Mitsubishi Electric Lossnay series Technical Manual page 53

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CHAPTER 4 Characteristics
* Approximate values of sound levels using practical examples
The following diagram shows typical everyday sounds.
Approximate degree of sound levels can be seen.
* Sound levels and perception
Boiler making
Forging, riveting,
drilling
Grinder
Engine, large
motor
Loud factory
Normal
machine
factory
U-44
Subway
Computer
Overhead
room
train
Typing
room
Many
Passenger
occupants
car
Few
Business
occupants
and
industrial
district
Suburb
Quiet
night
(dB)
130 Painful to ears
120
110 Slight pain to ears
100 Too loud want to cover
ears
90 Conversation with the
person near you is
not possible
80 Conversation is not
possible unless voice is
raised
70 Voice is raised
intentionally to converse
60 Loud, but normal
conversation is possible
50 Sound is audible and
disturbing
40 Quiet but not peaceful
30 Peaceful
20 Very quiet
10
0
Source: "Heibon Sha, Industrial Encyclopedia"
Near a airplane engine
Automobile horn
(2 m away)
Train with open
window in tunnel
Train passing on
overhead tracks
Train passing through
shopping district
Shopping district with
heavy traffic
In busy office
Among quiet group
of pedestrians
In quiet group of
people
In broadcasting studio
Sound of leaves
brushing against
each other