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Larson Davis SoundAdvisor 831C Reference Manual

Sound level meter
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SoundAdvisor
Model 831C
Sound Level Meter
Reference Manual

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Summary of Contents for Larson Davis SoundAdvisor 831C

  • Page 1 Larson Davis SoundAdvisor Model 831C Sound Level Meter Reference Manual...
  • Page 2 Changes and improvements to the information described in this manual may be made at any time. Safety If the equipment is used in a manner not specified by Larson Davis, the protection provided by the equipment may be impaired. Recycling PCB Piezotronics, Inc.

  • Page 3: Table Of Contents

    Enabling or Disabling Display Tabs 831C Display in FFT Mode Module 5 Calibrating Your SoundAdvisor 831C ..... 48 Understanding Calibration Values Choosing a Calibrator...
  • Page 4 9.10 Configuring an Email Server On the Meter 9.11 Enabling or Disabling Cloud Storage 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 ........98 Module 11 Managing 831C Security .
  • Page 5 Appendix A Technical Specifications ....... . A-1 Instrument Platform Specifications Model PRM831 Base Software Octave Band Analysis Software –...

  • Page 6: Module 1

    Module 1 Model 831C Features he 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 7: Applications And Basic Operations

    Up to 32GB USB • 2 GB internal industrial grade data memory TAKE NOTE memory can be purchased from • 240 x 320 full-color graphic LCD display with touchscreen user Larson Davis as an option. interface SoundAdvisor Model 831C Applications and Basic Operations...

  • Page 8: Performance Features

    The 831C is available as part of a specialized system or in a standard configuration. The following accessories come with the standard configuration: Report any damage or shortage immediately to Larson Davis/PCB TAKE NOTE Piezotronics, Inc. See the back cover of this manual for contact information.
  • Page 9 The 831C is shipped in protective packaging. First, verify the shipment contains all parts and accessories for the configuration you selected. Retain the packaging for safe shipment for calibration service. Table 1.1 SoundAdvisor 831C Standard Package Accessory Type Available Items SoundAdvisor 831C (377B02) ½-inch free-field...

  • Page 10: Available Options And Accessories

    Table 1.1 SoundAdvisor 831C Standard Package Accessory Type Available Items (831-CCS) Hard Shell Case (PSA029) Universal AC USB Power Adapter Accessory Kit (WS001) 3 ½-inch windscreen (831-ACC) includes (CBL138) USB to mini-B cable, 1.8 m these items: 4 Rechargeable AA NiMH batteries Includes: •...
  • Page 11 Make direct USB communication with Sierra Wireless RV50X cellular gateway. 831C-AUD Using the AudCal software from Larson Davis in conjunction with your SoundAdvisor 831C enables you to test the calibration of audiometers and sound booths. 831C-SCH Scheduling feature for G4 LD Utility.
  • Page 12 Pa, providing performance Pa, providing performance Note: These mics are available conforming to Class 1 sound level conforming to Class 1 sound level directly from Larson Davis. You meter standards meter standards can also use other microphones with the 831C.
  • Page 13 Table 1.2 Accessory Type Available Options Equivalent Electrical (ADP002) 6.8pF BNC Input Adapter for ¼-inch, Impedance Adapter Options 7 pF microphone equivalent Choose one of the following adapters in place of the (ADP090) 12 pF, BNC Input Adapter for ½-inch, microphone when making very 12 pF microphone equivalent high impedance...

  • Page 14: Module 2

    Module 2 Instrument Overview his module describes the hardware and display components that make the SoundAdvisor Model 831C the best meter for monitoring sound. In this module: Assembling Your 831C SLM ....................9 2.1.1 Connecting the Microphone and Preamplifier 2.1.2 Connecting the Preamplifier to Meter 2.1.3 Disconnecting the Preamplifier...
  • Page 15 • 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. The preamplifier body houses a single gold pin with threads on the top edge, which are designed to fit the 1/2-inch microphone.

  • Page 16: 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 17 The 831C is compatible with Energizer, Duracell, and other commercially- CAUTION recognized brands of these battery types: • AA nickel metal hydride (NiMH) • AA Alkaline • AA 1.5 Volt Lithium Optimal battery temperature is 0° C–45° C. CAUTION Understanding the Low Battery Indication As the battery nears the end of expected life, the empty battery symbol begins to flash.
  • Page 18 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 12. Step 1. On the 831C, press Tools ...
  • Page 19 You may also see this error when the batteries become too hot or too cold. Optimal battery temperature is 0° C–45° C. 2.2.2 Using External Power The following available external power sources augment the 831C’s internal battery: • USB port from a computer •...
  • Page 20 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

    2.2.5 Using the Power Control Page From the Live View, press the up button to view your meter’s current power settings (Live 8/8). FIGURE 2-4 831C Power Control Page (Live View) Battery settings display here. You can edit these settings from the Power Control page.
  • Page 22 FIGURE 2-6 Instrument Hardware AUX connector intended for use with USB mass storage, cellular modem, GPS, headphones, speak- ers, and future devices. Hardware Power Switch when set to “ 0 ” completely powers down the 831C for storage. Set to “...
  • Page 23 Table 2.1 831C Button Actions Action Button(s) Description In a menu, press a top soft key to navigate to left or right tabs When specific menu name displays above a top softkey, press that key to access the menu. When Close displays above the top- middle soft key, press to close or save.

  • Page 24: Display Elements Overview

    Entering Text The 831C allows for complete operation from the meter itself. When you select a field to enter text, a virtual keypad appears. Use the up, down ( ), and left, right ( navigation buttons to navigate. Press the Enter button to make a selection.
  • Page 25 FIGURE 2-7 Navigating Tabs to the Right Module 4 Using the Data For complete details on each tab and page, see LEARN MORE Display. 2.4.3 About Status Bar Icons and Indicators The status bar at the top of the screen displays the meter, measurement, connection, alert status, and battery status as shown in Figure 2-8.
  • Page 26 depleted, left to right. The bolt symbol appears over the battery icon if the battery is currently charging. External Power Icon The external power connection icon appears when the 831C is powered from an external power supply or from the USB port. WiFi Status Icon See 13.3 Using WiFi On Your 831C.
  • Page 27 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. OBA Under Range Icon When the signal from the preamplifier drops so that the noise level of the instrument and the preamplifier influence the measurement, an Under Range condition exists.
  • Page 28 Table 2.2 Using the Measurement Status Icon Resulting Measurement State Action Measurement State Run Pending Power Save Tap Once Sleep Icon When the 831C is not connected to a PC, it can be put in a battery power saving “sleep” mode that shuts down the analog circuitry, including the preamplifier.
  • Page 29 Access all data files on the meter or the inserted USB drive. For more information, see Module 8 Managing Measurement Data Files. Calibrate Calibrate the microphone for accurate measurement. See Module 5 Calibrating Your SoundAdvisor 831C. Setup Manager Setup measurement parameters and metrics. See Module 6 Creating a Measurement Setup.
  • Page 30 2.4.6 Power Control Menu Overview To access the following actions on the Power Control menu, press power once. • Battery Information • Display Brightness • Power Off • Reboot SoundAdvisor Model 831C Display Elements Overview...

  • Page 31: Module 3

    Module 3 Getting Started In this module: Operating the 831C Using the Meter Display ..............26 Operating the 831C Remotely ....................27 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 Setting File Storage Preferences ..................

  • Page 32: Operating The 831C Remotely

    Begin by completing the applicable processes in Module 2 Getting Started in The 831C can also operate on an automated weekly schedule when using G4 and the 831C Scheduling firmware option (831C-SCH), which is available from Larson Davis. For more information on this feature, see the G4 LD Utility Manual, Module LEARN MORE 6, G4 Features for 831C.

  • Page 33: Setting File Storage Preferences

    Step 2 Launch LD Atlas on your mobile device. Step 3 Establish a WiFi connection from the meter to your mobile device. For more information, see Module 13 831C Network and Connections. Step 4 In LD Atlas on your mobile device, and tap the name of your meter in the Meters Panel.
  • Page 34 • 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  System Properties  Preferences.
  • Page 35 9.11 For details about saving files to an SMTP or cloud storage account, see LEARN MORE "Enabling or Disabling Cloud Storage" on page 3.3.2 Using the 831C File Storage Calculator The Memory page on the Live view provides a helpful file storage calculator that can help you estimate the amount of storage a measurement might require.

