1. DL manuals
  2. Larson Davis
  3. Measuring Instruments
  4. SoundExpert LxT
  5. User Manual

Larson Davis SoundExpert LxT User Manual

Summary of SoundExpert LxT

  • Page 1

    ® lxt manual for soundtrack lxt & soundexpert lxt tm.

  • Page 2: Larson Davis

    I770.01 rev k supporting firmware version 2.301 larson davis lxt manual for soundtrack lxt & soundexpert lxt.

  • Page 3

    Copyright copyright 2016 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. Trademarks pcb , soundtrack lxt and soundexpert are registered trademarks of p...

  • Page 4: Table of Contents

    Table of contents chapter 1 lxt features 1-1 soundtrack lxt ................................................................................................. 1-1 soundexpert lxt ............................................................................................... 1-5 chapter 2 overview 2-1...

  • Page 5: Chapter 8

    Control panel - calibrate .......................................................................................7-2 acoustic calibration ..............................................................................................7-4 sensitivity tab ...................................................

  • Page 6: Chapter 13

    Chapter 13 lock/unlock the lxt 13-1 control panel - lock ........................................................................................... 13-1 fully locked ....................................................................................................... 13-4 locked with auto-store ....

  • Page 7: C-1

    Standards met by lxt .......................................................................................... A-1 lxt specifications ................................................................................................ A-2 electromagnetic emission ..........................................

  • Page 8: Soundtrack Lxt

    Lxt manual lxt features 1-1 c h a p t e r 1 lxt features this chapter describes the features for the soundtrack lxt and soundexpert lxt sound level meters. Soundtrack lxt the following sections describe the features for the soundtrack lxt. Hardware features the larson davis soundtrack lxt has the fo...

  • Page 9: Basic Operation

    1-2 soundtrack lxt lxt manual • e, e8, e40 • sea peak exposure • 2 rms event counters and 3 peak event counters basic operation • auto-store with auto-reset • run timer and stop-when-stable control • real-time clock • start time, elapsed time and paused time • time stamping for lmax, lmin, lpeak(max...

  • Page 10: Standard Accessories

    Lxt manual soundtrack lxt 1-3 • lxt-dva : digital voice annotation (includes headset acc003) standard accessories the lxt is delivered with the standard accessories described below. • one of the following preamplifier/microphone combinations: - prmlxt1 preamplifier with a 377b02 micro- phone - prmlx...

  • Page 11

    1-4 soundtrack lxt lxt manual cables direct input cable or adaptor • excxxx microphone extension cable, where xxx is the length in feet (xxx = 010, 020, 050, 066, 100 and 200 available) • cbl138 usb cable • cbl139 ac/dc output cable power supplies • psa029 universal ac power adaptor • psa031 12 volt...

  • Page 12: Soundexpert

    Lxt manual soundexpertâ lxt 1-5 • lxt-ccs storage case environmental protection • eps2116 environmental shroud • eps2106-2 environmental shroud • eps2108-2 environmental shroud • eps030-lxt environmental case with one lead acid battery to be used with an external microphone tripod (the tripod is not...

  • Page 13: Hardware Features

    1-6 soundexpertâ lxt lxt manual hardware features the hardware features for the soundexpert lxt are the same as those for the soundtrack lxt. Additionally, the following accessories are included with the soundexpert lxt: • psa029 power supply • cbl138 usb cable standard features the soundexpert lxt ...

  • Page 14: Optional Accessories

    Lxt manual soundexpertâ lxt 1-7 • lanyard optional accessories equivalent electrical impedance adaptor an equivalent electrical impedance adapter can be used in place of the microphone when a measurement is being made electrically. The adapter is simply a series capacitor with the same capacitance a...

  • Page 15

    1-8 soundexpertâ lxt lxt manual • eps2106/8-2 environmental shroud for outdoor microphone protection • eps030-lxt environmental case with one lead acid battery to be used with an external microphone tripod (the tripod is not included) tripods • trp001 instrument/camera tripod with adp032 1/2 inch mi...

  • Page 16: Lxt Components

    Lxt manual overview 2-1 c h a p t e r 2 overview this chapter provides an overview of the soundtrack lxt sound level meter, including the following sections: • lxt components • summary of displays and icons • navigating and selecting • basic run functions • tab and setting displays lxt components fi...

  • Page 17

    2-2 lxt components lxt manual the standard lxt shown in figure 2-1 includes the following: • 1/2 in. Diameter condenser microphone • backlit graphic 160 x 240 pixel lcd display • 13-key soft rubber backlit keypad • ac/dc output, control, usb, and external power connectors (shown in figure 2-2) • tru...

  • Page 18: Display

    Lxt manual lxt components 2-3 • ac/dc output and headset jack : this jack is used to output analog ac and dc signals or to connect to headsets for recording and playback of voice records • auxiliary usb connector: the auxiliary usb connector allows attaching usb storage devices. Display the lxt has ...

  • Page 19: Keypad

    2-4 lxt components lxt manual keypad the lxt has a 13 button keypad. This section describes the buttons on the keypad. Softkeys the three buttons just beneath the display, on the body of the lxt, are called softkeys, as shown in figure 2-3. Above each softkey, on the bottom of the display, is an ico...

  • Page 21

    2-6 summary of displays and icons lxt manual summary of displays and icons tabs data on the lxt is presented in a tabbed format. Move between tabs by using the right and left softkeys. Pages tabs are divided into pages that logically group the data together (i.E., 1/3 octave data on the live tab). N...

  • Page 22

    Lxt manual summary of displays and icons 2-7 while the overload is present, the icon flashes. When the overload is removed, the icon disappears from the display. If a measurement is running and an overload occurs, the icon shown below flashes during overloads. When the overload has been removed, the...

  • Page 23: Navigating and Selecting

    2-8 navigating and selecting lxt manual starts the run after the initialization has completed (less than 10 seconds). Run icon the run icon is animated, moving from left to right to indicate that a measurements is in progress. Pause icon the pause icon indicates that the current measurement has been...

  • Page 24: Basic Run Functions

    Lxt manual basic run functions 2-9 basic run functions the basic measurement run functions are as follows: • running • pausing • stopping • storing the 9 (run/pause) key initiates a run. If a measurement is running, this key pauses the run. It does not end the run; to end the measurement run, press ...

  • Page 25: Data Display Tabs

    2-10 tab and setting displays lxt manual measurement settings tabs opening from the data display tabs, pressing the center softkey labeled menu brings up the menu shown in figure 2-5. Figure 2-5 menu select settings and press 5 to open the settings tabs. Closing press the center softkey to return th...

  • Page 26: Measurement Settings Tabs

    Lxt manual tab and setting displays 2-11 • session log: the session log is a record of data accumulation actions. A time-stamped record is made for every run, pause, stop or voice message action. • current (optional) used in conjunction with measurement history. Similar to the overall tab except tha...

  • Page 27

    2-12 tab and setting displays lxt manual • markers (optional): use in conjunction with time history measurements, this feature permits the user to annotate portions of a time history record to identify noise sources or make other notes. • day/night (optional): defines hours for day, night, and eveni...

  • Page 28

    Lxt manual tab and setting displays 2-13 data explorer for a detailed description of data explorer, see chapter 12  in  the section entitled “data explorer” on page 12-1. The data explorer is used to examine data that has been stored following previous measurements. It is also used to mana...

  • Page 29

    2-14 tab and setting displays lxt manual about for a detailed description of the about tabs, see chapter 14 in  the section entitled “about” on page 14- 1. The about tabs provide the user with information specific to this instrument, such as serial number, options, etc. The about tabs...

  • Page 30: Unpacking and Inspection

    Lxt manual preparing for first use 3-1 c h a p t e r 3 preparing for first use this chapter outlines the steps to unpack the soundtrack lxt and prepare it for first use, including: • unpacking and inspection • connecting the microphone and preamplifier • disconnecting the preamplifier • powering the...

  • Page 31

    3-2 connecting the microphone and preamplifier lxt manual the microphone model and serial numbers are engraved on the outside of the microphone, as shown in figure 3-1. The preamplifier model and serial numbers are engraved on the preamplifier body as shown in figure 3-2. Figure 3-1 microphone you m...

  • Page 32

    Lxt manual connecting the preamplifier to the lxt 3-3 connecting the preamplifier to the lxt the connectors are keyed for correct alignment. Insert the preamplifier into the mating connector on the lxt and rotate the preamplifier until the keyways line up. Press the assemblies together until a small...

  • Page 33: Powering The Soundtrack Lxt

    3-4 disconnecting the preamplifier from the lxt lxt manual disconnecting the preamplifier from the lxt when transporting the lxt, it is recommended that the preamplifier be detached and placed in a secure location in the carrying case. On the front of the lxt, just below the preamplifier connector, ...

  • Page 34: Batteries

    Lxt manual powering the soundtrack lxtâ 3-5 if the lxt is being powered externally via a usb cable, do not unplug the cable without ensuring that the batteries in the instrument have adequate charge or properly powering down the lxt first. The lxt should also be properly shut off prior to changing b...

  • Page 35: Hardware Power Switch

    3-6 powering the soundtrack lxtâ lxt manual hardware power switch do not use the hardware power switch to turn the lxt off. This may cause data to be lost. Press the 0 key, then the off soft key to turn the lxt off. The hardware power switch on the bottom of the lxt, shown in figure 2-2 disconnects ...

  • Page 36: Power Settings

    Lxt manual powering the soundtrack lxtâ 3-7 external power is being supplied, the battery icon is replaced with the icon shown in figure 3-6. Figure 3-6 external power icon the lxt cannot be operated with an external power supply if the internal batteries are discharged (flat). You can run solely on...

  • Page 37

    3-8 powering the soundtrack lxtâ lxt manual the backlight can also be adjusted from the power page as described in the section "power" on page 11-4. The backlight mode and display contrast are adjusted using the 4 , 6 , 8  and 2  keys. there are three options for backlight : off , dim ,...

  • Page 38: Measurement Settings Tabs

    Lxt manual basic measurement setup 4-1 c h a p t e r 4 basic measurement setup this chapter describes how to setup the lxt to perform basic sound level measurements, including the following: • leq, lmax, lmin corresponding to user-selected values of frequency weighting and detector • lpeak and lpeak...

  • Page 39

    4-2 measurement settings tabs lxt manual settings in use message if the lxt is not already connected to a computer running blaze, slm utility-g3, or g4 software, ignore this section. If the blaze, slm utility-g3, or g4 software is already connected to the lxt when an attempt is made to access the me...

  • Page 40: General Tab

    Lxt manual measurement settings tabs 4-3 general tab figure 4-2 shows the general tab. Figure 4-2 general tab the slm utility-g3 or g4 software can be used to easily enter both the file name and the measurement description. The general tab is used to enter file names and measurement descriptions for...

