LxT Manual
for
SoundTrack LxT
TM
®
& SoundExpert LxT
Larson Davis
LxT Manual
for
SoundTrack LxT
& SoundExpert LxT
I770.01 Rev K Supporting Firmware Version 2.301
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 PCB Piezotronics, Inc.
Swithcraft
is a registered trademark of Switchcraft, Inc. All other trademarks are property of their
respective owners.
Disclaimer
The following paragraph does not apply in any state or country where such statements are not
agreeable with local law:
Even though PCB Piezotronics, Inc. has reviewed its documentation, PCB Piezotronics, Inc. makes no
warranty or representation, either expressed or implied, with respect to this instrument and
documentation, its quality, performance, merchantability, or fitness for a particular purpose. This
documentation is subject to change without notice, and should not be construed as a commitment or
representation by PCB Piezotronics, Inc.
This publication may contain inaccuracies or typographical errors. PCB Piezotronics, Inc. will
periodically update the material for inclusion in new editions. Changes and improvements to the
information described in this manual may be made at any time.
Record of Serial Number and Purchase Date
LxT Model: LxT1 LxT2 Serial Number: ___________
Preamplifier Model: ________ Serial Number: ___________
Microphone Model: _________ Serial Number: ___________
Recycling
PCB Piezotronics, Inc. is an environmentally friendly organization and encourages our customers to
be environmentally conscious. When this product reaches its end of life, please recycle the product
through a local recycling center or return the product to:
PCB Piezotronics, Inc.
Attn: Recycling Coordinator
1681 West 820 North
Provo, Utah, USA 84601-1341
where it will be accepted for disposal.
Warranty
For warranty information, refer to our Terms and Conditions of Sale on our website at
www.larsondavis.com/TermsConditions.aspx.
Table of Contents
Chapter 1 LxT Features 1-1
SoundTrack LxT ................................................................................................. 1-1
SoundExpert
Chapter 2 Overview 2-1
LxT Components ................................................................................................... 2-1
Summary of Displays and Icons ........................................................................... 2-6
Navigating and Selecting ...................................................................................... 2-8
Basic Run Functions ............................................................................................. 2-9
Tab and Setting Displays ...................................................................................... 2-9
Chapter 3 Preparing for First Use 3-1
Unpacking and Inspection ..................................................................................... 3-1
Connecting the Microphone and Preamplifier ...................................................... 3-2
Connecting the Preamplifier to the LxT ............................................................... 3-3
Disconnecting the Preamplifier from the LxT ...................................................... 3-4
Powering the SoundTrack LxT ............................................................................. 3-4
Chapter 4 Basic Measurement Setup 4-1
Measurement Settings Tabs .................................................................................. 4-1
LxT ............................................................................................... 1-5
Chapter 5 Data Display 5-1
Data Labels ........................................................................................................... 5-1
Tabbed Display ..................................................................................................... 5-1
Live Tab ................................................................................................................ 5-3
Overall Tab ........................................................................................................... 5-8
Session Log Tab .................................................................................................. 5-20
View Spectrum Normalized (Optional) .............................................................. 5-21
Chapter 6 Making Measurements 6-1
Preparation ............................................................................................................ 6-1
Positioning the LxT ............................................................................................... 6-1
Performing Measurements .................................................................................... 6-2
Storing Measurements ........................................................................................... 6-7
Data Storage After Improper Shutdown ............................................................... 6-8
Chapter 7 Calibration 7-1
Calibration Overview ............................................................................................ 7-1
Control Panel - Calibrate .......................................................................................7-2
Acoustic Calibration ..............................................................................................7-4
Sensitivity Tab .....................................................................................................7-11
Calibration Without Preamplifier ........................................................................7-13
Certification .........................................................................................................7-14
Chapter 8 Voice Recording 8-1
Launching the Voice Recorder Dialog ..................................................................8-1
Making a Voice Recording ....................................................................................8-2
Playing a Voice Recording ....................................................................................8-3
Storing Voice Recordings ......................................................................................8-3
Chapter 9 Time History 9-1
Parameters Logged ................................................................................................9-1
Time History Setup ................................................................................................9-3
Time History Tab ...................................................................................................9-5
Link to Measurement History Display ..................................................................9-8
Markers ..................................................................................................................9-9
Chapter 10 Measurement History 10-1
Enabling Measurement History ...........................................................................10-1
Continuous and Timer Modes .............................................................................10-2
Timed Stop Mode ................................................................................................10-3
Manual and Stop When Stable Modes .................................................................10-3
Display of Measurement History .........................................................................10-3
Link to Time History .........................................................................................10-12
Chapter 11 Data Explorer 11-1
Control Panel - Data Explorer .............................................................................11-1
Chapter 12 System Properties 12-1
Control Panel - System Properties .......................................................................12-1
Device ..................................................................................................................12-2
