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1. INTRODUCTION
1.1 General Description
The Simpson 886-2 Sound Level Meter (hereafter referred to as the 886-2 or the
Instrument) is a portable, general purpose sound level instrument, capable of
accurate sound level measurements over a range of 40 to 140 dB. This encom-
passes the noise level of a quiet residence to that beyond the threshold of pain.
This dB range is compatible with current Federal, State, and local noise ordi-
nance requirements; including safety and environmental noise checks.
The 886-2 meets the requirements of the American National Standards Institute
(ANSI) Standard Specification S1.4 - 1983 for “Type 2 General Purpose Sound
Level Meters and the International Electro-Technical Commission (IEC) 651.” It
can be used by industry to measure noise levels to comply with Occupational
Safety and Health Act of 1970 (OSHA) and the Walsh-Healy Act, except for direct
measurement of impact (impulse) noise.
The 886-2 can be hand-held for rapid testing or mounted on a tripod for measure-
ments over extended periods of time. The microphone is detachable and can be
extended from its case by use of an optional 25-foot microphone extension cable.
The meter case is constructed of high-impact molded plastic, especially con-
toured at the microphone end to minimize reflections of the sound energy field
being measured.
The 886-2 is equipped with a range selector switch which references the 0 dB
point of the indicating instrument to the range selected. For example, when the
range switch is set to 70, the zero (0) mark on the black arc is equal to 70 dB.
Push-button switches provide quick, direct selection of “A”, “B” or “C” weighting
networks and a battery check function. Fast or slow meter response is switch
selectable.
The 886-2 offers three outputs which are proportional to the sound level input; a
RMS output, a dB output, and an external filter output that is compatible with the
Simpson 898 Octave Band Filter.
1.2 Specifications
The specifications for the 886-2 are listed in Table 1-1.
Table 1-1. Specifications
1. Microphone: The microphone is a condenser type with the size
as type L per ANSI S1.12 - 1967. The nominal
electrical impedance is 350 ⍀, 20% @ 23°C. The
microphone is omnidirectional; its angle of inci-
dence which approximates random incidence
response is 70°.
2. Sound Level: Measurement Ranges: 40 dB to 140 dB. Zero (0)
dB reference is 20 μPascals. Maximum SPL: 140
dB SPL for linearity within 1 dB.
3. Accuracy: Meets ANSI S1.4 - 1983 for a Type 2 instrument.
4. Weighting: Three selectable networks modify overall fre-
quency response to meet the ANSI specification
for the A, B, or C weighting curves for a Type 2
instrument. The “External Filter” jack may be used
to obtain a flat response.
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