Introduction

Rhythm is often considered the most difficult feature of music to understand. I have left it until after considering the hearing mechanism for at least we now know why it is so time-sensitive to the arrival of transients. There is, however, a more fundamental reason for considering it as a quite separate phenomenon; it is not a sensation like sound produces. There are also terminology difficulties. ‘Rhythm’ is often used unselectively for almost anything concerned with the time characteristic in which music is played and heard, and sometimes interchangeably with ‘the time’. The word ‘beat’ is used, and in reference books one finds ‘when there are four beats in a bar’, but no attempt anywhere to describe or define what a beat is. What a conductor provides is also called ‘the beat’. The term sometimes used by players is ‘the pulse’ which has the virtue that it is only used in one sense, as a feature of playing.

The automatic machinery of people with normal hearing offers the same signals to everyone's auditory cortex. From then on, how an individual responds to the sensations produced depends on that individual's cortex. Amongst their responses they may react in a regular way as a result of the time of arrival of transients. We will call that a rhythmic response. If we assume that it is entirely a cortical matter, there is no difficulty in accepting that it varies enormously between individuals, from zero to the almost compulsive. It is a consequence of hearing music and, in a subtle way, of having heard music, as we shall see.

Sound that conveys such a regular time pattern has to be produced, and, mechanical and electronic generators aside, it is produced by people. They require a time-base upon which to produce the transients. If the player has an awareness of that time-base we can call that the pulse. Both the pulse and the rhythmic response are mental activities not sensations. They are normally characterised by having a very simple distribution in time but they are not necessarily synchronous with transients of the music being received. Neither are usually at the fully conscious level. The pulse is, and the rhythmic response may be, directly associated with physical activity. This is quite different to the sensations of pitch, loudness and direction.