Source localization using array signal processing is an important technique for audio and speech processing systems. For example, the knowledge about the location of the potential listener can help the system to provide a better audio service by using beamforming technique that uses an array of microphones. Similarly, the technique of beamforming can also be used to capture an audio signal from a desired source location and attenuate environmental noises or undesired signals. This discussion also leads us to say that the location information of the source can help in the separating the desired audio sources from each other or from the undesired audio source signal, using blind source separation with the help of microphone array.