I found the website www.youarelistening.to providing some good playlist of chillout music (relax ambiant) with on top of it a second audio stream in direct depending on the city you choose.

For example, if you choose the default city, Los Angeles, you will have the LAPD Aero and Special Unit Dispatch radio, for Indianapolis, Indianapolis Metro Police radio and I didn’t look for the other places.

I listen to this when I want to focus, explore the deep web or to lay on the ground, back straight and eyes closed taking long and deep breath (I recommand this to you if you feel stressed, sad, or if you are feeling an overdose of any activity).