Time .....................................................................................................................12-3
Power ...................................................................................................................12-4
Preferences ...........................................................................................................12-8
Localization .......................................................................................................12-15
Displays .............................................................................................................12-17
Options ...............................................................................................................12-21
Chapter 13 Lock/Unlock the LxT 13-1
Control Panel - Lock ........................................................................................... 13-1
Fully Locked ....................................................................................................... 13-4
Locked With Auto-Store ..................................................................................... 13-5
Locked With Manual-Store ................................................................................. 13-7
Calibration When The LxT Is Locked ................................................................ 13-7
Chapter 14 About 14-1
Control Panel - About ......................................................................................... 14-1
About Tab ........................................................................................................... 14-1
Standards ............................................................................................................. 14-2
Options ................................................................................................................ 14-3
User ..................................................................................................................... 14-3
Chapter 15 System Utilities 15-1
System Utilities ................................................................................................... 15-1
File System .......................................................................................................... 15-2
Chapter 16 Parameters Measured 16-1
Basic Sound Level Measurements ...................................................................... 16-1
Sound Exposure Metrics Measured .................................................................... 16-3
Statistical Metrics Measured ............................................................................... 16-4
Community Noise Parameters ............................................................................ 16-4
Exceedance Counters .......................................................................................... 16-5
Miscellaneous Parameters ................................................................................... 16-5
Chapter 17 Memory Utilization 17-1
Out Of Memory Stop .......................................................................................... 17-1
Overall Data ........................................................................................................ 17-1
Session Log ......................................................................................................... 17-1
Measurement History .......................................................................................... 17-1
Time History ....................................................................................................... 17-2
Voice Messages ................................................................................................... 17-2
Chapter 18 Upgrading Firmware and Options 18-1
SLM Utility-G3 ................................................................................................... 18-1
Upgrading LxT Firmware ................................................................................... 18-1
Upgrading LxT Options ...................................................................................... 18-4
Appendix A Technical Specifications A-1
Standards Met by LxT ..........................................................................................A-1
LxT Specifications ................................................................................................ A-2
Electromagnetic Emission ..................................................................................A-15
1/1 and 1/3 Octave Filters ...................................................................................A-16
Position of Instrument and Operator ...................................................................A-19
Frequency Response ...........................................................................................A-20
Microphone Preamplifier Specifications ............................................................ A-43
Vibration Sensitivity ...........................................................................................A-59
Appendix B Testing to IEC61672-1 1
Sections 5, 6, 7 and 9 (except 9.3) ........................................................................ B-1
LxT1 ..................................................................................................................... B-8
LxT2 ................................................................................................................... B-13
Appendix C Glossary and Formulas C-1
CHAPTER
LxT Features
1
SoundTrack LxT
Hardware Features
This chapter describes the features for the SoundTrack
LxT
and SoundExpert LxTsound level meters.
The following sections describe the features for the
SoundTrack LxT.
The Larson Davis SoundTrack LxT has the following
features:
• Precision integrating sound level meter
• 2 GB unformatted standard data memory
• 160 X 240 pixel LCD display with backlight and icondriven user interface
• Silent Touch elastomeric keypad
• Large dynamic range
• Jack for AC/DC output or headset (ACC003)
• Preamplifier can drive a 61 m (200 ft.) microphone
extension cable (EXC200)
• 4-AA batteries provide 16 hour operating time
• USB 2.0 peripheral connector
• Field-upgradeable firmware
• Windscreen (WS001)
Basic Measurements
• SPL, Leq, Lmax, Lmin, SEL, Lpeak, Lpeak(max)
• RMS Detectors: Slow, Fast & Impulse
• RMS Frequency Weighting: A, C & Z
• Peak Frequency Weighting: A, C & Z
•L
statistics: 6 user-selected values over the range (L
N
through L
• 2 Sets of hygiene metrics: Lavg, TWA(x), Dose,
ProjDose, Lep,d
LxT Manual LxT Features 1-1
) and Histogram tables
99.99
0.01
Basic Operation
•E, E8, E40
• SEA peak exposure
• 2 RMS event counters and 3 Peak event counters
• 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) metrics
• Session Log
• Lock functions
• Calibration with calibration history and list of calibrators
• Power management
• Status bar and About display
• Multiple language support
• Data files and Data Explorer
• Automatic data backup to prevent data loss on power
failure
• Overall measurement
Available Options
• LXT-OB1: Real-time 1/1 Octave Frequency Analysis
• LXT-OB3: Real-time 1/3 & 1/1 Octave Frequency
Analysis
• LXT-LOG: Automatic data logging with intervals from
1 second to 24 hours
• LXT-HSLOG: Extends data dogging (LXT-LOG) with
intervals down to 100 milliseconds
• LXT-ENV: Measurement History Environmental Data
Logging
• LXT-CN: Community Noise
1-2 SoundTrack LxT LxT Manual
Standard Accessories
• LXT-DVA: Digital Voice Annotation (includes headset
ACC003)
The LxT is delivered with the standard accessories described
below.
• One of the following preamplifier/microphone
combinations:
- PRMLXT1 preamplifier with a 377B02 microphone
- PRMLXT1L preamplifier with a 377B02 microphone
- PRMLXT2B preamplifier with a 375B02 microphone
- PRMLXT2L preamplifier with a 375B02 microphone.
