Acoustics Flashcards by Delaney Payne

The rapid fluctuation in are pressure can be defined as?

Sound

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sound is defined as a _______ wave

Physical

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Sound is defined as a ______ vibration

Mechanical

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______ is defined as a series of pressire variations in air or in an elastic medium

sound

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What requirements are needed in order for sound to exist?

Source, transmission path, receiver

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Mechanical waves require?

A medium

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Sound waves are ____ waves, as opposed to the ________ waves of light and electricity

Mechanical, Electromagnetic

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This best decsribes what type of wave?
those waves in which the parcles of the medium move parallel to the propagation of the wave. For example sound waves are this
1) Longitudinal wave
2) Transverse Wave

Longitudinal Wave

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This best decsribes what type of wave?
Those waves in which the particle of the medium move perpendicular to the direction of the propagation of the wave. for example, ripples fromed on the surface of the water is this
1) Longitudinal wave
2) Transverse Wave

Transverse Wave

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_______ refers to the sound pressure or volume, and is perceived as loudness

Amplitude

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The frequency with which these pass a given point is measured as the number of cycles completed per second, measure in?

Hertz (Hz)

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Sound pressure, sound power, and sound intensity can all be expressed in?

Decibles (dB)

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______ is the decrease in energy or pressure for each unit area of a sound wave. Occurs as the distance from the source increases as a result of absorption, scattering, or spreading in 3 dimensions

Attenuation

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Sound ____ occurs where sound is reflected froma convex surface

Diffusion

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Sound _______ is the physical process by which sound passes around obstructions and through smalle openings

Diffraction

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_____ occurs when sounds reflected from a concave surface converge at a single point

Focusing

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the reflection of sound along a curved surface from a source near the surface is called?

Creep

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Areas near walls collect the majority of sound as a result of reflectionsl; these areas are known as?

Reverberant Fields

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_____ is the persistence of sund after the source of the sound as ceased, as a result of repeated reflections

Reverberation

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an ____ is a single reflection of a soundwave off a distant surface

Echo

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The ____ _____ of a room or space is defined as the time it takes for sound to decay by 60 dB. for example. if the sound in a room took 10 seconds to decay from 100dB to 40dB, the ____ _____ would be 10 seconds.

Reverberation Time

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the reverberation time is ______ proportional to the volume of the space and _______ proporional to the absoprtion of the surfaces

Directly, Inversely

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Natural ____ _____ is the amplificcation of the sound being heard from various reflections as well as directly from the source

Sound Reinforcement

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____ is a reflection of sound that arrives at the listener with a delay after the direct sound. the delay is directly proportional to the distance of the reflecting surface from the source and the listener.

Echo

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_____ _____ is produced by repetitive reflections off hard surfaces arriving at different times. We perceive it as a buzzing or clicking sound

Flutter Echo

_____ is another phenomenon that must be examined along with velocity and pressure when we are dealing with low-frequency energy within our smaller room acoustical enviornments. sound is produced by something vibrating. this vibration produces a sound that has a particular frequency.

Resonance

ASTM stands for?

American Society for Teting and Materials

______ is international has established methods fro measuring, analyzing, and quantifying noise

ASTM

ANSI stands for?

American National Standards Institute

____ sets scientific parameteres and cruterua used in acoustic analysis

ANSI

______ determines sound levels for mechanical systems

ASHRAE

ASHRAE stands for?

the American Society of Heating, Refrigerating and Air-Conditioning Engineers

What is the interior designers role when it comes to noise control?

1. Reduction at the source 2. Reduction along the paths of transmission 3. Reduction at the receiver

____ _____ is a sound that travels through the air. Examples: talking, sounds from radio and television, sounds from pets like a dog barking and sounds of cars starting

Airborne Sound

_____-_____ ____ is defined as sound that is carried via the structure of a building. Example: the noise of footsteps across an upper floor that are audible in the room below

Structure-borne sound

NRC stands for?

Noise Reduction Coefficient

AC stands for?

