Page 1 831C Sound Level Meter Reference Manual...
Page 2 Larson Davis SoundAdvisor Model 831C Sound Level Meter Reference Manual SoundAdvisor™ Model 831C...
Page 3 Copyright Copyright 2022, by PCB Piezotronics, Inc. This manual is copyrighted, with all rights reserved. The manual may not be copied in whole or in part for any use without prior written consent of PCB Piezotronics, Inc. Disclaimer The following paragraph does not apply in any state or country where such statements are not agreeable with local law: Even though PCB Piezotronics, Inc.
Page 4: Table Of Contents
Table of Contents Module 1 Model 831C Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 Applications and Basic Operations Hardware Features Performance Features...
Page 5 9.12 Utilizing the Logic In or Logic Out Feature 9.13 Choosing Preamp Heater Options 9.14 Setting Reference Spectra 9.15 Generating an App Password Module 10 System Information - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 101 Module 11 Managing 831C Security - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 102 11.1 Using the Meter Lock 11.2 Using Network Security...
Page 6 Time History Software (Option 831C-LOG) FFT Analysis Software Specifications (Option 831C-FFT) PTB Approved Firmware Frequency Response Appendix B Measuring Sound Using IEC 61672-1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - B-1 Overview IEC 61672-1 Section 9.3 Appendix C...
Page 7: Model 831C Features
Module 1 Model 831C Features The SoundAdvisor™ Model 831C SLM is a Class 1 acoustic monitoring instrument with a full-color touchscreen that measures noise frequency, sound pressure level, and community and environmental sound. The “C” in 831C refers to the full-color screen. G4 LD Utility software (G4) connects your meter to your PC via USB, WiFi, or TCP/IP.
Page 8: Hardware Features
• Communicate via USB, Ethernet, WiFi, or cellular (with cellular gateway) • Operate completely from the device itself, or remotely using G4 LD Utility software • Easily expand memory using USB memory • Select desired color theme on the full-color graphic LCD display with touchscreen user interface 1.2 Hardware Features The 831C is a precision-integrating sound level meter with the following hardware...
Page 9: Standard 831C Package Contents
The 831C is shipped in protective packaging. First, verify the shipment contains all parts and accessories for the configuration you selected. Report any damage or shortage immediately to Larson Davis/PCB Piezotronics, Inc. See the back cover of this manual for contact information. We also recommend that you retain the packaging for safe shipment for calibration service.
Page 10: Available Options And Accessories
1.4.1 About Serial Numbers The 831C serial number is printed on the back panel label. The microphone model and serial numbers are engraved on the outside of the microphone. The preamplifier model and serial numbers are engraved on the outside surface of the preamplifier. We recommend that you record the purchase date, model and serial numbers for your instrument, preamplifier, and microphone.
Page 11 Optional Firmware Packages Scheduling Meter measurement scheduling feature for 831C and G4 LD Utility. (831C-SCH) When installed and enabled, the Agency Approval firmware enables you Agency Approval to produce measurement data that is approved by the following agencies: (831C-LNE/PTB/METTAS) LNE, PTB, METTAS. When in use, the “LNE” or “PTB” icon displays above the menu bar as shown in Fig.
Page 12 Description Available Options Environmental Shell (EPS2116) Protects microphone and preamplifier from rain and wind with mounting options for pipes, poles, and most tripods Weather-proof Enclosure (EPS030-831) Environmental Protection For remote noise monitoring; includes battery Options Solar-powered noise monitoring system (NMS/EPS044) For outdoor, long-term, and unattended sound monitoring Permanently-installed, solar-powered noise monitoring system (NMS/ EPS045) For outdoor, long-term, and unattended sound monitoring...
Page 13: Instrument Overview
Module 2 Instrument Overview This module describes the hardware and display components that contribute to the SoundAdvisor™ Model 831C. In this module: Assembling Your 831C SLM - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -7 2.1.1 Connecting the Microphone and Preamplifier 2.1.2...
Page 14 • Never use excessive force. • Gripping tightly or screwing tightly is unnecessary. • Do not remove the microphone grid cap and expose the diaphragm. FIGURE 2-1 Microphone and Preamplifier PRM831 The bottom of the microphone attaches to the top of the preamplifier.
Page 15: Powering The 831C Slm
2.1.4 Preparing the 831C for Long Term Storage The Hardware Power Switch on the bottom of the 831C disconnects the batteries from the 831C hardware. (For reference, see Figure 2-6.) The real-time clock maintains its value while the switch is off. The power switch prevents battery drain when the meter is not in use for an extended period of time.
Page 16 incorrect battery type, which may happen to fully discharged NiMH batteries. Use an external battery charger to restore charge, then install in meter. Additionally, the batteries may be too hot or too cold. The 831C is compatible with Energizer, Duracell, and other commercially- CAUTION recognized brands of these battery types: •...
Page 17 Charging Batteries in the 831C You can charge batteries (NiMH only) in the meter in about 7 hours when the meter is powered off. Before you begin: • Install batteries as shown in "Installing Batteries" on page 10. Step 1. On the 831C, press Tools ...
Page 18 Resolving an “Incorrect Battery Type” Session Log Entry Infrequently, when the battery becomes too old to charge, the meter may register the battery as the incorrect battery type. This can also occur when newer NiMH batteries are fully discharged. In this case, charge the batteries using an external battery charger, then install them in the meter.
Page 19 Table 2.1 Charging Status LED Indicator (Continued) Charging Status Green LED Charging stopped short green blink (charger or battery fault) Meter is powering up or shutting down fast, quick green blink In addition to keypad indications, the appearance of one the following icons on the meter display indicate a significant power event.
Page 20 Understanding Low Input Power Indicator When “Low Input Power” displays on the Power Control Page (see Figure 2-4 on this page), the USB cable cannot supply sufficient power to charge the internal batteries. To resolve this issue, contact Larson Davis (see back cover of this manual) and request the CBL138—which is a 3-foot, USB 2.0 A Male to Mini-B, 5-pin Male 28/24 AWG Cable with Ferrite Core.
Page 21: Instrument Hardware Overview
2.3 Instrument Hardware Overview FIGURE 2-5 831C Instrument Overview (front) Standard 1/2” free field or random incidence microphone PRM831 Preamplifier Release button to disconnect the preamp from the meter 240 x 320 full-color graphic LCD display with touchscreen user interface (shown with Dark color theme) Display navigation softkeys Multicolor LED back-lit keypad...
Page 22 FIGURE 2-6 Instrument Hardware AUX connector intended for use with USB mass stor- age, cellular modem, GPS, headphones, speakers, and future devices. Hardware Power Switch when set to “ 0 ” completely powers down the 831C for storage. Set to “...
Page 23 831C Button Actions Table 2.2 831C Button Actions Action Button(s) Description In a menu, press a top soft key to FIGURE 2-7 navigate to left or right tabs When specific menu name displays above a top softkey, press that key to access the menu.
Page 24: Display Elements Overview
Table 2.3 Measurement Status LED Indicators Measurement Red LED Green LED State Stopped with long, quick red blink Reset Stopped long then short red blink Paused short red blink short green blink Running Long then short green blink Waiting for valid short delayed blink data to begin running...
Page 25 2.4.2 Using Tabs and Pages The 831C interface is organized into tabs. The Live and Overall tabs are further organized into pages that can be accessed using the up or down navigation buttons ( ). If needed, additional pages of measurement data are available to purchase from Larson Davis.
Page 26 Power and Battery Power Indicators The battery icon indicates the state of the battery charge by color and volume. When using battery power, the battery icon indicates the state of the battery from fully charged to depleted, left to right. The bolt symbol appears over the battery icon if the battery is currently charging.
Page 27 FIGURE 2-11 Display for Under Range vs. Normal Range Live Data Under Range Display Normal Range Display Values in an “under range” condition appear in dark blue on the Live tab. OBA Overload Icon The OBA Overload icon displays while the input to the Octave Band Analyzer is overloaded. When the OBA Range property is set to Normal, the OBA Overload Icon TAKE NOTE displays at a level 33 dB lower than if the OBA Range had been set to High.
Page 28 If the touchscreen is enabled, or if youʼre operating the meter remotely, tapping the icon produces the following result: Table 2.4 Using the Measurement Status Icon Resulting Measurement State Action Measurement State Tap Once Stop Double Tap Pause Pause Tap Once Stop/Reset Tap Once Stop/Reset...
Page 29 during the measurement. See 19.2 Using Mark Sound Type to Make Manual Sound Recordings. Adjust Graph Menu Allows you to adjust the X and Y on the visual graph when needed. Reset This feature operates the same as the Reset button on the meter. Press once to clear any unsaved data for that measurement.
Page 30 Lock Lock the meterʼs screen to prevent tampering. See Module 11 Managing 831C Security. System Utilities Format or restore file system. See Module 12 Using System Utilities. Communication Quick access to communication properties. See Module 13 831C Network and Connections. 2.4.6 Power Control Menu Overview To access the following actions on the Power Control menu, press power once.
Page 31: Getting Started
Module 3 Getting Started In this module: Operating the 831C by Using the Meter Display - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -26 Operating the 831C Remotely - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -27 3.2.1 Operating the 831C from G4 LD Utility Software...
Page 32: Operating The 831C Remotely
3.2 Operating the 831C Remotely In this section: • 3.2.1 Operating the 831C from G4 LD Utility Software • 3.2.2 Operating the 831C from the LD Atlas App • 3.2.3 Operating the 831C from a Web Browser 3.2.1 Operating the 831C from G4 LD Utility Software Step 1.
Page 33: Setting File Storage Preferences
Step 4. In LD Atlas on your mobile device, and tap the name of your meter in the Meters Panel. If the meter is connected, the meter type icon displays in blue. FIGURE 3-1 LD Atlas Meters Screen Tap Refresh to update the Meters list.
Page 34 In this section: • 3.3.1 Selecting a File Storage Location • 3.3.2 Using the 831C File Storage Calculator 3.3.1 Selecting a File Storage Location In this section, choose how and where files are saved when a measurement stops. Step 1. On your 831C, go to Tools ...
Page 35 Step 4. Click OK to confirm a meter reset, if needed, then click Close to save your changes. For information about copying files to USB, see 8.3.2 "Moving or LEARN MORE Copying Data Files to a USB Drive" on page 80. For information about moving internal files to a PC via G4, see the G4 LD Utility Manual.
Page 36: Using The Data Display
Module 4 Using the Data Display The 831C takes a measurement, and simultaneously displays the resulting data a series of themed tabs, such as the Live tab, Overall tab, etc. At a minimum, tabs and pages display the following SLM metrics: •...
Page 37 Press the up or down buttons to scroll up or down on the pages of the Live tab. The labels for sound metrics on the 831C are designated by international standards. For many displayed values, the frequency and time weighting are indicated in the name of the metric.
