Decibels

Question 1

intensity is measured in ___ which is 1/10 of a ___

Answer 1

dB
Bel

Question 2

a decibel is named after

Answer 2

Alexander Graham Bell

Question 3

unit of intensity most commonly used is the

Answer 3

dB

Question 4

dynamic range

Answer 4

difference between softest sound and loudest sound a human can hear

Question 5

threshold of hearing

Answer 5

power: 1 x 10^-12 watt/m2
pressure: 20 uPa of .0002 dyne/cm2

Question 6

threshold of pain

Answer 6

max amount to damage ossicles
power: 1x10^12 watt/m2
pressure: 200,000,000 uPa

Question 7

decibel features

Answer 7

uses ratio
uses logarithm
nonlinear scale
various reference levels

Question 8

dB IL

Answer 8

intensity level
watts/m2
electronics
10^-12

Question 9

dB SPL

Answer 9

sound pressure level
noise levels
20 uPa

Question 10

dB HL

Answer 10

hearing level
audiometers and audiograms
audiometric zero = 0 dB HL

Question 11

dB SL

Answer 11

sensation level
20 above threshold
speech recognition testing

Question 12

ratios mean

Answer 12

in relation to itself

Question 13

audiometric zero

Answer 13

average pressure needed at each frequency

Question 14

sensation level

Answer 14

presentation level - patient’s threshold

Question 15

if the speech presentation level is 75 dB HL and the patient’s speech threshold is 30 dB HL what is the sensation level?

Answer 15

75 - 30 = 45

Question 16

if the patient’s threshold is 50 dB HL and the presentation level should be 30 dB SL, what should the presentation level be in HL?

Answer 16

50 + 30 = 80

Question 17

relationship between power and pressure

Answer 17

power = pressure 2

Question 18

Power reference

Answer 18

dBIL = 10log
power output / power reference

Question 19

Pressure reference

Answer 19

dBSPL = 20 log (power output / power reference)

Question 20

rules: doubling

Answer 20

IL: 3
SPL: 6

Question 21

rules: factor of 10

Answer 21

IL: 10
SPL: 20

Question 22

70 dB SPL + 70 dB SPL

Answer 22

76 dB
just adding 6 because there are 2 speakers at 70

Question 23

if the total SPL of two speakers is 140 dB, what is the SPL of each speaker?

Answer 23

140 - 6 = 134 dB

Question 24

inverse square law

Answer 24

every time we double we subtract 6
every time we half we add 6

Question 25

If Jimmy is sitting four feet from the teacher and receiving the teacher’s voice at 66 dB SPL and Jenna is sitting 8 feet from the teacher, what SPL is Jenna receiving the teacher’s voice at?

Answer 25

66 - 6 = 60 dB SPL

Question 26

when sound intensity doubles the sound intensity level increases by

Answer 26

3

Question 27

when sound pressure doubles, the sound pressure level increases by

Answer 27

6

Question 28

when the sound intensity increases by a factor of 10, the sound intensity increases by

Answer 28

10

Question 29

when the sound pressure increases by a factor of 10, the sound pressure increases by

Answer 29

20

Question 30

every doubling of the distance from the sound source in a free field situation, the sound intensity will diminish by

Answer 30

6