Personally I don't use the ambient noise, I use
- {l Code}: {l Select All Code}
play_sound("sounds/rain.wav");
as a script.
Ambient sound is more like a way to constantly play a sound, such as rain or a saw.
"Distance Factor" is going to be a bit hard to explain in a formula. The higher the number is, the closer you need to be to the ambient sound trigger. 1 is the max capacity. My recommended values are: "0.001" (Sound can be heard from around 75 blocks away), and "0.01" (Sound can be heard from around 10 blocks away). So, all in all, this determines how much you want to hear the sound from a distance.
"Distance Bias" is the 'fade' from the sound. Setting the distance bias to 1000 means the sound will slowly fade away and by the time it reaches the 'length' of the sound (shown above,) the sound will then just disappear. Setting the distance bias to 0 means the sound will equally fade away depending on how far you are from it, also that accords to the Distance Factor.
It's a complicated recipe to get it going so that's why I don't use it. Hope my explanation above helps.