Close your eyes and have a partner walk around you at about ten steps distance and at any time he wants he will either shout or clap his hands and at the same time throw a tennis ball or knife at you (according to where you are in the work) You need to step away from where you are or drop or move in some way to survive and throw something at the direction of the voice you heard. Start with a loud voice and than lower it to a normal speaking voice. Vary the distance and the nature of the sound and than make it a specific sound like an order of GO or a click of one of those baby food covers. Next have several people working at the same time and you need to distinguish from the mass of voices and sounds the one that is aimed at you. You will also recall direction by sound better this way and remember not to be where you are aimed at.