• SWW-SLM-UTILG4 SLM Utility-G4 software
• SWW-SLM-UTILG3 SLM Utility-G3 software
• WS001 Windscreen, 3 1/2 in. diameter
• Alkaline Batteries: 4-AA
•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 as the microphone it is replacing. The
following adapters are available:
• ADP002 6.8pF adaptor for 1/4 in., 7pF microphone
(377C01 or 377C10)
• ADP005 18pF adaptor for 1/2 in., 18pF microphone
(375B02)
• ADP090 12pF adaptor for 1/2 in., 12 pF microphone
(377B02)
LxT Manual SoundTrack LxT 1-3
Cables
Power Supplies
Software
Accessory Kits
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
• PSA029 Universal AC Power Adaptor
• PSA031 12 Volt DC to USB Power Adaptor
• BAT015 External battery powering device for the LxT,
holding 4 or 8 D-sized alkaline 1.5 volt batteries to
extend run time
• SWW-BLAZE-LXT Blaze
• SWW-DNA DNA
• LXT-ACC including
- LXT-CCS Hard Shell Case
- CAL200 Class I Calibrator
- PSA029 Power Supply
- CBL138 USB Cable
• LXT-ACC1 including
- LXT-CCS Hard Shell Case
- CAL150 Class I Calibrator
- PSA029 Power Supply
- CBL138 USB Cable
Other
• 377C20 1/2” random incidence pre-polarized
microphone, 50 mV/Pa, providing performance
conforming to Class 1 sound level meter standards
• ACC003 Headset with microphone for voice recording/
Playback (included LXT-DVA)
1-4 SoundTrack LxT LxT Manual
• 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 included)
Tripods
• TRP001 Instrument/Camera Tripod with ADP032 1/2
in. microphone clip. Use with EPS2108-2
• TRP002 Microphone Stand with adjustable height and
boom angle
• TRP003 Support Tripod, heavy duty, can be used with
EPS030 or EPS2106-2
Calibrators
• CAL150
• CAL200
Printer
• PRN003 USB Serial Printer
SoundExpert LxT
The SoundExpert LxT sound level meter provides targeted
measurement of environmental noise, and is sold in two base
models:
• LXT1-SE-FF: SoundExpert LxT with free-field
microphone (377B02)
• LXT1-SE-RI: SoundExpert LxT with random
microphone (377C20).
LxT Manual SoundExpertâ LxT 1-5
Hardware Features
Standard Features
Standard Accessories
The hardware features for the SoundExpert LxT are the
same as those for the SoundTrack LxT.
following accessories are included with the SoundExpert
LxT:
• PSA029 Power Supply
• CBL138 USB Cable
The SoundExpert LxT is delivered with the standard
features listed below.
• LXT-LOG: Automatic data logging with intervals from
1 second to 24 hours
• LXT-ENV: Measurement History Environmental Data
Logging
• LXT-CN: Community Noise
• LXT-OB3: Real-time 1/1 & 1/3 Octave Band Analysis
The SoundExpert LxT is delivered with the standard
accessories described below.
• CBL138 USB Cable
• PSA029 Universal AC Power Adaptor
• One of the following preamplifier/microphone
combinations:
Additionally, the
- PRMLXT1 preamplifier with a 377B02 microphone
- PRMLXT1L preamplifier with a 377B02 microphone
- PRMLXT1 preamplifier with a 377C20 microphone
- PRMLXT2L preamplifier with a 375C20 microphone.
• SWW-SLM-UTILG4 SLM Utility-G4 software
• SWW-SLM-UTILG3 SLM Utility-G3 software
• WS001 Windscreen, 3 1/2 in. diameter
• Alkaline Batteries: 4-AA
1-6 SoundExpertâ LxT LxT Manual
•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 as the microphone it is replacing. The
following adapters are available:
• ADP090 12pF adaptor for 1/2 in., 12 pF microphone
(377B02)
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)
• CBL139 AC/DC Output Cable
Power Supplies
• PSA031 12 Volt DC to USB Power Adaptor
• BAT015 External battery powering device for the
SoundExpert
volt batteries to extend run time
LxT, holding 4 or 8 D-sized alkaline 1.5
Software
• SWW-BLAZE-LXT Blaze
• SWW-DNA +SWW-DNA-LXT
Other
• 377C20 1/2” random incidence pre-polarized
microphone, 50 mV/Pa, providing performance
conforming to Class 1 sound level meter standards
• LXT-CCS Storage Case
Environmental Protection
• EPS042 LxT1-SE-XX +BAT015 in small hard-shell
carrying case
LxT Manual SoundExpertâ LxT 1-7
• 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 microphone clip. Use with EPS2108-2
Calibrators
• CAL200
•CER-LXT1 LxT calibration with report
•CER-MIC Microphone calibration
1-8 SoundExpertâ LxT LxT Manual
CHAPTER
Microphone
Preamplifier
LCD Display
Keypad
Connectors
2
LxT Components
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
FIGURE 2-1 The LxT
LxT Manual Overview 2-1
The standard LxT shown in FIGURE 2-1 includes the
Hardware Power Switch
USB Interface
AC/DC Output and Headset Jack
Auxiliary Connector
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)
• True “hand held” instrument with “sure grip” pads
DO NOT use the hardware power
switch to turn the LxT OFF. This may
cause data to be lost. Press the 0
(ON/OFF) key, then the Off soft key
to turn the LxT off.
