What is louder : -20 dB or -30 dB ?
2006-12-26 05:14:19 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Decibels work like negative numbers 0db is whats refered to as nominal hearing. -30 -20 -10 0 +10 +20 +30
2006-12-26 11:18:54 · answer #1 · answered by Anonymous · 0⤊ 0⤋
-20 db of course
2006-12-26 13:18:29 · answer #2 · answered by topbakamuna 1 · 0⤊ 0⤋
-20 dB might be louder if it is really a sound. does a engative dB actually make a hearable noise?
2006-12-26 13:22:28 · answer #3 · answered by Anonymous · 0⤊ 0⤋
-20 dB is louder.because of the negative sign in front of it.
2006-12-26 13:19:21 · answer #4 · answered by Renaud 3 · 0⤊ 0⤋
Activity
Noise Level [dB(A)]
Apparent Loudness
Typical Physical Response
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Rocket launching 180 Danger level
Threshold of pain
Gunshot
Jet engine taking off
140 Danger level
Military jet
Air raid siren
Shotgun
Hydraulic press (3 m away)
130
512 times as loud
Limited ability to hear amplified speech.
Noise may cause pain.
Can damage hearing after 3.75 minutes exposure per day
Car horn
Propeller aircraft
Air-raid siren 120 256 times as loud Can damage hearing after 7.5 minutes exposure per day
Sand-blasting
Squealing pigs
Inboard motorboat
Typical night club
Unsilenced motorcycle (7m away)
110
Over 128 times as loud!!
Maximum vocal effort.
Can damage hearing after 30 minutes exposure per day
Amplified Rock Music 110-130 Over 128 to 512 times as loud!! Can damage hearing after
3.75 – 30 minutes
exposure per day
Helicopter
Motorised/power mower 105 Can damage hearing after 1 hour
exposure per day
Jet takeoff @ 500m
Train horn @ 30m
Diesel truck
Pneumatic drill/jackhammer
100
64 times as loud
Can damage hearing after 2 hours exposure per day
Heavy truck @ 15m
Busy city street
passing motorcycle
Lawn mower
Loud shout
Screaming child
90
32 times as loud
Very annoying.
Can damage hearing after
8 hours exposure per day
Average factory
Electric shaver 85
Busy traffic intersection
Motorway construction site
Outboard motor
Alarm clock (with bell)
Freight train (15m away)
80
16 times as loud
Annoying .
Motorway traffic @ 15m
Roadside traffic
Train horn @ 500m
Vacuum cleaner
Mixer
electric sewing machine
Noisy restaurant
Conversation in a loud voice
70
8 times as loud
Telephone use difficult.
Washing machine/dishwasher 65
Light car traffic @ 15m
City or commercial areas
Noisy office
Normal conversation
Clothes dryer
Background music
60
4 times as loud
Intrusive.
Quiet office
50
2 times as loud
Speech interference.
Refrigerator 45
Quiet residential area
Kitchen/bathroom
Public library
40
Arbitrary Base
Reference Level
Quiet .
Leaves rustling
Very soft music
Recording studio
Living/dining/bedroom
30
1/2 as loud
Very quiet.
Threshold of sound perception
10
1/8 as loud
Just audible.
Threshold of hearing
0
N/A
Not audible.
2006-12-26 13:25:37 · answer #5 · answered by OK 3 · 0⤊ 0⤋
20db
2006-12-26 13:36:22 · answer #6 · answered by todd s 4 · 0⤊ 0⤋