  • Page 41: Slm Tab

    4-4 measurement settings tabs lxt manual slm tab figure 4-2 shows the slm tab. Figure 4-3 slm tab to modify settings on the slm tab, navigate to either frequency weighting , detector , peak weighting , or integration method page and press 5 . Frequency weighting a, c and z frequency weightings are p...

  • Page 42

    Lxt manual measurement settings tabs 4-5 octave band analyzer tab (optional) the default values for these parameters are as shown in figure 4-4. This tab only appears when the lxt has the optional lxt- ob1 or lxt-ob3 firmware enabled. Figure 4-4 oba tab oba parameter selection the oba parameters are...

  • Page 43

    4-6 measurement settings tabs lxt manual graph scaling range can be modified by the user, as described in “graph scale adjustment” on page 5-2. Oba frequency weighting the user can select that the 1/1 and/or 1/3 octave frequency analysis modules process data from the a, c or z weighting filters. Oba...

  • Page 44: Dosimeter 1 and 2 Tabs

    Lxt manual measurement settings tabs 4-7 dosimeter 1 and 2 tabs figure 4-6 shows the dosimeter 1 tab. Figure 4-6 dosimeter 1 the dosimeter 1 and dosimeter 2 tabs are provided to permit the evaluation of two independent noise dose data sets. Other than being on separate tabs, they are identical. Pred...

  • Page 45

    4-8 measurement settings tabs lxt manual the name field is already highlighted when the dosimeter view is opened. If this has been changed, use the 8 key to move the highlight back to the name field. The names of the predefined setups can be accessed from the name field at the top of the display. Pr...

  • Page 46: Ln Tab

    Lxt manual measurement settings tabs 4-9 ln tab figure 4-8 shows the ln tab. Figure 4-8 ln tab the ln value is the measured sound level that exceeds n% of the measurement time. For example, a value of l 90 = 35 db means that the measured sound level is above 35 db for 90% of the measurement period. ...

  • Page 47: Control Tab

    4-10 measurement settings tabs lxt manual control tab the control tab, shown in figure 4-9, is used to set the run mode for the measurement to be performed. Figure 4-9 control tab when the optional firmware lxt- env has been enabled, measurement history can be enabled in the run control setup. The r...

  • Page 48

    Lxt manual measurement settings tabs 4-11 • daily timer: the measurement is initiated manually by pressing the 9 key and is stopped by pressing the 7 key. Measurements are made only during the separate time blocks defined by the setup. When the control tab is opened, the run mode field is already se...

  • Page 49

    4-12 measurement settings tabs lxt manual entering run time for the timed stop mode to enter the run time, navigate to select the time data field and press 5 . You can then move left and right to different digit positions in the data field using the 4 and 6 keys, as shown in figure 4-12. Figure 4-12...

  • Page 50

    Lxt manual measurement settings tabs 4-13 the following sections are for setups without measurement history enabled. When measurement history is not enabled, the measurement must be manually stored at the conclusion of the duration. Because only a single measurement exists, the data displayed on the...

  • Page 51

    4-14 measurement settings tabs lxt manual the selection and setting of appropriate parameters for the continuous , single block timer and daily timer run modes is shown in figure 4-14. Figure 4-14 setup of continuous, daily timer and single block time run modes for each run mode option, select the c...

  • Page 52: Triggers Tab

    Lxt manual measurement settings tabs 4-15 select the data field and use the navigation keys to specify the start time. Run mode with measurement history measurement history requires that the optional firmware lxt-env be enabled. To measure and store sequences of measurements using the same setup, ei...

  • Page 53

    4-16 measurement settings tabs lxt manual figure 4-17 shows the day/night tab. Figure 4-17 day/evening/night definition l dn the day-night level l dn defined by the following formula: l den the day-evening-night level l den is defined by the following formula: in the default form, the day has twelve...

  • Page 54

    Lxt manual measurement settings tabs 4-17 • day: 07.00 to 19.00 • evening: 19.00 to 23.00 • night: 23.00 to 07.00 lday, levening and lnight are a-weighted long-term average sound levels measured during the day, evening and night, respectively. To account for the increased impact of environmental noi...

  • Page 55

    4-18 measurement settings tabs lxt manual.

  • Page 56: Data Labels

    Lxt manual data display 5-1 c h a p t e r 5 data display this chapter describes how data is displayed for basic sound level measurements. Data labels the lxt sound metrics labels are designated by international standards. For many displayed values, the frequency and time weighting are indicated in t...

  • Page 57: Under Range Condition

    5-2 tabbed display lxt manual selecting options for settings within tabs by using the 4 and 6 keys or the 8 or 2 keys to move between options on tabs or pages, you can select options by highlighting them. Once the desired value or option is selected, press 5 (enter). On some tabs, you can also selec...

  • Page 58: Live Tab

    Lxt manual live tab 5-3 select adjust graph and press 5 to obtain the adjust graph menu shown in figure 5-3 figure 5-3 adjust graph menu move the 4 and 6 keys to change the baseline level and the 8 or 2 keys to adjust the height (range between the baseline and the top of the display). The arrow icon...

  • Page 59: Profile Page

    5-4 live tab lxt manual profile page the profile page presents recent graphic history of l eq , using the user-selected frequency weighting, calculated for each second. The graph presents the last 120 seconds of the measurement. Figure 5-4shows the profile page. Figure 5-4 live tab, profile page the...

  • Page 60: Digital Page

    Lxt manual live tab 5-5 digital page the digital page displays both the instantaneous sound level and the value of the user-selected spl1 trigger level, as shown in figure 5-5. Figure 5-5 live tab, digital page in addition to displaying the current value of leq, this page displays check marks to ind...

  • Page 61: 1/1 Octave Page (Optional)

    5-6 live tab lxt manual 1/1 octave page (optional) the 1/1 octave band analyzer appears only when the sound level meter is loaded with the optional lxt-ob1 or lxt-ob3 firmware. The 1/1 octave page displays bar graphs of sound level in 1/ 1 octave frequency bands, as shown in figure 5-6. The right mo...

  • Page 62: 1/3 Octave Page (Optional)

    Lxt manual live tab 5-7 1/3 octave page (optional) the 1/3 octave band analyzer page appears only when the sound level meter is loaded with the optional lxt-ob3 firmware. The 1/3 octave page is similar to the 1/1 octave page, but the graph and data are presented for 1/3 octave filters, as shown in f...

  • Page 63: Power Page

    5-8 overall tab lxt manual power page the power page displays the current date and time , the run time for the measurement, the battery voltage, the calculated run time and the memory usage. The memory section indicates the amount of memory available as a percentage and in number of kilobytes. The n...

  • Page 64: Profile (With Overall Leq)

    Lxt manual overall tab 5-9 • percentiles • exceedances • overloads • community noise • miscellaneous • memory profile (with overall leq) figure 5-10 shows the profile page of the overall tab. Figure 5-10 overall tab, profile page digital figure 5-11shows the digital page of the overall tab. Leq usin...

  • Page 65: Leq

    5-10 overall tab lxt manual figure 5-11 overall page, digital page the digital page presents a profile of the sound level for the run time of the measurement. The run time for the average calculation is shown at the top of the screen. The graph is updated once per second and the calculation of the a...

  • Page 66: 1/1 Octave (Optional)

    Lxt manual overall tab 5-11 1/1 octave (optional) the 1/1 octave band analyzer page appears only when the optional firmware lxt-ob1 or lxt-ob3 has been enabled and this measurement mode has been selected in the setup. The 1/1 octave page displays bar graphs of sound level in 1/ 1 octave frequency ba...

  • Page 67: Dosimeter 1 and 2

    5-12 overall tab lxt manual figure 5-14 overall tab, 1/3 octave page dosimeter 1 and 2 there are two separate, but similar, dosimeter data displays in these pages. Figure 5-15 shows the measurement parameters that correspond to the setup named “osha-1”. . Figure 5-15 overall tab, dosimeter 1 & 2 pag...

  • Page 68

    Lxt manual overall tab 5-13 value of criterion time is set by selecting predefined setups, as described in “predefined setups” or by entering numerical values, as described in “threshold and criterion”. For example, suppose a measurement was performed over a time period of ten minutes. The value of ...

  • Page 69: Sel (Sound Exposure)

    5-14 overall tab lxt manual sel (sound exposure) figure 5-16 shows the sel page. The sel page displays sound exposure metrics, (in this instance for a-weighted, slow). Figure 5-16 overall tab, sel page l ase is the sound exposure level (previously known as sel). The sound exposure metrics indicate t...

  • Page 70: Sea

    Lxt manual overall tab 5-15 sea the sea parameter is used mainly in the canadian province of quebec. The sea page is an integration of 1 second peaks that exceeded 120 db, as shown in figure 5-17. Both the sea value and the frequency weighting used for the measurement are displayed. See “sea” in the...

  • Page 71: Percentiles

    5-16 overall tab lxt manual percentiles the percentiles page displays the ln statistics for the measurement based on the run time, as shown in figure 5- 18. Also shown are the maximum and minimum sound levels measured. An ln is the level that was exceeded “n” percent of the time. Figure 5-18 overall...

  • Page 72: Exceedances

    Lxt manual overall tab 5-17 exceedances exceedances occur when the instantaneous sound levels are greater than set trigger levels. The exceedances page shows the number of exceedances that have occurred during the measurement and the total duration of exceedances. Exceedances are shown for two thres...

  • Page 73: Overloads

    5-18 overall tab lxt manual overloads the overloads page displays any overloads that might have occurred during the measurement, as shown figure 5-20. Figure 5-20 overall tab, overloads page community noise the times intervals associated with the day, evening and night periods are set as described i...

  • Page 74: C Minus A And Impulsivity

    Lxt manual overall tab 5-19 c minus a and impulsivity figure 5-22 shows the c minus a level and impulsivity pages. Figure 5-22 c-a level and impulsivity page the integrated levels for l aeq are always calculated using the linear detector, regardless of the value selected in the slm setup. The laieq ...

  • Page 75: Memory

    5-20 session log tab lxt manual memory the memory page presents the quantity of each type of measurement made and the memory status, as shown in figure 5-23. Figure 5-23 overall tab, memory page session log tab the session log is a record of sound measurement actions, as shown in figure 5-24. Select...

  • Page 76

    Lxt manual view spectrum normalized (optional) 5-21 a time-stamped record is made for every run, pause, stop, voice message or marker action. The source responsible for each action is also recorded, which may be any of the following: • key press • usb command • run timer compete • low battery • out ...

  • Page 77

    5-22 view spectrum normalized (optional) lxt manual a standard spectrum displayed on the live tab appears as shown in figure 5-25. Figure 5-25 live spectrum display to access the view normalized display, press the center softkey menu to display the menu shown in figure 5-26 when viewing 1/1 or 1/3 o...

  • Page 78

    Lxt manual view spectrum normalized (optional) 5-23 select view normalized . This displays the spectrum in the normalized view, as shown in figure 5-27. Figure 5-27 normalized live spectrum display by default the display represents a spectrum normalized to reference spectrum 1. If reference spectrum...

