Abstract: Invention provides a system and method for separating sound from an object of interest from its background and condition monitoring system and mobile phone using the same. The sound separating system includes a sound source localizing part, including at least one microphone and a processing unit, and an object direction reference determination part, determining, as object direction reference, information on directions of the object of interest with respect to the sound source localizing part; wherein the processing unit obtains information on a direction from which sound arrives at the sound source localizing part from the sound source by using microphone signal, and comparing it with the object direction reference so as to filter the sound from the background of the sound source. By having the sound separating system, it can extract the background noise from a specific device respective location and analyse only these signals from the object of interest.