Page 38 FIGURE 4-2 Live Tab: Big Digit Display Page The current value on the Big Digit display corresponds to the “Any Level” value you select. To change this metric, highlight it, press Enter , and select an option. This is the Exceedance Trigger level you selected in the measurement setup.
Page 39 Similar to the regular octave band pages, the normalized band pages show octave bands (for 1/1 or 1/3) and the numerical values of the highlighted band. However, the data is normalized using the reference spectra you define at Tools System Properties Reference Spectra.
Page 40 FIGURE 4-5 Live Tab: Triggering Page Current live sound as measured with the frequency weight and detector chosen in the measurement Setup. When the SPL1 & SPL2 trigger levels are exceeded they display in orange, and then red for higher levels. If sound levels in the measurement exceed the Peak triggers, the values here display in orange, and then red for the highest values.
Page 41 FIGURE 4-7 Live Tab: Power Page Current date and time "Battery States On the Power See the section Page" on page 36 for important battery state reference information. Voltage of the battery and the USB external power source can be tracked here. Checking the internal temperature of the meter here periodically is good safety practice.
Page 42 FIGURE 4-8 Live Tab: Memory Page After you configure the measurement Setup, the File Size Estimation Total becomes valid for your proposed measurement. Time History (h/d): When 2 values display on this line, the first value is the amount of memory required to store each hour of time history data.
Page 43 FIGURE 4-9 Overall Tab: SLM Page Run time of the current measurement. This time continues during a pause. The data graph presents info from beginning (left) to end (right). This Leq value uses the frequency weighting and detector from the measurement setup file. It is the equivalent sound based on the run time of the measurement.
Page 44 FIGURE 4-11 Overall Tab: Leq Page and the L of the overall measurement. The L (Z frequency weighting) is the overall reading of Zpeak the peak detector during the measurement. These three SPL detectors give the date and time when these metrics were met during the measurement: The highest level the peak detector has measured Zpeak(max):...
Page 45 is the maximum sound level of the highlighted frequency band. The maximum spectrum is determined by the Max Spec setting. Bin Max: When set to Bin Max, this value is the maximum value which occurred during the entire measurement for that frequency band.
Page 46 Table 4.3 User-Defined Reference Spectra Definitions User Defined 1 2 3 4 Positive Frequency Weighting Negative Frequency Weighting -A -C If the frequency components are too small or too large to view in the graph, press Menu (  Adjust Graph. The Buffer Overrun line item is an indication that rarely displays when using the 831C in FFT Mode while sampling sound at higher frequency resolutions.
Page 47 FIGURE 4-15 For example: L = 60.8 dB NF50 The Fast (F) time-weighted level exceeded 60.8 dB 50% of the time during the measurement. For a more in-depth discussion of LEARN MORE Appendix C Ln values, see Ln Value in the “...
Page 48 FIGURE 4-17 The Overloads page shows the number of times, the percent of time, and the amount of time that the Sound Level Meter and the OBA have been overloaded. 5.1.2 You can find more overload information in Determining Noise Floor, Overload, and Under Range Levels About the Community Noise Page (Overall Page) FIGURE 4-18...
Page 49 FIGURE 4-19 The “C minus A” metric provides an indication of the low frequency content of noise measured. This is done by subtracting the A-weighted equivalent level from the C- weighted equivalent level. The integrated levels for L are always calculated using the linear detector, regardless of the value selected in the SLM Setup.
Page 50 About the Metrics Matrix Page (Overall Page) FIGURE 4-21 The metrics matrix page displays the data the meter is always measuring in one page. Press Enter move the cursor. Viewing the Power Page (Overall Page) FIGURE 4-22 The power page on the Overall tab shows all records for that measurement, and the status of the meterʼs internal memory.
Page 51 Figure 4-24 • The Overall Tab: Weather Page (as shown in • In the resulting data for Event History and Event Time History (as shown in the G4 LD Utility Manual) FIGURE 4-23 Live Tab, Weather Pages Live Weather page displays the current precipitation rates for Rain and Hail.
Page 52 4.1.4 Understanding the Session Log Tab On the Session Log tab, the 831C creates a time-stamped record for every meter action, including Calibrate, Run, Pause, Resume, Stop, Voice Message, and Sound Recording, and others. When you store a data file or press the Reset button , the session log clears and begins a new log.
Page 53: Enabling Or Disabling Display Tabs
4.1.5 Adjusting the Graph Scale On Any Tab The default amplitude (dB) setting for the graphic display of sound pressure level versus time and frequency spectra for this meter are shown in Table 4.5. Table 4.5 Level vs. Time Graphs 20 dB to 140 dB Frequency Spectra, Normal Range 20 dB to 140 dB...
Page 54: Display For Fft Mode
Step 5. In the Pages section, select the checkbox in-line with the options you want visible on the meter. FIGURE 4-27 Measurement, Current, and Time History Tab Options Step 6. Press Close ( ), then select Yes to save your changes. Or select No to exit without saving.
Page 55 Module 5 Calibrating Your SoundAdvisor 831C This module covers acoustic calibration of your SoundAdvisor 831C. This is the most commonly used calibration method, and the one required by most national and international standards prior to making a measurement. In acoustic calibration, a sound level calibrator provides an acoustic signal of a known amplitude and frequency to the microphone.
Page 56 5.1.2 Determining Noise Floor, Overload, and Under Range Levels A secondary role of calibration is to determine the sound level which would overload the instrument (Input Overload level) and the minimum sound level (Under Range level) that can be accurately measured without being influenced by the operational noise from the meter (Noise Floor).
Page 57 This table includes data and date/time for the 10 most recent calibrations. Itʼs a good idea to periodically review the instrumentʼs Calibration History, which is found on the meter under Tools  Calibration  )...Cal Hist. • Large Change Notifications During calibration, the meter makes an automatic comparison between the sensitivity determined by the calibration and the previous value.
Page 58 Step 2. Choose an option from the Select Calibrator drop-down menu as shown in Figure 5-1. FIGURE 5-1 Calibrate tab The microphone type, sensitivity, and peak overload values are available on this page The under range and noise floor capabilities. Step 3.
Page 59 Step 5. Navigate to the Calibration History tab by using the top right softkey ( FIGURE 5-3 Calibration History tab Every calibration is logged as an event in the Calibration History. Values in the Delta dB column show the difference between the level measured during the current calibration and the level from the previous calibration.
Page 60: Calibrating Your Soundadvisor 831C
5.4 Calibrating Your SoundAdvisor 831C We recommend that you complete this process prior to each measurement. When you schedule service and certified internal calibration for your meter at the factory, the resulting correction data is stored on the meter, and stated in the calibration documentation that returns with your meter.
Page 61 Step 2. Complete the calibration process as shown in 5.4 "Calibrating Your SoundAdvisor 831C" on page 54. 5.4.2 Performing an E.A. Check The LD Model 426A12 Outdoor preamplifier and power supply or Model 2100 outdoor preamplifier each contain an E.A. (electrostatic actuator) in the rain hat, which can be used to perform a remote calibration check.
Page 62: Creating A Measurement Setup
Module 6 Creating a Measurement Setup The 831C takes measurements based on the values you save in the setup file (Setup). Setups are created, edited, and deleted using the meterʼs Setup Manager. This module describes using the Setup Manager on the 831C, and guides you through the process of saving a Setup.
Page 63: Creating A Custom Setup File On The Meter
6.2 Creating a Custom Setup File On the Meter While you can edit and save measurement settings directly in the Active setup, itʼs a good practice to save a setup file with a unique name for each kind of measurement. This section shows you how.
Page 64 Step 2. Highlight and select your setup file in the list ( ). The name of your setup displays in the Settings: line (see Figure 6-2). Step 3. Use the right softkey ( ) to navigate to the General tab, and enter your preferred details.
Page 65 About Using the Gain Feature When using a microphone with sensitivity of 50 mV/Pa, the input overload occurs approximately as shown in Table 6.1. Table 6.1 Input Gain, dB OBA Range Overload Level, dB peak High High Normal Normal About Integration Methods Although the 831C measures levels at all 3 detector and frequency weighting settings according to your selection, some features require a single combination.
Page 66 Step 6. Use the right softkey ( ) to navigate to the Ln Percentiles tab and select your preferred settings. FIGURE 6-5 Setup Manager: Ln Percentiles Tab Enter any value from 00.01 to 99.99%. For more information, see “Ln Value” in the Appendix C Glossary on page C-1.
Page 67 FIGURE 6-7 Setup Manager: Exceedance Triggers Tab SPL Trigger Levels: When the measured SPL (Slow, Fast, or Impulse) is greater than the trigger level you set here, the exceedance begins. The measured SPL is defined by the current weighting and detector. Peak Trigger Level: Set 3 peak levels independent of the SPL triggers.
Page 68 Step 13. (Optional) If you plan to collect weather data for your measurement, we recommend that you save the Setup, then select your preferred weather settings as shown in 20.3 Choosing Weather Settings in the Setup Manager. 6.2.3 Saving the Setup File Before you begin: •...
Page 69 In this section: When combined with the Using Manual Run/Stop Mode • Measurement History feature, these 3 modes can be used to create Using Timed Stop Mode • multiple measurement intervals Using Stop When Stable Mode • stored in a data file, with new data files created at regular time Using Continuous Mode •...
Page 70 Using Stop When Stable Mode on-site or off-site control of a measurement Recommended for: Measures sound (noise) until it stops changing. Strength: Step 1. Select Stop When Stable from the Run Mode drop-down menu. Step 2. Enter values for Delta (dB) and Time as stability parameters. If the parameter is detected, the measurement stops.
Page 71: Troubleshooting A Measurement Setup File
Using Single Block Timer Mode unmonitored measurements Recommended for: One measurement automatically starts and Strength: stops at the date and time you set. Step 1. Select Single Block Timer from the Run Mode drop-down menu. Enter a Start (y-m-d) date and Time, and an End (y-m-d) date and Time, where Time is the time of day.
Page 72 Step 2. Select Default by highlighting it, then pressing Enter . This opens a pop-up menu. Step 3. Highlight, select Set to Active, and confirm your choice if required. Step 4. Press the Close softkey to save the meter settings. SoundAdvisor™...
Page 73: Making A Measurement
Module 7 Making a Measurement Making a measurement on the 831C can be as simple as viewing a live reading of the area using the Big Digit display, or as sophisticated as setting it up with environmental accessories, deploying it in the field, and logging measurements when the sound level is above 80 dB over the course of many months in all weather conditions.
Page 74 Each step has a link to the first 6 Modules in the manual, and if read LEARN MORE through, will lead to optimal performance of the 831C. Step 1. Connect preamplifier and microphone to the 831C. For complete instructions, see 2.1.2 "Connecting the Preamplifier to Meter" on page 8. Step 2.
Page 75 necessary when using Larson Davis microphone extension cables in combined lengths up to 200 feet. XXX is the length in feet (XXX = 010, 020, 025, 035, 050, 060, 100 and 200) available. This configuration has been applied with success in certain circumstances for RT60 Interrupted Method Reverberation Time measurements.
