Sense of hearing

Your ears pick up your own sounds and those made by others, human or animal. Unlike your eyes, your ears are positioned at the side of your head. Your ears are open to sounds from your entire surroundings; it is not necessary to position the ears directly in front of a sound. You cannot close your ears, so that you are connected with the world of sound during all your waking hours. You cannot help but hear them.

Listening – conscious hearing – requires you to be quiet. You must keep still yourself and take a back seat, as it were. Listening is a social activity focused on others, but it is also an internal activity. How often did your teacher say ‘sit still and listen carefully’?

Animals can turn their ears towards a source of sound. Humans do not have this ability to ‘see’ with their ears. Animals hear well, but they do not listen, as they cannot step out of themselves and become silent. The hearing organ can be divided into three parts (figure 3, page 34). The external ear, consisting of the concha and the ear canal, captures sounds. The eardrum is situated at the end of the ear canal. The middle ear carries the sound further. The middle ear is made up of the tympanum which in turn contains the three ossicle bones (malleus, incus and stapes) and the Eustachian tube which connects the tympanum with the throat. The Eustachian tube stays open when you swallow so that a constant pressure is maintained on both sides of the tympanic membrane. The ossicle bones pick up vibrations in air and pass these on from the tympanic membrane to the inner ear.

The ear

The inner ear is located in the temporal bone and consists of a labyrinth, a cavity filled with fluid that is made up by the vestibule, cochlea and three semi-circular canals which are used to maintain balance. The cochlea is the actual hearing organ, where vibrations of air are transformed back into sounds. You can distinguish three types of sounds. First, there are the common, everyday sounds such as the rustling of leaves, the wind howling round the house, babbling water and all sorts of mechanical noises such as cars, creaking doors, and so on. The second type of sound is music, which is made up of sounds and tones. The third type of sound is human speech.

You can observe three aspects of every sound, regardless of which type it is: the volume, the pitch and the tone colour. You can also observe the distance to the source of the sound, since the sound does not reach both ears simultaneously. The second ear will hear the sound 0.001 second later, so that you can estimate where the sound originated. Accurately assessing the distance and direction of a sound is a matter of experience.

Hearing declines with age, but to compensate we are born with a very wide range of hearing. Children can hear 11 octaves, and even in old age you can still hear 10 octaves.

Looking at an object gives you an idea of its exterior. Listening to an object gives you an idea of what is within. Often, for example, it is difficult to distinguish a glass pane from a plastic one by sight alone. If you tap the pane, however, the sound will tell you which it is right away. You can also hear if a plate or a bell is cracked, even if you cannot see the damage. Listening to people can also reveal information about their inner lives. People might look smart, but if they feel bad inside it is immediately apparent in their voice. Someone’s intonation betrays whether they are sad, happy or excited.

The resonation of sound by objects is always the sum of its parts, of substance and shape. In order to resonate, objects must be solid and free-standing. A free-standing copper bell rings, but a bell standing on the ground is like a soft chunk of clay: it makes no sound. Sound is considered an unearthly (immaterial) phenomenon.

We have a very fine perception for music and sound, and we can feel intimately connected with tones and melodies. High tones are generally perceived as clear, light, sharp and distinct, while low tones are perceived as dark, full, warm, big and less distinct.

A final point of interest is the relationship between sight and hearing. When you look at something, you can hear it better. This does not only apply to speech, but also to music. If you were to listen to a philharmonic symphony and keep your eyes on the oboe, you would hear that instrument more clearly than the others. If you then switched your gaze to the clarinet, you would hear it more clearly, and so on.

Exercises
Stand somewhere, indoors or out, and describe all the sounds you hear. What feelings do the sounds evoke? You can do this exercise with your eyes open or blindfold. Does it make a difference to what you experience?

This is an exercise for two people, one of whom is blindfold. Stand 5 metres apart. The person who is not blindfold must whisper something, articulating well, and the blindfold person must repeat what the other whispered. Then remove the blindfold, so that the listener can see the speaker. Again, the listener must repeat what the speaker whispered. What is the result? What was the listener’s experience?

This exercise is for a group. One person sits behind a sheet or screen. Out of sight of the other subjects, this person makes sounds using various objects. For example, silver, lead, iron and wooden spoons can be used to tap objects such as a plate, a cracked plate, a glass, a porcelain cup, a plastic beaker, a free-standing bell, a bell on a table, a small bell, and so on. The rest of the group must try to identify the objects by the sounds.