No TJ has stated it's the same effect used on helmets, it was in before and it just wasn't working properly due to high bitrate making it sound like a dieing whale. So it was disabled.
Edit:
So unrelated, but very cool, I was fiddling around with the audio settings and did some comparisons to fallout 3, new vegas and skyrim. I find these really helped with voices blaring from other rooms like they're right next to you, also the ambient sounds seem to blend better now. It makes a subtle difference for me at least.
http://pastebin.com/LiJhG178
Also still trying to find a solution to re-adding modulation to intercoms and holotapes, however TJ is not sure it ever was in TTW (could this have possibly been lost between conversion due to different file structures and flags?) I cannot recall if that BoS intercom in FNV had any modulation applied to it.