Page 76: Performing The Measurement
FIGURE 7-3 Standard Area Sound Before Measurement The time reads 00:00:00.0 on both the Live and Overall displays. (Otherwise the previ- ous measurement was not stored or reset.) The measurement status icon is set to Stop. The live sound is steady and within range. For more detail about the information displayed here, see 4.1.1 LEARN MORE Understanding the Live Tab.
Page 77 Table 7.1 Measurement State LED Indicators Measurement State Red LED Green LED Stopped Winking **-*-* Paused Flashing *-*- Flashing -*-* Running Winking **-*-* Waiting for valid data Delayed ----* to begin running wink To learn more about the displays and icons, see 2.4 Display Elements LEARN MORE Overview.
Page 78 • Measurement History • Event History • Spectral Ln • Event Sound Recording FIGURE 7-4 Using 831C Back Erase Use Back-Erase by pressing the middle softkey ). This erases the last 10 seconds. To erase only 5 seconds, choose Undo ( ), then select Back-5s when it appears.
Page 79: Storing The Measurement
Back Erase in the Time History Record When you use the back-erase feature, time history resumes at the time the measurement resumes. In the resulting Time History data log, the back-erased period is marked as a record type as shown in Figure 7-6. FIGURE 7-6 Back Erase In the Resulting Time History Data 7.2.2 Resetting a Measurement...
Page 80 Step 2. Press the Store button . The meter Auto-Stores or prompts you to store the measurement. (For more information about Auto-Store, see 8.1 "Setting Data File Storage Preferences" on page 75). Step 3. If youʼre prompted to store the file, you can change the name of the data file by highlighting the name and pressing Enter .
Page 81: Managing Measurement Data Files
Module 8 Managing Measurement Data Files Each time you manually or automatically store measurement results, a new data file is created or appended and saved to the location you specify. While the 831C has 1.8 GB of available internal memory, you may also choose USB or cloud storage. In this module: Setting Data File Storage Preferences - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -75 Using the File Manager - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -77...
Page 82 • Prompt: When you press the Stop button , or a stop occurs, you are prompted to save the measurement data file. We recommend this setting for manual measurements only. • Store: A measurement is automatically stored when a measurement is stopped.
Page 83: Using The File Manager
8.2 Using the File Manager The File Manager is a directory of all saved data files. Only one user at a time can perform actions on data files. If a user is in the Data File Manager and another attempts to open it, the second is prompted to end the first userʼs session before they can begin their own.
Page 84 FIGURE 8-3 Using the File Manager Highlight a data file, press Menu ), and choose an option from the pop-up menu. For data files stored to the 831C internal memory, you can Rename, Delete, and Delete All Internal Files. Use the following menu items to navigate the data Files view: Refresh List, Jump to Beginning, Jump to End.
Page 85 Step 1. On the 831C, select Tools  Data File Manager. Step 2. Highlight the desired data file, press Menu ( ), and select Load Settings from the pop-up menu. (No confirmation appears.) Step 3. Close ( ) the Data Manager, then select Tools ...
Page 86: Saving, Moving, Or Copying Data Files
8.3 Saving, Moving, or Copying Data Files In this section: 8.3.1 About File Naming Conventions • • 8.3.2 Moving or Copying Data Files to a USB Drive 8.3.1 About File Naming Conventions In addition to manually naming a data file, there are 2 conventions the 831C uses to automatically generate unique file names.
Page 87 Step 1. Insert a USB drive in the 831C. Wait for the USB icon to appear in the meter Status bar. (About 10 seconds.) If the Data Storage setting is set to “USB,” but no USB drive is inserted, the USB not available icon appears.
Page 88: Setting System Properties
Module 9 Setting System Properties This module is a reference for all SoundAdvisor™ 831C system properties. In this module: Setting Instrument Identification - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -82 Updating the Meter Time - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -83 Editing Power Settings - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -84 Setting Meter Preferences - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -87...
Page 89: Updating The Meter Time
9.2 Updating the Meter Time Step 1. On your 831C, select Tools  System Properties. Step 2. Press the right softkey ( ) until the Time page displays. There are several ways to update the time on the meter: by using a GPS receiver antenna, NTP servers, PC clock, or by manually setting the time.
Page 90: Editing Power Settings
Step 2. Press the right softkey ( ) until the NTP tab displays. Step 3. Enter the Primary and Secondary NTP Time Servers as shown in Figure 9-2. For details and server addresses, see the NIST Physical Laboratory Time Frequency Services website (https://www.nist.gov/pml/time-and-frequency- division/services/internet-time-service-its).
Page 91 9.3.1 Changing Batteries and Editing the Battery Type The 831C can be powered by alkaline, 1.5V lithium, or nickel-metal hydride (NiMH) batteries. Do not mix alkaline and NiMH batteries. CAUTION Do not mix batteries from different manufacturers. CAUTION Do not replace only 1, 2, or 3 batteries. Replace all 4 batteries when installing CAUTION fresh cells.
Page 92 • Remote communication Pressing the Power button returns the instrument and the display to the state it was in when the Auto-Off time expired. 9.3.3 Using Analog Power-Save Mode Step 1. On your 831C,select Tools  System Properties. Step 2. Press the right softkey ( ) until the Power tab displays.
Page 93: Setting Meter Preferences
Step 3. If desired, select the LCD screen back light intensity as a percentage. When battery life is below 10%, the 831C overrides this setting and downgrades the LCD Brightness to 50%. If the user-defined setting is below 50% brightness, it remains the same.
Page 94 Step 2. Select a option from the Mic Correction drop-down menu. Use Table 9.1 as a reference. Table 9.1 Microphone Correction Options Option Current Microphone Simulates Any Microphone Windscreen response without WS001 presence of physical windscreen (Default) No Correction RI:FF Random Incidence Free-Field FF:RI...
Page 95 FIGURE 9-4 831C AC/DC Output Step 1. On your 831C, select Tools  System Properties, then press the right softkey ( ) until the Preferences tab displays. Step 2. Select an option from the AC Output drop-down menu, then press Close ) to save your changes.
Page 96: Setting Localization Options
8.3 "Saving, Moving, or Copying Data Files" on page LEARN MORE When using G4, you can also save data files to a remote (cloud) TRY THIS storage account. For more information, in G4 go to Help  Manuals  G4 LD Utility Manual.
Page 97: Setting Active/Hidden Pages On The Displays Tab
Selecting a Decimal Symbol Depending on your preference, select a period or a comma for the decimal place, and save your change. Selecting a Date Format Select one of the 2 available date formats: dd-mm-yyyy and yyyy-mm-dd, then Save your change. For example: 2020-02-14. Setting a Unit of Measurement The default unit of measurement for the 831C is SI (International System of Units).
Page 98: Enabling Or Disabling Options
9.7 Enabling or Disabling Options This section shows how to enable or disable any firmware option purchased from Larson Davis. Default options donʼt appear in the list since they cannot be disabled. Table 9.2 Firmware options available on the System Properties Options tab: 1/1 Octave OBA 1/3 Octave OBA Sound Recorder...
Page 99: Configuring An Email Server On The Meter
9.9 Configuring an Email Server On the Meter Complete this section to designate an email server on the meter to access all user account features when using G4 LD Utility or LD Atlas. While this process can be completed from the meter interface as described in this section, it is most easily be accomplished in G4 LD Utility software.
Page 100: Enabling Or Disabling Remote (Cloud) Storage
Step 5. Click Send a Test Email. If you donʼt receive a notification within a few minutes of initiating a test, check to see if your meter is connected to the Internet. Also, make sure a proxy is not filtering your email. For additional questions or troubleshooting, contact your local IT support.
Page 101: Utilizing The Logic In Or Logic Out Feature
Step 1. To enable or disable cloud storage on the 831C, select Tools  System Properties, then press the right softkey ( ) until the Cloud Storage page displays. Step 2. Select the checkbox in-line with Auto Push to Cloud as shown in Figure 9-8, then press Close ( ) to save your changes.
Page 102 Step 2. Select a signal trigger from the Logic In drop-down menu as shown in Figure 9-9. FIGURE 9-9 System Properties: Other tab A device connected to the 831C using the I/O Interface cable (via Logic In) can be activated by the following external triggers: Run/Stop State A measurement run or stop can be initiated when the Time...
Page 103: Choosing Preamp Heater Options
Marker When Logic Out is set to Marker, a marker for sound recording is initiated, the output is activated for the Recording Time as indicated in the setup. To utilize this state you must purchase, install, and enable the Sound Recording firmware option (831C-SR) on your meter.
Page 104: Setting Reference Spectra
• Off: The heater remains off. 9.13 Setting Reference Spectra This feature applies to SoundAdvisor™ 831C meters with the Octave Band Analysis firmware option (831C-OB1) purchased, and installed. When you apply octave band data, you have the option to choose a negative or positive A, or C weighting, or you can define up to 4 unique reference spectra as shown in the following process.
Page 105: Generating An App Password
9.14 Generating an App Password Once you set up the App Password, you will not need to log in each time you want to connect to your mail account. An app password is a 16-digit pass code that gives a non- Google app or device permission to access your Google account.
Page 106 Module 10 System Information System information is contained on the About Menu. On the 831C, select Tools  About to view the following details on 3 tabs: FIGURE 10-1 About, Standards, Options Tabs SoundAdvisor™ Model 831C...
Page 107 Module 11 Managing 831C Security The SoundAdvisor 831C provides a meter lock and network security options to prevent the unauthorized use of an instrument or tampering with measurement data when operating remotely. In this module: 11.1 Using the Meter Lock - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -101 11.1.1 Locking the Meter 11.1.2...
Page 108 Step 2. Choose an option from the Lock Mode drop-down menu. In each lock mode option, the meter displays differently, and certain meter operations are restricted. Refer to Table 11.1 to understand which lock mode fits your measurement study needs. Table 11.1 Allowed Operations Per Lock Mode Available Lock Mode...
Page 109 For more information on calibrating the meter while locked, see LEARN MORE 5.4.1 Calibrating While Using Meter Security (Lock Mode) Step 5. Press Close, then choose Yes to save your changes. 11.1.2 Unlocking the Meter from the Meter Interface To unlock the 831C from the meter interface, follow these steps: Step 1.
Page 110 Refer to the G4 LD Utility Manual, Module 6.2 Using Network Security for 831C for complete details. The following outline provides an overview of the process: Step 1. Install or update G4 LD Utility to version 4.5 + on your PC. Step 2.
Page 111 Module 12 Using System Utilities The System Utilities can repair or recover any file system problems. These functions are similar to what you might use to troubleshoot a hard drive. To access these features on the 831C, select Tools  System Utilities.