  • Page 36: Module 4

    This module shows how to navigate and view SLM data, and how to adjust or customize the data display to fit your requirements. In this module: SoundAdvisor 831C Display In SLM Mode ................31 Enabling or Disabling Display Tabs ..................47 831C Display in FFT Mode ....................47 4.1 SoundAdvisor 831C Display In SLM Mode...
  • Page 37 Adjusting the Graph Scale You can adjust the Y-axis of the graph to show dB values between 340 and -20. For details, see 4.1.5 Adjusting the Graph Scale On Any Tab. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 38 The purple band on the far right represents an average sum of all the bands. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 39 If sound levels in the measurement exceed the Peak triggers, the values here display in orange and red, the higher they go. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 40 See the section "Battery States On the Power Page" on page 36 for important battery state reference information. Checking the internal temperature of the meter here periodically is good safety practice. Amount of internal memory currently available. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 41 Event Num: Enter a number, which is the number of events you anticipate during the measurement. 4.1.2 Understanding the Overall Tab The Overall tab values include all records in the current measurement. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 42 Maximum sound level during measurement. Peak level reached during measurement. Time since pause was initiated. The time accrues each time you pause a measurement. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 43 For example, the blue box next to the L data corresponds to the blue bands in the graph. See Table 4.2, “ Overall Octave Band Colors,” on page 39 to view more reference colors. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 44 Enter Press Enter to jump from Ref, Set Reference, and back to Octave labels. When you change the weighting and reference, reset Spectra values by selecting Set Reference. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 45 LEARN MORE Ln Value in the Appendix C Glossary. “ ” = 60.8 dB means that the Fast (F) time-weighted level NF50 exceeded 60.8 dB 50% of the time during the measurement. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 46 Sound Level Meter and the OBA have been overloaded. You can find more overload information in 5.1.2 LEARN MORE Determining Noise Floor, Overload, and Under Range Levels. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 47 This metric is primarily used in Germany. To turn off this display, or any other display that is not related to your measurement, see 4.2 Enabling or Disabling Display Tabs. About the Sound Exposure Level Page (Overall Page) SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 48 You can use the ENTER 5 button to move the cursor and enable more information; for example, if you want to see when a peak was measured, as shown in Figure 4-21. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 49 Live Weather page displays the current precipitation. For more information about weather accessories, LEARN MORE view the SoundAdvisor 831C brochure at www.LarsonDavis.com. For more information on viewing weather-related data in G4, see the G4 LD Utility Manual from LarsonDavis.com. 0.54...
  • Page 50 The source responsible for each logged action is also recorded. Session Log meter actions include the following: Table 4.4 831C Meter Actions that Create Session Log Items Key press Measurement stop Measurement run Measurement pause SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...
  • Page 51 20 dB to 140 dB Frequency Spectra, Low Range -10 dB to 110 dB To adjust the graph scale, do the following: Select the Menu softkey ( ). This opens the Live Menu. SoundAdvisor Model 831C SoundAdvisor 831C Display In SLM Mode...

  • Page 52: Enabling Or Disabling Display Tabs

    Select Adjust Graph. This opens the graph range. Highlight Y Max or Y Min and press the up or down buttons ( ) to adjust the scale. You can adjust the Y-axis of the graph to show dB values between 340 and -20. Press the Close softkey ( ), then select Yes to save your changes.

  • Page 53: Module 5

    Module 5 Calibrating Your SoundAdvisor 831C his 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 54 can be accurately measured without being influenced by the operational noise from the meter (Noise Floor). Noise Floor Level The noise floor is calculated as the energy sum of the noise generated by the microphone, preamplifier, and instrument circuitry. The appropriate noise floor, and nominal sensitivity compute automatically in the 831C with the following preamplifiers and their commonly paired microphones: •...

  • Page 55: Choosing A Calibrator

    5.2 Choosing a Calibrator Acoustic Measurements Larson Davis recommends the following calibrator for the 831C for acoustic measurements: • Larson Davis Model CAL200: 94/114 dB @ 1 kHz. If using a 1/4-inch microphone, the 1/4-inch adapter (ADP024, or ADP109) is TAKE NOTE required.
  • Page 56 Step 3 Navigate to the Calibration Settings tab using the top-right softkey ( When you’re using a known preamplifier, the 831C supplies the preamplifier serial number, or type (ICP or Direct), and the saved sensitivity on the Calibration Settings tab. Step 4 If needed, select your microphone from the Microphone drop-down menu.
  • Page 57 Step 6 Select a log entry from the list, and Calibration Spectrum window appears as shown in Figure 5-3. FIGURE 5-3 Calibration Spectrum Since space is limited on the meter display, you’ll find a more detailed version of the Calibration History in G4. For more information, see section 1.4.3 Calibration Histories Tab in the G4 LD Utility Reference Manual Step 7...

  • Page 58: Calibrating Your Soundadvisor 831C

    5.4 Calibrating Your SoundAdvisor 831C Step 1 On your SoundAdvisor, press Tools Calibrate. Step 2 Choose your calibrator from the Select Calibrator drop-down menu. Refer to the calibrator’s user guide for more information. LEARN MORE For more information on the Other option, see 5.2 "Choosing a Calibrator"...

  • Page 59: Module 6

    Module 6 Creating a Measurement Setup he 831C makes measurements based on the values you save in the setup file (Setup). Setups are created, edited, and deleted using the Setup Manager. This module describes using the Setup Manager on the 831C, and guides you through the process of saving a Setup, to receive the following values and sound metrics for your measurement: corresponding to values you select for and L...

  • Page 60: Creating A Custom Setup File On The Meter

    6.2.2 Customizing Setup Values On the Setup Manager Tabs Some tabs (pages) in this section become available when you purchase and install optional firmware from Larson Davis. If a step indicates a feature that isn’t available on your meter, move on to the next step.
  • Page 61 Step 1. On the 831C, navigate to the Setup Manager File List (first page). Step 2. Highlight and select your setup file in the list ( ). The name of your setup displays in the Settings: line (see Figure 6-3). Step 3.
  • Page 62 FIGURE 6-4 Setup Manager: SLM Tab Select a Frequency Weighting, Detector, and Peak Weighting. Your choice for the Detector setting communicates to the meter hardware how quickly it needs to begin measuring the current sound. See also “Detector” in the Appendix C Glossary on page C-1.
  • Page 63 FIGURE 6-5 Setup Manager: OBA Tab Normal or High: For measurement range specifications, Table A.15, “Octave Band Analysis 1/ 1 Octave Linearity Range,” on page A-18 Select 1/1 Octave bandwidth, 1/3 Octave band- width, or both simultaneously. Choose a Frequency Weight for the 1/1 Octave and 1/3 Octave bandwidth frequency analysis.
  • Page 64 FIGURE 6-7 Setup Manager: Control Tab The Sound Advisor 831C has 6 Run Modes to control the meter during a measurement. For more information on each run mode, see 6.2.4 Choosing a Run Mode Step 8. If enabled on your meter, use the right softkey ( ) to navigate to the Time History tab.
  • Page 65 The Weather tab is only available when the 831C Weather option is enabled TAKE NOTE and weather accessories are connected (such as SEN031 or SEN032 from Larson Davis). For more information, see section 9.8 on page 90 On the Setup Manager Weather tab, select the Weather station type.
  • Page 66 During a wind exceedance (with sound exceedance paused), the wind speed must drop below the Hysteresis before the sound exceedance pause turns off. The Larson Davis weather sensor (SEN03x) TAKE NOTE takes a running average over 1 min, then reports an average rate over 10 minutes.
  • Page 67 FIGURE 6-12 Setup Manager: Weather With Time History On the Time History tab scroll down in the Options section to select from the following, selectable measurement options: • Wind Speed, Wind Direction, Gust Speed, Gust Direction • Temp Average, Temp Max, Temp Min •...
  • Page 68 In this section: When combined with the Using Manual Run/Stop Mode • Measurement History feature, these 3 modes can be used to Using Timed Stop Mode • create multiple measurement Using Stop When Stable Mode • intervals stored in a data file, with new data files created at Using Continuous Mode •...
  • Page 69 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 70: 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 71 Step 1. On the meter, select Menu (  Setup Manager. 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.