  • Page 79

    5-24 view spectrum normalized (optional) lxt manual select the ref: data field and press 5 to open the reference menu, as shown in figure 5-29. Figure 5-29 live reference menu the items listed in this menu are as follows: • 1 • 2 • 3 • 4 • a • c • -a • -c the first four items permit the user to defi...

  • Page 80: Graph Relative

    Lxt manual view spectrum normalized (optional) 5-25 figure 5-30 shows an -a reference display for an a- weighted version of a spectrum. Figure 5-30 normalized spectrum with -a weighting graph relative selecting graph relative changes the graph to show the difference between the current data and the ...

  • Page 81

    5-26 view spectrum normalized (optional) lxt manual.

  • Page 82: Preparation

    Lxt manual making measurements 6-1 c h a p t e r 6 making measurements this chapter describes how to make and store accurate sound level measurements. Preparation before making a measurement, make sure of the following: • the instrument hardware has been properly assembled as described in "preparing...

  • Page 83: Use of A Windscreen

    6-2 performing measurements lxt manual use of a windscreen wind blowing across the microphone generates pressure fluctuations on the microphone diaphragm that can produce errors in the measurement. As a result, when performing measurements in the presence of low level airflows, it is recommended tha...

  • Page 84: Measurement Range

    Lxt manual performing measurements 6-3 measurement range the measurement ranges in which the lxt meets the standards, which depend upon the selected frequency weighting, are shown in table a-4, “lxt performance specifications,” on page a-4. Measurements which include levels outside this range should...

  • Page 85: Pausing Measurements

    6-4 performing measurements lxt manual pausing measurements at any time the measurement of overall data can be temporarily suspended by pressing the 9 key. Note that the run clock also pauses. However, instantaneous data continues to be displayed on the live tab. Measurements may be paused and then ...

  • Page 86

    Lxt manual performing measurements 6-5 > ten seconds since last stop or pause after pressing the center softkey to implement a five second back erase, if the measurement duration since the last stop or pause has been more then ten seconds, the center softkey is then labeled back-10s , as shown in fi...

  • Page 87

    6-6 performing measurements lxt manual after pressing the center softkey, if the measurement duration since the last stop or pause has been less than ten seconds, the center softkey is then labeled undo , as shown in figure 6-5. Figure 6-5 back erase undo indication the user can take one of the foll...

  • Page 88: Resetting Measurements

    Lxt manual storing measurements 6-7 resetting measurements a measurement is most often reset when a noise event which is not typical of the desired measurement takes place. For example, an aircraft passing overhead when attempting to measure the background noise in a normally quiet area may be cause...

  • Page 89

    6-8 storing measurements lxt manual after a file has been successfully stored, the lxt automatically resets when the 9 key is pressed to begin another measurement. The data is stored under the file name defined in the section "general tab" along with a file number. The file number automatically begi...

  • Page 90: Case 1

    Lxt manual data storage after improper shutdown 6-9 to continue with the overwrite operation, select yes and press 5 . Data storage after improper shutdown when the lxt has been shutdown improperly during a measurement, for example during a power outage, the procedure for handling the data depends u...

  • Page 91

    6-10 data storage after improper shutdown lxt manual improper shutdown following an improper shutdown, when the instrument is next turned on: step 1 the user is prompted to save the data. • if the user responds by selecting to store the data, the data is stored and the instrument is reset • if there...

  • Page 92

    Lxt manual data storage after improper shutdown 6-11 figure 6-9 improper shutdown sequence, case 2 instrument reset no response for 10 seconds no reset instrument prompt yes no no response for 10 seconds save data prompt data saved yes.

  • Page 93

    6-12 data storage after improper shutdown lxt manual.

  • Page 94: Calibration Overview

    Lxt manual calibration 7-1 c h a p t e r 7 calibration this chapter describes both the purposes and steps for calibrating the soundtrack lxt and soundexpert lxt. Calibration overview sensitivity determination the primary role of sound level meter calibration is to establish a numerical relationship ...

  • Page 95: Control Panel - Calibrate

    7-2 control panel - calibrate lxt manual large change notification during calibration, an automatic comparison is made between the sensitivity determined by the calibration and a published value of sensitivity. An on-screen window appears to warn the user when the difference between these two values...

  • Page 96

    Lxt manual control panel - calibrate 7-3 the four calibration tabs are shown in figure 7-2. Figure 7-2 calibration tabs calibrate tab the calibrate tab is used when performing an acoustic calibration, including the selection of the sound level calibrator to be used and the implementation of the cali...

  • Page 97: Acoustic Calibration

    7-4 acoustic calibration lxt manual history tab to create a history record for a calibration, it must be saved; calibrations must also be saved to export post-calibration data to software. The history tab lists the results, along with the date and time, of the ten most recent calibrations performed ...

  • Page 98: Calibrator

    Lxt manual acoustic calibration 7-5 frequency weighting the lxt automatically switches to c frequency weighting and fast detector response for calibration. This permits 250 hz and 1000 hz calibrators to be used. The fast detector response reduces the stabilization time required before calibration. A...

  • Page 99

    7-6 acoustic calibration lxt manual temperature (23° c) and near sea level (101.3 kpa) then no other corrections need to be made. For example, if the calibration sheet for the cal200 indicates 113.98 db for its level when set to 114 db then set the cal level in the lxt to 113.86 db and 1000 hz. When...

  • Page 100: Instrument Class

    Lxt manual acoustic calibration 7-7 when the microphone and instrument are at a temperature other than near room temperature or static pressures not near sea level, then corrections need to be added for the ambient temperature and the prevailing static pressure. Check the calibration data shipped fr...

  • Page 101: Instrument Class

    7-8 acoustic calibration lxt manual set the cal200 level switch to 94 or 114 db. Adding a calibrator when adding a calibrator to the list, the following information may be entered: • calibration level • calibration frequency • calibrator description the calibration level and frequency values are as ...

  • Page 102: Microphone Selection

    Lxt manual acoustic calibration 7-9 figure 7-3 new calibrator if the desired calibrator is already in the list, highlight the calibrator and press 5 . The radio button next to the selected calibrator is filled in and the calibration information appears, as shown above. Microphone selection the micro...

  • Page 103: Performing The Calibration

    7-10 acoustic calibration lxt manual that microphone and preamplifier combination appears in the self noise data field. Other microphone in order for the noise floor and under range levels to be determined when the microphone is not selected from the drop down list as described in ‘larson davis micr...

  • Page 104: Calibration Results

    Lxt manual acoustic calibration 7-11 you can simply verify the calibration by selecting no . Also, if no significant changes are seen you may choose to answer no . However, to create an historical record for it, or to export post-calibration data, you must save it. When the calibration is completed,...

  • Page 105: Sensitivity Tab

    7-12 sensitivity tab lxt manual sensitivity tab the sensitivity tab, shown in figure 7-8, is used primarily to establish the noise floor of the instrument with the preamplifier and microphone presently being used and, from that, determine the under range levels for a, c and z- weighting sound level ...

  • Page 106: Overload Level

    Lxt manual calibration without preamplifier 7-13 when a calibration has been performed using any of the four preamplifiers listed above, that calibration information is saved for that preamplifier. If the preamplifier is switched from one of these types to another, then the calibration information a...

  • Page 107

    7-14 calibration without preamplifier lxt manual figure 7-9 sensitivity tab without preamplifier in this situation, the sensitivity of the transducer and the self noise can be entered directly, if known..

  • Page 108: Certification

    Lxt manual certification 7-15 certification the certification tab is shown in figure 7-10. Figure 7-10 certification tab a certification interval of one year is recommended but this can be lengthened or disabled depending on applicable requirements. The user has the opportunity to set the calibratio...

  • Page 109

    7-16 certification lxt manual available values of certification interval are as follows: • 1 year • 2 years • 3 years • 4 years • never the default value is never available values of certification reminder are as follows: • 15 days • 30 days • 45 days • 60 days • never the default value is never not...

  • Page 110

    Lxt manual certification 7-17.

  • Page 111

    Lxt manual voice recording 8-1 c h a p t e r 8 voice recording the lxt provides a voice recorder as a convenient way to annotate measurements. Voice recordings can be made with or without a headset, are sampled at 8 khz, and can be up to 20 seconds long. Launching the voice recorder dialog to activa...

  • Page 112: Making A Voice Recording

    Lxt manual making a voice recording 8-2 the voice record list is initially empty. Select the voice recorder icon and press 5 to open the dialog shown in figure 8-2. Figure 8-2 voice recorder making a voice recording with headset when using a headset, the jack function must to set to “headset” as des...

  • Page 113: Playing A Voice Recording

    8-3 playing a voice recording lxt manual playing a voice recording voice recordings can also be played back from the session log. Figure 8-2 shows that voice records are presented in a list on the dialog. To play back a recording via the headset jack, select the desired recording in the list and pre...

  • Page 114: Parameters Logged

    Lxt manual time history 9-1 c h a p t e r 9 time history this chapter describes the measurement features associated with the optional data logging firmware lxt- log and lxt-hslog. Parameters logged with the optional firmware lxt-log enabled, the time history mode permits the lxt to automatically log...

  • Page 115: Parameter Label

    9-2 parameters logged lxt manual table 9-2 shows additional acoustical parameters that are logged for time history. Instantaneous values when the lxt-hslog firmware is enabled, three instantaneous values are available. These are continuously varying sound levels, based on slow (s), fast (f) and impu...

  • Page 116: Time History Setup

    Lxt manual time history setup 9-3 increased timer resolution tms resolution when the optional firmware lxt-hslog is enabled and the time history interval has been selected to be 500 ms or less, the parameter tms causes the time value to be measured and saved with higher resolution. Time history setu...

  • Page 117: Set Time History Period

    9-4 time history setup lxt manual set time history period to set the time history period, select the period data field and press 5 to list all the available values of time, as shown (partially) in figure 9-2. Figure 9-2 time history period menu the values 100 ms, 200 ms and 500 ms appear only when t...

  • Page 118: Time History Tab

    Lxt manual time history tab 9-5 the first item in the options list is highlighted, as shown in figure 9-3. Figure 9-3 time history options window press 6 to select a check box option. Press 4 to deselect a box already checked. Exiting time history options when the options have been selected, press 5...

  • Page 119

    9-6 time history tab lxt manual graph scaling can be modified as described in section “graph scale adjustment”. The first display, labeled run , represents the keypress initiating the measurement, with the corresponding data and time. There is no measured data associated with this sample point. Data...

  • Page 120

    Lxt manual time history tab 9-7 at any time, the role of the left and right arrow keys, as well as the means to change it, are indicated in the lower portion of the display, as shown in figure 9-6. Figure 9-6 left/right arrow change record when the left/right arrow symbols appear to the left of reco...

