~Chapter 12 - Lecture Section 12.2

Question 1

Our perception of sound quality is influenced by the ___, and much of it can be attributed to ___ vs ___ sounds.

Answer 1

environment // indirect // direct

Question 2

What are Direct Sounds?

Answer 2

Sound waves reaching your ear traveling straight from the source

Question 3

What are Indirect Sounds?

Answer 3

Sound waves reaching your ear later, after they have bounced off other objects

Question 4

The outdoors are mostly ___ sounds, whilst indoors has more ___ sounds.

Answer 4

direct // indirect

Question 5

Even though ___ sounds reach our ears from many different directions, they usually don’t affect ___.

Answer 5

indirect // sound localization

Question 6

Indirect sounds still affect our perception of ___, but the time it takes for the reflected sounds to reach the ears is usually too long, and we end up treating it slightly different than the ___.

Answer 6

sound quality // ITD’s

Question 7

If sound is coming from the lag and the lead speaker simultaneously, there will be fusion, and they’re gonna perceive the sound as coming from the ___, because there is ___ IDT.

Answer 7

center // 0

Question 8

If there is a very slight delay between 0.1-1ms, with the lead (R) speaker stimulating first followed by the lag (L) speaker, the subject will perceive the sound as coming slightly to the ___ on the Azimuth, because the lead speaker is activated first.

Answer 8

right //

Question 9

With a longer delay from the lag (L) speaker of 1-5ms, there is the ___, where all of the sound is attributed as coming from the ___ speaker. In other words, ITD is too ___, and all localization info is assigned to the extreme range.

Answer 9

precedence affect // lead // long

Question 10

If the delay from the lag (L) is longer than 5ms, then the two sounds are perceived ___, such that, the second sound is perceived as an ___.

Answer 10

separately // echo

Question 11

Longer time means a ___ Echo Threshold.

Answer 11

higher

Question 12

When the delay between ___ and ___ sound exceeds a certain time we start to hear an ___

Answer 12

direct // indirect // echo

Question 13

For brief clicks, the Echo threshold is ___.

Answer 13

5ms

Question 14

You can have a longer difference/Echo Threshold if between the lead and the lag, if the lag speaker is ___. This occurs naturally in the environment because indirect sounds lose some of their sound energy to the walls as the sound is bouncing off of the walls.

Answer 14

slightly quieter

Question 15

Indirect sounds are usually ___ than direct sounds.

Answer 15

quieter

Question 16

The Echo Threshold is longer for sounds with ___ durations, such as ___ and ___, and that has to have very ___ differences between the lead and lag speaker to be perceived as echoing.

Answer 16

long // speech // music // long

Question 17

What are Architectural Acoustics?

Answer 17

Architectural Acoustics is the study of how sound is reflected in rooms. Provides a practical application for auditory psychophysics.

Question 18

What is our perception of sound and our enjoyment of live music depend on?

Answer 18

1. The sound that is produced at the source

2. How sounds are reflected by the environment before they reach our ears

Question 19

Acoustic Engineers are mostly concerned with the ___.

Particularly the auditory ___ of live music.

Answer 19

perception of music // quality

Question 20

Certain concert halls give the ___ impression of “good acoustics”, such as the Symphony Hall in ___ and the Concertgebouw in ___.

Answer 20

subjective // Boston // Amsterdam

Question 21

If there is lots of absorption, there is going to be ___ reflected sound waves, and ___ indirect sound

Answer 21

very few // very little

Question 22

If there is little absorption, there’s going to be ___ reflected sound waves, and a ___ amount of indirect sound, this is a recipe for making something very echoey.

Answer 22

many // large

Question 23

The room ___ affects how long it takes indirect sounds to reach the listener

Answer 23

size

Question 24

If you have a ___, the indirect sounds don’t have to travel very far.

Answer 24

small room

Question 25

If you have a very large hall, sometimes the sound wave goes a very long distance and takes a very long time to get back, and so there will be a ___ between the direct and indirect sound.

Answer 25

very large delay

Question 26

The room shape affects the ___ that sound waves are reflected towards.

Answer 26

direction

Question 27

In a room where there is reflection of sounds away from the audience, that will emphasize ___, but there can also be very undesirable patterns of constructive and destructive interference if the room is shaped in an ___ way.

Answer 27

direct sounds // odd

Question 28

The New York Philharmonic Hall was built in 1962 with “optimal” reverberation time of ___. The entire interior was destroyed and rebuilt in 1992.

Answer 28

2s //

Question 29

What do Acoustic Engineers use to characterize the mix of direct and indirect sounds?

Answer 29

Reverberation time, Intimacy ratio, Bass ratio, and Spaciousness factor