AR 324-ARCH32S1 | Building Utilities 3: Acoustics Background

Focus of Acoustics

• Acoustics is the branch of physics concerned with the study of sound, its production, transmission, and effects.

Human Reaction to Sound

• Psychoacoustics is the field that examines human responses to audible sound, including perception and cognition of sound.

Environmental Acoustics

• Environmental acoustics focuses on sound in natural and built environments, including noise pollution and its effects on people and wildlife.

Noise Control in Man-Made Surroundings

• Architectural acoustics addresses the management of sound in built environments, aiming to minimize unwanted noise and enhance desirable sound characteristics.

Electroacoustics

• Electroacoustics involves the study of sound reproduction and transmission through electronic means, focusing on devices like microphones and loudspeakers.

Sonics

• Sonics pertains to the behavior and characteristics of sound waves, exploring their properties and interactions in various mediums.

Threshold of Audibility

• The threshold of audibility refers to the lowest sound level that the average human ear can perceive, typically measured at around 0 dB.

Unit of Frequency

• Frequency is measured in Hertz (Hz), representing the number of cycles of sound waves per second.

Loudness

• Loudness is the perceptual response to the intensity of sound, influenced by the sound’s amplitude and frequency.

Pitch

• Pitch refers to the perceived frequency of a sound, determining how high or low a tone is, which is closely linked to sound wave frequency.

Intensity Measurement

• Sound intensity is measured in Watts per square meter (W/m²), indicating the power of sound waves passing through a given area.

High Frequency Sounds

• High frequency sounds typically exhibit more directional radiation patterns, concentrating sound energy in a narrow beam compared to lower frequencies.

Wavelength

• Wavelength is the distance between successive peaks or troughs of a sound wave, inversely related to frequency; higher frequencies have shorter wavelengths.

Natural Elements Affecting Sound

• Natural elements like temperature, humidity, wind, and obstacles can significantly influence the propagation and perception of sound.

Sound Pressure

• Sound pressure is the local pressure variation from the ambient atmospheric pressure caused by a sound wave, measured in Pascals (Pa).

Speed of Sound

• The speed of sound refers to how quickly sound waves travel through a medium, typically measured in meters per second (m/s), and varies with temperature and medium density.