  • Page 121: Frequency Spectra

    9-8 link to measurement history display lxt manual frequency spectra when the lxt is equipped with the optional firmware lxt-oba and either the 1/1 octave spectra or the 1/3 octave spectra, or both, have been selected for the measurement, the frequency spectra appears in the list of metrics that can...

  • Page 122: Markers

    Lxt manual markers 9-9 markers markers are used to annotate portions of the time history, especially for the purpose of identifying sound sources as they become dominant in the measurement. The lxt offers ten separate user-definable markers. Markers setup the default values for these parameters are ...

  • Page 123: Using Markers

    9-10 markers lxt manual naming a marker the process of naming markers is simplified by using the slm utility- g3 or g4 software. Select the field of the marker to be named and press 5 . This produces a cursor that can be moved left and right to different digit positions in the data field using the 4...

  • Page 124: Markers Display

    Lxt manual markers 9-11 highlight mark sound type and press 5 , which modifies the time history display as shown in figure 9-14. Figure 9-14 time history display with markers setting markers on/off at any time during a measurement, any of the markers can be set on or off. Select the field of the des...

  • Page 125

    9-12 markers lxt manual the first display, labeled run , represents the keypress initiating the measurement, with the corresponding data and time. There is no measured data associated with this sample point..

  • Page 126: Enabling Measurement History

    Lxt manual measurement history 10-1 c h a p t e r 10 measurement history this chapter describes measurement history setup and operation, as well as the data displays associated with the feature. The optional firmware lxt-env must be enabled to perform measurement history (timed stop and continuous r...

  • Page 127: Continuous and Timer Modes

    10-2 continuous and timer modes lxt manual table 10-1 shows when measurement histories are created for each run mode. Table 10-1 measurement history creation for run modes continuous and timer modes for these run modes, when the measurement history is enabled, a series of measurements are performed ...

  • Page 128: Timed Stop Mode

    Lxt manual timed stop mode 10-3 valid measurement times when other values are selected, the interval time sync still functions, but the time for which the first measurement is cut short is different. See "timed stop mode" below for further detail. The interval time sync function is intended to be us...

  • Page 129: Measurement Displays

    10-4 display of measurement history lxt manual measurement displays when a measurement is in progress, the data appears on the current tab, as shown in figure 10-4. The first numerical value displayed, l aseq in this example, is leq using the frequency weighting and detector from the setup. The seco...

  • Page 130: Measurement Tab

    Lxt manual display of measurement history 10-5 measurement tab during the first measurement, the same data appears on the overall and current tabs. After that, the overall measurement continues while new current measurements are made as the measurement sequence proceeds. The measurement tab displays...

  • Page 131

    10-6 display of measurement history lxt manual selecting and changing record numbers for all pages of the measurement tab, except the history page, the selected record number is indicated below the graph, as shown in figure 10-6. Figure 10-6 profile page level versus time graph for the selected reco...

  • Page 132: Page

    Lxt manual display of measurement history 10-7 depending on firmware options and the configured setup, the measurement tab may include up to 14 tabs. Table 10-2 shows measurement tab pages that may appear on your meter. The table includes the page name and an example of how the page may appear. Page...

  • Page 133: Page

    10-8 display of measurement history lxt manual 3 digital 4 leq 5 1/1 octave page sequence page name example table 10-2 measurement tab pages.

  • Page 134: Page

    Lxt manual display of measurement history 10-9 6 1/3 octave 7 dose 1 7 dose 2 page sequence page name example table 10-2 measurement tab pages.

  • Page 135: Page

    10-10 display of measurement history lxt manual 9 sel 10 sea 11 percentiles page sequence page name example table 10-2 measurement tab pages.

  • Page 136: Page

    Lxt manual display of measurement history 10-11 12 exceedances 13 overloads 14 miscellaneous page sequence page name example table 10-2 measurement tab pages.

  • Page 137: Link to Time History

    10-12 link to time history lxt manual there is no cursor on the profile graph, nor a numerical display of amplitude or time. Non-spectra displays with the exception of frequency spectra displays, the 6 and 4 keys are used to step the selected measurement record number up or down, respectively. Frequ...

  • Page 138

    Lxt manual data explorer 11-1 c h a p t e r 11 data explorer this chapter describes how to view the stored data files in the soundtrack lxt and soundexpert lxt data explorer. Control panel - data explorer to display the data explorer page, press the 3 (tools) key. Select the data explorer icon as sh...

  • Page 139: Menu Softkey

    11-2 control panel - data explorer lxt manual data explorer consists of just one page, the data explorer page, as shown in figure 11-2. Figure 11-2 data explorer navigational scrolling modes there are two navigational scrolling modes: • by item (default mode) : pressing the up or down arrow key move...

  • Page 140

    Lxt manual control panel - data explorer 11-3 to leave this menu without selecting an option, press the close softkey. View view opens the selected file to see its contents. Delete delete causes a message box to appear asking you to confirm the request, as shown in figure 11-4. Figure 11-4 delete fi...

  • Page 141

    11-4 control panel - data explorer lxt manual overwrite an existing file you can also overwrite a stored file. In the rename file prompt, select the browse button and press 5 to display a list of file names, as shown in figure 11-6. Figure 11-6 file name list select a name from the list and press 5 ...

  • Page 142

    Lxt manual control panel - data explorer 11-5 jump to beginning the jump to beginning option selects the first data file listed. Jump to end the jump to end option selects the last data file listed.

  • Page 143

    11-6 control panel - data explorer lxt manual.

  • Page 144

    Lxt manual system properties 12-1 c h a p t e r 12 system properties this chapter describes the system properties tabs, which you can use to identify or control functions of the sound level meter not related to sound measurement or calculations. Control panel - system properties to activate the syst...

  • Page 145: Device

    12-2 device lxt manual device it is easier to enter the text information for these three fields using the blaze software or the slm utility-g3 or g4 software. The device tab displays three fields in which the user may enter information about the instrument, as shown in figure 12-2. This can identify...

  • Page 146: Time

    Lxt manual time 12-3 time use the time tab to specify the time and date for the lxt, as shown in figure 12-3. Figure 12-3 time tab setting day and year navigate to select the day and year fields for system date . Press 5 to select the 1st character position. Use the 8 , 2 , 4 and 6 keys to change th...

  • Page 147: Power

    12-4 power lxt manual setting the time navigate to the system time field and specify the time for the meter in the same manner used for setting the day and year. Navigate to the set time button and press 5 . Sync data/time with pc selecting the sync date/time with pc check box enables the lxt time t...

  • Page 148: Auto-Off Time

    Lxt manual power 12-5 select the desired time and press 5 . The default is alkaline . Do not use 3.8 volt lithium batteries; they will blow the fuse. Warning: do not mix alkaline and nimh batteries. Warning: do not mix batteries from different manufacturers warning: replace all four batteries when i...

  • Page 149

    12-6 power lxt manual display and to the analog circuitry to save power when the power-save time is set to a value other than never . The display is powered down when no keys on the instrument have been pressed for the time set. Pressing any key reactivates the display. The analog circuitry, includi...

  • Page 150: Backlight Time

    Lxt manual power 12-7 exit from power save mode press any of the following keys to exit from the power save mode: • 7 (stop/store) • 1 (reset) • 9 (run / pause): there is a short delay before the instrument starts recording data. The following actions also cause an exit from the power save mode: • c...

  • Page 151: Backlight

    12-8 preferences lxt manual backlight using the backlight on bright significantly increases power consumption and decreases battery life. The backlight field sets the intensity of the backlight. To set it, select the field and press 5 to open the backlight menu, as shown in figure 12-10. Figure 12-1...

  • Page 152: Microphone Correction

    Lxt manual preferences 12-9 figure 12-11 shows the preferences tab. Figure 12-11 preferences tab to change the fields on the preferences tab, navigate and select values as described in previous sections. Microphone correction when using a free-field microphone, a correction can be applied to provide...

  • Page 153

    12-10 preferences lxt manual • none • prompt • store to set the auto-store preference, select the field and press 5 , as shown in figure 12-13. Figure 12-13 auto-store preferences select the desired setting and press 5 . None press the 7 key to stop the measurement. Press it again to store the data ...

  • Page 154: Jack Function

    Lxt manual preferences 12-11 jack function the ac/dc out/headset jack on the bottom of the instrument can be configured to provide one of the following: • as an ac/dc output of the signal from the detector. Use with the optional ac/dc output cable (clbl139); ac signal is output via the red bnc, and ...

  • Page 155: Reset Prompting

    12-12 preferences lxt manual the jack function setting becomes active as soon as it is selected. To set the jack function preference, select the field and press 5 , as shown in figure 12-14. Figure 12-14 jack function preferences select the desired jack function setting and press 5 . Reset prompting...

  • Page 156

    Lxt manual preferences 12-13 • auto : store data to usb memory if available; otherwise, store to internal memory. Select the usb storage field and press 5 , as shown in figure 12-16. Figure 12-16 usb storage preferences select the desired usb storage and press 5 . When data is stored to usb memory, ...

  • Page 157

    12-14 preferences lxt manual figure 12-18 print screen menu item selecting either option and pressing 5 initiates the corresponding printing action. When the print is successfully completed, the message shown in figure 12-19 appears. Figure 12-19 print complete message print error messages printing ...

  • Page 158: Localization

    Lxt manual localization 12-15 localization the default values for the localization tab are shown in figure 12-22. The localization tab contains display options for values that may vary from one country or region to another, as shown in figure 12-22. Figure 12-22 localization tab to change the fields...

  • Page 159: Decimal Symbol

    12-16 localization lxt manual select the language field and press 5 , as shown in figure 12-23. Figure 12-23 language preferences select the desired language and press 5 . Decimal symbol the lxt supports two formats for the decimal symbol: • period ( . ) • comma ( , ) select the decimal symbol field...

  • Page 160: Units

    Lxt manual displays 12-17 units the lxt supports both english and si units. Select the units field and press 5 , as shown in figure 12-26. Figure 12-26 units menu select the desired units and press 5 . Displays the default values for the displays tab are shown in figure 12-27. The displays tab conta...

  • Page 161

    12-18 displays lxt manual select the start field and press 5 , as shown in figure 12-28 figure 12-28 display start options select the desired start display and press 5 . Selecting displays to appear when there are measurement functions not being used or data displays which are not of interest for a ...

  • Page 162

    Lxt manual displays 12-19 live tab displays (6) figure 12-30 live tab displays overall tab displays (15) figure 12-31 overall tab displays session log display figure 12-32 session log displays.

  • Page 163

    12-20 displays lxt manual current display (14) measurement display (13) time history displays (5) figure 12-33 time history tab displays all checked displays appear on the lxt..

  • Page 164: Options

    Lxt manual options 12-21 to modify any of the displays associated with one of the tabs, select the field listing those displays and press 5 to obtain the display shown in figure 12-34. Figure 12-34 display; set to appear or hide pressing the 4 key toggles the state of the highlighted display between...

