MelloToneGen is a generative ambient music and noise machine application for OS X.
Built with Max/MSP, it runs as a native Mac application, and creates soothing, meditative soundscapes, using sounds of nature recorded in the Pacific Northwest, along with algorithmically-generated synthetic tones.
You can choose from multiple soundscape themes, created from layers of original field recordings. Along with that, mellow tones are generated, that evolve over time (especially enjoyable on headphones).
Having a non-repeating source of ambient sound can be beneficial in many situations. Focusing on work or creative tasks in a totally quiet space can be difficult. Similarly, it's hard to concentrate when listening to music with melodies or lyrics. MelloToneGen aims to strike a balance by providing more than just white noise, and avoiding melodic repetition.