Does what it says

This app listens to your background noise and then outputs some gentle white noise and a subtle remix of voices or specific noises in your environment. This helps keep the user from being distracted by conversations and voices since the remix of ambient sounds makes the voices sound more like babble, so that you cant focus on them intentionally or subconsciously. I use this app in addition to noise canceling headphones to keep nearby conversations from distracting me as much in my cubicle. Noise canceling apps & headphones dont cancel out human speech yet, so this is a great first step in the right direction.

Fuzz54 about SoundCurtain, v1.5