Is there any outdoor noise cancelling equipment?

There seems to be none available in the market which can be used as a general utility device for an outdoor environment. In any case noise cancellation can work for a specified area only and that too with a single focal point. However, such a noise cancellation equipment shall be adding more noise to the environment away from the perimeter of the device zone due to interference of the sounds. One of the interesting sites is www.comfozone.com. One mans noise cancellation device could turn into anothers noise generator!