This is AFRS, Radio Saigon.
4 seconds sound clip from the Good Morning, Vietnam movie soundboard.
You can hear this line at 00:03:48 in the Blu-ray version of the movie.
Quote context
[...]
- Heh-heh-heh. I like you already, sir.
- Jesus, that guy's as boring as whale shit.
- See, the purpose is to inform you as to the radius of the radio waves.
- Mantovani? They play Mantovani to insomniacs who don't respond to strong drugs.
[...]