Page 112: Configuring 831C Network Connections
Module 13 831C Network and Connections This section shows how to create physical and network connections for operating the 831C remotely, and other uses. In this module: 13.1 Configuring 831C Network Connections - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -106 13.1.1 Connecting 831C to an Ethernet Port 13.2 Setting the Meterʼs Network ID - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -107...
Page 113: Setting The Meterʼs Network
Step 2. Connect the assembly as shown in Figure 13-1. FIGURE 13-1 831C Connected to Ethernet Port Insert the Ethernet adapter (DVX012) into the auxil- iary port on the bottom of the 831C. Connect the Ethernet cable to the Ethernet adapter (DVX012) adapter.
Page 114: Using Wifi On Your 831C
Step 3. Enter your IP, Subnet, and Gateway, and DNS addresses. Coordinate with your IT professional if you need more information. If you want the meter to return to using a unique (dynamically-assigned) IP address instead click the Disable button. Step 4.
Page 115 13.3.1 Connecting to a WiFi Network To connect the 831C to an existing WiFi network, complete the process in this section. Before you begin: • Connect a WiFi USB adapter to the 831C. The WiFi status icon appears in the top left. Step 1.
Page 116: Disconnecting A Cloud Storage Dropbox Account
• Download the LD Atlas app for mobile devices. • Connect a WiFi USB adapter or USB hub (for multiple devices) to the 831C. The WiFi status icon appears in the top left. • Disable Mobile Data on the mobile device Enable Bluetooth on the mobile device, but do not select a device to connect to.
Page 117 Module 14 Software, Firmware, and Options In addition to meter operation, the G4 LD Utility (G4) is also used to install firmware and option upgrades as shown in the following processes. For a complete list of available firmware (versions) and firmware options (additional features or extended capability), see 1.5.1 "Firmware Options"...
Page 118 FIGURE 14-1 The meter connection types displays in the Meters Panel. Four connection types are available: WiFi Ethernet (LAN or other) TCP/IP via Internet Step 2. Click the Menu icon in-line with your meter, and select Upgrade Firmware from the pop-up menu. This opens the Upgrade Firmware or Options window.
Page 119 Step 1. In the G4 Meters Panel, connect your meter to your PC via the included USB cable or via TCP/IP. When connected, the meter icon displays in blue in-line with one of four connection types, as shown in FIGURE 14-3 G4 Connection Types The meter connection types displays in the Meters Panel.
Page 120 Step 3. Select the checkbox in-line with the option you want to enable or disable on the meter. If you have unsaved data or are currently running a measurement, TAKE NOTE the meter notifies you that a reset is needed to save the Options settings. Select OK and press the Reset button to reset the measurement.
Page 121 Module 15 Using Measurement History This module shows how to use the Measurement History (MH) feature of firmware option 831C-ELA, which allows you to segment the data gathered between Run and Stop into measurement intervals. Measurement intervals are saved as individual records within in a single data file.
Page 122 LEARN MORE To view suggested applications for each run mode, see 6.2.4 Choosing a Run Mode Selecting Manual or Stop When Stable Mode With Measurement History Select the Enable Measurement History checkbox. If you want to send a measurement interval exceedance alert, select your preferred method in-line with Alerts, then select a Trigger Source and Trigger Level (dB) for the alert.
Page 123 FIGURE 15-1 Timed Stop Mode The measurement setup shown here makes one measurement history interval that lasts 20 seconds. This is because the instrument requires at least one minute to process and digitize acoustic samples for any measurement. To enable alert notifications for measurements using this Setup, see the G4 LD Utility Manual, Module 6 “G4 Features for SoundAdvisor 831C.”...
Page 124 Select the Enable Measurement History checkbox, and enter a duration (hh:mm) for each measurement record in the Interval Time field. Note: Interval Time cannot be less than 00:01 (1 minute). If desired, select Interval Time Sync. This forces a new measurement record to begin every n minutes (or hours), where n is the value of Interval Time.
Page 125 Select any additional settings on the Setup Manager tabs. For more information, see 6.2.2 Customizing Setup Values On the Setup Manager Tabs. Press Close ( ) and save your Setup. Set it as the Active setup file. Selecting Daily Timer Mode With Measurement History Enter a Start (y-m-d) date and Time, and an End (y-m-d) date and Time, where Time is the time of day.
Page 126 15.2.1 Viewing Live Measurement Interval Data When the first measurement interval is underway, FIGURE 15-3 metrics and data display on the Current tab. When the measurement interval is complete, that data displays on the Measurement tab. The Current tab resets and begins displaying data for the next measurement interval in progress.
Page 127 Frequency Spectra Displays • When a frequency spectrum is displayed at the top, use the Right and Left navigation buttons ( ) to highlight a frequency band and display the associated levels. • To change the displayed measurement record, shift to a non-spectrum page, then return to the frequency spectrum display.
Page 128 Module 16 Using Time History The Time History feature provides a table of metrics recorded at regular intervals according to the settings you choose, and provides a method of graphing the measurement metrics over time. This feature is active on your instrument when you purchase and enable firmware option 831C-LOG or 831C-ELA.
Page 129 Step 4. Enable the desired Time History Options. Not all options are available for every time period. Table 16.1 on page 123 shows data that is displayed for each Time History Metric, depending on the Time Interval Option you select. Step 5.
Page 130 Table 16.1 Time History Available Metrics (Continued) Time Interval Options LAFTM5 Miscellaneous Ln Statistics Battery Voltage Internal Temperature External Power Millisecond Time Resolution Weather** * Only 1/1 Octave or 1/3 Octave can be chosen, not both. ** 1 second resolution and will not update between queries at faster than 1 second. “ω”...
Page 131 Step 2. If desired, edit the marker names. Step 3. Select the checkbox in-line with the sound types which should generate sound recordings this measurement. 20.2 If youʼre also planning to make sound recordings, section TAKE NOTE Using Mark Sound Type to Make Manual Sound Recordings is a good reference.
Page 132 Figure 16-4 Time History Tab (Page 1) Highlight this line and use the Enter key to toggle from Record view to the metric view. Depending on the enabled firmware options and the measurement setup used, the Time History screen can display data pages just like Live or Overall.
Page 133 SoundAdvisor™ Model 831C Viewing Time History Data...
Page 134 Module 17 Using the Event History Firmware Option This module shows how to perform a measurement using Event History, a feature of option 831C-ELA. This firmware upgrade provides event-based logging analysis and event history data with manual or timed storage of statistical data and measurement history. Figure 17-1 Sound Event An event starts when the measured sound pressure level exceeds at least one Trigger...
Page 135 Before you begin: • Verify that firmware option 831C-ELA has been installed and enabled on your meter. For more information, see 14.4 Enabling or Disabling Firmware Options. Step 1. Navigate to Tools Setup Manager.  The G4 LD Utility also provides a simple, file transfer-style interface TAKE NOTE for configuring, saving, and transferring Setup files to your PC or to another meter.
Page 136 Step 8. If desired, enable Event Time History, and choose values for the following optional settings as shown in Figure 17-2: Figure 17-2 Event Time History Period The period is the duration of each time history sample during the course of an event. The Event Time History feature provides regularly logged metrics over the duration of a sound event according to the period you specify here.
Page 137 Step 12. Run an Event History measurement and store the data file, as shown in 17.2 Storing Event Data. 17.2 Storing Event Data Event history data can be displayed during a measurement and after it has been stopped. The 831C provides 3 data storage methods: •...
Page 138 17.3 Viewing Event History Data on the Events Tab From the Live Tab, press the right softkey ( ) until the Events tab displays. After the first time interval has passed, data displays on the Event History tab in single values. The Events tab can display multiple data pages just like the Live or Overall screens, depending on the firmware options enabled and the setup used.
Page 139 17.3.1 Viewing Octave Band and Spectral Events You can view the resulting events during a measurement in progress on the Live View  Events tab on pages 3–6, or after the measurement from the Measurement  Events tab on pages 3–4. If you enabled Spectral Mode in the measurement setup, the Events tab displays multiple pages of data.
Page 140 17.4.1 Using Running Leq as an Event Trigger Using this feature, if the L for the most recent period is greater than the set Trigger Level, the meter creates an event. Before you begin: • This section explains an advanced application of step 4 in 17.1 "Setting Up the Event History Measurement"...
Page 141 • Purchase and install firmware option 831C-OB1, or 831C-OB3. Step 1. 831C G4), Setup Manager  System Properties  Reference Spectra tab. Step 2. Edit or verify the saved values as shown in 9.13 "Setting Reference Spectra" on page 98. Step 3.
Page 142 17.5.1 Understanding Level Triggering Using this method, all triggers are determined directly by their set threshold level, which is static throughout the entire measurement. The threshold level is calculated using all measured sound. Figure 17-9 Event History with Level Triggering The yellow line indicates the event trigger level, which was set at 84dB.
Page 143 Figure 17-11 Event History with Dynamic Triggering 0:00:00 1:56:39 3:53:19 5:49:59 7:46:39 9:48:18 11:44:58 13:41:38 15:38:18 17:34:58 19:31:38 21:28:18 23:24:58 Background tracking level Dynamic Trigger Level The Leq is set the same as in Figure 17-9 Event History with Level Triggering. The background level is tracked throughout the measurement.
Page 144 About the Background Level The background sound level used with dynamic triggering is the user-indicated Ln level (Setup Manager  Ln Tab). Itʼs calculated using an algorithm that includes the rise rate in dB per minute. There are 5 Dynamic Trigger Parameters options available: Table 17.13 Dynamic Response Tracking Ln...
Page 145 Module 18 RT60 Reverberation Time When your SoundAdvisor™ 831C is equipped with the RT60 firmware option (831C-RA), use the 831C to determine the reverberation time of a room according to international RT60 specifications (ISO 3382 and ISO 354). An RT60 measurement determines the length of time for sound to decay 60 dB in a space. These measurement parameters are available on the 831C: •...
Page 146 the 831C to measure the reverberation time of an enclosed space. (Source: ISO 3382- 2:2008) Table 18.1 Response Method in Relation to Measurement Grade Resulting Grade Method (Bandwidth) Survey Engineering Precision    Impulse (Octave)    Impulse (Third octave) ...
Page 147 each source/microphone location, with at least six independent source/microphone locations. These details are available for comparison to other accuracy grades in Table 18.2. Details on the RT_Eng setup file are shown in 18.2.1 "Utilizing a Quick Start Setup" on page 141. Precision Grade The precision grade measurement is appropriate where high measurement accuracy is required.
Page 148 18.2 Preparing the RT60 Setup File Before you begin: • Verify that firmware option 831C-RA has been installed and enabled on your meter. For more information, see 14.4 Enabling or Disabling Firmware Options. The SoundAdvisor 831C Room Acoustics option (831C-RA) comes with four quick start, prepared setup files.
Page 149 Table 18.4 compare the measurement parameters of each quick start setup file on the 831C: RT_Eng, RT_Prec, ASTM2235, and RT_Surv. Table 18.3 Interrupted Noise Method Prepared Setup Parameters Filter Setup Name RT_Eng Mid- 5 ms High octave Band (80 dB) RT_Prec Mid- 5 ms...
