Model 831 is an
advanced Class 1 Sound Level Meter desgned for measurement
environmental, occupational and product noise. Different
Instrument Software are available to meet the most
demanding requirements, such as 1/1 and 1/3 octave analysis,
data logging, event history
Some of the features in 831 are specially
designed for long time monitoring and event analysis such as:
- Sound Recording can be triggered by
event so that noise source can be easily identified without
overflow of memory.
- Smart Dynanic
Trigger is useful for annoyance
analysis. For example, 831 can be setup for the event
logging when the SPL is 15 dB above the background noise
- The inclusion of Weather
Parameters (such as wind speed) and GPS
improves the outdoor environmental noise measurement
- Use of 3G, GPRS, WiFi, LAN in
remote control and dowload
of data, monitoring can
be achieved easily with significant saving in time.
- comply with IEC651, IEC804
- 120 dB dynamic range
- no range switching anymore
& Voice Recording*
support and Time Synchronous*
to outdoor microphone, up to 91.4m
- simple one-hand operation
GPRS, WiFi, LAN cable for
- Real-time 1/1 and 1/3 Octave Analysis
- Automatic Data Logging (20ms
to 24 hours)*
- USB 2.0 interface
- powered by computer through USB
- support USB
Stick (unlimited storage space)
rugged compact, light weight 0.5kg
||Real-time 1/1 and
1/3 octave frequency analysis
- event logging (Leq, Lmax,
audio recording of event if 831-SR option is enabled.
Time History - logging of event details down to 2ms
(together with 831-LOG)
Measurement History -
data logging of all parameters including spectra
& statistics, at time interval from
1 min to 24 hours.
Recording - audio recording of the
History - data logging of up to 16 parameters
from 20ms to 24 hours.
Time - measurement of RT60 according to ISO 3382-2.
||FFT Analysis - for
fine resolution frequency analysis
||Provides real-time 1/1 and
1/3 Octave frequency analysis, that is useful in tonality
assessment, selection of hearing protection, and qualifying of
Wide frequency ranges are
- 1/1 Oct : 8 Hz to
- 1/3 Oct : 6.3 Hz to 20kHz
Leq, Lmax, Lmin, Ln
measured with A, C or Z frequency weighting.
HISTORY logging of event details down to 20ms when over
triggered level. (together with 831-LOG). Smart Dynanic Trigger can
be used for event logging, for
example, when the SPL is 10 dB above L90.
MEASUREMENT HISTORY is
used to perform a sequence of measurements using the same setup, either
manually or automatically, at time interval from 1 min to 24 hours. All
parameters are logged including spectra and statistics
(Ln). The function is useful for environmental Base
Line Monitoring study and report.
The Interval Time Sync
feature ensures that all measurement records are properly aligned in
time for easy reporting. For example, if
the measurement time is five minutes, and the measurement begins at
08:14:00 (h:m:s format), the first measurement will be cut short such
that the subsequent measurements will begin at 08:15, 08:20, 08:25, etc.
Leq (Measurement Hitory) - New !!!
function in Measurement History is very handy in controlling the sound
level during public event like concert or Chinese opera held in open
area. The regulation asks the organizer to control the sound
within a limit.
For example, the limit /
'target' for 15 min Leq is 70 dB. If the 'current' Leq level
is 76 dB, for the remaining time, the 'remaining' Leq
should be controlled below 66.7 dB.
The LAeq (1s)
shows the real-time Leq level so that the event organizer or audio
controller can make adjustment of sound level accordingly.
||Sound Recording allows the recording of the
measured noise for documentation or noise identification, so
that there is no argument about the cause of noise.
Recording can be continous; or triggered by event (with
831-ELA); or triggered by markers (with 831-LOG).
mode, 831 can automatically log up to 16 acoustic and
non-acoustic parameters (e.g. Wind Speed) including spectra,
at time intervals from 20ms to 24 hours.
10 markers are available for
annotation of time history for different
sound sources (truck, aircraft...etc). Marker can also
trigger the sound recording if 831-SR is enabled.
: for precise timing of
noise event, logging down to 2.5ms can
be achieved by 831-FST option.
was designed with simplicity in mind yet complies with the latest
ISO 3382-2 measurement standards. It supports both the Integrated
Impulse Response and Interrupted Noise excitation
methods. The on-board signal generator provides a pink or white
noise source for optional amplifiers and omni-directional or façade
The user can
display an individual RT spectrum and discard those with
erroneous data. The spectra from multiple positions are
ensemble averaged to display an overall RT60 calculation.
supports the validation of measurements.
Additionally, grading of the measurement according to ISO 3382-2
indicates whether sufficient positions (microphone-source combinations)
have been acquired to obtain the expected grade: survey,
engineering or precision.
To download 831-RT pdf brochure....
||When better frequency resolution than 1/3 octave
spectral analysis is required, Model 831 FFT Frequency Analysis is the
ideal solution. The Fast Fourier Transform (FFT) algorithm is
implemented in the Model 831 for precision spectral analysis of
acoustic or vibration signals.
6400 FFT lines with resolution down to 0.016 Hz allows accurate
determination of the frequency, for example, in tone detection.
For transient noise analysis, multi-spectra can be logged by spectra
history so that its variation can be investigated in detail.
Spectrum can be downloaed to PC for display by G3-Utility
program, which is FOC.
download 831-FFT pdf brochure...
web access - NEW !!
|NoiseTutor is an
integrated solution, ideally suited to web publishing of noise
monitoring data in real time. Learn more....
hosts the Model 831 sound level meter as the heart of
a noise monitoring system; and provides the interface to different
peripheral devices such as Meterological Transducers, 3G modem,
solar panel and battery.
- Class 1
Calibrator for 1/2" microphone
- 94 or 114 dB ( 0.2dB)
|Free of Charge
SLM Utility-G4 is availble for download. It can be used for remote
control of 831 and data download to PC for reporting,
printing and export to other program like Excel.
For more information at LD website....