  • Page 72: Module 7

    Module 7 Making a Measurement aking 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 73: Before You Start

    Setup File On the Meter. Step 4. Calibrate the meter. For complete instructions, see 5.4 Calibrating Your SoundAdvisor 831C. 7.1.1 Positioning the 831C The best position for sound recording is to mount the 831C on a tripod. If held in hand, position your body away from and on an angle to the meter to minimize interference of the sound field at the microphone resulting from body reflections.
  • Page 74 No correction is necessary when using Larson Davis Model EXCXXX 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.

  • Page 75: 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 previous measure- ment 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 LEARN MORE displayed here, see...
  • Page 76 Table 7.1 (Continued)Measurement State LED Indicators Measurement State Red LED Green LED Waiting for valid Delayed ----* data to begin wink running To learn more about the displays and icons, see 2.4 Display Elements LEARN MORE Overview. The Measurement Range The measurement ranges over which the 831C meets the standards depend upon the selected frequency weighting.
  • Page 77 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. To close Back Erase, press Run to resume, or Stop to end the measurement.

  • Page 78: Storing The Measurement

    7.2.2 Resetting a Measurement A measurement often needs to be reset when a radical noise event takes place that is unnecessarily recorded in your data. For example, an aircraft passes overhead when attempting to measure the background noise in a normally quiet area. To reset a measurement in progress, stop the measurement, then press the Reset .

  • Page 79: Module 8

    Module 8 Managing Measurement Data Files ach 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, USB, and cloud storage options are also available. In this module: Setting Data File Storage Preferences .................

  • Page 80: Using The File Manager

    Table 8.1 Auto-Store Preference and Stop Method Run Mode Type of Stop Prompt (Auto-Store) Store (Auto-Store) Stop When Stable Timer stop Prompts when stable Stores automatically Manual stop Prompts when stopped Stores automatically Single Block Timer Timer stop Prompts at timer’s end Stores automatically Manual stop Prompts when stopped...
  • Page 81 FIGURE 8-2 File Manager Overview When a USB drive is inserted, the USB icon displays. Shows the available internal storage by default. If you insert a USB drive and set your File Storage Meter Prefer-  ence to Store (Setup Manager System Properties ...
  • Page 82 file icon displays in-line with the file name to indicate that you are seeing a data file and not live data. 8.2.2 Using Load Settings From a data file, you can load the measurement Setup properties used to create the data file into the Active setup.

  • Page 83: Saving, Moving, Or Copying Data Files

    Step 6. Repeat steps 4–5 until all data files you want to average have been added. Step 7. Press Close ( ) to close the File manager, then navigate to the Overall display to view the average data. Step 8. To save the averaged data file, press Stop/Store 8.3 Saving, Moving, or Copying Data Files In this section:...
  • Page 84 For more information on continuous auto store, see section 6.2.3 Using LEARN MORE Continuous Mode. 8.3.2 Moving or Copying Data Files to a USB Drive Complete this section to move or copy a data file from internal memory to a USB drive. Step 1.

  • Page 85: Module 9

    Module 9 Setting System Properties his module is a reference for all SoundAdvisor™ 831C system properties and settings. In this module: Setting Instrument Identification ..................80 Updating the Meter Time ..................... 81 Using NTP to Sync the Meter Clock ..................81 Editing Power Settings ......................

  • Page 86: Updating The Meter Time

    9.2 Updating the Meter Time  On your 831C, go to Tools System Properties, press the right softkey ( ) until the Time page displays. There are several ways that you can update the time on the meter: by using GPS, NTP servers, PC clock, or by manually setting the time.

  • Page 87: Editing Power Settings

    FIGURE 9-2 NTP Servers If you’ve synced with NTP and lose the Internet connection, the 831C attempts to reconnect to servers for up to 2 ½ hours. During this time the NTP icon persists. If the servers cannot be reached after that time, the 831C stops trying to reconnect, and the NTP icon is removed.
  • Page 88 9.4.1 Changing Batteries and Editing the Battery Type  On your 831C, go to Tools System Properties, then press the right softkey ( ) until the Power tab displays. When changing batteries, the Battery Type must match the type of batteries you’re installing.
  • Page 89 Pressing the Power button returns the instrument and the display to the state it was in when the Auto-Off time expired. 9.4.3 Using Analog Power-Save Mode  On your 831C, go to Tools System Properties, then press the right softkey ( ) until the Power tab displays.

  • Page 90: Setting Meter Preferences

    9.4.6 Setting the External Shutoff Voltage  On your 831C, go to Tools System Properties, then press the right softkey ( until the Power tab displays. If desired, you can customize the external shutoff voltage. When the voltage of an external battery drops below this value, the 831C shuts off to prevent damage to the external batteries.
  • Page 91 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 No Correction RI:FF Random Incidence Free-Field FF:RI Free-Field Random Incidence FF:RI 2016/8 Free-Field with EPS2106 Random Incidence FF:FF 2016/8 Free-Field with EPS2106...
  • Page 92 Step 2. Select an option from the AC Output drop-down menu, then press Close ) to save your changes. 9.5.3 Enabling the Reset Prompt Whenever you make a measurement that you don’t want to keep, you can press the Reset button to clear the unsaved data. When you enable Reset Prompting, the meter requires you to confirm your choice before clearing the data.

  • Page 93: Setting Localization Options

    9.5.6 Customizing the Display Color Theme  On your 831C, go to Tools System Properties, then press the right softkey ) until the Preferences tab displays. The 831C LCD screen has 6 color theme options: 3 light and 3 dark. We recommend the light screens when you’re operating the meter in sunlight or outdoor settings.
  • Page 94 Customizing the Start Display Start option allows you to choose the display that you see when you boot up the 831C. Select your option from the Start drop-down. Your new start display appears on the next power up. Customizing Tab & Page Display Select an option from the Tabs drop-down menu, then select the checkbox in-line with the Pages list that you want to display on your meter as shown in Figure 9-6.

  • Page 95: Enabling Or Disabling Options

    File Averaging NF30 Ln Fast Weather Touch Screen Audiometer Calibration Scheduling Step 1. On your SoundAdvisor 831C, go to Tools  System Properties. Step 2. Press the right softkey ( ) until you see the Options page. Step 3. Select the checkbox in-line with the options you want available in the 831C interface.
  • Page 96 Before you begin: • We recommend that you use 2-Step Verification when using Google® G-mail™. If you use G-mail, complete section 9.15 Generating an App Password before proceeding. • If your meter is configured with a static IP address, you will need to enter the fixed network addresses you previously defined during this process.

  • Page 97: Enabling Or Disabling Cloud Storage

    9.10.1 Enabling Alert Notifications In 831C firmware version 4.5+, this workflow is only available by using G4 LD Utility software. Email and text alert notifications are now configured as part of the user account in G4. Additionally, with the optional Scheduling firmware (831C-SCH), users can schedule periods when they want to receive alert notifications.

  • Page 98: Utilizing The Logic In Or Logic Out Feature

    9.12 Utilizing the Logic In or Logic Out Feature The 831C can receive input from an external device using the Logic In or Logic Out feature, which can initiate a variety of actions. In this section: • 9.12.1 Utilizing the Logic In Feature •...

  • Page 99: Choosing Preamp Heater Options

    When Logic Out is set to Modem, a connected modem (such as a Sierra Wireless™ cellular modem), becomes active. This connection is particularly used in conjunction with the Larson Davis NMS044/045 system. For more information, access the system reference manual from LarsonDavis.com.

  • Page 100: Setting Reference Spectra

    FIGURE 9-10 Recommended Heater Settings Heater Control 100% High T e m p e r a t u r e ( C ) Timer: Turns the heater on and off automatically according to the Start Time • (24-hr time) and End Time (24-hr time) you set here. •...

