The Perception of Family and Register in Musical Tones

Abstract

This chapter is about the sounds made by musical instruments and how we perceive them. It explains the basics of musical note perception, such as why a particular instrument plays a specific range of notes; why instruments come in families; and why we hear distinctive differences between members of a given instrument family, even when they are playing the same note. The answers to these questions might, at first, seem obvious; one could say that brass instruments all make the same kind of sound because they are all made of brass, and the different members of the family sound different because they are different sizes. But answers at this level just prompt more questions, such as: What do we mean when we say the members of a family produce the same sound? What is it that is actually the same, and what is it that is different, when different instruments within a family play the same melody on the same notes? To answer these and similar questions, we examine the relationship between the physical variables of musical instruments, such as the length, mass, and tension of a string, and the variables of auditory perception, such as pitch, timbre, and loudness. The discussion reveals that there are three acoustic properties of musical sounds, as they occur in the air, between the instrument and the listener, that are particularly useful in summarizing the effects of the physical properties on the musical tones they produce, and in explaining how these musical tones produce the perceptions that we hear.