1D simplification
Even though we live in a multidimensional universe, the majority of the phenomena studied in these lectures will be treated as if unidimensional. For example, the movement of a driver (loudspeaker) membrane is guided in one direction. Thus, we will only interest ourselves with the movement in this direction. Although three dimensional physical quantities are described by vectors we will simplify the notation for one dimension. Hence, the norm of the quantity will be used for the intensity, and a sign (+/-) for its direction.