  • Page 101: Generating An App Password

    Step 2. Use any of the methods in Figure 9-11 to define reference spectra values. FIGURE 9-11 Setting Reference Spectra Values Use any of the meter navigation buttons to high- light a band. Press 5 to use the keyboard to define a spectrum value for that octave.
  • Page 102 Step 2. On the top navigation panel, choose Security. Step 3. On the “Signing in to Google” panel, choose App Passwords. If you don’t see this option: • 2-Step Verification is not set up on your account • 2-Step Verification is set up for security keys only •...
  • Page 103 Module 10 System Information ystem information is contained on the About Menu.  On the 831C, go to Tools About to view the following details on 3 tabs: FIGURE 10-1 About, Standards, Options Tabs SoundAdvisor Model 831C...

  • Page 104: Module 11 Managing 831C Security

    Module 11 Managing 831C Security he 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 ......................99 11.1.1...
  • Page 105 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 Lock Mode Available...

  • Page 106: Using Network Security

    11.1.2 Unlocking the Meter from the Meter Interface To unlock the 831C from the meter interface, follow these steps: Step 1. Press the Tools or Enter button. Step 2. Press Enter again to open the virtual keypad. Step 3. Enter your unlock code, then press Enter FIGURE 11-2 Unlock Code Dialog and Virtual Keypad 11.1.3 Unlocking the 831C in G4 LD Utility...
  • Page 107 Step 3. Update your meter firmware to version 4.5 + as shown in 14.2 "Upgrading 831C Firmware by Using G4 LD Utility" on page 109. Step 4. Set up an Administrator account as described in Section 2.2 of the G4 LD Utility Manual.

  • Page 108: Troubleshooting A Bad Flash Block Error

    Module 12 Using System Utilities he 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, go to Tools ...

  • Page 109: Module 13 831C Network And Connections

    Module 13 831C Network and Connections his 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 ................104 13.1.1 Connecting 831C to an Ethernet Port 13.2 Setting Up the Meter’s Network ID ..................
  • Page 110 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 auxiliary port on the bottom of the 831C. Connect the Ethernet cable to the Ethernet adapter (DVX012) adapter.

  • Page 111: 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 112 Before you begin: • Connect a WiFi USB adapter to the 831C. The WiFi status icon appears in the top left. Step 1. Navigate to Tools Setup WiFi. Step 2. Select an available network. If no network appears on the list, select Menu and select Refresh List as shown in Figure 13-3.

  • Page 113: Disconnecting A Cloud Storage Dropbox Account

    Step 2. Select Menu. Step 3. In the menu window that opens, select Set Access Point, and confirm your choice in the pop-up window. The Access Point icon appears in the top left. Step 4. On your mobile device, choose the 831C as the WiFi network, and enter the password: wifi831c.

  • Page 114: Updating The G4 Ld Utility

    Module 14 Software, Firmware, and Options n addition to meter operation, the G4 LD Utility (G4) is also used to install firmware and option upgrades as shown in the following processes. In this module: 14.1 Updating the G4 LD Utility ....................109 14.2 Upgrading 831C Firmware by Using G4 LD Utility .............

  • Page 115: Upgrading Meter Firmware Options

    Before you begin: • When you purchase a meter upgrade or option, you receive the firmware option file as an email attachment from Larson Davis. Save this file to your PC on the Desktop. • Power on your meter, and connect it to your PC via the USB cable (CBL138, part of the PSA029 power supply) or via TCP/IP.

  • Page 116: Enabling Or Disabling Optional Firmware

    FIGURE 14-1 G4 Connection Types 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 the name of your meter, then select Upload Options from the pop-up menu.
  • Page 117 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, the meter TAKE NOTE notifies you that a reset is needed to save the Options settings. Select OK and press the Reset button to reset the measurement.

  • Page 118: Setting Up A Measurement With Measurement History

    Module 15 Using Measurement History his module shows how to use the Measurement History 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 in a single data file.
  • Page 119 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 120 If you want to enable alert notifications for measurements using this Setup, see the G4 LD Utility Manual, Module 6 G4 Features for SoundAdvisor 831C. Select a Trigger Source and Trigger Level (dB) for the alert. The Trigger Level cannot be less than 0.1 (dB).
  • Page 121 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. If you enter an Interval Time (hh:mm) value less than 0:01, the measure- •...
  • Page 122 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 123: Viewing Measurement History Data Files

    15.2 Viewing Measurement History Data Files In this section: • 15.2.1 Viewing Live Measurement Interval Data • 15.2.2 Viewing Measurement History Data • 15.2.3 Viewing Measurement History Data From a Stored File 15.2.1 Viewing Live Measurement Interval Data When the first measurement interval is underway, metrics and data display on the Current tab.
  • Page 124 Changing the Displayed Record The selected record number for which data is being displayed is indicated in the upper right next to the measurement name as you navigate up and down through the pages. 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.

  • Page 125: Setting Up A Measurement With Time History

    Module 16 Using Time History he 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 126 Step 3. Check Enable Time History and select the desired time Period from the drop- down menu. Step 4. Enable the desired Time History Options. Not all options are available for every time period. Table 16.1 on page 122 shows data that is displayed for each Time History Metric, depending on the Time Interval Option you select.
  • Page 127 Table 16.1 Time History Available Metrics Time Interval Options Time History Metrics 2.5, 5, 10 ms 20 & 50ms 100 & 200 ms 500 ms, 1 s, 2 s 5 s -24 h ωeq ωpeak ω ω ω ω ω ω...

  • Page 128: Making A Time History Measurement With Sound Markers

    16.2 Making a Time History Measurement With Sound Markers The 831C Time History option also allows you to place sound type markers in the time history data as the sounds occur or during your post measurement analysis. To make a measurement with sound markers, follow these steps: Before you begin: •...

  • Page 129: Viewing Time History Data

    FIGURE 16-2 Marking a Sound Type Select the checkbox in-line with a sound type to mark the beginning of the sound. Deselect it to mark the end. 16.3 Viewing Time History Data Time History data displays on the Time History tab as shown in Figure 16-3. FIGURE 16-3 Time History Tab (Page 1) Highlight this line and use the Enter...
  • Page 130 Highlight, then press Enter on each Time History page to see which values TRY THIS you can edit on each page. FIGURE 16-4 Time History 1/1 Octave Page Use the Enter button to switch from the fre- quency graph to the record number. ω...

  • Page 131: Module 17 Using Event History Firmware

    Module 17 Using Event History Firmware his 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...
  • Page 132 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 Optional Firmware. Step 1. Navigate to Tools Setup Manager.  The G4 LD Utility also provides a simple, file transfer-style interface for TAKE NOTE configuring, saving, and transferring Setup files to your PC or to another meter.
  • Page 133 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 134: Storing Event Data

    Click Save, and confirm which meters this option applies to. 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: To manually store a data file after a measurement is stopped, press the Stop/ •...

  • Page 135: Viewing Event History Data On The Events Tab

    When using 5-, 2-, or 1-minute Daily Auto-Store settings, the 831C strictly observes the Time and Auto-Store period you select to fulfill the event logging function. For example, when a sound event persists across an Auto-Store boundary, the 831C stores and begins a new data file, which contains the remainder of the event data.
  • Page 136 FIGURE 17-4 Event Indicator Ready When this symbol displays, all the pre-samples are recorded and meter is waiting for an event. Trigger When this symbol displays, the sound level exceeds the Trigger Level. Valid When this symbol displays, the sound level exceeds the Trigger Level for the Minimum Duration.

  • Page 137: Setting Advanced Event Triggers

    FIGURE 17-6 Changing Record Number To jump to a different record number, press the Menu softkey ( ) and select Locate from the pop-up menu. 17.4 Setting Advanced Event Triggers Select either of the following advanced trigger options to complete Step 4 for setting up Event triggers in a setup file.
  • Page 138 Step 3. Enter a Running Leq period in seconds. Enter whole numbers only, such as 1– 3600 (1 hour). FIGURE 17-7 Setup Manager: SLM Tab In this example, the period is set to be the Leq of the last 1200 seconds of the measurement run time.