2-2 LxT Components LxT Manual
FIGURE 2-2 LxT Bottom View
• Hardware Power Switch: When set to “O”, the
hardware power switch completely powers down the
LxT for storage. Set the switch to “|” for instrument
operation.
• USB Interface: The USB 2.0 full-speed peripheral port
is used to control LxTs from PCs and transfer data to PCs
using a CBL138 or other USB cables under 5 m in
length. The LxT can also be powered via USB interfaces
using PSA029 external power supplies.
Display
Measurement
Name
OBA Overload Icon
Input Overload Icon
Run Time
Measurement
Status
Power Indicator
Ta bs
Position
Indicator
Scroll Bar
Stability
Indicator
Left
Softkey
Center
Softkey
Right
Softkey
• 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.
The LxT has a 160 x 240 graphic, liquid crystal display that
is backlit to provide comfortable viewing in most ambient
light situations. Controls are provided for contrast and
backlight adjustments.
When the LxT is first turned on, a display similar to
FIGURE 2-3 is shown.
LxT Manual LxT Components 2-3
FIGURE 2-3 Data Display Screen
Keypad
Left
Softkey
Center
Softkey
Right
Softkey
RUN/PAUSE
STOP/STORE
UP
RIGHT
DOWN
LEFT
ENTER
RESET
TOOLS
POWER
Softkeys
Hardkeys
The LxT has a 13 button keypad. This section describes the
buttons on the keypad.
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 icon or label
indicating the action that takes place when the key is
pressed. Softkeys are so named because the action
associated with the key can change.
The ten remaining keys below the Softkeys are shown in
FIGURE 2-4 and are described in TABLE 2-1.
2-4 LxT Components LxT Manual
FIGURE 2-4 LxT Keys
.
Use the Power, or ON/OFF button to turn the LxT on and off. The hardware
power wwitch on the base of the unit must be in the “|” position.
Use the Navigation buttons Up, Down, Left and Right to move to areas on the
display, to make selections from multiple options, or to enter alphanumeric
characters into data fields.
Use the Enter button to select data, options, or displays or to enter alphanumeric characters into data fields.
Use the Run/Pause button to initiate and pause measurements, and to continue
paused measurements.
Use the Stop/Store button to stop measurements and to store measurements
when measurements are stopped.
Use the Reset button to reset measurements.
Use the Tools button to specify settings such as date and time, managing power
options and setting personal preferences (i.e. language, decimal and date formats, etc.).
TABLE 2-1 Keypad Hardkeys
LxT Manual LxT Components 2-5
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). Navigate up
or down to different pages by using the 8 (Up) and 2
(Down) keys.
Scroll Bar and Position Indicator
The scroll bar represents the entire tab, and the position
indicator shows the relative position of the page you are
viewing. The position indicator in FIGURE 2-3 shows that
the first page on the Live tab is being viewed.
Power Indicator
The icon indicates whether the LxT is being powered by
batteries (battery level is also indicated), or by an external
power source.
Measurement Filename
The name of the data file, or the measurement filename, is
configurable as described on page 4.
Stability Indicator
For certain measurement modes and for calibration, an
indication of the stability of the measured signal is presented
by the following icon.
Run Time
This is the amount of time the measurement has been
running.
Input Overload Icon
When signals from the preamplifier exceed the calibrated
input range of the LxT, the Input Overload icon appears.
2-6 Summary of Displays and Icons LxT Manual
Under Range Icon
OBA Overload Icon
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 icon is still
present (not flashing) to indicate that overloads have
occurred during the measurement. Resets clears the icon
from the display.
When signals from the preamplifier drop below levels that
can be accurately measured, an under range condition exists.
When this happens the Under Range icon appears.
As long as the under range condition exists, the icon flashes.
When the measured level no longer produces an under range
condition, the icon is removed from the display.
When a measured level is in an under range condition, its
displayed level appears in gray rather than black.
If inputs to the Octave Band Analyzer (optional firmware
LXT-OBA required) become overloaded, the icon shown
below appears to indicate overloads.
This icon operates similar to the Input Overload Icon shown
in the above section “Input Overload Icon.”
Measurement Status
Reset Icon
The Reset icon indicates that a measurement is in a “reset”
state.
Run Pending Icon
The Run Pending icon appears when the
PAUSE) key is pressed and the LxT is waiting for filters and
detector initialization to complete. The LxT automatically
LxT Manual Summary of Displays and Icons 2-7
9 (RUN/
Run Icon
Pause Icon
Stop Icon
Store Icon
starts the run after the initialization has completed (less than
10 seconds).
The Run icon is animated, moving from left to right to
indicate that a measurements is in progress.
The Pause icon indicates that the current measurement has
been paused.
The Stop icon is displayed when a measurement has been
stopped.
The Store icon indicates that the current measurement has
been stored.
Navigating and Selecting
To navigate between tabs on the display, press the right or
left Softkeys. To navigate within tabs, use the 4 and 6 keys
for moving horizontally on screens. This includes moving
the highlight from one property to the next.
The 8 and 2 keys are used for moving vertically on
screens. This includes moving the highlight from one
property to the next and to move to previous or subsequent
tab pages.
These keys are also used for character entry by navigating
through lists of characters in text boxes.
The
5 key is typically used for completing selections,
completing actions, or accepting values.
