Just few words. I agree about loudspeaker disturbance when it plays the content louder and continuously for long time. But really don't know what kind of disturbance is there when Azaan is being played for few minutes. You are hearing it even when it is played 1km away? That is the purpose. Those olden days, a person will go to the top and say Azaan louder so people will listen and come for prayer. It is not possible in current crowded world which is already filled up with many other noises. So it is being played using loudspeaker.