Measuring The Sound Level - Monacor SM-2 Mode D'emploi

5 Measuring the Sound Level

1) For a precise measurement, check the calibration
beforehand: Set the sliding switch (9) to the posi-
tion "CAL". 94.0 dB should be displayed. If not,
adjust the trimming control (5) by means of a
screw driver so that 94.0 dB is displayed.
2) For measuring the sound level in accordance with
the auditory sensation of the human ear, set the
sliding switch to the position "A". In the position "C",
the physical sound level is measured (linear).
3) For measuring, hold the meter horizontally with the
microphone (1) pointing to the sound source.
4) After switching on, the lower measuring range
35 – 100 dB is always selected. On the left side of
the display "Lo" is indicated.
When measuring values exceeding 100 dB,
"OVER" is indicated at the right bottom of the dis-
play. In this case, switch to the upper range
65 – 130 dB with the key Lo/Hi (3). Instead of "Lo",
"Hi" is displayed.
When measuring values below 65 dB in the
upper range, "OVER" is also indicated. In this case,
return to the lower range with the key Lo/Hi.
5) After switching on, the dynamic measuring mode is
set to sound levels changing fast. On the right side
of the display, "F" (fast) is indicated. For measuring
sound levels changing slowly, switch to the second
mode with the key S/F (4). The indication changes
from "F" to "S" (slow).
6) For holding the present value measured, press the
key HOLD (8). At the top of the display "DATA
HOLD" is indicated. To return to the present value
measured, actuate the key HOLD once again.
7) To determine the maximum level occurring, press
the key MAX (6). At the top of the display "MAX
HOLD" is indicated. Now the level value of the
highest volume occurring after actuating the key
MAX will be held. For switching off the function,
actuate the key MAX once again.
Notes
a The sound level measured largely depends on the
distance of the meter from the sound source. When
measuring, observe a defined distance (e. g. 1 m
for speaker measurements) or state the distance at
which the measurement was made.
b The level measured also depends on the angle to
the sound source. It may be necessary to measure
the levels at different angles (but at the same dis-
tance) to determine the sound radiation be haviour
of the sound source.
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6 Picking up a Microphone Signal or a
DC Voltage proportional to Level
At the output jack (7), the following voltages are pres -
ent to be picked up for a control depending on the level
or for further analysis. For this purpose, connect a
3-pole 3.5 mm plug to the jack.
Signals at the 3.5 mm plug connected
tip – body:
microphone signal
in the lower measuring range "Lo" 38 mV/dB
in the upper measuring range "Hi" 8.3 mV/dB
impedance 100 Ω
ring – body:
DC voltage proportional to level 10 mV/dB
impedance 100 Ω
7 Specifications
Display: . . . . . . . . . . . . . . 17 mm LCD, 3
Measuring ranges
Lo (low): . . . . . . . . . . . 35 – 100 dB
Hi (high): . . . . . . . . . . . 65 – 130 dB
Resolution:. . . . . . . . . . 0.1 dB
Accuracy: . . . . . . . . . . . . . ±1.5 dB at 94 dB, 1 kHz
Frequency range: . . . . . . 31.5 – 8000 Hz
Level weighting:. . . . . . . . A or C
Type of microphone: . . . . electret microphone
Output jack
(signals at the plug)
tip – body:. . . . . . . . . . . microphone signal,
ring – body:. . . . . . . . . . DC voltage proportional to
Ambient temperature: . . . 0 – 40 °C
Power supply: . . . . . . . . . 1 × 9 V battery
Dimensions: . . . . . . . . . . . 63 × 253 × 30 mm
Weight:. . . . . . . . . . . . . . . 250 g
Subject to technical modification.
1
/ digits
2
impedance 100 Ω
level 10 mV/dB, 100 Ω
GB
7