Pretty but ineffective.

The lengthy marketing spiel in the description obfuscates what this app actually does. Simply put, it provides seven presets of base sound that increase in volume in response to sounds picked up by the microphone.

This doesnt provide silence, but trades external noise for headphone noise. There is a significant delay in responsiveness which isnt noticeable for constant sounds like the hum of conversation but very distracting for sound spikes, like a door closing.

I purchased it for use while reading in noisy environments, but I find that my older method of playing instrumental music is far more effective.

B.H. Vrux about SoundCurtain, v1.5