Evolving viable pitch contours

Abstract

At a very basic level, a piece of music can be defined as an organised arrangement of sounds occurring both sequentially (as in melody) and concurrently (as in harmony). As music evolved into a science and an established form of art, people started studying the characteristics of these sounds and drew sets of guidelines and rules, that if followed would produce pieces of music that are aesthetically more pleasing than others. Early examples can be seen in Pythagoras’ observations and experiments with blacksmiths’ hammers. Allegedly some 2500 years ago, he was walking by a blacksmith’s shop when he heard the ringing tones of hammers hitting an anvil. Upon further observation, he realised that a hammer weighing half as much as a previous one sounded twice as high in pitch (an octave – ratio 2:1). A pair of hammers whose weights had a ratio of 3:2 sounded a fifth apart. Eventually he came to the conclusion that simple ratios sounded good. In this paper, we are concerned with the generation of musical phrases constrained by the rules that governed music developed during the so called Common Practice Period (CPP). This period refers to an era in musical history spanning from the 17th to the early 20th centuries [2] and included the Baroque and Romantic styles amongst others. Colloquially, music in the style of the CPP is sometimes better (but incorrectly) known as ‘Classical’ music.