Simpson 886-2, Operator'S Manual, Page: 11 / 24

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any commercial, photography-type tripod for remote operation of the micro-
phone.
NOTE: The accuracy of a measurement will be affected by several factors, one of
which is the position of the microphone with respect to the sound source. Read
Section 3 carefully for general background information. (See Section 4 for oper-
ating instructions for obtaining correct data from the measurements
2.6 Care
a. Immediately clean any spilled materials from the Instrument and wipe dry. If
spillage is corrosive, use a suitable cleaner to remove it and to neutralize
corrosive action.
b. To protect the microphone, keep sharp objects away from the top. Never rest
the unit on the microphone. If the microphone is detached, always lay it on its
side.
c. Whenever the Instrument is not in use, set the range switch to the OFF posi-
tion.
d. Avoid prolonged exposure or usage in areas subject to temperature and
humidity extremes, vibration, mechanical shock, dust, corrosive fumes, and
strong electrostatic and electromagnetic interference.
e. Verify Instrument calibration with a 890-2 Acoustical Calibrator.
f. It is recommended that the Instrument be returned to factory annually (sooner
if required) for a complete overall check, adjustment, and calibration.
g. When the Instrument is not in use store it in a room free from temperature
extremes, dust, corrosive fumes, mechanical vibration and shock. If storage
time is expected to exceed 30 days, remove the battery.
3. APPLICATION
This section contains basic information required for effective application of the
886-2 Sound Level Meter, and must be understood before attempting to operate
the Instrument for the first time.
3.1 Decibel Scale
The human ear has a mid-frequency dynamic sound sensitivity range of greater
than one million to one, from the lowest level that can be detected to the highest
that can be tolerated without pain. Because of the large ratio of value involved, a
linear meter scale marked in pressure units becomes impractical. A scale based
on logarithms, called a decibel (dB) scale, is used. This scale expresses the ratio
between the sound pressure level being measured and a reference. This simpli-
fies notation and manipulation by reducing large ratios into smaller convenient
numbers. For example, a million-to-one pressure ratio can be expressed on a 0
to 120 dB scale.
3.2 Measurement And Exposure Standards
The American National Standards Institute (ANSI), in collaboration with scientific
and engineering societies, has established a standard, S1.4-1983, for conform-
ance of all approved sound level meters. Federal, state and local governments