  • Page 139: Understanding Level And Dynamic Triggering

    • When you select ALL, the meter triggers an event when all of the OBA values exceed the Reference Spectra selected for the Full Octave. • When you select ANY, the meter triggers an event when at least one of the OBA values exceeds the Reference Spectra selected for the Full Octave.
  • Page 140 FIGURE 17-9 Event History with Level Triggering and Events The bars represent events logged during the measurement. At a minimum of 3 sec- onds, there are about 5. 17.5.2 Understanding Dynamic Triggering With dynamic triggering, the 831C tracks the background noise level, and adjusts the Trigger Level to equal the background noise plus any indicated offset.
  • Page 141 FIGURE 17-11 Event History with Dynamic Triggering and Events 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 Event Dynamic Trigger Level With dynamic triggering, events only occur if the level exceeds the background level plus the offset.

  • Page 142: Preparing The Equipment

    SoundAdvisor™ 831C to make an FFT and Tonality measurement and analyze the resulting data on the meter. This process requires the SoundAdvisor 831C with firmware version 4.6 or newer, and the 831C FFT and Tonality option (831C-FFT) installed. All options and accessories shown here are available from Larson Davis.
  • Page 143 Recommended Next Step: • 18.2 Creating an FFT Setup File On the Meter 18.1.2 Preparing Other Transducers Step 1. Connect the SoundAdvisor 831C to the applicable transducer, cable, adapter, and mount. For important details and compatibility notes, see LEARN MORE A.7.5 “Supported Hardware Configurations for FFT Measurements”...

  • Page 144: Creating An Fft Setup File On The Meter

    (exponential) fluctuations or very small values. Step 5. Calibrate as shown in 5.3 Reviewing the Calibration Settings and 5.4 Calibrating Your SoundAdvisor 831C. Recommended Next Step: • 18.2 Creating an FFT Setup File On the Meter 18.2 Creating an FFT Setup File On the Meter...
  • Page 145 Lines, sometimes called “bins.” The result is the bandwidth of each line (bin) in Hz/line or bin. Also, note that selecting a greater number of lines increases the FFT computation time. For your selected frequency resolution, the SoundAdvisor 831C TAKE NOTE calculates the FFT measurement accurately to within 0.1 dB.
  • Page 146 FIGURE 18-2 Example- Rectangular Windowing Waveform With Windowing Sampled Sound Window Shape Samples 10 20 30 40 50 60 Flat Top: The Flat Top window shape descends below zero at the end of each time record and allows for wider-spaced peaks in the frequency domain. As a result, this method may more accurately show the true amplitude of peaks, but possibly with less detail in the signal overall.
  • Page 147 Step 10. Choose a Frequency Weighting for the pre-FFT filter. This weighting is used to provide a broadband Leq and peak level, and is also applied to the SLM data. When you choose “A”, or “C” weighting, the result can be used to provide an approximation of how the sound is perceived by the human ear.
  • Page 148 Step 11. Press the right softkey ( ) to view the Control tab. Step 12. 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 149 Using Continuous Run Mode The meter runs when you press the Run/Pause button and ends when you press the Stop/Store button or when the meter loses battery power. Select Continuous as the Run Mode. Select the Auto-Store period, and enter the Time of day to store in hours, minutes, and seconds.

  • Page 150: Making The Fft Measurement

    FIGURE 18-7 FFT Misc tab Select up to 3 Trigger Sources from the drop-down menus, and enter up to 3 Trigger Levels. If your Transducer is a microphone, integration is disabled. If you selected Other as the transducer, select option from Integration drop-down menu.
  • Page 151 (Optional) If desired, after the FFT measurement is complete, switch the 831C to SLM Mode, connect a weather sensor (such as the SEN031 or SEN032 from Larson Davis) and measure site conditions. 18.3.1 Viewing Live Data On the Meter In this section, take a tour of the live data on the meter display during a measurement, and learn how to customize display elements.
  • Page 152 FIGURE 18-9 FFT Live Display Elements Press the up button ( ) to Zoom in on a frequency range. The 831C allows zooming from the configured number of lines up to a 1:1 correspondence between displayed lines and FFT lines. 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...
  • Page 153 Using the Max-Tracking Cursor From the Cursor Type menu, you can enable the Max-Tracking cursor, which automatically adjusts to show the frequency band with the maximum amplitude. If the maximum is not within the meter display window when zoomed in, the window re-centers to display the max as shown in Figure 18-11.
  • Page 154 FIGURE 18-12 FFT History Tab Displays a Vibration Record The History tab is displaying record 1 of 2 total. Press the up and down buttons ) to zoom in and out of the graph. Press the left and right buttons )to move from one record to another.
  • Page 155 just like the other tabs. The cursor begins on the first valid tone (or the tone at the lowest frequency). With the cursor over the area, the following details display for each valid tone: Lpt, Lpn, Lta, Kt, Count. For details on each term, refer to the applicable ISO standard. FIGURE 18-14 Display Elements On the Live Tonality Tab- ISO1996-2 Tone indicator (green vertical bar);...

  • Page 156: Viewing Fft Data Files On The Meter

    TABLE 18.1 ISO 1996-2: Quality Indicators for Tonality Deficiencies (Continued) Icon Deficiency Remedy The effective bandwidth is not less Change the Windowing method in the than 5 percent of the critical measurement Setup. bandwidth. The sound measurement does not Increase the Regression Range in the contain sufficient regression data to measurement Setup (Tonality tab).

  • Page 157: Setting Up Markers For Sound Recording

    Module 19 Using 831C Sound Recording ound 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 158: Making A Manual Sound Recording Using Mark Sound Type

    FIGURE 19-1 Setup Manager Markers To enter or edit a sound type name, highlight the name field and press Enter Step 4. When your sound settings are complete, press the Close softkey ( ), and save the Setup. Step 5. Next, set your setup file as the Active Setup.

  • Page 159: Making An Automated Event Sound Recording

    FIGURE 19-2 Mark Sound Type Sound Recording Select a marker with sound recording enabled. This initiates the Pre-trigger period followed by the sound recording. Step 3. Select the checkbox in-line with a marker to start the recording. When finished, a labeled sound record displays in the data file. You can also press the left softkey ( ) to initiate a sound recording.

  • Page 160: Enabling Measurement History Sound Recording

    Step 4. Run a measurement and examine the resulting sound recordings. Based on the settings shown in Figure 19-3, when the measured sound is above 65 dB (SPL 1 Trigger Level) for at least 4 seconds (Trigger Time) the event recording would include 11 seconds of sound (Pre-trigger + Snapshot Time).
  • Page 161 Before you begin:  Setup Manager) • Open the Setup Manager (Tools and create a setup file with Measurement History enabled, as shown in 15.1 Setting Up a Measurement With Measurement History. Step 1. Go to Tools Setup Manager. Step 2. On the right side (meter side) of the screen, select a measurement history press the left softkey ( enabled setup file in the file list, then...

  • Page 162: Understanding Recording Settings And Sound Quality

    Press Tools Calibrate Settings, and reference section 5.4 Calibrating   Your SoundAdvisor 831C. The 831C automatically calculates the sound recording range based on the Peak Overload value. as shown in Figure 19-6. FIGURE 19-6 Step 2. Go to Tools Setup Manager ...

  • Page 163: Sound Recording Playback

    .WAV vs .OGG: Choosing a Format for your Application Sound recordings are saved in .WAV format (uncompressed) unless you select the Compression checkbox. The compression setting saves sound records in .OGG format. The .OGG file is more portable, and easily shared over email, and text, or as an alert notification.
  • Page 164 Step 3. Use the left softkey ( ) to display the Session Log tab. Step 4. Select a sound event from the list. This opens the sound player. FIGURE 19-7 Session Log Playback 19.6.2 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 G4 in the LEARN MORE G4 LD Utility Reference Manual.