2-8 Navigating and Selecting LxT Manual
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 the
(STOP/STORE) key. Pressing the 9 (RUN/PAUSE) key
when the unit is PAUSED continues the run. This key is only
active on a Data View screen.
7
Pressing the
when the unit is in STOP mode
continues the previous run.
9
(RUN/ PAUSE) key
The 7 (STOP/STORE) key ends a run. Pressing the key a
second time stores the data in a file. This key is only active
on a Data View screen.
Tab and Setting Displays
The LxT features and functions are organized into four
different types of displays.
• Data Display tabs: used to display measured data.
• Measurement Settings tabs: used to set the parameters
• Control Panel (Tools) Properties: used to set user
• Power Control Page: used to check battery power,
Data Display Tabs
When the
the Data Display tabs appear.
for a measurement.
preferences, to set non-measurement related parameters,
and to implement calibration.
control the contrast and backlight of the display and
other features.
0 (ON/OFF) key is pressed to turn on the LxT,
LxT Manual Basic Run Functions 2-9
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
Control Panel (Tools) Properties
Power Control Page
Data Display Tabs
For a more detailed description of
the Data Display tabs and their
associated pages, see Chapter 5 in
the section entitled “Basic Data
Display” on page 5-1.
Select Settings and press
Closing
Press the Center Softkey to return the Data Display tabs.
The Control Panel is accessed by pressing the
key at the lower right of the LxT front panel. To exit from
the Control Panel and return to the Data Display tabs, press
the Center Softkey labeled Close.
The Power Control Page is opened by pressing the
/ OFF) key while on Data View tabs. To exit from the Power
Control Page, press the Center Softkey labeled Close.
The Data Display tabs include the following: “<$paratext>”
• Live: Data is continuously displayed on this tab whether
there is a measurement in progress or not.
• Overall: The data displayed on this tab represents data
measured and averaged beginning from the time the
measurement was started by pressing the Run key until
the elapsed time indicated above the display. If the Pause
or Stop key is pressed, the elapsed time is stopped.
However, pressing the Run key continues the overall
measurement, as shown by the elapsed time restarting
from the time when it had previously been paused or
stopped.
5 to open the Settings tabs.
3 (TOOLS)
0 (ON
2-10 Tab and Setting Displays LxT Manual
Measurement Settings Tabs
• 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
that data is based on the most recent run instead of the
first run of the measurement.
• Measurement History (optional): This tab displays
current data measurement times or stops using the Time
History measurement feature.
• Time History (optional): This tab displays data
measured using the Time History measurement feature.
The screen is not wide enough to
show all thirteen setup tabs at the
same time. Use the Right and Left
Softkeys to navigate between tabs
and bring them within view.
For a more detailed description of
the Measurement Settings tabs and
their associated pages, see Chapter
4 in the section entitled "Basic
Measurement Setup" on page 4-1.
The Measurement Settings tabs allow for specific settings
and include the following:
• General: used to create a file name and a measurement
description.
• SLM: used to setup the parameters for the measurement
of sound levels.
• OBA (optional): used to setup the real-time octave band
frequency analysis.
• Dosimeter 1: used to setup the parameters for the
measurement of sound exposure and noise dose.
• Dosimeter 2: used to setup the parameters for the
measurement of sound exposure and noise dose.
• Ln: used to define the parameters for the measurement
of Ln statistics.
• Control: used to setup the mode of measurement timing.
• Time History (optional): Permits the automatic logging
of a specified number of parameters as a function of
time.
• Triggers: used to setup the triggers which define noise
exceedance events.
LxT Manual Tab and Setting Displays 2-11
• Markers (optional): Use in conjunction with time
• Day/Night (optional): Defines hours for day, night, and
Control Panel (Tools) Properties
The Control Panel uses icons to represent the different
functions available. Pressing the
the Control Panel icons.
The position indicator on the scroll
bar indicates that there are
additional icons not currently visible
on the screen.
history measurements, this feature permits the user to
annotate portions of a time history record to identify
noise sources or make other notes.
evening periods for 24-hour noise monitoring.
3 (TOOLS) key displays
FIGURE 2-6 Control Panel
For more information, see “Control
Panel - System Properties” on page
11-1.
2-12 Tab and Setting Displays LxT Manual
To select an icon, navigate to the desired icon and press
The functions for icons on the Control Panel are described
in subsequent chapters.
5.
Data Explorer
For a detailed description of Data
Explorer, see Chapter 12 in the
section entitled “Data Explorer” on
page 12-1.
For a detailed description of System
Properties, see Chapter 11 in the
section entitled “System Properties”
on page 11-1.
For a detailed description of the
Lock feature, see Chapter 13 in the
section entitled “Lock/Unlock the
LxT” on page 13-1.
The Data Explorer is used to examine data that has been
stored following previous measurements. It is also used to
manage stored measurements, such as rename or delete files.
System Properties
System Properties tabs are used for general instrument
bookkeeping. Functions such as setting the instrument date
and time, display contrast adjustment, date format, etc. are
located here. These are single page tabs.
The System Property tabs: are as follows:
• Device: Enter instrument identification.
• Time: Set the date and time.
• Power: Set controls that affect power consumption.