  • Page 165

    12-22 options lxt manual note that this is temporary and does not result in permanent loss of a purchased option. You can re-enable a purchased option at any time, as described in chapter 15 "format & restore defaults” on page 15-3. When the option is checked in mask, it is enabled in the instrument...

  • Page 166

    Lxt manual options 12-23 select yes and press 5 , which produces the message shown in figure 12-38, indicating that the instrument must be rebooted for the masking/unmasking changes to take effect. Figure 12-38 reminder to reboot instrument press 5 to return to the system properties menu and reboot ...

  • Page 167

    12-24 options lxt manual.

  • Page 168: Control Panel - Lock

    Lxt manual lock/unlock the lxt 13-1 c h a p t e r 13 lock/unlock the lxt to prevent unauthorized use or tampering with measurements and data, the lxt provides a lock feature. When this is enabled, the lxt is tamper proof to one of four user-selectable levels of security. Control panel - lock to acti...

  • Page 169: Lock Modes

    13-2 control panel - lock lxt manual select the lock mode list box. Press 5 to expand the drop down list, as shown in figure 13-2. Figure 13-2 lock mode list select the desired lock mode. Press 5 to accept the selection. Lock modes unlocked the user has complete access to the features of the instrum...

  • Page 170: Unlock Code

    Lxt manual control panel - lock 13-3 fully locked the user has no access to the instrument, except to start a run. Auto-store preferences are enabled in this mode. See chapter 13 "fully locked" on page 13-4. A measurement cannot be reset when the model lxt is locked in any mode. Unlock code navigate...

  • Page 171: Fully Locked

    13-4 fully locked lxt manual allow calibration when locked select allow cal. When locked . Press 5 to toggle the state of the check boxes shown in figure 13-4. If the box is checked, calibration is allowed while the unit is locked and not running. Figure 13-4 allow calibration when locked fully lock...

  • Page 172: Locked With Auto-Store

    Lxt manual locked with auto-store 13-5 also, while fully locked, pressing the 9 (run/pause) key starts a measurement with the message box shown in figure 13-6. Figure 13-6 measurement while locked message selecting yes begins the measurement. A measurement cannot be paused, stopped or stored in the ...

  • Page 173

    13-6 locked with auto-store lxt manual pressing the 7 key initiates storing the data file, as shown in figure 13-8. Figure 13-8 auto-store-stop if yes is selected, the data file is saved. The unit is still locked and a new measurement may be started by pressing the 9 key. If no is selected, the data...

  • Page 174: Locked With Manual-Store

    Lxt manual locked with manual-store 13-7 locked with manual-store if you seelect the locked w/manual-store mode, measurements are started by pressing the 9 key. Pressing the 9 key a second time pauses the measurement and pressing it again continues the measurement. The 7 key stops a measurement and ...

  • Page 175

    13-8 calibration when the lxt is locked lxt manual if the center softkey indicating cal is active, as shown in figure 13-11, press this key. This displays the calibration screen. See "calibration" for complete details on calibrating the lxt. Figure 13-11 locked with calibration permitted.

  • Page 176: Control Panel - About

    Lxt manual about 14-1 c h a p t e r 14 about the about tabs summarize information about the instrument. Control panel - about to activate the about tabs, press the 3 (tools) key and navigate to the about icon, as shown in figure 14-1. Figure 14-1 control panel about tab the about tab displays import...

  • Page 177: Standards

    14-2 standards lxt manual figure 14-2 shows the about tab. Figure 14-2 about tab standards the standards tab shown in figure 14-3 lists standards met by the lxt. For more information on the technical standards for the lxt, refer to the section "standards met by lxt". Figure 14-3 standards tab.

  • Page 178: Options

    Lxt manual options 14-3 options options may be added at any time. To purchase additional options, contact your local representative listed under “sales” on the larson davis web site. The options tab shown in figure 14-4 lists the options available for the lxt. Installed options have a check mark nex...

  • Page 179

    14-4 user lxt manual figure 14-5 shows the user tab. Figure 14-5 user tab.

  • Page 180: System Utilities

    Lxt manual system utilities 15-1 c h a p t e r 15 system utilities this chapter describes the system utilities for the lxt. System utilities press the 2 key one time in order to see the system utilities icon on the control panel. To activate the system utilities, press the 3 (tools) key. Use the 8 ,...

  • Page 181: File System

    15-2 file system lxt manual file system the file system tab is used to repair or recover from file system problems. The functions available on this page are similar to functions that would be used to manage a hard drive. See figure 15-2. Figure 15-2 file system the functions on the file system page ...

  • Page 182: Format

    Lxt manual file system 15-3 pc. If a problem is detected, an attempt is made to repair the problem. Format selecting this function formats the internal data storage area in the memory of the lxt. This operates similar to the format function on a pc. System and measurement settings are preserved. For...

  • Page 183: Format Usb

    15-4 file system lxt manual format usb caution: when the mass storage device is formatted, all data stored on it will be lost. If you believe that the check/repair usb operation described in "check/repair usb" on page 15-3 was not successful, try formatting the usb mass storage device. Set the usb h...

  • Page 184

    Lxt manual file system 15-5 as a result, the operation is denied and the message shown in figure 15-6 is displayed. The copy to usb icon appears on the upper left corner of this display. Figure 15-6 cannot check/repair/format message.

  • Page 185

    15-6 file system lxt manual.

  • Page 186: Frequency Weighting

    Lxt manual parameters measured 16-1 c h a p t e r 16 parameters measured this chapter describes the different acoustic parameters that can be measured, displayed, and stored using the lxt. Basic sound level measurements frequency weighting each of the sound level parameters measured at one time is f...

  • Page 187: Rms Averaging

    16-2 basic sound level measurements lxt manual rms averaging the exponential averaging time for rms sound levels is set to one of the following: • slow • fast an impulse detector is also available. Sound level metrics measured in table 16-1 "sound level metrics measured" the symbol x is used to repr...

  • Page 188

    Lxt manual sound exposure metrics measured 16-3 spectral data is displayed on both the live and overall tabs, but only the overall data can be stored. Live tab from the live tab, the graphic shows the instantaneous spl value for all frequencies and the bar to the far right shows the summation value ...

  • Page 189: Statistical Metrics Measured

    16-4 statistical metrics measured lxt manual in table 16-2: "sound exposure metrics measured" the symbol x is used to represent the user-selected rms and impulse frequency weighting (a, c or z) and the symbol y is used to represent the user-selected peak frequency weighting (a, c or z). The symbol v...

  • Page 190: Exceedance Counters

    Lxt manual exceedance counters 16-5 exceedance counters the lxt has three exceedance event counters: two rms event counters and three peak event counters. For each exceedance there is a threshold level, event counter, and duration. The thresholds l xv or l ypeak are the levels that the parameter mus...

  • Page 191

    16-6 miscellaneous parameters lxt manual.

  • Page 192: Out of Memory Stop

    Lxt manual memory utilization 17-1 c h a p t e r 17 memory utilization this chapter presents formulas to calculate the amount of memory used by the parameters that can be stored to internal memory. Out of memory stop in order to ensure that all measured data can be stored, the lxt is stopped automat...

  • Page 193: Time History

    17-2 time history lxt manual takt = 4 bytes time history the amount of memory utilized, in bytes, when storing time history blocks is calculated as follows: 52 + [16+4*(number of parameters enabled)]*(number of records) where number of records = number of samples + number of run, pause and stop even...

  • Page 194: Slm Utility-G3

    Lxt manual upgrading firmware and options 18-1 c h a p t e r 18 upgrading firmware and options this chapter describes the procedure for upgrading the lxt firmware and/or options. Slm utility-g3 in addition to slm utility-g3, you can use g4 software to install firmware and option upgrades. Refer to t...

  • Page 195

    18-2 upgrading lxt firmware lxt manual firmware upgrade is performed from the manual control tab as shown in figure 18-1. Figure 18-1 manual control page.

  • Page 196

    Lxt manual upgrading lxt firmware 18-3 click the upgradesoundtrack lxt button and follow the on screen prompts until the select file dialog box shown in figure 18-2 appears. Figure 18-2 select file menu firmware and options can be upgraded at the same time by enabling both check boxes. Click browse ...

  • Page 197: Upgrading Lxt Options

    18-4 upgrading lxt options lxt manual while the firmware upgrade is in progress, the status is indicated on the dialog box shown in figure 18-3. Figure 18-3 firmware upgrade progress upgrading lxt options to enable additional options on the lxt, a new options file is required. To purchase additional...

  • Page 198: Standards Met By Lxt

    Lxt manual technical specifications a-1 a p p e n d i x a technical specifications the specifications contained in this chapter are subject to change without notice. Please refer to calibration and measurement results for data on a specific unit. Standards met by lxt the soundexpert lxt meets the sa...

  • Page 199: Lxt Specifications

    A-2 technical specifications lxt manual lxt specifications features class 1 precision integrating sound level meter with real-time 1/3 octave filters. High contrast 1/8th vga lcd display with white led backlight; sunlight readable icon-driven graphic user interface soft rubber keys large dynamic ran...

  • Page 200

    Lxt manual technical specifications a - 3 sound level meter specifications rms time weighting slow, fast or impulse frequency weightings a, c or z see frequency weightings on page a-7. Peak detector frequency weighting a, c or z reference range: normal range exchange rate 3, 4, 5, or 6 db sample rat...

  • Page 201: Performance Specifications

    A-4 technical specifications lxt manual performance specifications physical characteristics lxt1 lxt1l lxt2 lxt2l direct in measurement range 1 a 39 to 140 db 27 to 118 db 37 to 139 db 31 to 125 db 13 to 117 db v c 39 to 140 db 29 to 118 db 37 to 139 db 35 to 125 db 10 to 117 db v z 44 to 140 db 34 ...

  • Page 202: General Specifications

    Lxt manual technical specifications a - 5 general specifications weight with batteries; no preamplifier or microphone 1.0 lb 471 g weight with batteries, preamplifier and microphone 1.1 lb 513 g reference level 114.0 db re 20 pa reference level range single large range for slm normal for oba option ...

  • Page 203: Resolution Specifications

    A-6 technical specifications lxt manual resolution specifications resolution of data shown on the instrument’s display is specified in table a-7. Higher resolution level, dose and elapsed time data are available via i/o commands and data file downloads. Levels 0.1db dose 0.01% elapsed time 0.1 secon...

  • Page 204: Frequency Weightings

    Lxt manual technical specifications a - 7 frequency weightings nominal frequency exact frequency z- weight (ideal) a weight (ideal) c weight (ideal) electrical limits: class 1 microphone limits: class 1 microphone limits: class 2 10 10.00 -0.0 -70.4 -14.3 + 1.4, - 0.7 ±1.5 ±2.0 12.5 12.59 -0.0 -63.4...

