This thesis presents a method of detecting transient noise using microphone array so the transient noise source orientation can be computed. Through the time-domain amplitude subtraction, the effect of both stationary and non-stationary noise in the microphone signal can be effectively eliminated. This includes signals such as voice. It is shown that this method is reliable when the environment is not ideal. This makes the method a better candidate to be a sound cue than key word based mechanism. This method operates on a low-dimensional matrix and needs only a few window frames of receive signals. Meanwhile the source location can also be determined from those frames. This low computational requirement makes it ideal for real-time applications.