Chapter 7

Question 1

Expresses the relative loudness of sounds in air as perceived by the human ear. The a-weighted system reduces the decibel values of sound at low frequencies to correct for the human ear’s lessened sensitivity at low frequencies.

Answer 1

A-weighted decibels (dBa)

Question 2

The ratio of sound energy absorbed to sound energy impinging on the surface of a material; depends on the frequency and angle of incidence of the sound.

Answer 2

Absorption coefficient

Question 3

The planning, shaping, finishing and furnishing of an enclosed space to establish and acoustic environment necessary for the distinct hearing of speech or musical sounds

Answer 3

Acoustical design

Question 4

The branch of physics that deals with the production, control, transmission, reception, and effects of sound

Answer 4

Acoustics

Question 5

Refers to sound pressure, apparent as the distance between a sound wave’s maximum compression and it’s maximum rarefaction. The wave’s amplitude is also referred to as its volume and is perceived as loudness.

Answer 5

Amplitude

Question 6

The reflection of sound along a curved surface from a source near the surface

Answer 6

Creep

Question 7

A unit for expressing the relative pressure or intensity of sounds on a uniform scale from 0dB for least perceptible sound and 130dB for the threshold of pain.

Answer 7

Decibels (dB)

Question 8

A rapid succession of echoes with sufficient time between each reflection for the listener to be aware of separate discrete signals, often reflected back and forth between two parallel flat or concave surfaces

Answer 8

Flutter

Question 9

The phenomenon when two separate sources of sound are perceived simultaneously and tend to obscure each other

Answer 9

Masking sound (sound masking)

Question 10

Any unwanted sound

Answer 10

Noise

Question 11

Sound that leaves a surface at an angle equal to the angle at which it strikes

Answer 11

Reflected sound

Question 12

Occurs when sound is intensified and prolonged by reverberation, accentuating a particular frequency

Answer 12

Resonance

Question 13

The persistence of sound within a space caused by multiple reflections after its source has stopped

Answer 13

Reverberation

Question 14

Essentially a rapid fluctuation in air pressure, a range of vibrations to which the human auditory system is specifically sensitive.

Answer 14

Sound

Question 15

A pressure variation perceived through touch.

Answer 15

Vibration