Articulation Class

_____ _____ _____ meaures the degree to which a ceiling panel absorbs sound

Noise Reduction Coefficient

_____ _____ measures how well a ceiling panel prevents sound from reflecting back down to adjacent workspaces in an open-plan enviornment

Articulation Class

CAC stands for?

Ceiling Attenuation Class

____ _____ _____ indicates the ability of a ceiling panel to block sound transmission

Ceiling Attentuation Class

STC stands for?

Sound TRansmission Class

_____ _____ ____ measures how well a wall or partition prevents sound from transmitting to the other side

Sound Tranmission Class

AI stands for?

Articulation Index

____ _____ represents how well speech can be understood in a given space. Expressed as a decimal value between 0 (unintelligible) and 1.00 (easily heard)

Articulation Index

what does PI srand for?

Privacy Index

____ _____ is the inverse of articulation index

Privacy Index

Sound tramission is measure by _____ ____ and by ______ _______ ______

Transmission losss / sound tranmission class

There are ___ families of asoptive materials. what are they?

3 1) Fibrous Materials 2) Panel Resonators 3) Volume Resonators

_____ ____ is a designed system using speakers that emit a finely tuned background white noise

Sound Masking

____ ____ is a combination of all the different frequencies of sound

White Noise

A ____ ____ is a space free from reflective surfaces or other interefernces , such as might occur outdoors

Free Field

the distance between the peak of one sound wave and the peak of the next is called its ____

Wavelength

Whether we perceive a sound as a high or low depends on its _____

Frequency

The frequency with which these peaks pass a given point is measured as the number of _____ completed per second, measured in ______

Cycles, Hertz (Hz)

A sources acoustical magnitude is a measure of the power of sound it may be termed _____ ______,

Sound Power, Sound Pressure, or Sound Intensity

Sound power varies over a very wide range from one source to another. It is expressed in ______ _____ ______ ______, the basic unit of acoustical energy

Watts (W) of acoustical power

the loudness of sounds is measured in a way that relates actual sound intensity to the way humans experience sound, rather than in ______ (sound pressure) or _____ (sound energy)

Pascals, Watts

Loudness is measyre according to a mathematical logarithmic scale of _______

Decibles (dB)

A _____ is a unit for expressing the relative pressure or intensity of sounds

Decibel (dB)

________ ____ expresses the realtive loudness of sounds in air as perceived by the human ear

A-Weighted Decibels (dBa)

_____ _____ occurs when two seperate sources of sound are perceived simultaneously, obscuring each other

Sound Masking

____ is simply defined as any unwanted sound

Noise

____ is pressure variation percieved through touch

Vibration

______ is the decrease in energy or pressire for each unit area of a sound wave

Attenuation

____ _____ leaves the surface at an angle equal to the angle at which it strikes it

Reflected Sound

The ____ ____ is the time it takes in a particular space for a sound to drop 60 dB

Reverberation Time

_____ occurs where sound is reflected from a convex surface

Diffusion

_____ is the physical process by which sound passes around obstructions and through small openings

Diffraction

____ is a rapid succession of echoes with sufficient time between each reflection for the listener to be aware of separate, discrete signals

Flutter

A ____ ____ is a steady, pure tone between two highly reflectuve parallel walls

Standing Wave

_____ occurs when sounds reflected from a concave surface coverage at a single point

Focusing

The reflection of sound along a curved surface froma source near the surface is called a _____

Creep

the ___ ____ is the ratio of sound energy absorbed to sound energy impinging on the surface of a material

Absorption Coefficient

The absorption coefficient depends on the frequency and ____ ___ _____ of the sound

Angel of incidence

There are 4 areas if concern when it comes to acoustics in an archecticetural sense. What are they?

1) room acoustics 2) sound isolation 3) mechanical equipment 4) sound systems

An ____ ____ ____ uses a hard-wired or wireless system to transmit an audible signal

Assistive listening system

Music would sound better in what kind of space?

A reverberant one

How does Attenuation work?

It reduces sound energy by seperating a sound source from the listener

What are the 3 acoustic fields?

