MarMonix MSL-761 User manual

Sound Level Meter
Products Code: MSL-761
User Manual
WWW.MARMONIX.CO

Content
1. Safety information
2. General description
3. Specifications
4. Name and functions
5. Measurement preparation
6. Operating precautions
7. Measurement
8. Calibration procedures

1. Safety Information
Read the following safety information carefully before attempting
to operate or service the meter.
Use the meter only as specified in this manual; otherwise, the
protection provided by the meter may be impaired.
Environment conditions
 Altitude up to 2000 meters
 Relatively humidity 90% max.
 Operation Ambient 0~40˚C
Maintenance & Clearing
 Repairs or servicing not covered in this manual should only be
performed by qualified personnel.
 Periodically wipe the case with a dry cloth. Do not use abrasives
or solvents on this instruments.
Safety symbols
Meter is protected throughout by double insulation or
reinforced insulation.
When servicing, use only specified replacement parts.
Comply with EMC
2. General Description
Thank you for using our sound level meter. To ensure that you can
get the most from it, we recommend that you read and follow the
manual carefully before use.
This unit conforms to the IEC61672-1 type 2, ANSI1.4 type 2 for
Sound Level Meters.

This sound level meter has been designed to meet the
measurement requirements of safety Engineers, Health, Industrial
safety offices and sound quality control in various environments.
 Range from 30dB to 130dB at frequencies between 31.5Hz and
8kHz.
 Display with 0.1dB steps on a 4-digits LCD.
 With two equivalent weighted sound pressure levels, A and C.

3. Specifications
Standard applied IEC61672-1 type2, ANSI S1.4 type 2
Frequency range 31.5Hz to 8kHz
Measuring level range 30 to 130dB
Frequency weighting A/C
Microphone 1/2 inch electret condenser microphone
Calibration
Electrical calibration with te internal oscillator
(1kHz sine wave)
Display LCD
Digital display 4 digits
Resolution 0.1dB
Display Up data 0.5 sec.
Time weighting FAST(125mS),SLOW(1sec.)
Level ranges
Lo: 30-
100dB
Hi: 60-130dB
Accuracy ±1.5dB (under reference conditions)
Alarm function "OVER" is show when input is out of range
Maximum hold
Hold readings the maximum value, with decay
<1dB/3minutes.
Auto power off
Meter automatically shuts down after approx.
15 minutes of activity.
Power supply
One 9V battery, 006P or IEC 6F22 or NEDA
1604.
Power life About 50hrs(alkaline Battery)
Operation temperature 0 to 40˚C (32 to 104˚F)
Operating humidity 10 to 90%RH
Storage temperature -10 to 60˚C(14 to 140˚F)
Storage humidity 10 to 75%RH
Dimensions 210(L) x 55(W) x 32(H)mm
Weight 230g(including battery)
Accessories 9V battery, carrying case, Instruction manual.

4. Name and Functions
1- Windscreen
if you operate at wind speed over 10m/sec,
please put protective accessories in front
of the microphone.
2- LCD Display
SYMBOL FUNCTION
LCD 4digits
MAX Maximum Value hold
OVER Over range
FAST Fast response
SLOW Slow response
dBA A-Weighting
dBC C-Weighting
Lo Low Range (30 to 100dB)
Hi High Range (60 to 100dB)
Low-Battery
3- Power ON/OFF Button
Turn the meter power ON/OFF
4- Backlight Button
Turn the meter backlight ON/OFF
5-A-Weighting/C-Weighting Select Button
A: A-Weighting. For general sound level measurements.

C: C-weighting. For checking the low-frequency content of noise.
(If the C-Weighted level is much higher than the A-Weighted level, then
there is a large amount of low-frequency noise)
6-Time Weighting Select Button
F(fast response): for normal measurements (fast varying noise)
S (slow response): for checking average level of fluctuating noise
7-Level Range Select Button
Lo: 30~100dB; Hi: 60~130dB
When “OVER” is indicated, the ranges switch to another range for
measurement.
8-MAX/HOLD Button
The “MAX. HOLD” position is used to measure the maximum level of
sounds. The maximum measured level is up to dated continuously. Press
once again the button, will release the hold and allow a further
measurement.
Data hold button: Press and hold button for over 2 second to turn on or off
data hold function.
The hold function freezes the reading in the display.
9-Microphone
½ inch Electret Condenser microphone
10-Battery Cover
5. Measurement Preparation
 Battery loading
Remove the battery cover on the back and put in one 9V battery.
 Battery Replacement
When the battery voltage drops below the operating voltage, mark “BAT”
appears.
If it appears, battery should be replaced with new one.

6. Operating Precautions
 Wind blowing across the microphone would bring additional extraneous
noise.
Once using the instrument in the presence of wind, it is a must to mount
the windscreen to not pick up undesirable signals.
 To achieve more accurate measurement, use an extension cable to
separate the Microphone from main body so that the effect of
unexpected sound reflection can be eliminated.
 Calibrate the instrument before operation if the instrument was not in
use for a long time or operated at bad environment.
 Do not store or operate the instrument at high temperature and high
humidity environment.
 Keep microphone dry and avoid severe vibration.
 Please take the battery and keep the instrument in low humidity
environment, when not in use.
7. Measurement
 Open battery cover and install a 9-volt battery in the battery
compartment.
 Turn on power and select the desired response Time and weighting. If
the sound source consists of short bursts or only catching sound peak,
set response to FAST. To measure average sound, use the slow setting.
Select A-weighting for general noise sound level and C-weighting for
measuring sound level of acoustic material.
 Select desired level
 Hold the instrument comfortably in hand or fix on tripod and point the
microphone at the suspected noise source, the sound pressure level will
be displayed.
 When MAX (maximum hold) mode is chosen. The instrument captures
and holds the maximum noise level for a long period using any of the
time weightings and ranges.

 When HOLD (data hold) mode is chosen. The hold function freezes the
reading in the display. Press the HOLD button momentarily to activate or
to exit the HOLD function.
 Turn off the instrument and remove battery when not in use.
8. Calibration Procedure
Using a standard acoustic calibrator (94dB, 1kHz Sine wave)
 Make the following buttons and
function switch settings.
Display: dB, A, Hi or Lo, F
Function: A-weighting
Response Time: FAST
Level range: 30~100dB(Lo) or
60~130dB(Hi)
Measurement Mode: MAX HOLD and
Data
Hold Mode function disable.
 Insert the microphone housing
carefully into the insertion hole of the
calibrator.
 Open battery cover and remove the
battery to adjust the CAL94dB
potentiometer of the unit. The level
display will indicate the desired level.
Our products are well calibrated before shipment. Recommended
Recalibration cycle: 1 year