• Preferences: Set a variety of system parameters such as
microphone correction, auto-store, jack function, reset
prompting, takt maximal and USB port.
• Localization: Set regional characteristics such as
language, decimal symbol, data format and units.
Lock
Lock permits the LxT to be configured such that certain keys
are locked to prevent unauthorized use or tampering.
Calibrate
For a detailed description of the
calibration procedure, see Chapter
Calibrate is used to verify and adjust the calibration of the
LxT prior to a measurement.
15 in the section entitled
“Calibration” on page 15-1.
For a detailed description of the
voice recording feature, see Chapter
8 in the section entitled “Voice
Voice Recorder
A method to allow voice annotation of the data is described
in Chapter 8 in the section entitled “Voice Recording” on
page 8-1.
Recording” on page 8-1.
LxT Manual Tab and Setting Displays 2-13
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 include the following:
• About: shows information such as serial number and
firmware revision.
• Standards: lists the standards that the LxT meets.
• Options: shows the options that are available in this
instrument.
• User: allows user entered instrument identification.
2-14 Tab and Setting Displays LxT Manual
CHAPTER
Preparing for First Use
3
This chapter outlines the steps to unpack the
SoundTrack LxT
• Unpacking and Inspection
• Connecting the Microphone and Preamplifier
• Disconnecting the Preamplifier
• Powering the SoundTrack LxT
Unpacking and Inspection
Retain the packaging for safe
shipment for calibration service.
Your LxT has been shipped in protective packaging. Please
verify that the package contains the items listed below.
Report any damage or shortage immediately to PCB
Piezotronics, Inc. at 888 258-3222 (U.S. toll free) or (716)
926-8243.
•LxT
• PRMLxT Microphone Preamplifier
• Microphone
•Lanyard
• WS001 3 1/2” Windscreen
• 4 - AA Alkaline Batteries
• SLM Utility-G3 software
• SLM Utility-G4 software
and prepare it for first use, including:
Record Serial Numbers of LxT and Components
If you have not already done so, please record the purchase
date, model and serial number for your instrument,
preamplifier and microphone in the spaces provided at the
beginning of this manual. You find the instrument model and
serial numbers printed on the label on the back panel of the
instrument.
LxT Manual Preparing for First Use 3-1
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 may be asked to provide this information during any
future communications with PCB
Piezotronics, Inc.
Connecting the Microphone and Preamplifier
Caution: Take care when handling
the preamplifier, as the gold pin is
sensitive to electrostatic discharge
(ESD).
Carefully place the bottom end of the microphone over the
top end of the preamplifier and gently screw the assembly
together. The microphone body seats smoothly against the
preamplifier body. DO NOT use excessive force.
When removing the microphone, turn while gripping the
microphone body, not the grid cap.
FIGURE 3-2 Microphone-Preamplifier
3-2 Connecting the Microphone and Preamplifier LxT Manual
Connecting the Preamplifier to the LxT
The connectors are keyed for correct
alignment.
Caution: Do not attempt to unscrew
the collar/ring at the top of the LxT
body.
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 click is heard.
If the LxT is powered when the preamplifier is inserted, a
message similar to the one in FIGURE 3-3 appears for
several seconds.
FIGURE 3-3 Preamplifier Connected
Press
5 (ENTER) to close the message.
LxT Manual Connecting the Preamplifier to the LxT 3-3
Disconnecting the Preamplifier from the LxT
Preamplifier Release Button
When transporting the LxT, it is
recommended that the preamplifier
be detached and placed in a secure
location in the carrying case.
FIGURE 3-4 Preamplifier Release Button
On the front of the LxT, just below the preamplifier
connector, is a small button. Press and hold this button while
pulling the microphone/preamplifier assembly out of the
LxT, as shown in Figure 3-4.
Powering the SoundTrack LxT
Important Notice Regarding Proper Shutdown
3-4 Disconnecting the Preamplifier from the LxT LxT Manual
The following sections provide power information for the
LxT, including the following:
• Important Notice Regarding Proper Shutdown
• Batteries
• Hardware Power Switch
•USB Power
• External Power Supply PSA029
•Power Settings
Improperly turning off the power to the LxT may damage
the instrument. To properly shut off power, use the on/off
button on the front of the meter.
Batteries
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
batteries.
Do not use 3.8 V Lithium batteries;
they will blow the fuse.
Battery Status
The LxT is compatible with AA alkaline, nickel-metal
hydride (NiMH) batteries and 1.5 volt Lithium batteries.
NOTICE:
• NiMH batteries cannot be charged in the LxT. Do not mix
alkaline and NiMH batteries in the LxT.
• Do not mix batteries from different manufacturers.
• Replace all four batteries when installing fresh cells.
• NiMH batteries may not be used in areas requiring Intrinsic
Safety Approval.
Battery voltage and estimated run time are displayed on the
Power Control page and the last page of the Live tab. When
the LxT is powered by batteries, one of the icons shown in
FIGURE 3-5 is shown on the status bar at the top of the
screen. The icon shows the state of the battery charge as a
full battery when the batteries are fresh, decaying to an
empty battery near the end of the battery life. The battery
voltage and the battery icon directly reflect the remaining
estimated run time as displayed by the instrument.