1) Free field 2) Reverberant Field 3) Reverberant Field with Absoption

What type of field best describes this? "... attenuates as it spreads out without interruption"

Free Field

What type of field best describes this? "... the area closests to large obstructions such as walls, where conditions approach a diffuse acoustic field"

Reverberant Field

When a sound reflects off a hard polished surace, the result is termed?

Specular (mirror-like)

____ ____ orginates in a space with any sound-producing source

Airborne Sound

___ ___ is energy delivered by a source that directly vibrates or hits the structure

Structure-borne

____ ____ can occure at any air passageways such as key-holes, cracks around doors or windows, or gaps between walls and floors

Sound Leaks

_____ ____ is the acoustic path of least resistance

Flanking Path

_____ ______ improves both airborne and structure-borne sound transmission problems

Discontinous Construction

____ _____ is a measure of of the performance of a building material or consutrction assembly in preventing transmission of airborne sound

Transmission Loss (TL)

_____ ____ is related to the wall Mass (heaviness and density), rigidity (layers and air spaces), absorbency of materials, and method of construction and attachment.

Transmission Loss

____ ____ is a another major acoustic concern for interior designers

Speech Privacy

A space with many absorptive surfaces that does not support sond is termed ___ ___

Dead Space

A ___ ____ has reflective sufaces to sustain the sound through several reflections before it attenuates to the point of inaudibility

Live Space

Sound absorption is measured by a materials ____ ____ ___ or its ____ ____ ____

Sound Absorption Coefficent, Noise Reduction Coefficent

____ ____ consist of a membrane of thin plywood or linoleum in front of a sealed air space that usually contains an absorbent material

Panel Resonators

____ ____ are usually hollow concrete blocks with open slits that allow sound waves to enter

Volume Resonators

_____ can be considered as a mixture of previous and more recent sounds

Reverberation

____ _____ generally depends on mass, resiliency, and tightness. The more massive the barrier the less likely sound is to make it vibrate significantly

Sound Isolation

Less stiffness results in high ____ ____

Internal Damping

_____ _____ ____ Separate the walls structure from its surface material

Resilient Furring Channels

____ ____ is acoustical insulation that is usually made of fiberglass impregnates with rubber neoprene compoud to avoid fibers crom coming loose in the air current

Duct Lining

_____ ____ ____ is a rating for floor construction similar to the STC rating for walls. It rates the ability of a floor system to isolate impact noise

Impact Insulation Class (IIC)

Acoustically ____ _____ like concrete and brick reflect sound while resisting vibrations that could allow the sound to continue on in adjacent spaces

Massive Materials

Soft, Porous, acoustically absorbent materials are often covered with perforate metal or other materials for protection and stiffness. These coverings are designed to be?

Acoustically Transparent

AI stands for?

Articulation Index

Which office acoustic measurement best fits this description? " relates speech intelligibility, speech intensity, and background sound level at 5 octave-band frequencies. Weighted to emphasize intelligibility. Requires complex computer calculations to derive"

Articulation Index (AI)

Which office acoustic measurement best fits this description? " derived from open-office cubicle measurements. indicates absorption at angles of incidence between 45 and 55 degrees. Higher ratings indicate less sound bounces off the ceiling int adjacent cubicles. Ratings range from from 170 to 210"

Articulation Class (AC)

AC stands for?

Articulation Class

Which office acoustic measurement best fits this description? "Measures how well a ceiling structure attenuates airborne sound between two closed rooms over the range of speech frequencies"

Ceiling Attenuation Class (CAC)

CAC stands for?

Ceiling Attenuation Class

Which office acoustic measurement best fits this description? "US General Servies Administration (GSA) rating summarizes background sound level and attenuation between source and listener"

Speech Privacy Potential (SPP)

SPP stands for?

Speech Privacy Potential

____ happens when a system changes the shape of the acoustical signal that it receives; some stages of the amplification

Distortion

____ _____ occurs when a reproduced sound loses its naturalness and acquires and unpleasant, ringing quality

Sound Coloration

When the system is turned up too loud it produces, _____ _____ or howling

Acoustic Feedback