Page 150 Step 3. From the 831C Live screen, press the right softkey ( ) to view the RT60 Status screen, which displays the name of the active setup in the top menu bar, as shown in Figure 18-2. Figure 18-2 831C RT60 Status page Name of the “Active”...
Page 151 • Measurement Description: Enter measurement characteristics, such as occupancy and ambient temperature. This can also be easily managed in G4 after the measurement is downloaded. Step 6. Press the right softkey ( ) to view the RT60 tab, and select or enter values for the following settings: •...
Page 152 Step 10. Select values for the following settings on the Source tab: • RT60 Noise • Off: Disables the 831C internal noise generator. Select this option when using an external noise generator. White: Noise generated with equal energy per frequency by the 831C •...
Page 153 Figure 18-4 Setup Manager List, RT60 Impulse Setup File “RT_Surv” is a quick start Setup file prepared for Impulse method measurements when using the 831C in RA Mode. Step 3. In the pop-up menu that opens, select Save As, enter a unique name, and press Enter Step 4.
Page 154 • OBA Range Choose the range (Normal/High) which best matches the levels produced by your noise generator and noise floor. • +20 dB Gain Selecting this option amplifies the signal entering the microphone. Step 8. Press the middle softkey ( ) to Close, and then Save the Setup file.
Page 155 • From the 831C Live page, press the right softkey ( ) until the Source page displays. See Figure 18-5 to verify the connection. Figure 18-5 831C Source page The AC/DC port status (near the bottom) shows “Connected” or “Not Connected” on the meter Source page.
Page 156 Figure 18-6 RT60 Status page and measurement prompt Follow measurement prompts shown here. Table 18.5 describes each prompt. Red line is the set Trigger Level. The area 45 dB below the Trigger Level is shaded gray. (ISO 3382-2, 5.3.2). The OBA Overload icon and SLM Overload icon appears only when the meter is overloaded.
Page 157 Table 18.5 RT60 Measurement Prompts (Continued) Measurement Indication Period Shown Prompt Triggered • (Interrupted) Trigger prompt displays when the Selectable by Max Run Time in the source level has dropped 5 dB below the Trigger setup file. Level; the measurement is triggered •...
Page 158 18.4.1 Excluding a Decay from the Ensemble For an unsaved data file, when the 831C display is showing data for an individual decay, you may exclude the current decay from the overall ensemble average as shown in this section. All frequencies for the selected decay are then excluded from the ensemble calculation.
Page 159 Table 18.6 (Continued) Quality Indicators and Reducing Measurement Uncertainty Quality Indicator Description BK is the difference between the signal used to energize the room and the Background background noise. (ISO 3382-2:2008, Sections 5.2.1 and 5.3.2). An indication of Noise Level how sufficiently the room was energized above the background noise level.
Page 160 Table 18.6 (Continued) Quality Indicators and Reducing Measurement Uncertainty Quality Indicator Description > 10% Poor 5% < SD ≤ 10% Fair ≤ 5% Good 18.5 RT60 Display Overview Two display areas are reviewed in this section: The 831C meter display provides feedback on the meter’s state, the current levels, and RT60 metrics.
Page 161 Figure 18-8 Meter Live, and RT60 Tabs The RT60 Live tab shows the metrics shown here. Current RT60 measurement status including measurement prompts. For a detailed description of each page on this tab, see 18.5.2 831C Data Display for RT60 . Press the right softkey ) to...
Page 162 Figure 18-10 RT60 Status Page The RT60 Status page shows the status of the measurement. Prompts in the bottom left help you coordinate noise generation and quiet as the meter takes measurement. Table 18.5 on page 149 for additional details. During the measurement, the display metrics are as follows: •...
Page 163 Figure 18-13 RT60 Decay Curve Page-Interrupted Method The decay curve page allows you Regression Line (orange) to examine or compare decays for T30 decay curve. taken from each position. As shown below, this decay curve here is the second of three decays measured for Position 2.
Page 164 Figure 18-16 Quality Summary The Quality Summary page displays RT60 values and quality indicators frequencies between highest lowest filter chosen in the Setup. For 1/3 Octave measurements, these details span two pages. Press Select T values Press Choose T20/T30 – or Select “Decay”/ Adjust “Decay No.”...
Page 165 Figure 18-18 Accuracy Grade Page The Accuracy Grade page compares the properties and settings you saved in the Setup with the properties and settings required to satisfy the Survey, Engineering, Precision grading criteria described in ISO 3382-2. This page may provide helpful feedback to verify appropriate setup of noise equipment and measurement properties prior to taking measurements in many positions.
Page 166 Module FFT & Tonality Measurement The SoundAdvisor™ 831C and the FFT and Tonality firmware option are used to determine the frequency content and tonality of the measured sound. In FFT Mode, the 831C captures the waveforms of even complex sounds, computes the time and frequency domains, extracts peak frequencies and amplitudes, and applies chosen digital filters and data windowing preferences to produce the resulting data for view on the meter and in G4 LD Utility.
Page 167 Enter the sensitivity for the Nominal, Actual, and Self Noise, then select Save. This information can be found on the mic certification document TAKE NOTE that came with it. 1. SoundAdvisor and ICP are registered trademarks of PCB Piezotronics, Inc. SoundAdvisor™ Model 831C Preparing the Equipment...
Page 168 • Obtain the specified cable (see “Supported Hardware Configurations”). Step 1. Insert the ADP074 5-pin connector into the top of the 831C. 1. SoundAdvisor and ICP are registered trademarks of PCB Piezotronics, Inc. SoundAdvisor™ Model 831C Preparing the Equipment...
Page 169 Step 2. Connect the cable end (BNC) to the ADP074 (BNC) and the cable end (10-32) to the accelerometer. FIGURE 19-1 Example Connection: 831C, ADP074, Cable, and Accelerometer Step 3. Switch the meter from SLM Mode to FFT Mode. To do this, select Tools , and choose FFT Mode from the menu.
Page 170 This section shows FFT-specific properties and settings and also refers you to portions of Module 6 Creating a Measurement Setup for non-FFT related settings. If you plan to measure tonality, this module also includes instructions for creating a measurement Setup file thatʼs fully compliant with ISO 1996-2 or ISO/PAS 20065. Before you begin: •...
Page 171 Sampled Data and the Windowing Function With fast Fourier transform mode, when the measured signal doesnʼt use up an even number of lines or when the number of lines is not a multiple of the sampling frequency, the resulting data “smears” into the adjacent lines. This results in additional high-frequency values that were not part of the original signal.
Page 172 FIGURE 19-4 Example- Flat Top Windowing Waveform With Windowing Sampled Sound Window Shape Samples 10 20 30 40 50 60 Hanning: This windowing method forces the ends of the time record to zero and changes the wave form to a curve with side lobes to reduce any spectral leakage. The spectral leakage sometimes results when a sine wave signal is captured non-periodically.
Page 173 • When using a time-based meter control, the measurement duration (“Time”), must be longer than the minimum period in the table. • The FFT History (measurement history for FFT) record Time (in hours, minutes, and seconds) must be longer than the minimum period in the table. Measuring According to ISO 1996-2 Note that any combination of frequency span and FFT lines that produces a resolution of at least 3.3333 Hz/Line (with A-weighting and Hanning window)
Page 174 Step 12. Press the right softkey ( ) to view the Control tab. Step 13. Select a Run Mode from the drop-down menu. This controls how the meter ends a measurement and how history records are accumulated. The following segments describe FFT Run Modes in detail. Using Manual Stop A Manual Stop measurement begins when you press the Run/Pause button and ends...
Page 175 Select Continuous as the Run Mode. Select the Auto-Store period, and enter the Time of day to store in hours, minutes, and seconds. If your preamplifier is equipped for a calibration check, select the checkbox in- line with Cal. Check, and enter a time of day in the Time field in hh:mm:ss format.
Page 176 FIGURE 19-8 FFT Misc tab Select up to 3 Trigger Sources from the drop-down menus, and enter up to 3 Trigger Levels. your Transducer microphone, integration disabled. If you selected Other as the transducer, select an option from the Integration drop-down menu.
Page 177 Enter the Setup Manager (Tools  Setup Manager). Highlight the name of the FFT setup you created for this measurement. Press Enter , and select Set To Active. Step 2. (Optional) If you want to enable and define alert notifications, open G4 LD Utility and select the Accounts/Schedule view.
Page 178 FIGURE 19-10 FFT Live Display Elements When zoomed in on a 1:1 ratio, the level indicator (“@ max”) changes to show that the displayed level is no longer the max value of multiple overlapping levels, but the max value of a single level at the cursor. Press the left or right button ( ) to advance the Manual cursor.
Page 179 Editing the Cursor When viewing Live data you can select the cursor type. Choose Menu (  Cursor Type on the 831C, then select Manual, or Max-Tracking. Each can be displayed with or without harmonics. Editing the cursor is also shown in Figure 19-10. Use the left and right buttons ( ) to advance the Manual cursor and investigate tone details in the graph.
Page 180 Live Data On the History Tab Live historical data takes time to accumulate, so data on the History tab may not be immediately available during a measurement. In the following example of a vibration measurement, Figure 19-13 shows historical vibration records. FIGURE 19-13 FFT History Tab Displays a Vibration Record The History tab is displaying record 1 of 2...
Page 181 FIGURE 19-14 Display Elements on the Live Tonality Tab (ISO/PAS 20065) Tone indicator (green vertical bar) Critical Bandwidth (green horizontal bar) Harmonic Cursors (orange vertical lines) Noise Regression indicator (red line) As on other screens, press the left or right buttons ) to advance the Manual cursor and navigate tones in the graph.
Page 182 FIGURE 19-15 Display Elements On the Live Tonality Tab- ISO1996-2 Tone indicator (green vertical bar); Critical band- width (green horizontal bar) To navigate from one record to another, press the left and right buttons ( ). To switch to navigating tones in the graph, press Enter then press the left and right buttons ( Lpt: Tone Level, Lpn: Noise Level, Lta: Tone Audibility Level, Kt: Suggested Adjustment Level...
Page 183 Table 19.1 ISO 1996-2: Quality Indicators for Tonality Deficiencies (Continued) Icon Deficiency Remedy The tone bandwidth is not less Increase the resolution of the than 10 percent of the critical measurement by increasing the number bandwidth. of Lines, or by decreasing the Frequency Span in the Setup (FFT tab).
Page 184 Module 20 Utilizing 831C Sound Recording Sound recordings on the 831C are often created to identify the source of loud noises during a measurement. The Sound Recording feature is available when you purchase and install firmware option 831C-SR. The upgrade allows you to trigger a recording and add a sound type label to the resulting measurement data using 3 methods: by creating a manual sound recording, by setting automated event-triggered recording, and by using measurement history event recording.
