Architectural Acoustics Basics

Elements of Acoustic Situations

• All acoustic situations contain three elements: sound source, a medium, and a receiver
• Sound sources are objects that vibrate and produce sound
• The medium is the substance through which sound waves travel
• The receiver is an object that receives the sound waves

Transmission Path in Architectural Acoustics

• The transmission path refers to the route sound waves take from the source to the receiver
• It can be direct, reflected, or diffracted

Airborne Sound Medium

• Air is the most common medium for airborne sound in architectural acoustics
• Sound can travel through other mediums like water, wood, or metal

Sound in Architectural Acoustics

• Sound is defined as a form of energy that travels in the form of waves
• These waves cause vibrations in the air, which are perceived by our ears

Wave Motion Characterization

• Wave motion involves a disturbance that propagates through a medium
• The disturbance causes particles in the medium to vibrate
• The vibration pattern is repetitive and characterized by a wavelength

Reverberation in Architectural Acoustics

• Reverberation refers to the persistence of sound waves in a space after the sound source has stopped
• This occurs as sound reflects off surfaces, creating multiple echoes
• Reverberation time is the time it takes for the sound intensity to decay by 60 dB

Sound Energy Radiated by a Source

• The total sound energy radiated by a sound source is called acoustic power
• It is measured in watts

Spherical Sound Wave Spread

• In the free field, the sound wave spreads spherically from the source
• This is because there are no obstacles to reflect or diffract the sound waves

Intensity Level Description

• Intensity Level describes the amount of sound energy passing through a unit area per second
• It is expressed in decibels (dB)

Noise Reduction Materials

• Materials applied externally to surfaces to reduce noise penetration are known as sound insulation
• These materials absorb or reflect sound waves to prevent them from passing through

Sound Pressure Level Measurement

• The sound pressure level is measured using a sound level meter
• This instrument converts sound pressure waves into an electrical signal, which is then displayed on a scale

Noise Reduction (NR)

• Noise Reduction (NR) represents the difference in sound pressure level between two locations
• It is a measure of how much sound energy is reduced by a barrier or other sound-absorbing material