SOUND

• SOUND:

  • It is composed of waves of compression and rarefaction in which the human ear is sensitive.
• Compression: is a region in a longitudnal wave where the particles are closest together
• Rarefaction: is a region in a longitudnal wave where the particles are furthest apart
• Properties of sound:

  • Amplitude
  • Wavelenght
  • Frequency
• Amplitude:

  The measure of the height of the wave or amount of maximum vertical displacement of vibrating particles of the medium from their mean position.
• Wavelength:

  The size of a wave is measured by the distance between two consecutive crests or troughs.
• Frequency:

  The number of times per second that a sound pressure wave repeats itself.
• Frequency= Velocity/ Wavelenght

  Unit of Frequency: Hz
• Characteristics of Sound:

  Loudness (dB)

  Pitch (Hz)

  Quality / Timbre
• Loudness (dB):

  The relation between the intensity or energy of any given sound in terms of the largeness of its amplitude to the intensity at the threshold hearing

  Quantitative: Higher amplitude = Louder

  Higher intensity/energy = Louder

  Increasing decibels = Louder

  Qualitative:

  Percieved loudness: Human perception

  Comparative loudness: louder/softer than

  Dynamic range: Softest/loudest parts
• Pitch (Hz)

  The sensation of a frequency of vibration of the sound waves.

  Quantitative:

  Higher frequency = Higher pitch

  Shorter wavelengths = Higher pitch

  Qualitative:

  Octave: One step higher = Doubling Frequency

  Musical Terms: High, Low, Sharp, Flat...

  Comparative Pitch: Higher / Lower than...
• Quality / Timbre:

  The characteristic enables us to distinguish one sound from another having the same pitch and loudness.

  Quantitative:

  Spectral Analysis: Harmonics / Overtones

  Harmonics-Noise Ratio: Purity of Sound

  Formant Analysis: Resonant Frequencies

  QUALITATIVE:

  Descriptive Terms: Upbeat, Soft, Metallic...

  Comparative Analysis: Different Quality

  Genre: Metal, Jazz, Classical, Country.
• Resonance:

  -The occurrence of a vibrating object causing another object to vibrate at a higher amplitude.

  -happens when the frequency of the initial object's vibration matches the resonant frequency or natural frequency of the second object.
• Constructive:

  When two waves travel in the same direction and are in phase with each other, their amplitude gets added, and the resultant wave is obtained.
• Destructive:

  Takes place in any location along with the medium when the two waves that interfere with each other have a displacement in the opposite direction.
• Variations in pitch to convey different emotions or emphasize key points.

  Pitch modulation enhances communication.
• Vocal chords have gap between them

  
• Narrow gap between Vocal Chords

  
• Sound Generation

  Higher tension and faster vibrations result in higher pitches.
• Articulatory System

  
• Vocal resonance

  
• kinds of sound:

  Infrasonic

  audible

  ultrasonic
• Infrasonic

  The sound waves are lower in frequency (below 20 Hz) than what humans can hear. It includes small vibrations that can harm the body.
• Audible

  The frequencies residing between the limit of 20Hz and 20KHz can be perceived by human beings.
• Ultrasonic

  The acoustic waves are so high in frequency (above 20,000 Hz) that humans can't hear them. Can be used in medicine and heard by other animals.
• Sound travels slowest in gases:

  • because the particles in gases are spaced farther apart, leading to lower collision frequencies and slower transmission of sound waves through the medium.
  • The lower density and greater distance between particles in gases result in a lower speed of sound compared to liquids and solids.
• The primary factor that affects the speed of sound in air is temperature.

  • Sound travels faster in warmer air and slower in colder air. This relationship is a result of the way temperature influences the average speed of air molecules. As temperature increases, the molecules move faster, transmitting sound more rapidly.
  • Other factors, such as humidity and air pressure, also have some influence on the speed of sound, but their effects are generally secondary compared to the dominant impact of temperature
• sound cannot travel in a vacuum:

  • Sound requires a medium, such as air, water, or a solid substance, to propagate because it relies on the vibration of particles in that medium. In a vacuum, matter is absent, and thus, there are no particles for sound waves to interact with.
  • Since sound is a mechanical wave that travels through the oscillation of particles, it cannot travel through the space of a vacuum where there are no particles to transmit the vibrations.
• In the context of sound, diffraction refers to the bending of sound waves around obstacles or the spreading of sound waves as they encounter openings.