1. SOUND & INTENSITY
1. SOUND, SILENCE AND NOISE
Sound is a physical phenomenon that is produced when an object vibrates. The vibration is transmitted in the form of sound waves and it must travel through a “medium” such as air, water and wood. The speed of sound through air is 340 meters per second (m/s). Sound cannot travel through a vacuum because there are no particles to carry the vibrations.
Chladni plates experiment
Acoustics is the scientific study of sound and how it behaves in a room through reflection, refraction, and absorption. Controlling sound is essential to design spaces like auditoriums (where sound must travel well) or libraries (where sound must be blocked). When a sound wave hits a surface, it is partially reflected, absorbed, and transmitted. Materials change this behavior; for example, a tiled floor causes more reverberation than a carpeted one.
Silence is the absence of sound or noise. In music, rests are just as important as sound because both form the basis of musical creation. Composers use rests for different purposes: as a contrast, as a brief pause between sections, or to mark the beginning or end of a piece. Some composers, like John Cage, use silence as the main element of their work; for example, his piece 4’33'' consists of 4 minutes and 33 seconds of silence.
John Cage - 4'33''
Anechoic chamber
"There is no such thing as silence.
Something is always happening that makes a sound."
– John Cage
Noise is usually defined as a disagreeable auditory experience, but this is a subjective definition. The difference between sound and noise is the sort of waves: sound waves are regular and noise waves are irregular.
Noise pollution occurs when sound is too loud or lasts too long. It is a common society problem that can harm our health.
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Causes: Transportation, industry, construction and social events.
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Health effects: Hearing loss, sleep disorders, stress and aggressive behavior.
2. HEARING
The ear is the organ that perceives sound. Hearing is the process in which sound waves are captured by the outer ear and cause the eardrum to vibrate in the middle ear. These vibrations are turned into electrical signals and transmitted to the brain in the inner ear.
Ear parts: A outer ear, B middle ear, C inner ear; 1 pinna, 2 ear canal, 3 eardrum, 4 hammer/malleus, 5 anvil/incus, 6 stirrup/stapes, 7 Eustachian tube, 8 semicircular canals, 9 cochlea, 10 auditory nerve.
Human hearing limits
The human ear cannot detect all sounds.
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Regarding pitch, the range of human hearing normally goes from 20 to 20.000 hertz (Hz). Frequencies below the human hearing range are known as infrasounds and those above it are known as ultrasounds. But age and prolonged exposure to loud sounds can significantly lower your ability to hear high frequencies.
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Regarding intensity, the range of human hearing normally goes from 10 decibels (dB) which is the threshold of hearing to 120 decibels (dB) which is the threshold of pain.
Ear care tips
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Don't stick cotton swabs or your nails into your ears because you can damage the ear canal, push earwax deeper into the ear and even rupture your eardrum.
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Lower the volume of video games, television and music, especially if you listen to them with in-ear earphones (those that are worn inside the ear) as they can damage your hearing.
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Wear protective earplugs or earmuffs when you are exposed to loud noises at concerts, car races, etc.
3. QUALITIES OF SOUND
Every sound has four qualities: intensity, pitch, duration and timbre.
Intensity is the quality of sound that depends on the wave amplitude and allows us to distinguish between loud and soft sounds. We represent intensity in scores by means of dynamic markings.
Pitch is the quality of sound that depends on the wave frequency and allows us to distinguish between low and high sounds. We represent different pitches in scores by means of musical notes.
Duration is the quality of sound that depends on the wave persistence and allows us to distinguish between long and short sounds. We represent duration in scores by means of note values and rests.
Timbre is the quality of sound that allows us to identify the object that produces the sound (different voices and instruments). It depends on the shape of the object, the material from which it is made and the way the sound is made. The result is a complex wave composed of a fundamental frequency and its harmonics.
4. INTENSITY AND DYNAMICS
In music, the word dynamics describes the volume of sound, which is represented in scores with dynamic markings. These markings are usually placed below the staff using Italian words, abbreviations or signs. Sound intensity is measured in decibels, but dynamic markings are relative because they do not match a specific number of decibels. For example, a fortissimo played by a whole orchestra is much louder than a fortissimo played by a single violin.
Haydn - Symphony n. 94 'Surprise' II. Andante
Björk - It's Oh So Quiet
Types of dynamic markings
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Uniform dynamic markings indicate that the volume stays the same until a new marking changes it. The basic terms are piano (soft) and forte (loud), which can be modified with prefixes like mezzo- or suffixes like -issimo. Some composers use these extreme dynamics. E.g. Tchaikovsky’s Pathetique symphony includes six pppppp, Holst's Mars uses four ffff and Ligeti's The Devil's Staircase goes up to eight ffffffff.
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Variable dynamic markings indicate a gradual change in volume. The signs < and > are called hairpins and they are as long or short as necessary to indicate how long the effect should last.
Debussy - Clair de lune
(pianissimo)
Carl Orff - Carmina Burana. O Fortuna
(fortissimo - pianissimo)
R. Strauss - Also Sprach Zarathustra
(crescendo)
Grieg - The death of Aase
(crescendo - diminuendo)
ACTIVITIES
1. Write the type and meaning of the following dynamic markings.
2. Order these dynamic markings from softest to loudest.
Mezzopiano – Fortissimo – Pianississimo – Mezzoforte – Fortississimo – Pianissimo – Piano – Forte
3. Sound meter task.
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a) Measure 3 sounds you hear in your environment with a sound meter app and write down the result in dB.(Sound Meter: Android or Decibel X: Android & iOS). Describe them using these adjectives: high, low, loud, soft, long, short, pleasant, unpleasant, irritating, stressful, serene, calm.
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b) Analyze the results taking into account that the limit noise level per day accepted by the World Health Organization (WHO) is 55-65 dB. Is there noise pollution in your environment? How can we reduce noise pollution?
REVIEW