1. Sounds around us / Soundscape #

What is sound? #

• Sound is mechanical oscillation/vibration; it can oscillate in two ways: regularly and irregularly.

s.boot;
s.scope;

Ndef(\chaos,{Gbman2DL.ar(2 + LFNoise2.kr(2).range(0.5,10), 800+LFNoise0.kr(100).range(2,5000)).dup * 0.2}).play(fadeTime:2)
Ndef(\chaos).stop(2)
Ndef(\regular,{LFTri.ar(200).dup * 0.2}).play(fadeTime: 2)
Ndef(\regular).stop(2)

• If there were a perfect mechanical system, it could oscillate periodically like a sine wave.

Ndef(\sine,{SinOsc.ar(440).dup * MouseX.kr(0,0.5)}).play(fadeTime: 2)
Ndef(\sine).stop(2)

{SinOsc.ar(1000)}.plot;

Speed of sound #

Physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph)

In fresh water the speed of sound is approximately 1,482 m/s (5,335 km/h; 3,315 mph). In steel, the speed of sound is about 5,960 m/s (21,460 km/h; 13,330 mph). Sound moves the fastest in solid atomic hydrogen at about 36,000 m/s (129,600 km/h; 80,530 mph)

Properties of sound #

Sound has several fundamental properties that determine how we perceive it. These properties can be categorized into the following main groups:

• 1. Frequency (Pitch)

  Frequency: Measured in Hertz (Hz), frequency refers to the number of oscillations (vibrations) per second. Higher frequency sounds are perceived as higher in pitch, and lower frequency sounds are perceived as lower in pitch.

  The human ear/brain is capable of capturing frequencies within the range of <20,20,000><20,20,000> Hz. Anything above this range is called ultrasound, and anything below it is called infrasound. As we age, or are frequently exposed to noisy environments, this range decreases.

  Ndef(\sine, {SinOsc.ar(5570) * 0.2}).play
  Ndef(\sine).stop
  

  Human	20Hz-20kHz
  Chimpanzee	100Hz-20kHz
  Cat	30Hz-50kHz
  Rabbit	300Hz-45kHz
  Mouse	1kHz-100kHz

  • Sine wave

    Ndef(\sine,{SinOsc.ar(200).dup * 0.3}).play(fadeTime: 2)
    Ndef(\sine).stop(2)
    {SinOsc.ar(1000)}.plot;
    

    • When two sine waves vibrate

      1. If they have the same frequency, the resulting tone will be louder or quieter depending on how they combine.
      2. If they have very different frequencies, we perceive them as two separate tones.
      3. If they are close to each other in frequency, it creates a pulsating effect (beating).

  • Chladni patterns

    https://en.wikipedia.org/wiki/Ernst_Chladni

• 2. Amplitude (Loudness)

  Amplitude: This property measures the height of the sound wave. Greater amplitude results in a louder sound, while lower amplitude results in a quieter sound. Loudness is typically measured in decibels (dB).

• 3. Duration

  Duration: This refers to the length of time a sound lasts. Duration can vary from very short, like a drum beat, to very long, like a sustained note on a violin.

• 4. Timbre (Tone Color)

  Timbre: Also known as “tone color,” timbre is what allows us to distinguish between different musical instruments or voices when they are playing the same note at the same loudness. Timbre is affected by multiple factors, including the harmonic content of the sound, the attack and decay characteristics, and more.

• 5. Direction / Spatial location

  Direction: Sound can come from various directions and can also be reflected, refracted, and absorbed by materials in the environment. The directionality of sound is crucial in spatial awareness and is a key factor in sound recording and reproduction systems.

Phonemes #

The smallest units of sound in a language that can distinguish one word from another. https://phoible.org/

Does silence exists? #

John Cage 4'33''

Excercise 1a. #

• Go out and write down all the sounds you’ll hear.

Which one was the loudest? Which one was the quietest? Which one was the closest? Which one was the farest? Which one you like the best?

Acoustic Ecology #

Acoustic ecology, also known as soundscape ecology, is an interdisciplinary field that explores the relationship between living beings and their environment through sound. It encompasses various aspects, including the study of environmental soundscapes, the impact of noise on ecosystems, and the conservation of acoustic environments.

Soundscapes #

• The term “soundscape” refers to the sonic equivalent of a landscape, encompassing all sounds in an environment, whether natural, human, or mechanical.

Environmental Impact #

• Acoustic ecologists examine how sounds within an environment affect its inhabitants and how changes in soundscapes can signal environmental shifts or the presence of noise pollution.

Recording and Analysis #

• The field involves capturing environmental sounds for pattern analysis and monitoring, aiding in understanding and preserving the sonic signatures of different ecosystems.

Conservation Efforts #

• Acoustic ecology contributes to conservation by emphasizing the importance of the sonic environment and advocating for the reduction of noise pollution.

Education and Awareness #

• The field aims to raise awareness about the role of sound in our perception of the world and to promote active listening to foster a deeper connection with our environment.

Interdisciplinary Approach #

• It intersects with environmental science, music, anthropology, psychology, and urban planning, requiring a multidisciplinary perspective on sound and its effects.