Industrial Technologies

division of BIOLAB 

Larson Davis Environmental Sound Level Meters

Models 812-820 Sound Level Meters

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  • There exists a need to select an instrument that will do just what you need it to do. The 812 and 820 were designed with this in mind. For example, a consultant that works heavily in the industrial hygiene sector will greatly benefit from having the Model 812, a hand held data logging integrating sound level meter and a personal noise dosimeter. The Model 820 is the perfect environmental noise analyzer, maintaining all of the features of the 812 but with added memory, modem capability, daily and exceedance histories. 

  • The ½" condenser microphones used with our Models 812 and 820 allow for a wider dynamic range and greater level of accuracy. The Models 812 and 820 meet the IEC and ANSI requirements for Type 1, Precision Integrating Sound Level Meters. 

  • Fundamental to each of these instruments is an integrating sound level meter. Each features true RMS and dual Peak detectors that operate simultaneously. Each has Slow, Fast, and Impulse detector rates. Each has A and C frequency weighting filters. 

Features

Applications

  • ANSI/IEC Type 1 integrating SLM 

  • 110 dB dynamic range 

  • Long Term logging capabilities: Interval and Time histories (812 only);

  • Interval, Time, Daily and Event histories (820 only) 

  • Statistics - user selectable Ln values: 4 in the 812, 6 in the 820 

  • Slow, Fast and Impulse Detectors 

  • True RMS with two separate Peak detectors 

  • A & C weighting 

  • ½" condenser microphone - extension cables up to 20 feet available 

  • 64K bytes of memory (812) / 256 K bytes of memory (820) 

  • AC/DC Output 

  • RS-232 Interface 

  • Remote communications via modem (820 only) 

  • Sound Level Measurements 

  • Community Noise Assessment 

  • Environmental Noise Monitoring 

  • Statistical Analysis 

  • Transportation Noise/Passby Measurement 

  • Sonic boom/artillery fire measurements 

  • Production Line Testing 

  • Remote Outdoor Noise Monitoring (Model 820) 

Communications & AC/DC Outputs 
Also common to this family of meters is a serial digital interface for communication with a computer or direct connection to a printer. Each meter also features AC and DC outputs for transferring data to DAT or chart recorder during data acquisition. The analog output can be weighted (A or C) or unweighted, independent of how the data is acquired and stored within the instrument. 

Dynamic Range 
Each of these instruments has a unique 110dB dynamic range without the need for range switching thus removing the problems of missed critical data. 

Measurements 
Measurements include instantaneous Sound Pressure Level, Lmin (rms), Lmax (rms), Lpeak and Unweighted Peak Levels, Ln (statistics), Leq, SEL, Time Weighted Average (TWA), and Taktmaximal 3 & 5. All of these parameters are measured simultaneously making this family very flexible in an extremely wide variety of applications. 

Modem Capability (820) 
The 820 can be connected to a modem for remote data acquisition from portable or permanent monitors. The modem control mode enables the 820 to automatically dial out upon a high level event or a low memory condition.

SPECIFICATIONS

Linearity range

> 107 dB

Max peak level

142 dB (based on normal sensitivity free field microphone)

RMS noise floor

17.5 dBA (based on high sensitivity random incidence microphone)

Time weighting

Slow, fast, and impulse

Frequency weighting

A and C

Microphone

½" air condenser

Microphone polarization

0, 28, & 200 volts DC

Memory

64KB

DC output

0 - 3 volts @ 600 ohms

AC output

 

A - weight range

38.4 dBuV to 128.4 dBuV

C - weight range

36.3 dBuV to 126.3 dBuV

Linear range

36.1 dBuV to 126.1 dBuV

Output impedance

600 ohms

Gain

0 or 20 dB (user selectable)

Quartz clock/calendar

24 hour format (hh:mm:ss), 1 second resolution, 100 yr. calendar (mo/day/yr)

Power Supply

Internal

9 Volt battery, 24 hr operation

External

7 to 16 Vdc, 30 ma current draw

Dimensions

13.2" L x 3.3" W x 1.1" D (with preamp connected)

Standards Met

 

ANSI S1.4 - 1983

 

ANSI S1.25 - 1991

 

IEC 651

 

IEC 804

 

Directive 86/188/EEC

 

IEC/TC - 29

Accessories (included)

CCS009

Cordura nylon pouch

WS001

3 ½" windscreen

SWW_SLM_UTIL

Windows software for instrument setup, data download, and data export 9V alkaline battery

 

Operator's manual

Accessories (optional)

 

Acoustic calibrators

 

Outdoor environmental cases

 

Tripods

 

Software

 

Printer, computer and modem cable

 

Outdoor preamp (Model 820 only)

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