  • Page 205

    A-8 technical specifications lxt manual 1000 1000.00 0.0 0.0 0.0 ±0.2 ±0.5 ±1.0 1250 1259.00 0.0 0.6 0.0 ±0.2 ±0.5 ±1.0 1600 1585.00 0.0 1.0 -0.1 ±0.2 ±0.5 ±1.3 2000 1995.00 0.0 1.2 -0.2 ±0.2 ±0.5 ±1.3 2500 2512.00 0.0 1.3 -0.3 ±0.2 ±0.5 ±1.7 3150 3162.00 0.0 1.2 -0.5 ±0.2 ±0.5 ±1.7 4000 3981.00 0.0...

  • Page 206

    Lxt manual technical specifications a - 9 typical z-weight frequency response.

  • Page 207: Ac/dc Output

    A-10 technical specifications lxt manual ac/dc output the purpose of the ac output is to drive a headset to listen to live and recorded sounds. It may be used for other purposes, but may not function as expected as a source for additional analysis equipment. The output is amplified for listening pur...

  • Page 208: Min/max Integration Time

    Lxt manual technical specifications a - 11 min/max integration time minimum and maximum integration time for measurement of time-average levels and sound exposure levels. Dc output voltage range 0 to +3 volt (0 to 300 db) v0 = spl/100 spl = 100*v0 or sensitivity = 0.01 v/db with resolution of 0.001 ...

  • Page 209: Time of Day Drift

    A-12 technical specifications lxt manual time of day drift the lxt displays the time of day and also time-stamps various single events (i.E. Maximum level). Two different time reference sources are used in the lxt depending on whether the unit power is on or off, as described in table a-11. Figure a...

  • Page 210: Power Supply

    Lxt manual technical specifications a - 13 power supply battery operating lifetime battery life test conditions continuous run until instrument shuts off due to low battery. Measuring 1/3 octave data power save feature set to "never" batteries 4-aa (lr6) alkaline, nimh or lithium cells external powe...

  • Page 211

    A-14 technical specifications lxt manual memory retention psa029 ac to dc usb power adapter specifications data memory permanently stored in non-volatile flash memory every one minute. If power fails, maximum data loss is less than one minute. Always shut down the lxt completely before unplugging us...

  • Page 212: Electromagnetic Emission

    Lxt manual technical specifications a - 15 electromagnetic emission declaration of conformity pcb piezotronics, inc. Declares that: lxt sound level meter has been measured in representative configuration with: prmlxt1 preamplifier, 377b02 microphone and the following cables: exc010 microphone extens...

  • Page 213: 1/1 and 1/3 Octave Filters

    A-16 technical specifications lxt manual cbl139 ac/dc output cable with an applied acoustic field of 74 db at 1 khz in accordance with the following directives: • 89/336/eec the electromagnetic compatibility directive and its amending directives has been designed and manufactured to the following sp...

  • Page 214

    Lxt manual technical specifications a - 17 table a-16 passband of 1khz 1/1 octave filter sound level meter model: lxt1 serial number: 0000033 firmware: certificate of 1000.0 hz full octave filter shape this sound level meter (including attached prmlxt1 preamplifier and adp005 18pf input adapter) was...

  • Page 215

    A-18 technical specifications lxt manual . Table a-17 filter skirts of 1khz 1/3 octave filter sound level meter model: lxt1 serial number: 0000033 firmware: certificate of 1000.0 hz third octave filter shape this sound level meter (including attached prmlxt1 preamplifier and adp005 18pf input adapte...

  • Page 216: Effect of Windscreen

    Lxt manual technical specifications a - 19 position of instrument and operator when making a measurement, it is recommended that the observer be positioned as far behind and to the right of the instrument as possible to minimize interference of the sound field at the microphone resulting from body r...

  • Page 217: Frequency Response

    A-20 technical specifications lxt manual table a-18 directional response, 3 1/2" windscreen frequency response plane parallel to display screen lxt with 377b02 free field microphone and prmlxt1 preamplifier. Frequency angle from reference direction (degrees) (hz) 0 15 30 45 60 75 90 105 120 135 150 ...

  • Page 218

    Lxt manual technical specifications a - 21 figure a-2 lxt with 377b02 microphone: 0 60,120 and 180 degree figure a-3 lxt with 377b02 microphone: 15 75 and 135 degrees ld model: lxt1, serial #: 0010, normalized to 251.19hz @ 0° tested 11/23/05 12:25:57 by alex t. Note: prmlxt1/0155 and 377b02/100650 ...

  • Page 219

    A-22 technical specifications lxt manual figure a-4 lxt with 377b02 microphone: 30 90 and 150 degrees figure a-5 lxt with 377b02 microphone: 45 105 and 165 degrees ld model: lxt1, serial #: 0010, normalized to 251.19hz @ 0° tested 11/23/05 12:25:57 by alex t. Note: prmlxt1/0155 and 377b02/100650 ref...

  • Page 220

    Lxt manual technical specifications a - 23 directional characteristics figure a-6 lxt with 377b02: 250.19 hz ld model: lxt1, serial #: 0010, normalized to 251.19hz @ 0° tested 11/23/05 12:25:57 by ld note: prmlxt1/0155 and 377b02/100650 reference mic: b&k model: 4189, serial number: 2440346, tested:...

  • Page 221

    A-24 technical specifications lxt manual table a-19 lxt with 377b02: 1000.00 hz, 1995.26 hz, 3981.07 and 7943.28 hz figure a-7 lxt with 377b02 microphone: 1258.93 hz 2511.89 hz, 5011.87 hz and 10000.00 hz ld model: lxt1, serial #: 0010, normalized to 251.19hz @ 0° tested 11/23/05 12:25:57 by alex t....

  • Page 222

    Lxt manual technical specifications a - 25 figure a-8 lxt with 377b02 microphone: 1584.89 hz 3162.28 hz, 6309.57 hz and 12589.25 hz ld model: lxt1, serial #: 0010, normalized to 251.19hz @ 0° tested 11/23/05 12:25:57 by alex t. Note: prmlxt1/0155 and 377b02/100650 reference mic: b&k model: 4189, ser...

  • Page 223

    A-26 technical specifications lxt manual lxt with 375b02 free field microphone and prmlxt2b preamplifier figure a-9 lxt with 375b02 microphone: 0 60 and 120 degree figure a-10 lxt with 375b02 microphone: 15 75 and 135 degrees ld model: 375b02, serial #: 010512, normalized to 251.19hz @ 0° tested 06/...

  • Page 224

    Lxt manual technical specifications a - 27 figure a-11 lxt with 375b02 microphone: 30 90 and 150 degrees figure a-12 lxt with 375b02 microphone: 45 105 and 165 degrees ld model: 375b02, serial #: 010512, normalized to 251.19hz @ 0° tested 06/22/11 15:49:15 by ld note: with lxt2 and prmlxt2b preamp r...

  • Page 225

    A-28 technical specifications lxt manual directional characteristics figure a-13 lxt with 375b02 microphone: 251.19 hz figure a-14 lxt with 375b02 microphone: 1000.00 hz, 1995.26 hz, 3981.07 and 7943.28 hz ld model: 375b02, serial #: 010512, normalized to 251.19hz @ 0° tested 06/22/11 15:49:15 by ld...

  • Page 226

    Lxt manual technical specifications a - 29 figure a-15 lxt with 375b02 microphone: 1258.93 hz 2511.89 hz, 5011.87 hz and 10000.00 hz ld model: 375b02, serial #: 010512, normalized to 251.19hz @ 0° tested 06/22/11 15:49:15 by ld note: with lxt2 and prmlxt2b preamp reference mic: b&k model: 4189, seri...

  • Page 227: Noise Levels

    A-30 technical specifications lxt manual figure a-16 lxt with 375b02 microphone: 1584.89 hz 3162.28 hz, 6309.57 hz and 12589.25 hz noise levels the noise of the lxt includes contributions from the following components: • instrument and preamplifier • microphone in the following sections, the noise l...

  • Page 228

    Lxt manual technical specifications a - 31 lxt1, prmlxt1 with 377b02 figure a-17 noise: lxt1, 377b02, prmlxt1; low range lxt1 low range, prmlxt1 and 377b02 noise -20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 20.0 25.0 1.0 10.0 100.0 1000.0 10000.0 100000.0 hz d b spl electronic noise mic noise total nois...

  • Page 229

    A-32 technical specifications lxt manual figure a-18 noise: lxt1, 377b02, prmlxt1; normal range lxt1 normal range, prmlxt1 and 377b02 noise -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 1.0 10.0 100.0 1000.0 10000.0 100000.0 hz d b spl electronic noise mic noise total noise.

  • Page 230

    Lxt manual technical specifications a - 33 table a-20 noise; lxt1, prmlxt1 with 377b02; low range 17-nov-05 377b02, prmlxt1 and lxt1 noise lxt1 & prmlxt1 377b02 lxt1, prmlxt1 and 377b02 frequency noise noise noise hz db spl db spl db spl 6.3 18.6 -21.2 18.6 7.9 18.0 -20.2 18.0 10.0 17.5 -19.2 17.5 1...

  • Page 231

    A-34 technical specifications lxt manual lxt1, prmlxt1l with 377b02 figure a-19 noise: lxt1, 377b02, prmlxt1l; low range lxt1 low range, prmlxt1l and 377b02 noise -20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 1.0 10.0 100.0 1000.0 10000.0 100000 hz d b spl electronic noise mic noise total noise.

  • Page 232

    Lxt manual technical specifications a - 35 figure a-20 noise: lxt1, 377b02, prmlxt1l; normal range lxt1 normal range, prmlxt1l and 377b02 noise -20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 20.0 1.0 10.0 100.0 1000.0 10000.0 100000.0 hz d b spl electronic noise mic noise total noise.

  • Page 233

    A-36 technical specifications lxt manual table a-21 noise; lxt1 with prmlxt1l and 377b02; low range 17-nov-05 377b02, prmlxt1l and lxt1 noise lxt1 & prmlxt1l 377b02 lxt1, prmlxt1l and 377b02 frequency noise noise noise hz db spl db spl db spl 6.3 10.3 -21.2 10.3 7.9 9.2 -20.2 9.2 10.0 8.2 -19.2 8.2 ...

  • Page 234

    Lxt manual technical specifications a - 37 lxt2, prmlxt2b with 375b02 figure a-21 noise: lxt2, 375b02, prmlxt2b; low range lxt2 low range, prmlxt2b and 375b02 noise -15 -10 -5 0 5 10 15 20 1 10 100 1000 10000 100000 hz d b spl electronic noise mic noise total noise.

  • Page 235

    A-38 technical specifications lxt manual figure a-22 noise: lxt2, 375b02, prmlxt2b; normal range lxt2 normal range, prmlxt2b and 375b02 noise -15 -10 -5 0 5 10 15 20 25 30 35 1 10 100 1000 10000 100000 hz d b spl electronic noise mic noise total noise.

