
2) the vegetable truck, in which someone with a loudspeaker blurts out in rapidfire fashion the trucks wares and accompanying prices.
Here's a video of the gas truck. I am resolved to capturing a similar film of the veggie truck during my last week-plus here.