  • Page 165: Appendix A Technical Specifications

    Appendix A Technical Specifications Instrument Platform Specifications ...................A-2 Model PRM831 ........................A-8 Base Software ........................A-12 Octave Band Analysis Software – Option 831C-OB3 ............A-17 Event Logging Software (Option 831C-ELA) ..............A-31 Time History Software (Option 831C-LOG) ..............A-33 FFT Analysis Software Specifications (Option 831C-FFT) ..........A-34 PTB Approved Firmware ....................A-36 Frequency Response ......................A-36 A.10 Declaration of Conformity ....................A-59...

  • Page 166: 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 CE-mark indicates EMC Emission: compliance with the CISPR 11:2015 with Amend 1 (EN 55011) EMC, Low Voltage, and RoHs Directives...
  • Page 167 A.1.4 SLM Performance Specifications Table A.2 SLM Performance (Nominal Values) Direct Input PRM831 with PRM831 with PRM831 with 378A04 (dB SPL) (dBµV) 377B02 (dB SPL) 377C20 (dB SPL) 377A15 (dB SPL) 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB...
  • Page 168 Display: • TFT full color LCD, 240 by 320 dot matrix • White backlight with adjustable brightness and on–time • 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...
  • Page 169 • GPS Receiver HOLUX M-215, PN GPS001 • Multi–Metric Weather Sensor, Vaisala WXT520, PN SEN031 • 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 170 Windspeed Pulse Input: Input accepts 0 to +3 pulses Analog Inputs: 3 channels, 0 to +2.5 V, 100kΩ load, from anemometer (+5V tolerant), 100kΩ load, setting settings for scale and offset selects function A.1.12 I/O Connector Pinouts Specifications The pinouts for the I/O Connector are shown in Table Pin # Description Signal Type...
  • Page 171 A.1.14 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.1.15 External DC Power Supply Specs Provides power to operate instrument, supply USB Table A.5 Low Power At Boot-Up (Continued) Host port with 500mA and charge batteries.

  • Page 172: Model Prm831

    A.2 Model PRM831 The Larson Davis PRM831 is an electret microphone preamplifier for use with a Larson Davis Model 831 Sound Level Meter. It requires little supply current and is capable of driving 300 feet of cable. The preamplifier operates over wide ranges of temperature and humidity.
  • Page 173 A.2.1 Model PRM831 Specifications Table A.7 Frequency Response With respect to the response at 1 kHz with 1 Volt rms input and 12 pF equivalent microphone, the frequency response is as follows: 8 Hz to 16 Hz +0.1, -0.2 dB 16 Hz to 100 kHz +0.1, -0.1 dB Lower -3 dB limit <...
  • Page 174 Table A.7 (Continued) Test Conditions All values are at 23° C, 50% RH, 35 Volt supply, 3 m (10') cable and equivalent microphone of 12 pF unless otherwise stated. Output Connector: Switchcraft TA5M 5-Pin male Table A.8 Output Connector Key Signal Signal Ground Signal Output...
  • Page 175 Table A.9 Certificate of Conformance; PRM831 Preamplifier Model: PRM831 Serial Number: 10123 Certificate of Electrical Conformance Frequency response of this model PRM831 preamplifier was tested at a level of 1 Vrms with 12pF microphone capacitance and driving a short cable. Output level at 1kHz is 0.9878 Vrms (-0.107 dBV), uncertainty 0.033 dB. Results are displayed relative to the level at 1kHz.

  • Page 176: Base Software

    A.3 Base Software A.3.1 Standards Met Sound Level Standards: • IEC 61672-1:2013 Class 1, Group X • IEC 60651 Ed 1.2 (2001) plus Amendment 1 (1993-02) and Amendment 2 (2000-10) Type 1, Group X • IEC 60804 (2000-10) Type 1, Group X •...
  • Page 177 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 1. Add numbers in this column to levels read on the SLM to correct to the 0° Free Field level at frequency. 2.
  • Page 178 Table A.11 (Continued) Linear Linear AƬeq CƬeq ZƬeq ASmin CSmin ZSmin Slow Maximum ASmax CSmax ZSmax Slow Minimum AFmin CFmin ZFmin Fast Minimum AFmax CFmax ZFmax Fast Maximum AImin CImin ZImin Impulse Minimum AImax CImax ZImax Impulse Maximum Peak Apeak(max) Cpeak(max) Zpeak(max) 1.
  • Page 179 Table A.13 (Continued) ωƬn3 ωƬn4 ωƬn5 ωƬn6 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.14 Label Count...
  • Page 180 C minus A Mathematical subtraction of C and A-weighted equivalent levels Linear Exponential Units AƬeq aƬeq Impulsivity Mathematical subtraction of impulse and linear equivalent levels Linear Exponential Units AIeq Location GPS (internal or external GPS, records last fix of measurement): •...

  • Page 181: 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 182 A.4.1 Filter Linearity Ranges (Normal and High) Table A.15 Octave Band Analysis 1/1 Octave Linearity Range Nominal Nominal Normal OBA Frequency High OBA Range Normal OBA Range Frequency High OBA Range Range (Hz) (Hz) 0 dB +20 dB 0 dB +20 dB +20 dB 0 dB...
  • Page 183 Table A.16 Octave Band Analysis 1/3 Octave Linearity Range (Continued) ≥ 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 184 Table A.17 Table A.12 Octave Band Analysis 1/3 Octave Linearity Range (Continued) Nominal Nominal Normal OBA Frequency High OBA Range Normal OBA Range Frequency High OBA Range Range (Hz) (Hz) 0 dB +20 dB +20 dB 0 dB +20 dB 0 dB +20 dB 0 dB...
  • Page 185 Overall Metrics: Linear Exponential Units OBA Overall Equivalent Level Spectrum ωeq(f) ωeq(f) OBA Overall Maximum Level Spectrum ωmax(f) ωmax(f) OBA Overall Minimum Level Spectrum ωmin(f) ωmin(f) 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.18. Table A.18 Units ωn1(f)
  • Page 186 FIGURE A-3 Self-Generated Noise Levels for 1/1 Octave Filter With Direct Input 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-4 Self-Generated Noise Levels for 1/3 Octave Filter With PRM831 30.0 20.0 High +0dB...
  • Page 187 FIGURE A-6 377A15/831C Instrument Noise, 1/1 Octave, Normal Range + O dB Gain + 2O dB Gain FIGURE A-7 377A15/831C Instrument Noise, 1/3 Octave, Normal Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-23...
  • Page 188 FIGURE A-8 377A15/831C Instrument Noise, 1/1 Octave, High Range + 2O dB Gain + O dB Gain FIGURE A-9 377A15/831C Instrument Noise, 1/3 Octave, High Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-24...
  • Page 189 FIGURE A-10 377B02/831C Instrument Noise, 1/1 Octave, Normal Range + 2O dB Gain + O dB Gain FIGURE A-11 377B02/831C Instrument Noise, 1/3 Octave, Normal Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-25...
  • Page 190 FIGURE A-12 377B02/831C Instrument Noise, 1/1 Octave, High Range + 2O dB Gain + O dB Gain FIGURE A-13 377B02/831C Instrument Noise, 1/3 Octave, High Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-26...
  • Page 191 FIGURE A-14 377C20/831C Instrument Noise, 1/1 Octave, Normal Range + 2O dB Gain + O dB Gain FIGURE A-15 377C20/831C Instrument Noise, 1/3 Octave, Normal Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-27...
  • Page 192 FIGURE A-16 377C20/831C Instrument Noise, 1/1 Octave, High Range + 2O dB Gain + O dB Gain FIGURE A-17 377C20/831C Instrument Noise, 1/3 Octave, High Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-28...
  • Page 193 FIGURE A-18 378A04/831C Instrument Noise, 1/1 Octave, Normal Range + 2O dB Gain + O dB Gain FIGURE A-19 378A04/831C Instrument Noise, 1/3 Octave, Normal Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-29...
  • Page 194 FIGURE A-20 378A04/831C Instrument Noise, 1/1 Octave, High Range + 2O dB Gain + O dB Gain FIGURE A-21 378A04/831C Instrument Noise, 1/3 Octave, High Range + 2O dB Gain + O dB Gain SoundAdvisor Model 831C A-30...