  • Page 236

    Lxt manual technical specifications a - 39 . Table a-22 noise; lxt2, prmlxt2b with 375b02; low range 375b02, prmlxt2b and lxt2 noise low range lxt2 & prmlxt2b 375b02 lxt2, prmlxt2b and 375b02 frequency noise noise noise hz db spl db spl db spl 6.3 18.1 -18.3 18.1 7.9 16.7 -17.3 16.7 10.0 15.0 -16.3 ...

  • Page 237

    A-40 technical specifications lxt manual lxt2, prmlxt2l with 375b02 figure a-23 noise lxt2, 375b02, prmlxt2l; low range lxt2 low range, prmlxt2l and 375b02 noise -15 -10 -5 0 5 10 15 20 1 10 100 1000 10000 100000 hz d b spl electronic noise mic noise total noise.

  • Page 238

    Lxt manual technical specifications a - 41 figure a-24 noise: lxt2, 375b02, prmlxt2l; normal range lxt2 normal range, prmlxt2 and 375a02 noise -10.0 -5.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 1.0 10.0 100.0 1000.0 10000.0 100000.0 hz d b spl electronic noise mic noise total noise.

  • Page 239

    A-42 technical specifications lxt manual table a-23 noise; lxt2, prmlxt2l with 375b02; low range 375b02, prmlxt2l and lxt2 noise low range lxt2 & prmlxt2l 375b02 lxt2, prmlxt2l and 375b02 frequency noise noise noise hz db spl db spl db spl 6.3 10.1 -18.3 10.1 7.9 9.0 -17.3 9.0 10.0 7.9 -16.3 7.9 12....

  • Page 240: Model Prmlxt1

    Lxt manual technical specifications a - 43 microphone preamplifier specifications the general specifications for the lxt microphone preamplifiers are shown in table a-24 table a-24 lxt preamplifiers the following sections present the specifications for the four different microphone preamplifiers whi...

  • Page 241

    A-44 technical specifications lxt manual attenuation 22.8 db (typical) input impedance 10 g ohm // 5.3 pf output impedance 50 ohm maximum output 2.8 vpp 143 db peak for microphones with 50 mv/pa sensitivity maximum output current 10 ma peak distortion harmonics output slew rate 2 v/µs (typical) elec...

  • Page 242: Pin Signal

    Lxt manual technical specifications a - 45 humidity sensitivity dimensions 12.7 mm diameter x 73 mm length (0.50" dia x 2.88" length) microphone thread 11.7 mm - 60 uns (0.4606 - 60 uns) cable driving capability lxt slm (1 v rms output signal) to 20 khz with 200'(61 m) cable output connector switchc...

  • Page 243

    A-46 technical specifications lxt manual figure a-25 certificate of conformance; prmlxt1 preamplifier model: prmlxt1 serial number: 0163 certificate of electrical conformance frequency response of this model prmlxt1 preamplifier was tested at a level of 13.858 vrms with 18pf microphone capacitance a...

  • Page 244: Model Prmlxt1L

    Lxt manual technical specifications a - 47 model prmlxt1l the larson davis prmlxt1l is a prepolarized microphone preamplifier for use with larson davis lxt sound level meters. It requires very little supply current and will drive 200 feet of cable. The preamplifier operates over wide temperature and...

  • Page 245

    A-48 technical specifications lxt manual electronic noise with 18pf equivalent microphone 1.8 µv typical a-weighted (2.5 µv max) 3.2 µv typical flat 20 hz to 20 khz (5 µv max) power supply voltage 6 to 15 volts dc output level ~1/2 power supply voltage power supply current 1.3 ma typical temperature...

  • Page 246: Pin Signal

    Lxt manual technical specifications a - 49 output connector switchcraft ta5m 5-pin male compatibility use with larson davis 377b02 or any ½" prepolarized microphone having about 50 mv/pa sensitivity and meeting the mechanical requirements of iec 61094-4. It can be used with either the larson davis a...

  • Page 247

    A-50 technical specifications lxt manual figure a-26 certificate of conformance; prmlxt1l preamplifier model: prmlxt1l serial number: 0102 certificate of electrical conformance frequency response of this model prmlxt1l preamplifier was tested at a level of 1.157 vrms with 18pf microphone capacitance...

  • Page 248: Model Prmlxt2B

    Lxt manual technical specifications a - 51 model prmlxt2b the larson davis prmlxt2b is a prepolarized microphone preamplifier for use with larson davis lxt sound level meters. It requires very little supply current and will drive 200 feet of cable. The preamplifier operates over wide temperature and...

  • Page 249

    A-52 technical specifications lxt manual output slew rate 2 v/µs (typical) electronic noise with 18pf equivalent microphone 1.0 µv typical a-weighted (1.4 µv max) 1.5 µv typical flat 20 hz to 20 khz (2.4 µv max) power supply voltage 6 to 15 volts dc output level ~1/2 power supply voltage power suppl...

  • Page 250: Pin Signal

    Lxt manual technical specifications a - 53 output connector switchcraft ta5m, 5-pin male compatibility use with pcb 375b02 or any ½" prepolarized microphone having about 35.5 mv/pa sensitivity and meeting the mechanical requirements of iec 61094-4. It can be used with either the larson davis adp043 ...

  • Page 251

    A-54 technical specifications lxt manual figure a-27 certificate of conformance; prmlxt2b page 1 of 1 preamplifier model: prmlxt2b serial number: 020912 frequency response test report frequency response of this model prmlxt2b preamplifier was tested at a level of 139.0 dbµv with 18 pf microphone cap...

  • Page 252: Model Prmlxt2L

    Lxt manual technical specifications a - 55 model prmlxt2l the larson davis prmlxt2l is a prepolarized microphone preamplifier. It requires very little supply current and will drive 100 feet of cable. The preamplifier operates over wide temperature and humidity ranges. It is for use with 20 mv/pa sen...

  • Page 253

    A-56 technical specifications lxt manual electronic noise with 18pf equivalent microphone 1.8 µv typical a-weighted (2.5 µv max) 3.2 µv typical flat 20 hz to 20 khz (5 µv max) power supply voltage 6 to 15 volts dc output level ~1/2 power supply voltage power supply current 1.3 ma typical temperature...

  • Page 254: Pin Signal

    Lxt manual technical specifications a - 57 output connector switchcraft ta5m, 5-pin male compatibility use with pcb 375b02 or any ½" prepolarized microphone having about 35.5 mv/pa sensitivity and meeting the mechanical requirements of iec 61094-4. It can be used with either the larson davis adp043 ...

  • Page 255

    A-58 technical specifications lxt manual figure a-28 certificate of conformance; prmlxt2l preamplifier model: prmlxt2l serial number: 0104 certificate of electrical conformance frequency response of this model prmlxt2l preamplifier was tested at a level of 1.157 vrms with 18pf microphone capacitance...

  • Page 256: Vibration Sensitivity

    Lxt manual technical specifications a - 59 vibration sensitivity in these tests, the lxt is mounted on an electrodynamic exciter and vibrated sinusoidally at an amplitude of 1.0 m/s 2 at the following frequencies: 35.5, 63, 125, 250, 500, 630, 800 and 1, 000 hz. The tests are performed with the mete...

  • Page 257: Frequency

    A-60 technical specifications lxt manual vibration perpendicular to the microphone diaphragm figure a-30 vibration perpendicular to microphone diaphragm 500 52.6 51.4 630 60.5 50.4 800 61.0 54.4 1,000 62.2 60.0 frequency l aeq ref table a-29 axis of vibration parallel to the microphone diaphragm vib...

  • Page 258: Frequency

    Lxt manual technical specifications a - 61 frequency l aeq ref 31.5 35.9 35.6 63 38.6 34.5 125 46.0 35.5 250 54.1 39.4 500 67.1 44.2 630 82.6 70.0 800 69.7 45.7 1,000 69.2 51.7 table a-30 axis of vibration perpendicular to the microphone diaphragm.

  • Page 259

    A-62 technical specifications lxt manual.

  • Page 260

    Lxt manual lxt manual b - 1 a p p e n d i x b testing to iec61672-1 this appendix presents information for measuring the sound level meter functionality of the lxt according to iec61672-1. Sections 5, 6, 7 and 9 (except 9.3) the following table references sections and tables in this manual where inf...

  • Page 261

    B - 2 sections 5, 6, 7 and 9 (except 9.3) lxt manual 5.1.15 typical z-weight frequency response electrical insert signals 5.1.16 highest sound pressure level for lxt1 and lxt2 5.1.17 the model lxt is a single channel instrument 5.1.18 performing measurements 5.2.1 calibrator 5.2.3 calibrating the lx...

  • Page 262

    Lxt manual sections 5, 6, 7 and 9 (except 9.3) b - 3 5.11.2 lxt measures sound level using a single range. The lower limit for level linear- ity error is caused by the inherent noise from the microphone and electronic elements within the sound level meter. 5.12.1 lxt performance specifications 5.14 ...

  • Page 263: 9.2.1 General

    B - 4 sections 5, 6, 7 and 9 (except 9.3) lxt manual 5.20.5 the lxt is not intended to be powered by a public source of ac power 6.1.2 typical stabilization time 6.2.2 calibrating the lxt1 and 377b02 micro- phone calibrating the lxt2 and the 375b02 micro- phone 6.5.2 general specifications 6.6.1 ac ...

  • Page 264: 9.2.3 Power Supply

    Lxt manual sections 5, 6, 7 and 9 (except 9.3) b - 5 a parameters measured b frequency response c sound level meter specifications d sound level meter specifications e lxt performance specifications f the lxt measures sound level using a single range g lxt specifications lxt performance specificatio...

  • Page 265: 9.2.6 Accessories

    B - 6 sections 5, 6, 7 and 9 (except 9.3) lxt manual a general specifications b positioning the lxt c the lxt measures sound level using a single range d data storage after improper shutdown e performing measurements f integration method on slm tab g control tab time h manual, timed stop, or stop wh...

  • Page 266

    Lxt manual sections 5, 6, 7 and 9 (except 9.3) b - 7 the following two sections are related to the lxt1 and the lxt2 configurations, respectively. In each, information is provided which corresponds to the specific item number in this standard. A no components of the lxt are intended to be operated o...

  • Page 267: Lxt1

    B - 8 lxt1 lxt manual lxt1 section 9.2.4 a) calibrator the calibrator to be used with the lxt1 is the larson davis model cal200. B) calibration frequency the calibration check frequency is 1000 hz. C) calibration procedure for calibration refer to the chapter "calibration" on page 7-1..

  • Page 268

    Lxt manual lxt1 b - 9 d) frequency response and corrections . Continued on next page. Lars on davis lxt 1 with p r mlxt 1 and typical 377a02 microphone average frequency res pons es and corrections r equired by ie c 61672-1 s ections 5.2.4, 5.2.5, 5.2.6 and 9.2.4 (d) 0° f ree f ield expan w ind s cr...

  • Page 269: Section 9.3

    B - 10 lxt1 lxt manual section 9.3 a) reference sound pressure level the reference sound pressure level is 114 db re 20 µpa. B) reference level range the reference level range is normal. C) microphone reference point the microphone reference point is the center of the diaphragm of the 377b02 microph...

