Introduction to acoustics
Page 1: Introduction
Title: The Science of Acoustics: Man, Space, and Sound
Prepared by: Ar. Jay Jabonete, UAP
Notes by: Ar. Danilo Ravina, UAP RMP
Page 2: Architectural Acoustics
Definition: Architectural acoustics is the art and technique of designing spaces and structures to meet hearing needs.
Importance: Knowledge of architectural acoustics allows designers to integrate sound control requirements with other building functions.
Page 3: Objective of Architectural Acoustics
Designing considerations: Architectural acoustics ensures rooms or buildings provide comfort and facilitate communication, tailored to the building's specific purpose and use.
Page 4: Acoustical Objectives in Buildings
Control Echoes: Analyze room shape and sound absorbing materials for optimal sound distribution.
Reduce Sound Transmission: Implement proper insulation to minimize sound between rooms.
Isolate Noise: Prevent noise from machines and equipment from affecting the acoustic environment.
Goal: Allow 'wanted' sound to be clearly heard while masking 'unwanted' sound to prevent annoyance.
Design Stage: Acoustical objectives should be integrated early in the design process.
Page 5: What is Sound?
Definition:
The oscillation in atmospheric pressure detectable by the human ear.
A form of energy that propagates in waves, converting into heat through material friction.
The sensation from air pressure fluctuations perceived by the ear.
Page 6: Nature of Sound
Essential Elements:
Source of sound
Medium or Transmission Path
Receiver
Page 7: Source of Sound
Definition: A vibrating body that converts energy into sound vibrations.
Transducers: Devices converting energy into sound, e.g., loudspeakers, microphones.
Page 8: Transmission Path
Definition: Any medium that allows sound vibrations to travel as waves.
Types:a. Airborne Sounds: transmitted through airb. Structure borne Sounds: transmitted through solid materials
Page 9: Receiver
Definition: The human ear as the receiver of sound.
Influences: External factors can affect how sound is received.
Page 10: Types of Sound
Music: Organized sounds with melody, rhythm, harmony.
Speech: Vocal expression to communicate.
Noise: Loud and harsh sounds classified as disorganized sound, e.g., street noise.
Page 11: Sound Waves
Definition: Longitudinal waves through which sound energy travels, transporting energy away from the source without moving the material itself.
Mechanical Requirement: Sound requires a medium for wave propagation; cannot travel through a vacuum.
Page 12: Components of Sound Waves
Cycle: Full particle circuit.
Frequency: Complete cycles per second, measured in Hertz (Hz).
Amplitude: Maximum particle displacement from equilibrium.
Period: Time for one complete vibration, measured in seconds.
Page 13: Properties of Sound
Speed or Velocity
Frequency (Pitch or Tone)
Power (Intensity or Loudness)
Sound Pressure
Threshold of Audibility
Threshold of Pain
Directionality of Sound Sources
Page 14: Speed or Velocity of Sound
Sound travels at 330 meters/second at room temperature (20°C).
Speed increases in denser media; faster in liquids and solids than in air.
Temperature affects speed; sound travels faster at 30°C than at -17°C.
Page 15: Frequency and Pitch
Definition: Frequency indicates pitch. Higher frequencies yield higher pitches.
Measurement: Number of vibrations in cycles per second (Hertz).
Hearing Range: Human hearing ranges approximately from 20 to 20,000 Hz, with sensitivity highest around 500 to 4,000 Hz.
Page 16: Power and Intensity
Sound Intensity: Describes loudness/pressure against the eardrum, measured in decibels (dB).
Decibel Scale: 0 dB signifies threshold hearing; 3 dB increase doubles sound intensity.
Examples:
Whisper: 15 dB
Normal Speech: 60 dB
Loud Talking: 75 dB
Shouting: 90 dB
Page 17: Conclusion
End of Document