Page 185 Adjusting Peak Overload, Gain, and Range During calibration, the 831C automatically calculates the peak overload based on the current microphone type. To ensure the calibration will be accurate, you may adjust the peak overload value as shown here: In G4, open the meter tab and select the Calibrate view.
Page 186 Table 20.2 describes the approximate file size for a 60-second sound recording in each format. The WAV file sizes are accurate to the nearest 50 kB. The OGG (Compression: “Normal”) file sizes are approximations, since every compressed file is unique. Table 20.2 Approximate Sound Recording File Sizes Per 60 Seconds Sample Rate...
Page 187 Before you begin: Verify that 831C-SR firmware is installed and enabled on your meter. For more information, see 14.4 Enabling or Disabling Firmware Options. 20.2.1 Configuring Markers for Sound Recording Markers help you label and initiate a recording of the sound being measured. You can also use markers to simply mark the sound occurrence with a label thatʼs saved in the measurementʼs Time History.
Page 188 20.2.2 Making a Manual Sound Recording by Using Mark Sound Type Mark, label, and record sounds by using the mark sound type feature, as shown in this section. Before you begin: Complete the process shown in 20.2.1 Configuring Markers for Sound •...
Page 189 Measurement" on page 127. Note: You may still record event sounds without Event History, as shown in this section. Step 1. In G4, navigate to the Setup Manager Event Triggers page on your connected meter. To do this, do the following: Select Setup Manager from the top menu bar.
Page 190 Step 6. Select the checkbox in-line with Save Event Sound, and enter any other applicable values. Figure 20-7 Sound Event Settings For more information on selecting a range, see "Choosing Resolution, Peak Overload, and Range Settings" on page 177 . Select an Audio Compression setting.
Page 191 Before you begin: • Create a saved Setup file with Measurement History enabled. For reference, see 15.1 Configuring Measurement History (MH). • Review 20.5 Listening to Sound Recordings • Connect your meter in G4 Step 1. In G4, navigate to the Setup Manager Sound page on your connected meter. To do this, select Setup Manager (Right side) [select your measurement history- enabled Setup file from the list].
Page 192 Figure 20-9 Measurement Setup Sound Page If you enable Audio Compression, sound recordings are saved in a compressed file format. For details, see "Choosing a File Format for Recorded Sound Files" on page (Optional: Applies only when Event History is also enabled in the Setup) When you select Save Event Sound, the shorter one of the associated options is included in the resulting data file: either a recording of the snapshot time,...
Page 193 Step 4. Select a sound event from the list. This opens the sound player. Figure 20-10 Session Log Playback Playback After Saving in G4 After the sound recording is stored, you can access it most easily from the G4 LD Utility. For more information, see section “4.8 Accessing Audio Files in LEARN MORE G4”...
Page 194 Appendix A Technical Specifications In this module: Instrument Platform Specifications - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - A-2 Model PRM831 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - A-9 Base Software - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - A-10 Octave Band Analysis Software –...
Page 195: Instrument Platform Specifications
A.1 Instrument Platform Specifications A.1.1 Standards Met Safety: Other Standards: IEC 61010-1:2010: Safety Requirements for Electrical Test results and certificates compliant with ISO 17025 Equipment for Measurement, Control and Laboratory Table A-1 Safety Marks EMC Emission: CE-mark indicates CISPR 11:2015 with Amend 1 (EN 55011) compliance with the EMC, Low Voltage, and RoHs EMC Immunity:...
Page 196 A.1.4 SLM Performance Specifications Table A-2 SLM Performance (Nominal Values) PRM831 with PRM831 with PRM831 with Direct Input 378A04 377B02 377C20 377A15 (dBµV) (dB SPL) (dB SPL) (dB SPL) (dB SPL) 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB...
Page 197 • Touch screen to assist in data navigation and measurement control • Multiple color themes for various lighting conditions Display update rate: ≤ 1 s Lock: User interface may be locked and unlocked Languages: Czech, English, French, German, Italian, Norwegian, Portuguese, Russian, Spanish, Swedish, Turkish A.1.6 Input Specifications Connector: Latching 5-pin circular connector, mates to PRM831 or EXCxxx cables...
Page 198 • Ultrasonic Wind Sensor, Vaisala WMT52, PN SEN032 • Wireless LTE Gateway, Sierra Wireless AirLink RV-50, PN COM-RV50-DC-E or COM-RV50-DC-U A.1.9 AC/DC Output Specifications Connector: 2.5mm (3/16”) Sub-Miniature Phone Jack, For Preamp selection: ±14.14 Vpeak Maximum AC Output on RING, DC Output on TIP AC Output Impedance: 1kΩ...
Page 199 Analog Inputs: 3 channels, 0 to +2.5 V, 100 kΩ load. customize Scale and Units. See Choosing Weather Use the Weather settings in the measurement setup to Settings in the Setup Manager on page 169 The pinouts for the I/O Connector are shown in Table A-4. Table A-4 I/O Connector Pinouts Table A-5 Description...
Page 200 A.1.13 External Power Specifications Via USB Client Connector: Powered by computer or PSA029 Power Adapter, 5.0 ±0.5 V typical, 16 V absolute maximum A.1.14 External DC Power Supply Specifications Provides power to operate the instrument, supply the USB Host port with 500mA, and charge the batteries.
Page 201 Table A-7 831C Power-On Attempts After External Power Failure The 831C automatic power on attempts shown in this table occur only when the meter is utilizing TAKE NOTE “Continuous” Meter Control, in SLM mode. Period Since Last Power-On Time: < 2 minutes Power On Attempts Power Fail Real-Time Clock: Documented Drift is <...
Page 202: Model Prm831
A.2 Model PRM831 The Larson Davis PRM831 is an electret microphone operates over wide ranges of temperature and preamplifier for use with a Larson Davis Model 831 humidity. It has very little attenuation for use with 50 Sound Level Meter. It requires little supply current and mV/Pa sensitivity microphones up to 140 dBSPL.
Page 203: Base Software
Output Connector: Switchcraft TA5M 5-Pin male Table A-9 Output Connector Key Signal Signal Ground Signal Output Power Supply + 35 Volts Preamp sensor No Connection Shell Connect to preamp housing A.3 Base Software A.3.1 Standards Met Sound Level Meter Standards: •...
Page 204 0° Free Field 0° Free Field Expanded 0° Free Field 0° Free Field Corrections Corrections uncertainty of Frequency 2 Corrections Corrections with WS with WS Corrections 0.10 -0.01 0.07 -0.03 0.25 0.25 0.17 0.26 0.18 0.25 1000 0.00 0.00 0.00 0.00 0.25 2000...
Page 205 A.3.3 Measurement System Specifications Integration Method: • Equivalent level integration method can be Linear or Exponential. • Exponential integrates the output of the selected time weighting (Slow, Fast, or Impulse) Integration Time: Minimum: 0.1 s, Maximum: < 0.5 dB error: > 23 days Frequency Weightings: A, C, Z parallel and simultaneous for each Time Weighting, selected frequency weighting (A, C, or Z) indicated by ...
Page 206 Table A-12 (Continued) Fast Minimum AFmin CFmin ZFmin Fast Maximum AFmax CFmax ZFmax Impulse Minimum AImin CImin ZImin Impulse Maximum AImax CImax ZImax Peak Apeak(max) Cpeak(max) Zpeak(max) 1. Linear integration method selected by user 2. Exponential Integration method selected by user Table A-13 Occurrence Time for Minimum and Maximum Levels Time Weighting Units...
Page 207 Exceedance Metrics Exceedance levels (L1, L2, P1, P2 and P3) selectable in dB from 0.0 to 200.0, counts each time the level rises above the threshold and measure the duration while above the level minus 2 dB. Table A-15 Label Count Duration SPL 1...
Page 208 • Longitude: dg m.m • Elevation: m or feet • Time Acquired: h:m:s A.3.6 Measurement Control Specifications The following control modes provide for a variety of manual and automated measurements: Manual: Manually control measurements-- RUN, PAUSE, RESUME, STOP, STORE Timed Stop: Start manually and runs for set run time (1 second to 99 hours) Stop When Stable: Start manually and runs until levels are stable Continuous: Start manually or at power on and runs without interruption, Daily Auto-Store available, special restart after low battery features enabled...
Page 209: Octave Band Analysis Software - Option 831C-Ob3
A.4 Octave Band Analysis Software – Option 831C-OB3 Complies with the following Octave Filter Standards: • IEC 61260-1:2014/Part 1, 1/1 and 1/3-octave Bands, Class 1, Group X, all filters • ANSI/ASA S1.11-2014/Part 1, 1/1 and 1/3-octave Bands, Class 1, Group X, all filters OBA Specifications Bandwidth: 1/1 Octave, 1/3 Octave, or simultaneous 1/1 and 1/3 Octave...
Page 210 A.4.1 1/1 and 1/3 OBA Filter Linearity Ranges (Normal and High) Full Octave ranges are shown in Table A-16. Third Octave ranges are shown in Table A-17. Table A-16 1/1 OBA Octave Linearity Range High Range Normal Range High Range Normal Range Nominal Nominal...
Page 211 ≥ 107 ≥ 90 ≥ 81 ≥ 62 ≥ 99 ≥ 97 ≥ 104 ≥ 86 34 to 140 31 to 120 29 to 110 28 to 90 41 to 140 24 to 120 6 to 110 4 to 90 ≥...
Page 212 Table A.17 1/3 Octave OBA Linearity Range (Cont...) Normal OBA Nominal High OBA Range Normal OBA Range Nominal High OBA Range Range Frequency Frequency 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB (Hz) (Hz) Gain (...
Page 213 Percentile Spectrum Levels, uses same percentages n1 through n6 selected in SLM, 0.01 to 99.99%. Statistics are sampled every 100ms from the selected OBA frequency weighting and time weighting into 0.1 dB wide amplitude classes, as shown in Table A.17. Units ωn1(f) ωn2(f)
Page 214 Instrument Noise Levels With OBA, by Preamp The following charts show the 831C instrument noise levels for the OBA filter With PRM831 and Direct Input. FIGURE A-2 Self-Generated Noise Levels for 1/1 Octave Filter With PRM831 50.0 40.0 30.0 20.0 High +0dB High +20dB 10.0...
Page 215 FIGURE A-4 Self-Generated Noise Levels for 1/3 Octave Filter With PRM831 50.0 40.0 30.0 20.0 High +0dB High +20dB 10.0 Normal +0dB Normal +20dB -10.0 -20.0 -30.0 1000 10000 FIGURE A-5 Self-Generated Noise Levels for 1/3 Octave Filter With Direct Input 50.0 40.0 30.0...
Page 216 Instrument Noise Levels With OBA, by Microphone The following charts (Figure A-6 through Figure A-13) show the typical instrument noise level for each microphone type in Normal and High range for 1/1 and 1/3 octave bands. Zoom in to view graph details. FIGURE A-6 377A15/831C Instrument Noise, 1/1 Octave FIGURE A-7...
