Well I mentioned attaching it to the player/camera because then you can use getowner/vector 3 and send it to the sound vector3 in case the "camera"/player moves. So, if you want your sound source to move with the audio listener, put it on the object with the audio listener
To be honest I've never used playmaker audio before, but since Play Sound has a vector3 input I assume it's because the sound will be stationary unless you tell it to move with the audio listener if it moves. With other methods you can just get rid of the audio falloff but I don't know if there's a way to do that with playmaker.
I just thought to search for "audio source" and i see there are also audio actions. unfortunately i've never used this so I don't know if using set audio clip or audio play uses the sound falloff.