FIGURE 3-5 Battery Status Icons
When the battery voltage becomes critically low, the empty
battery icon begins to flash, indicating that the LxT is about
to shut down. When the LxT shuts down, it stops running,
saving all data and the instrument state, and then turns off.
When the unit is powered on again, either with fresh
batteries or an external power supply, the unit returns to the
state it was in when it shut down.
LxT Manual Powering the SoundTrack LxTâ 3-5
Hardware Power Switch
DO NOT use the hardware power
switch to turn the LxT OFF. This may
cause data to be lost. Press the
key, then the Off soft key to turn the
LxT off.
It is recommended that the batteries
be removed from the instrument if it
will not be used for a month or
longer as the batteries may selfdischarge and leak, damaging the
instrument.
0
USB Power
The LxT cannot be operated under
USB power if the internal batteries
are discharged (flat). You can run
solely on USB power if you remove
the depleted batteries. However, if
operated on external power only,
with no batteries installed, an
interruption of power to the LxT, for
any reason, may result in instrument
malfunction.
The Hardware Power Switch on the bottom of the LxT,
shown in Figure 2-2 disconnects the batteries from the LxT
hardware, including the real time clock. This prevents
battery drain when the LxT is not in use for an extended
period of time (
in the “O” position, the batteries are disconnected.
After installing batteries be sure to move the switch to the "|"
position. This applies power to all of the LxT hardware.
The Hardware Power Switch should not be used to turn the
LxT on and off. If the Hardware Power Switch is used to
turn the LxT off, data may be lost and Flash corruption may
result.
The LxT can be powered from batteries or, if available, from
the USB host portion of your computer.
The LxT must run on batteries until allowed by the host to
run on USB or external power. If the batteries cannot
provide sufficient power, the LxT does not power on, even
with USB external power. If batteries are installed in the
LxT, ensure that they are good so that the LxT can power on.
If the LxT has discharged batteries installed, the batteries
should be removed or replaced with fresh batteries in order
for the LxT to be USB powered.
To avoid memory corruption when using USB Power or
flash drives, follow these precautions:
• Always shut down the LxT completely before
unplugging USB power connections.
• Do not unplug USB drives from the USB port on the
LxT while the drive is being copied, or if the LxT is
within Data Explorer mode.
> 2 weeks)If the Hardware Power Switch is
External Power Supply PSA029
In addition to running on batteries, or USB power, the LxT
can be powered from a PSA029 power supply. When
3-6 Powering the SoundTrack LxTâ LxT Manual
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 external power if
you remove the depleted batteries.
However, if operated on external
power only, with no batteries
installed, an interruption of power to
the LxT, for any reason, may result in
instrument malfunction.
Power Settings
The PSA029 is designed to work on power systems
worldwide.
The LxT must run on batteries until allowed by the host to
run on external power. If the batteries cannot provide
sufficient power, the LxT does not power on, even with
external power. If batteries are installed in the LxT, ensure
that they are good so that the LxT can power on.
If the LxT is ON, pressing the 0 (ON/OFF) key brings up
the Power Control Page, as shown in FIGURE 3-7.
FIGURE 3-7 Power Control Page
The first section of this page shows the estimated battery run
time (calculated using the voltage of the installed batteries),
battery voltage, and the USB power voltage.
LxT Manual Powering the SoundTrack LxTâ 3-7
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, and Bright, which are adjusted using
the 4 and 6 keys. The Display Contrast has a range of -9 to
9, which is adjusted using the 8 and 2 keys.
The bottom of the Power Control page displays the LxT
temperature that is used to automatically adjust the contrast
of the display to compensate for temperature changes.
The Center Softkey provides an exit,
escape or cancel function as well as
the function displayed above it on
the display.
Pressing the Center Softkey, labeled Close, closes the
Power Control page.
3-8 Powering the SoundTrack LxTâ LxT Manual
CHAPTER
Basic Measurement Setup
4
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(max) corresponding to a userselected value of frequency weighting
• 1/1 and/or 1/3 Octave real-time spectra (LxT-OB3
required)
• Six values of Ln based on six user-selected values of
the parameter n
• Count of the number of times the levels (RMS and
Peak) exceeded user-selected threshold values
• Sound exposure and sound exposure level data
The LxT can measure many additional sound
parameters simultaneously with these basic sound
measurements, as described in subsequent chapters.
Measurement Settings Tabs
Accessing the Measurement Settings Tabs
The parameters defining measurements are set from the
Measurement Settings tabs.
To access these tabs, press the Center Softkey labeled
Menu, press the 2
5 (ENTER) key. The Measurement Settings tab most
appropriate for the data now appears.
key to select Settings, and press the
LxT Manual Basic Measurement Setup 4-1
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
Measurement Settings Screen, the display shown in
FIGURE 4-1 "Settings In Use By PC Message" appears.
FIGURE 4-1 Settings In Use By PC Message
This message indicates that setup changes made with SLM
Utility-G3 or G4 software in this session will be lost if you
continue.
To continue and access the Measurement Settings tabs,
highlight Ye s and press
the Measurement Settings Screen, highlight No and press
5. To cancel the attempt to access
5.
4-2 Measurement Settings Tabs LxT Manual
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 the measurements being
defined. Upon opening, the Default File Name “LxT_Data”
may appear in the file name field.