  • Page 270

    Lxt manual lxt1 b - 11 d) periodic testing table 2 lists values of larson davis lxt1 with prmlxt1 and 377b02 microphone adjustment data of a-weighted levels used for periodic measurements. . E) linear operating range a-weighted sound levels for the lxt1l at the upper and lower limits of the linear o...

  • Page 271

    B - 12 lxt1 lxt manual f) linear measurement starting level the starting point for measuring level linear errors on the reference range is 114 db. G) electrical insert signals the electrical design of the input device to insert electrical signals into the preamplifier for the 377b02 microphone is a ...

  • Page 272: Lxt2

    Lxt manual lxt2 b - 13 l) typical stabilization time the typical time interval needed to stabilize after changes in environmental conditions: for a temperature change of 5°c then 30 minutes are required. For a static pressure change of 5 kpa then 15 seconds are required. For a humidity change of 30%...

  • Page 273

    B - 14 lxt2 lxt manual d) frequency response continued on next page larson davis lxt2 with prmlxt2b preamp and typical 375b02 microphone average frequency responses and corrections required by iec 61672-1 sections 5.2.4, 5.2.5, 5.2.6 and 9.2.4 (d) 0° free field expanded wind screen corrections with ...

  • Page 274: Section 9.3

    Lxt manual lxt2 b - 15 section 9.3 a) reference sound pressure level the reference sound pressure level is 114 db re 20 µpa. B) reference level range the reference level range is normal. C) microphone reference point the microphone reference point is the center of the diaphragm of the 7052 microphon...

  • Page 275

    B - 16 lxt2 lxt manual e) linear operating range a-weighted sound levels for the lxt2 at the upper and lower limits of the linear operating ranges. F) linear measurements starting level the starting point for measuring the level linear errors on the reference range is 114 db. G) electrical insert si...

  • Page 276

    Lxt manual lxt2 b - 17 h) inherent noise inherent noise of the lxt2: 1 combination of the electronic noise and the thermal noise of the microphone at 20°c measured in a sealed cavity and vibration isolated 2 electronic noise of the instrument with an adp005 in place i) highest sound pressure level t...

  • Page 277

    B - 18 lxt2 lxt manual l) typical stabilization time the typical time interval needed to stabilize after changes in environmental conditions. For a temperature change of 5°c then 30 minutes are required. For a static pressure change of 5 kpa then 15 seconds are required. For a humidity change of 30%...

  • Page 278: Allowed Exposure Time (T

    Lxt manual glossary and formulas c - 1 a p p e n d i x c glossary and formulas this appendix contains technical definitions of key acoustical and vibration terms and formulas commonly used with larson davis instruments. Refer to american national standards institute document s1.1-1994 for additional...

  • Page 279: Average Sound Level (L

    C - 2 glossary and formulas lxt manual average sound level (l avg ) the logarithmic average of the sound during a measurement duration (specific time period), using the chosen exchange rate factor. Exposure to sounds at this level over the measurement duration result in the same noise dose as the ac...

  • Page 280: Criterion Duration (T

    Lxt manual glossary and formulas c - 3 criterion duration (t c ) the time required for a constant sound level equal to the criterion level to produce a noise dose of 100%. Criterion duration is typically 8 hours. Example : if the criterion level = 90 db and the criterion duration is 8 hours, then a ...

  • Page 281

    C - 4 glossary and formulas lxt manual the continuous equivalent sound level is generally calculated on an hourly basis and is shown in the equation as l. The levels for the hourly periods from midnight to 7 a.M. Have 10 added to them to represent less tolerance for noise during sleeping hours. The ...

  • Page 282: Day-Night Average  Sound

    Lxt manual glossary and formulas c - 5 to account for the increased impact of environmental noise during the evening and night, penalties are added to the measured level; 5 db for evening and 10 db for night, as can be seen in the equation. The directive 2002/49/ec of the european parliament and of ...

  • Page 283

    C - 6 glossary and formulas lxt manual decibel is the name; db is the sym- bol. It is not possible to directly add or subtract physical quantities when expressed in decibel form since the addition of logarithmic values correspond to multiplication of the original quantity. The word level is normally...

  • Page 284: Department of Defense Level

    Lxt manual glossary and formulas c - 7 table 1 shows the actual value of a specific item, such as sound power, for which the sound level is calculated. First, the sound power value is divided with the reference used and then the ten-based logarithm is applied. This value is then multiplied by 10 to ...

  • Page 285: Dose

    C - 8 glossary and formulas lxt manual dose see noise dose . Dose and projected dose calculations dose is a measure of sound exposure and is defined in ansi s1.25 section 4.7 as: see figure c-1 “dose and pro- jected dose" where: d(q) is the percentage criterion exposure for exchange rate q t c is th...

  • Page 286

    Lxt manual glossary and formulas c - 9 the factor of 100 in the equation produces a result that is a percentage. Dose is obtained from the accumulations made for twa and sel using the formula: where, l (s) is the current spl at sample s ; for measurements that include a threshold l(s) is set to × if...

  • Page 287: Detector

    C - 10 glossary and formulas lxt manual projected dose in the analyzer is obtained with an equation similar to that of dose except that the actual duration (time) of the measurement is used rather than a criterion time, as shown: where the log( n ) is the actual time factor, n being the total number...

  • Page 288: Eight Hour Time-Weighted

    Lxt manual glossary and formulas c - 11 eight hour time-weighted average sound level (l twa(8) ) the constant sound level that would expose a person to the same noise dose as the actual (unsteady) sound levels. The equation for it is lc = criterion sound level q = exchange rate factor d = noise dose...

  • Page 289: Exchange Rate (Q),

    C - 12 glossary and formulas lxt manual p a ( ) is the a-weighted sound pressure p 0 is the reference sound pressure of 20 µpa in the equation, the numerator of the argument of the logarithm is the root-mean-square, frequency-weighted sound pressure level over the averaging time interval t. The form...

  • Page 290: Free Field

    Lxt manual glossary and formulas c - 13 the far field for all frequencies measured, the lowest frequency should be chosen for determining the 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 f...

  • Page 291

    C - 14 glossary and formulas lxt manual high pass : a frequency filter that permits signals to pass through that have frequencies above a certain fixed frequency, called a cutoff frequency. It is used to remove lower frequencies. Bandpass : a frequency filter that permits signals to pass through tha...

  • Page 292: Measurement Duration (T)

    Lxt manual glossary and formulas c - 15 flat-weighting, or z-weighting : a filter that does not adjust the levels of a frequency spectrum. It is usually an alternative selection for the frequency-weighting selection. L eq see “equivalent continuous sound level.” measurement duration (t) the time per...

  • Page 293: Microphone Guidelines

    C - 16 glossary and formulas lxt manual 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. It can be composed of one of the following types: capacitor (condenser): a mic...

  • Page 294

    Lxt manual glossary and formulas c - 17 guidelines : 1. Do not permit any solid or liquid to touch the microphone diaphragm. Keep a protective grid over the diaphragm. 2. Do not blow on a microphone and use a wind screen over the microphone to reduce the effect of wind noise. 3. Mount microphones so...

  • Page 295: Near Field

    C - 18 glossary and formulas lxt manual a microphone measures sound 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. When making hand-held measurements...

  • Page 296: Noise

    Lxt manual glossary and formulas c - 19 noise typically is unwanted sound. This word adds the response of humans to the physical phenomenon of sound. The descriptor should be used only when negative effects on people are known to occur. Ambient: the all encompassing sound at a given location caused ...

  • Page 297

    C - 20 glossary and formulas lxt manual l t is the threshold sound level. L c is the criterion sound level. Q is the exchange rate in db, and q = the parameter that determines the exchange rate, where: q = 10 for a 3db exchange rate. Q = 13.29 = 4/log(2) for a 4db exchange rate. Q = 16.61 = 5/log(2)...

  • Page 298

    Lxt manual glossary and formulas c - 21 t c is the criterion sound duration as set by the lxt’s “criterion time hours” setting which by default is set to 8 hours l c is the criterion sound level as set by the lxt’s “overall criterion” or “current criterion” settings. Addition of the term “log(100)” ...

  • Page 299: Noise Exposure

    C - 22 glossary and formulas lxt manual noise exposure (see sound exposure) osha level (l osha ) the average sound level calculated in accordance with the occupational safety and health administration exchange rate and threshold level. Preamplifier a part of the sound level meter that matches a part...

  • Page 300: Sound Exposure (Se)

    Lxt manual glossary and formulas c - 23 sound exposure (se) the total sound energy of the actual sound during a specific time period. It is expressed in pascal-squared seconds. Where p a is the instantaneous sound pressure and t 2 - t 1 is the measurement duration (specific time period). The lxt dis...

  • Page 301: Sel Calculations

    C - 24 glossary and formulas lxt manual sel calculations the lxt displays sel as l xe , where x is the frequency weighting ( x = a, c or z ). Sel is available for the overall measurement and is calculated using this formula: alternatively, sel can also be calculated with this formula: all of the sel...

  • Page 302: Sound Exposure Level (Sel,

    Lxt manual glossary and formulas c - 25 figure c-3 sound exposure level and sound exposure sound exposure level (sel, l e ) the total sound energy in a specific time period. The sound pressure is squared and integrated over a specific period of time (t 2 -t 1 ) this is called the sound exposure and ...

  • Page 303

    C - 26 glossary and formulas lxt manual (20 pa x s = 400 x 10 -12 pa 2 s t 0 = 1 s t = t 2 - t 1 , the time interval for measurement, in seconds, for sound exposure level and time-average sound level sea the sea parameter is used mainly in the canadian provence of quebec. It is based on the theory t...

  • Page 304: Sound Pressure

    Lxt manual glossary and formulas c - 27 : sound pressure the physical characteristic of sound that can be detected by microphones. Not all pressure signals detected by a microphone are sound (e.G., wind noise). It is the amplitude of the oscillating sound pressure and is measured in pascals (pa). So...

  • Page 305: Spectrum (Frequency Spec-

    C - 28 glossary and formulas lxt manual spectrum (frequency spec- trum) the amplitude of sound or vibration at various frequencies. It is given by a set of numbers that describe the amplitude at each frequency or band of frequencies. It is often prefixed with a descriptor that identifies it such as ...

  • Page 306

    Lxt manual glossary and formulas c - 29 figure c-4 twa the lxt displays the time weighted average as twa[hr] where hr is the time in hours over which the average is performed. The actual equations used within the lxt are implemented according to this equation: where: l (s) is the current sound press...

  • Page 307: Time Weighting

    C - 30 glossary and formulas lxt manual 16.61 for an exchange rate of 5db (l osha ) 20.00 for an exchange rate of 6db (l avg ) n is the total number of samples taken in the measurement. The sample rate is 32 samples per second. Time weighting the response speed of the detector in a sound level meter...