  • Page 195: 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 196 Table A.19 Event Logging Measurable Levels Linear Exponential Units Equivalent ωeq ωeq Level Sound ωE ωE Exposure Level Sound Pa²s ωE ωƬE Exposure OBA Live Equivalent Level Spectrum ωeq(f) ωeq(f) (requires 831C- OB3) OBA Live Maximum Level Spectrum ωmax(f) ωmax(f) (requires 831C- OB3) Table A.20 Event Time History Measurable Levels...

  • Page 197: 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, 10,...

  • Page 198: 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...
  • Page 199 G4 software: Full Spectra display, with the ability to zoom beyond 1:1 line to pixel ratio for characterizing data. A.7.5 Supported Hardware Configurations for FFT Measurements The 831C in FFT mode is capable of computing both acoustic and vibration signals. Supported hardware configurations include: For Acoustic Measurements •...

  • Page 200: Ptb Approved Firmware

    A.9 Frequency Response 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 20K Hz.
  • Page 201 A.9.1 Plane Parallel To Display Screen FIGURE A-22 Model 831 with 377B02 Microphone Mic at n° 20° 60° 100° 140° 180° Frequency (Hz) SoundAdvisor Model 831C A-37...
  • Page 202 FIGURE A-23 Model 831 with 377B02 Microphone Mic at n° 40° 80° 120° 160° Frequency (Hz) FIGURE A-24 Model 831 with 377B02 Microphone Mic at n° 10° 50° 90° 130° 170° Frequency (Hz) SoundAdvisor Model 831C A-38...
  • Page 203 FIGURE A-25 Model 831 with 377B02 Microphone Mic at n° 0° 30° 70° 110° 150° Frequency (Hz) FIGURE A-26 Directional Characteristics 0° 350° 10° 340° 20° 330° 30° 320° 40° 310° 50° 300° 60° 290° 70° 280° 80° 1000 Hz 270°...
  • Page 204 FIGURE A-27 Model 831 with 377B02 Microphone 0° 350° 10° Frequency (Hz) 340° 20° 281.84 330° 30° 320° 40° 354.81 446.68 310° 50° 562.34 300° 60° 707.95 290° 70° 891.25 1122.02 280° 80° 1412.54 1778.28 270° 90° 2238.72 260° 100° 2818.38 3548.13 250°...
  • Page 205 FIGURE A-29 Model 831 with 377B02 Microphone 0° 350° 10° Frequency (Hz) 340° 20° 298.54 330° 30° 320° 40° 375.84 473.15 310° 50° 595.66 300° 60° 749.89 290° 70° 944.06 1188.5 280° 80° 1496.24 1883.65 270° 90° 2371.37 260° 100° 2985.38 3758.37 250°...
  • Page 206 FIGURE A-31 Model 831C with 377C20 Microphone FIGURE A-32 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-42...
  • Page 207 FIGURE A-33 Model 831C with 377C20 Microphone FIGURE A-34 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-43...
  • Page 208 FIGURE A-35 Model 831C with 377C20 Microphone FIGURE A-36 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-44...
  • Page 209 FIGURE A-37 Model 831C with 377C20 Microphone A.9.2 Perpendicular to Plane of Display Screen FIGURE A-38 SoundAdvisor Model 831C A-45...
  • Page 210 FIGURE A-39 Model 831C with 377B02 Microphone Mic at n° 20° 340° 60° 300° 100° 260° 140° 220° 180° Frequency (Hz) FIGURE A-40 Model 831C with 377B02 Microphone Mic at n° 40° 320° 80° 280° 120° 240° 160° 200° Frequency (Hz) SoundAdvisor Model 831C A-46...
  • Page 211 FIGURE A-41 Model 831C with 377B02 Microphone Mic at n° 0° 30° 330° 70° 290° 110° 250° 150° 210° Frequency (Hz) FIGURE A-42 Model 831C with 377B02 Microphone Mic at n° 10° 350° 50° 310° 90° 270° 130° 230° 170° 190°...
  • Page 212 FIGURE A-43 Model 831C with 377B02 Microphone 0° 350° 10° 340° 20° Frequency Hz 330° 30° 320° 40° 310° 50° 300° 60° 290° 70° 280° 80° 1059 1334 270° 90° 1679 2113 260° 100° 2661 250° 110° 3350 4217 240° 120°...
  • Page 213 FIGURE A-45 Model 831C with 377B02 Microphone 0° 350° 10° Frequency (Hz) 340° 20° 330° 30° 320° 40° 310° 50° 300° 60° 290° 70° 1189 280° 80° 1496 270° 90° 1884 2371 260° 100° 2985 250° 110° 3758 4732 240° 120°...
  • Page 214 FIGURE A-47 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-50...
  • Page 215 FIGURE A-48 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-51...
  • Page 216 FIGURE A-49 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-52...
  • Page 217 FIGURE A-50 Model 831C with 377C20 Microphone FIGURE A-51 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-53...
  • Page 218 FIGURE A-52 Model 831C with 377C20 Microphone FIGURE A-53 Model 831C with 377C20 Microphone SoundAdvisor Model 831C A-54...
  • Page 219 Random Incidence of 831C With 377B02 Free-Field Mic A.9.4 Typical Z-Weight Frequency Response For frequency responses of the Model 831C with the PRM2103 Outdoor Microphone Preamplifier Manual. PRM2103 preamplifier, see the Larson Davis FIGURE A-55 Z-Weight Frequency Weighting, Direct Input -10.0 -20.0...
  • Page 220 A.9.5 Frequency Response for 831C Low Noise Microphone Set (831C-LOWN) The 831C-LOWN mic set uses an extension cable to case reflections often shown with other microphone connect to the 378A04 Low Noise Microphone and setups. Preamplifier combination. Because of this, the directional response characteristics don’t include the FIGURE A-56 831C With LOWN Mic Set Directional Response, Referenced to Free-Field Response...
  • Page 221 FIGURE A-58 831C With LOWN Mic Set FIGURE A-59 831C With LOWN Mic Set SoundAdvisor Model 831C A-57...
  • Page 222 FIGURE A-60 831C With LOWN Mic Set FIGURE A-61 831C With LOWN Mic Set SoundAdvisor Model 831C A-58...

  • Page 223: Declaration Of Conformity

    A.10 Declaration of Conformity SoundAdvisor Model 831C A-59...

