Decibels Flashcards

1
Q

dBm Reference

A

1mW

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2
Q

dBm=

A

dBm=10LogP/.001

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3
Q

dBu Reference

A

.775V

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4
Q

dBu=

A

dBu=20LogE/.775

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5
Q

dBV Reference

A

1V

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6
Q

dBV=

A

dBV=20LogE/1

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7
Q

Threshold of Hearing, Feeling, & Pain

A

Hearing: 0dBSPL

Feeling: 118 dBSPL

Pain: 140 dBSPL

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8
Q

2x Power=

A

3dB

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9
Q

2x SPL=

A

6dB

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10
Q

2x Voltage=

A

6dB

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11
Q

10x SPL=

A

“Twice” as Loud

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12
Q

0 VU= ? for Pro Audio

A

0VU= 1.23V for +4dBm (Pro Audio)

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13
Q

0 VU= ? for Broadcasting Equipment

A

0 VU= 1.09V for +8dBm (Broadcasting)

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14
Q

0 VU= ? for Consumer Audio

A

0 VU= .316V for -10dBV (Consumer)

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15
Q

A dBm meter is only accurate across ____Ω

A

600Ω

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16
Q

Level Changes:

1) 2x Power
2) 2x Voltage
3) 10x Increase in Sound

A

1) dB=10Log P1/P2
2) db=10Log E1/E2
3) dB=20Log SPL1/ SPL2

17
Q

Each Doubling in Distance There Is a ____dB Decrease in Level

A

6dB

(dB=20Log d1/ d2)

18
Q

Doubling Distance Sound Will Radiate by ____times

A

4

(4πr2)

19
Q

Voltmeter

A

Will show relative volume or loudness
Divided into Volume Units

A voltmeter of a specified transient response

20
Q

Full Scale Meter
Peak Program Meter

A

Calibrated in dBFS
Does not correlate with percived volume

21
Q

Near Field

A

An area in the immediate vicinity of the transducer

22
Q

Far Field

A

Area just beyond the near field

23
Q

Free Field

A

Where the inverse square law applies

24
Q

Reverberant Field

A

When the contribution of the sound source is not the strongest

25
Q

Echo

A

The delayed arrival of a reflected sound

26
Q

Flutter Echo

A

Short rapid succession of echos
Created by parallel walls or diagonally opposite corners

27
Q

Reverberation

A

A series of multiple echoes so closely spaced to merge into a continuous sound, decreasing in amplitude over time

28
Q

Reverberation Time

A

The time it take the original steady state sound to decay 60 dB @ 500 Hz