Page 217 FIGURE A-8 377B02/831C Instrument Noise, 1/1 Octave FIGURE A-9 377B02/831C Instrument Noise, 1/3 Octave SoundAdvisor Model 831C A-24...
Page 218 FIGURE A-10 377C20/831C Instrument Noise, 1/1 Octave FIGURE A-11 377C20/831C Instrument Noise, 1/3 Octave SoundAdvisor Model 831C A-25...
Page 219 FIGURE A-12 378A04/831C Instrument Noise, 1/1 Octave FIGURE A-13 378A04/831C Instrument Noise, 1/3 Octave SoundAdvisor Model 831C A-26...
Page 220 A.4.3 Typical Residual OBA Filter Decay Time for RT60 (Firmware Opt 831C-RT) Table A-18 shows the typical residual decay time (TR) and the bandwidth-time product (BT) for each of the OBA filters on the Model 831C when in RA Mode. The source is a sine wave from a signal generator. The residual decay time for each frequency is the T30 of the ensemble average of 50 decays.
Page 221: Event Logging Software (Option 831C-Ela
A.5 Event Logging Software (Option 831C-ELA) Measurement History Selectable Properties Time Period: Selectable from 1 minute to 99 hours 59 minutes Synchronization: Selectable to sync to time-of-day clock, for periods of 1, 2, 5, 10, 15, 20, 30 minutes, and 1, 24 hours Measurements: Same measurements as Overall measurement Event History Selectable Properties Detection Methods: Level or Dynamic...
Page 222: Time History Software (Option 831C-Log
A.6 Time History Software (Option 831C-LOG) Time History Measurement System Time History can log an abundant selection of acoustic and non-acoustic metrics at equal time intervals. Time Period: Selectable for periods 2.5 ms, 5 ms, 10 ms, 20 ms, 50 ms, 100 ms, 200 ms, 500 ms, 1 s, 2 s, 5 s, 10 s, 15 s, 20 s, 30 s, 1 min, 2 min, 5 min, 10 min, 15 min, 20 min, 30 min, 1 h, and 24 h Synchronization: Selectable to sync to time-of-day clock, for periods of 1, 2, 5,...
Page 223: Fft Analysis Software Specifications (Option 831C-Fft
A.7 FFT Analysis Software Specifications (Option 831C-FFT) Specifications for FFT analysis are given for the SoundAdvisor 831C with firmware option 831C-FFT installed. A.7.1 FFT Analysis Sampling Frequency: Down sampling from 51.2 kHz Frequency Span: 100 Hz, 200 Hz, 500 Hz, 1 kHz, 5 kHz, 10 kHz, 20 kHz Lines of Resolution: 400, 800, 1600, 3200, 6400 Weighting: A, C, and Z FFT Windowing Options: Hanning, Flat Top, Rectangular.
Page 224 A.7.4 Display Spectra Latest (Live), Linear Average, and Maximum Spectra X-axis display: Full frequency range, with the ability to zoom to 1:1 line to pixel ratio (with 215 lines possible) in Hz or CPM. Y-axis display: Linear, or Logarithmic with a user-selectable scale feature (selectable from -60 dB to 340 dB).
Page 225: Ptb Approved Firmware
A.8 PTB Approved Firmware In order to be compliant with PTB requirements, the PTB firmware option and approved firmware must be installed on the Model 831C SLM. When the option and approved firmware are installed, an indicator will be displayed on the status bar indicating the PTB seal is intact.
Page 226: Frequency Response Charts
A.9 Frequency Response Charts The following data was taken using the SoundAdvisor 831C sound level meter with a PRM831 preamplifier at degrees increasing by 10, starting with 0° and rotating to 350°. The frequency was measured in Hertz and ranged from ~200 Hz to 20 kHz.
Page 227 377B02, XY Plane Frequency Response FIGURE A-15 Model 831C with 377B02 Microphone / XY Plane Mic at n° 20° 60° 100° 140° 180° Frequency (Hz) FIGURE A-16 Model 831C with 377B02 Microphone/ XY Plane Mic at n° 40° 80° 120° 160°...
Page 229 FIGURE A-19 Model 831C with 377B02 Microphone/ XY Plane, Referenced to Level at 0° Updated 11/20/2021 End of 377B02 XY Plane Frequency Response Graphs SoundAdvisor Model 831C A-36...
Page 230 377C20, XY Plane Frequency Response FIGURE A-20 Model 831C with 377C20 RI Microphone/ XY Plane, Relative to 1000 Hz at O° Updated 11/20/2021 FIGURE A-21 Model 831C with 377C20 RI Microphone/ XY Plane, Relative to 1000 Hz at O° Updated 11/20/2021 SoundAdvisor Model 831C A-37...
Page 231 FIGURE A-22 Model 831C with 377C20 Microphone/ XY Plane, Relative to 1000 Hz at O° Updated 11/20/2021 FIGURE A-23 Model 831C with 377C20 RI Microphone/ XY Plane, Referenced to Level at 0° Updated 11/20/2021 SoundAdvisor Model 831C A-38...
Page 232 377A15, XY Plane Frequency Response FIGURE A-24 Model 831C with 377A15 Pressure Mic with ADP008A/ XY Plane, Relative to 1000 Hz at O° Updated 11/20/2021 FIGURE A-25 Model 831C with 377A15 Pressure Microphone with ADP008A XY Plane Directional Response, Relative to 1000 Hz at O° Updated 11/20/2021 SoundAdvisor Model 831C A-39...
Page 233 FIGURE A-26 Model 831C with 377A15 Pressure Mic with ADP008A/ XY Plane, Relative to 1000 Hz at O° Updated 11/20/2021 FIGURE A-27 Model 831C with 377A15 Pressure Mic with ADP008A/ XY Plane, Ref to Level at O° Updated 4/28/2022 Updated 11/20/2021, 04/28/2022 with bottom legend item snip.
Page 234 A.9.2 XZ Plane Frequency Response Sound Source Perpendicular to Plane of Display Screen (XZ Plane) FIGURE A-28 SoundAdvisor Model 831C A-41...
Page 237 FIGURE A-33 Model 831C with 377B02 Microphone/ XZ Plane, Referenced to Level at 0° Updated 11/20/2021 377C20, XZ Plane FIGURE A-34 Model 831C with 377C20 Microphone/ XZ Plane, Relative to 1000 Hz at 0° SoundAdvisor Model 831C A-44...
Page 238 FIGURE A-35 Model 831C with 377C20 Microphone/ XZ Plane, Relative to 1000 Hz at 0° FIGURE A-36 Model 831C with 377C20 Microphone/ XZ Plane, Relative to 1000 Hz at 0° SoundAdvisor Model 831C A-45...
Page 239 FIGURE A-37 Model 831C with 377C20 Microphone/ XZ Plane, Referenced to Level at 0° Updated 11/20/2021 End of 377C20 XZ Plane Frequency Response Graphs SoundAdvisor Model 831C A-46...
Page 240 377A15, XZ Plane FIGURE A-38 Model 831C with 377A15 Microphone/ XZ Plane, Relative to 1000 Hz at 0° Updated 11/20/2021 FIGURE A-39 Model 831C with 377A15 Microphone/ XZ Plane, Relative to 1000 Hz at 0° Updated 11/20/2021 SoundAdvisor Model 831C A-47...
Page 241 FIGURE A-40 Model 831C with 377A15 Microphone/ XZ Plane, Relative to 1000 Hz at 0° Updated 11/20/2021 FIGURE A-41 Model 831C with 377A15 Microphone/ XZ Plane, Referenced to Level at 0° Updated 11/20/2021 4/28/2022 with last legend item snip SoundAdvisor Model 831C A-48...
Page 242 A.9.3 Random Incidence Response FIGURE A-42 831C With 377B02 Free-Field, Random Incidence Mic/ Normalized to 1 kHz at 0° Frequency (Hz) Random Incidence Response - No Correction Random Incidence Response - No Correction A.9.4 Typical Z-Weight Frequency Response For frequency responses of the Model 831C with the PRM2103 preamplifier, see the Larson Davis PRM2103 Outdoor Microphone Preamplifier Manual.
Page 243 A.9.5 831C Low Noise Microphone Set (831C-LOWN) Frequency Response The 831C-LOWN microphone set uses an extension cable to connect to the 378A04 Low Noise Microphone and Preamplifier combination. Because of this, the directional response characteristics donʼt include the case reflections often shown with other microphone setups. FIGURE A-44 831C With LOWN Mic Set Directional Response, Referenced to Free-Field Response FIGURE A-45...
Page 244 FIGURE A-46 831C with LOWN Mic Set/ Directional Response, Referenced to Level at 0° Updated 04/28/2022 End of Appendix A Technical Specifications SoundAdvisor Model 831C A-51...
Page 245 Appendix Measuring Sound Using IEC 61672-1 B.1 Overview This appendix presents information for assessing the sound level meter functionality of the Larson Davis SoundAdvisor Model 831C according to IEC 61672-1 Edition 2.0 2013-09. Microphone correction filters should be set to “Off” except when testing to IEC 61672-2 Section 9.4.2 - Windscreen Corrections.
Page 246 Table B.1 831C with PRM831/377B02 Microphone average frequency responses and corrections, required by IEC 61672-1 0° Free Field Expanded 0° Free Corrections, uncertainty 0° Free Effect of Field, 831C 831C with Exact Field 0° Free Field Wind with Wind Wind Corrections Frequency Response...
Page 247 Table B.1 831C with PRM831/377B02 Microphone average frequency responses and corrections, required by IEC 61672-1 (Continued) 3548.13 -0.13 0.13 -0.01 -0.14 0.14 0.35 3758.37 0.10 -0.10 -0.00 0.10 -0.10 0.35 3981.07 0.10 -0.10 0.00 0.10 -0.10 0.35 4216.97 -0.03 0.03 -0.20 -0.23 0.23...
Page 248 Table B.2 831C with PRM831/377C20 Microphone average frequency responses and corrections, required by IEC 61672-1 Random Random Random Incidence Windscreen Incidence Corrections Expanded Exact Incidence Response Effect of on 831C on 831C with Uncertainty of Frequency Response Corrections Windscreen in RI Field Windscreen Corrections 251.19...
Page 249 Table B.2 831C with PRM831/377C20 Microphone average frequency responses and corrections, required by IEC 61672-1 (Continued) 1258.93 -0.06 0.06 0.13 0.07 -0.07 0.25 1333.52 -0.07 0.07 0.14 0.08 -0.08 0.25 1412.54 -0.07 0.07 0.13 0.06 -0.06 0.25 1496.24 -0.06 0.06 0.13 0.08 -0.08...