  • Page 224: Appendix B Measuring Sound Using Iec 61672-1

    Appendix B 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. B.2 IEC 61672-1 Section 9.3 a) Reference Sound Pressure Level d) Periodic Testing The reference sound pressure level is 114 dB re 20 µPa.
  • Page 225 Table B.1 831C with PRM831 and 377B02 Microphone average frequency responses and corrections Required by IEC 61672-1 1412.54 -0.27 0.27 0.20 -0.07 0.07 0.25 1496.24 -0.13 0.13 0.07 -0.06 0.06 0.25 1584.89 -0.02 0.02 0.23 0.21 -0.21 0.25 1678.80 0.01 -0.01 0.24 0.25...
  • Page 226 Table B.1 831C with PRM831 and 377B02 Microphone average frequency responses and corrections Required by IEC 61672-1 8912.51 0.06 -0.06 0.13 0.19 -0.19 0.55 9440.61 0.01 -0.01 -0.03 -0.02 0.02 0.55 10000.00 0.01 -0.01 0.21 0.22 -0.22 0.55 10592.54 0.07 -0.07 0.09 0.16...
  • Page 227 Table B.2 Directional Response of 3 ½-inch Windscreen 0.10 0.10 0.13 0.07 -0.03 0.07 0.00 0.00 0.13 0.10 -0.07 0.03 0.00 501.19 0.03 0.10 0.13 0.07 -0.07 0.07 0.03 0.03 0.07 0.00 -0.03 0.03 0.00 530.88 0.10 0.10 0.13 0.07 0.03 0.07 0.00 -0.03 0.13...
  • Page 228 Table B.2 Directional Response of 3 ½-inch Windscreen 0.10 0.10 0.13 0.13 0.00 0.13 0.10 0.10 0.23 0.20 0.13 0.27 0.23 3981.07 0.03 0.00 0.10 0.03 -0.10 0.07 0.00 -0.03 0.07 0.03 0.03 0.10 0.13 4216.97 0.00 -0.07 -0.07 -0.07 -0.17 -0.07 -0.10 -0.10 -0.07 0.00 -0.07 0.00 0.00 4466.84 -0.30 -0.20 -0.17 -0.23 -0.27 -0.30 -0.30 -0.43 -0.27 -0.20 -0.37 -0.20 -0.20 4731.51...
  • Page 229 FIGURE B-1 Windscreen Direction EPS2116 Corrections The following table and graph display correction factors for effects of the EPS2116 on the response of the sound level meter. These are corrections are intended for laboratory use when testing to IEC 61672-3 to account for effects of the EPS2116.
  • Page 230 FIGURE B-2 Situational Correction Factors for the EPS2116 Correction Factors for the EPS2116 2.00 0.00 -2.00 -4.00 -6.00 -8.00 -10.00 -12.00 2000 20000 Frequency (Hz) EPS2116 at 0 Degrees EPS2116 at 90 Degrees EPS2116 at Random Incidence Table B.4 EPS2116 Windscreen Corrections FF to 90 Degree, FF to Random FF to FF, EPS2116...
  • Page 231 316.23 0.10 -0.02 -0.04 0.20 334.97 0.09 -0.06 -0.04 0.20 354.81 0.10 0.00 -0.01 0.20 375.84 0.08 -0.06 -0.04 0.20 398.11 0.12 -0.03 0.03 0.20 421.7 0.11 -0.02 -0.01 0.20 446.68 0.14 -0.01 0.03 0.20 473.15 0.12 -0.05 0.00 0.20 501.19 0.29 -0.01...
  • Page 232 1778.28 0.79 0.04 0.23 0.20 1883.65 0.77 0.02 0.18 0.20 1995.26 0.85 0.10 0.17 0.20 2113.49 0.70 0.15 0.12 0.20 2238.72 0.75 0.20 0.08 0.20 2371.37 0.55 0.15 0.00 0.20 2511.89 0.72 0.12 -0.07 0.20 2660.73 0.74 0.14 -0.07 0.20 2818.38 0.77 -0.21...
  • Page 233 10000 -0.30 -4.42 -3.32 0.30 10592.54 -0.42 -4.45 -3.30 0.30 11220.18 -0.66 -4.49 -3.12 0.30 11885.02 -0.50 -4.31 -2.90 0.30 12589.25 -0.57 -4.41 -2.76 0.30 13335.21 -1.17 -4.64 -2.90 0.30 14125.38 -1.59 -4.95 -3.41 0.30 14962.36 -2.20 -5.41 -4.07 0.30 15848.93 -3.05 -6.30...
  • Page 234 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 235 n) Radio Frequency Emission The mode of operation of the 831C that produces the greatest radio frequency emission levels is with the 831C set to run with the LCD backlight on, an external charger (PSAA20R-120 charger), Ethernet dongle, and USB cable attached and with an EXC020 (20' microphone extension cable) between the PRM831 and meter.

  • Page 236: Appendix C Glossary

    Glossary his 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.
  • Page 237      L p t    q     -- - L avg qLog 10       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"...
  • Page 238 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 239 All dB values are unit free and therefore, the dB value is not the value of the quantity itself, but the ratio of that quantity to an actual reference quantity used. Thus, for every level in decibels there must be a well defined reference quantity. Sound versus vibration uses different references, but the dB principal is the same.
  • Page 240 units, like sound pressure in acoustics or voltage in electrical engineering. This is illustrated in equation below: 20Pa ------- - ----- 10Log 20Log Table C.1 illustrates how a a tenfold increase of the sound pressure will result in an increase in 20 dB steps, while sound power increases in 10 dB steps.
  • Page 241 Eight Hour Time-Weighted Average Sound Level (L TWA(8)) It is the constant sound level that would expose a person to the same Noise Dose as the actual (unsteady) sound levels. According to the ANSI S12.19 standard, the equation for it is ...
  • Page 242 distance. For example, if the lowest frequency is 20 Hz, the wavelength at normal temperatures is near 56 ft. (17 m); at 1000 Hz, the wavelength is near 1.1 ft. (1/3 m). "Acoustic Near Field:" for the advantages of being in the acoustic far field. Geometric Far Field: The distance from a source of sound is greater than the largest dimension of the sound source.
  • Page 243 A-Weighting: A filter that adjusts the amplitude of a frequency spectrum (20 Hz to 20 kHz) to be perceived the same way the human ear does when exposed to low levels of sound. This weighting is most often used for evaluation of environmental sounds. See table below. B-Weighting: A filter that adjusts the amplitude of a frequency spectrum (20 Hz to 20 kHz) to be perceived the same way the human ear does when exposed to higher levels of sound in the lower frequencies (below 1 kHz).
  • Page 244 Table C.4 Frequency Filter Response Center Frequencies, Weighting Network Frequency Response 1 Octave A Octave 6300 -0.1 -1.9 -2.0 8000 8000 -1.1 -2.9 -3.0 10000 -2.5 -4.3 -4.4 12500 -4.3 -6.1 -6.2 16000 16000 -6.6 -8.4 -8.5 20000 -9.3 -11.1 -11.2 Integration Method See "Linear Integration", or "Exponential Integration".
  • Page 245 Microphone Guidelines Microphone - Types: A device for detecting the presence of sound. Most often it converts the changing pressure associated with sound into an electrical voltage that duplicates the changes. It can be composed of one of the following types: Capacitor (Condenser): A microphone that uses the motion of a thin diaphragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal.
  • Page 246 Rules to obtain the most accurate measurement: 1. Do not use a microphone at frequencies higher than specified by the manufacturer; to increase the frequency response choose smaller microphones. 2. Choose a microphone for free field or random incidence to minimize the influence of orienta- tion.
  • Page 247 fore measurements made here can be used to separate the various sources of sound, but are not useful in predicting the sound levels and sound spectrum far from the source. Noise Typically it is unwanted sound. This word adds the response of humans to the physical phenome- non of sound.
  • Page 248 Projected Noise Dose Projected Noise Dose is the Noise Dose expected if the current rate of noise exposure continues for the full Criterion Duration period. Quality Indicators A portion of Tonality standard (ISO 1996-2, or ISO/PAS 20065), which rates the audibility of tones in a measured spectrum according to the following values: Lpt: the sound pressure level of tones in the critical band.
  • Page 249 exposure in terms of E, where p is the sound pressure and T is the Measurement Duration (specific time period). Sound Exposure Level (SEL, LE) The total sound energy in a specific time period usually expressed in decibels. The following equation shows that the sound pressure is squared and integrated over a specific period of time ...
  • Page 250 Fixed Average: The averaging process is over a fixed time period. The equation for it is  t   t d ----------------------- p –   The sound pressure is squared and averaged over a fixed time period. Unlike the moving average, the sound pressures in all time intervals are equally weighted.
  • Page 251 Weighted Peak: The peak value of a sound with a meter that has a frequency weighting other than flat and a peak detector. Sound Power (W) The sound power emitted by a sound source. It is measured in Watts. Sound Power Level (PWL, Lw) The logarithmic form of sound power.
  • Page 252 Threshold Sound Level (Lt) The A-weighted sound level below which the sound produces little or no Noise Dose accumula- tion and may be disregarded. It is used for hearing damage risk assessment. Standard: ANSI S1.25 Time Weighted Average Sound Level (TWA, LTWA(TC)) It is the level of a constant sound over the Criterion Duration, that would expose a person to the same Noise Dose as the actual (unsteady) sound over the same period.
  • Page 253 where c is the sound speed and f is the frequency in Hz. It has the dimensions of length. Wavenumber (k) A number that is related to the wavelength of sound and is used to compare the size of objects rel- ative to the wavelength or the time delay in sound propagation.
  • Page 254 Larson Davis - a PCB Piezotronics division LarsonDavis.com P/N I831C.01 Rev O, SoundAdvisor 831C Reference Manual firmware version 4.6 ©2021 PCB Piezotronics, Inc. Worldwide Corporate Headquarters Toll-free (in the US): 888-258-3222 3425 Walden Avenue Phone: 716-926-8243 Depew, NY 14043-2495 USA...

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