Noizer is described as 'lets you to mix multiple ambient sound sources to create the perfect mesh for relaxation and focus. Mix sounds like fireplace, birds or even a bar and street, all adjustable with individual volume sliders'. There are more than 50 alternatives to Noizer for a variety of platforms, including iPhone, Android, Online / Web-based, iPad and Mac. The best alternative is myNoise, which is free. Other great apps like Noizer are Blanket (Free, Open Source), A Soft Murmur (Freemium), Tide (by Moreless) (Free) and Noizio (Paid).
myNoise creates beautiful noises to mask the noises you don't want to hear: your chatty colleagues, tinnitus, or even your inner voice when you can't shut it down! The concept is simple, works extremely well, and does not require expensive noise-cancelling headphones.