Page 250 Table B.2 831C with PRM831/377C20 Microphone average frequency responses and corrections, required by IEC 61672-1 (Continued) 7943.28 0.61 -0.61 -0.35 0.25 -0.25 0.45 8413.95 0.74 -0.74 -0.73 0.01 -0.01 0.55 8912.51 0.77 -0.77 -1.22 -0.45 0.45 0.55 9440.61 0.73 -0.73 -1.29 -0.56 0.56...
Page 251 Table B.3 Directional Response of 3 ½-inch Windscreen (Continued) 0.07 0.10 0.13 0.07 -0.03 0.03 0.00 0.00 0.10 0.07 -0.03 0.07 0.00 595.66 0.03 0.00 0.07 -0.03 0.00 0.07 0.10 0.07 0.13 0.10 0.03 0.10 0.10 630.96 0.10 0.10 0.13 0.07 0.03 0.00...
Page 252 Table B.3 Directional Response of 3 ½-inch Windscreen (Continued) 0.00 -0.07 -0.03 -0.17 -0.20 -0.33 -0.37 -0.43 -0.47 -0.50 -0.53 -0.43 -0.43 5623.41 0.17 0.07 0.10 -0.13 -0.17 -0.23 -0.33 -0.37 -0.43 -0.50 -0.57 -0.50 -0.40 5956.62 0.10 0.20 0.23 -0.03 -0.07 -0.03 -0.10 -0.33 -0.37 -0.40 -0.47 -0.40 -0.30 6309.57 0.13 0.10...
Page 253 WS001 3 ½” Windscreen Corrections The following table and graph display correction factors for effects of the WS001 on the response of the sound level meter. These corrections are intended for laboratory use when testing to IEC 61672-2 Section 9.4.2 to account for effects of the WS001 windscreen.
Page 254 Table B.4 Correction Factors for WS001 WS001 Windscreen Expanded Uncertainty Frequency Correction Factor of Corrections @ 95% 63.10 0.00 0.20 79.43 0.00 0.20 100.00 0.00 0.20 125.89 0.00 0.20 158.49 0.00 0.20 199.53 0.00 0.20 251.19 0.00 0.20 266.07 0.00 0.20 281.84 0.00...
Page 255 891.25 0.10 0.20 944.06 0.13 0.20 1000.00 0.20 0.20 1059.25 0.10 0.20 1122.02 0.20 0.20 1188.50 0.20 0.20 1258.93 0.13 0.20 1333.52 0.20 0.20 1412.54 0.20 0.20 1496.24 0.23 0.20 1584.89 0.33 0.20 1678.80 0.30 0.20 1778.28 0.40 0.20 1883.65 0.40 0.20 1995.26...
Page 256 5623.41 0.00 0.30 5956.62 0.17 0.30 6309.57 0.10 0.30 6683.44 0.13 0.30 7079.46 0.03 0.30 7498.94 -0.10 0.30 7943.28 -0.30 0.30 8413.95 -0.40 0.30 8912.51 -0.40 0.30 9440.61 -0.37 0.30 10000.00 -0.13 0.30 10592.54 -0.20 0.30 11220.18 -0.47 0.30 11885.02 -0.67 0.30 12589.25...
Page 257 EPS2116 Corrections The following table and graph display correction factors for effects of the EPS2116 on the response of the sound level meter with either the PRM831 or PRM2103 preamplifier and the 377B02 microphone. These corrections are intended for laboratory use when testing to IEC 61672-2 to account for effects of the EPS2116. The corrections are added to the electrical signals to replicate the acoustical response when the EPS2116 windscreen is in place.
Page 258 Table B.7 Effects of EPS2116 Environmental Shroud by Frequency EPS2116 at Expanded Frequency EPS2116 at 0 Degrees EPS2116 at 90 Degrees Random Incidence Uncertainty (Hz) (dB) (dB) (dB) (dB) 0.05 -0.03 -0.10 0.20 0.05 -0.03 -0.10 0.20 0.05 -0.03 -0.10 0.20 0.06 -0.03...
Page 259 2985 0.60 -0.50 -0.37 0.20 3162 0.70 -0.55 -0.48 0.20 3350 0.97 -0.53 -0.60 0.20 3548 0.70 -0.60 -0.76 0.20 3758 0.60 -0.92 -0.94 0.20 3981 0.75 -1.35 -1.13 0.20 4217 0.70 -1.82 -1.23 0.30 4467 0.43 -2.17 -1.38 0.30 4732 0.65 -2.30...
Page 260 Sections f) through o) are applicable for both the PRM831 and PRM2103 preamplifiers. f) Linear Operating Range Table B.8 Linearity Range (Nominal Values) 31.5 Hz 1 kHz 4 kHz 8 kHz 12.5 kHz Weighting Gain Lower Upper Lower Upper Lower Upper Lower Upper...
Page 261 j) Highest Sound Pressure Level The highest sound pressure level the Larson Davis 831C is designed to accommodate at the level of overload is 140 dB. The maximum peak-to-peak voltage is 28 Vpp input through the ADP090. k) Battery Power Voltage Range The battery power supply voltage range for which the 831C conforms to this standard: 16.8 Volts maximum.
Page 262 Appendix C Glossary This appendix contains technical definitions of key acoustical and vibration terms commonly used with Larson Davis instruments. The reader is referred to American National Standards Institute document S1.1-1994 (R2004) for additional definitions. Specific use of the terms defined are in the main body of this manual. Allowed Exposure Time (T The allowed time of exposure to sound that a constant A-weighted sound level in a chosen Criterion Level, Criterion Duration, and Exchange Rate.
Page 263 Bin Max Bin Max is one of 2 choices for the Max Spec setting on the OBA Page of the Setup Manager. See also "At Lmax" Bin Max is the maximum value that occurred during the entire measurement for that frequency band.
Page 264 Criterion Sound Level (L It is the sound level which if continually applied for the Criterion Duration will produce a Noise Dose of 100%. The current OSHA Criterion Level is 90 dB. Standard: ANSI S12.19 Daily Personal Noise Exposure (L EP,d It is the level of a constant sound over the Criterion Duration that contains the same sound energy as the actual, unsteady sound over a specific period.
Page 265 The word level is normally attached to a physical quantity when expressed in decibels; for example, L represents the sound pressure level. The difference between the sound pressure for silence versus loud sounds is a factor of 1,000,000:1 or more, and it is very unpractical to use these large numbers. Therefore, a measure that would relate to “the number of zeros”...
Page 266 doubling of the sound power is equal to 3 dB, and a doubling of the sound pressure is equal to 6 dB, since a doubling of the sound pressure will result in a quadruple increase of the sound power. The advantage with using dB is simply that they remain the same even if we use sound pressure or sound power.
Page 267 averages it in accordance with the time-weighting characteristic, and then takes the square root. This results in an amplitude described as rms (root-mean-square). The Slow and Fast detector responses were originally developed to slow down the movement of the needle on an electro-mechanical meter, so that the amplitude could be determined.
Page 268 Table C.3 Exchange Rate Exchange Rate, Exchange Rate Exposure Factor, q Factor, k 3.01 13.29 16.61 6.02 Standard: ANSI S12.19 Exponential Integration The alternative to "Linear Integration" for the 831C SLM. Exponential integration shows a long decay of energy after an impulse. However, it may hide small events or loud impulsive events.
Page 269 Frequency Band Pass Filter The part of certain sound level meters that divides the frequency spectrum on the sound or vibration into a part that is unchanged and a part that is filtered out. It can be composed of one or more of the following types: Low Pass: A frequency filter that permits signals to pass through that have frequencies below a certain fixed frequency, called a cutoff frequency.
Page 270 Table C.4 Frequency Filter Response Center Frequencies, Weighting Network Frequency Response 1 Octave A Octave -50.4 -24.2 -6.2 -44.7 -20.4 -4.4 31.5 31.5 -39.4 -17.1 -3.0 -34.6 -14.2 -2.0 -30.2 -11.6 -1.3 -26.2 -9.3 -0.8 -22.5 -7.4 -0.5 -19.1 -5.6 -0.3 -16.1 -4.2...
Page 271 often added after the number to express the same thing. When frequency weighting is used the annotation is often expressed as dB(A) or dB(B). Linear Integration The alternative to "Exponential Integration" for the 831C SLM. This is the default and most commonly used integration method for measuring sound.
Page 272 Random incidence: The microphone has been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions. Pressure: The microphone has not been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions. What a microphone measures: A microphone detects more than just sound.
Page 273 2. Choose a microphone for free field or random incidence to minimize the influence of orientation. A microphone measures what is there from any direction: Most measurements are intended to measure the sound level of a specific source, but most microphones are not directional so they measure whatever is there, regardless of source.
Page 274 Pink: It is a random sound that maintains constant energy per octave. Pink light is similar to pink noise in that it has a higher level at the lower frequencies (red end of the spectrum). White: It is a random sound that contains equal energy at each frequency. In this respect, it is similar to white light.
Page 275 Kt: Possible adjustment to the measured sound pressure level that may be suggested to account for the impact of more prominent tones on the human ear. Regression Range When applying the 1996-2 Tonality standard, the Regression Range value enables you to set what percentage of the critical band should be represented to the left and right of the center frequency.
Page 276 When extracting sound records from LDBIN files, the file name code “$L,” for meter location, is added to the Default File Name (Tools Options Command Line   Settings). Each resulting sound record also bears the meter location id. Sound Sound is comprised of rapid oscillatory compression changes in a solid, liquid, or gas medium that propagate to distant points.
Page 277 Moving Average: The averaging process is continually accepting new data so it is similar to an exponential moving average. In the equation, the sound pressure is squared and multiplied by a exponential decay factor, so that when the time of integration is near the current time (t) it is essentially undiminished.
Page 278 Calibrators often use a level of 94 dB so they generate a sound pressure of 1 Pascal. If the sound pressure level = 76.3 dB, then the sound pressure is 6 – – –  76.3 20 3.815 6 2.185 ...
Page 279 Taktmaximal-5 An integration of the five second maximum, A-frequency-weighted, fast time-weighted sound pressure levels.                    AFTM       Where L is the maximum, A-weighted, fast exponential time-weighted sound Amax 5s(n)
Page 280 Tone Seek Delta This FFT and Tonality setting—associated with the 1996-2 Tonality standard—is used to distinguish noise pauses from masking noise in the measurement. The default value is 1 dB. Refer to ISO 1996-2 C.4.2 to determine which value to use for your measurement. Vibration The oscillatory movement of a mechanical system (generally taken to be solid).
Page 281 Larson Davis - a PCB Piezotronics division LarsonDavis.com P/N I831C.01 Rev Q, SoundAdvisor 831C Reference Manual firmware version 4.7 ©2022 PCB Piezotronics, Inc. Contact Larson Davis Toll-free (in the US): 888-258-3222 Worldwide Corporate Headquarters Phone: 716-926-8243 3425 Walden Avenue USA fax:...

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PCB LARSON DAVIS SoundAdvisor 831C Reference Manual

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