To enter new file names, select the Default File Name text
box and press
new names and press
5. Use the 4, 6. 8 and 2 keys to enter
5.
LxT Manual Measurement Settings Tabs 4-3
SLM Tab
Frequency Weighting
Integration Method
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
A, C and Z frequency weightings are provided for the RMS
and peak detectors. These are selected separately.
Two Integration methods are available: Linear and
Exponential.
5.
Exponential Integration
Exponential integration would typically be selected to
provide compatibility with older analog instruments in
which measurements are exponential time weighted signals.
Exponential detectors tend to hide small events in the long
decay of loud impulsive events.
Linear Integration
Linear integration utilizes sampled sound pressure levels to
compute RMS levels directly, without an intermediate time
weighting.
4-4 Measurement Settings Tabs LxT Manual
Octave Band Analyzer Tab (Optional)
Left Click to Select
The default values for these
parameters are as shown in
FIGURE 4-4.
OBA Parameter Selection
This tab only appears when the LxT has the optional LxTOB1 or LxT-OB3 firmware enabled.
FIGURE 4-4 OBA Tab
The OBA parameters are selected as shown in FIGURE 4-5.
LxT Manual Measurement Settings Tabs 4-5
FIGURE 4-5 OBA Parameter Selection
OBA Range Setting
In the Low range, the full scale level is reduced by 30 dB on
the display. The default display ranges are as follows:
• Normal Range: 20 to 140 dB
•Low Range: -10 to 110 dB
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 Max Spectrum Setting
Two methods can be used to define the maximum spectrum:
• At Lmax: using this method, the maximum values for
each frequency band are those that are being measured at
the instant the overall sound pressure level reached its
maximum value during the measurement period.
•Bin Max: using this method, the level measured for each
frequency band is the maximum measured during the
measurement period. Since the maximum levels for the
different frequency bands may have occurred at different
times, the ensemble of frequency band maximum levels
may represent a spectrum that never existed at any single
instant during the measurement.
4-6 Measurement Settings Tabs LxT Manual
Dosimeter 1 and 2 Tabs
Predefined Setups
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.
In most cases, measurements of this type are setup to
conform to specific standards. The LxT permits the user to
create such setups in a single step by simply selecting the
applicable standard. The standards addressed by the LxT and
the corresponding parameters are as shown in Table 4-1
"Predefined Noise Dosimeter Setups".
Standard
Exchange
Rate
Threshold Criterion
Level Hours
OSHA-1 5 90 90 8
OSHA-2 5 80 90 8
ACGIH 3 80 85 8
NIOSH 3 80 85 8
IEC 3 Not Enabled 85 8
Table 4-1 Predefined Noise Dosimeter Setups
LxT Manual Measurement Settings Tabs 4-7
The Name field is already
highlighted when the Dosimeter
View is opened. If this has been
changed, use the
the highlight back to the Name field.
8
key to move
The names of the predefined setups can be accessed from the
Name field at the top of the display. Press
of predefined setups by name as shown in FIGURE 47 "Predefined Dose Setups"
.
Parameters Individually Defined
The Dosimeter tab contains two fields (Name and
Exchange Rate) and two sections (Threshold and
Criterion).
Name Field
If a predefined setup has been
selected and any of the preset
parameters are modified, the user
should consider changing the name
of the setup.
Threshold and Criterion
When setting the Threshold value,
the Enabled check box must be
checked before data can be entered
into the numeric field. Use the Left
Softkey to highlight the box and
press
5.
Auto-Calculate
The Name field is optional, although many users enter text
associated with the measurement to be performed, such as
specific company Dose standards (“My Dose”) or names of
standards not in the list.
To set these parameters, after highlighting the appropriate
section, press
the numeric value desired, then press
The Criterion Level and Time are set independently.
However, Criterion Level and the Time have a linear
relationship, so when Auto-Calculate is activated for either,
both are automatically set to follow the applicable standard.
5 to show a list
FIGURE 4-7 Predefined Dose Setups
5, use the 4, 6, 8, and 2 keys to enter
5.
4-8 Measurement Settings Tabs LxT Manual
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
= 35 dB
90
means that the measured sound level is above 35 dB for 90%
of the measurement period. These statistical values are
commonly used to describe the characteristics of non-steady
sound such as environmental noise.
The LxT can calculate six different Ln values based on userdefined values of n, which can be in the range 00.01 to
99.99%.
LxT Manual Measurement Settings Tabs 4-9
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 LXTENV has been enabled,
Measurement History can be
enabled in the Run Control Setup.
The Run Mode on the Control tab can be setup for one of
six modes, including the following.
• Manual Stop: The measurement is initiated manually by
pressing the 9 (Run/Pause) key and is stopped by
pressing the 7 (Stop) key.
•Timed Stop: The measurement is initiated manually by
pressing the 9 key and is stopped automatically after a
user-defined time period.
• Stop When Stable: The measurement is initiated
manually by pressing the 9 key. The measurement
stops when the measured level has remained within a
user-defined range and the measurement has run for a
user-defined time period.
• Continuous: The measurement is initiated manually by
pressing the 9 key and is stopped by pressing the 7
key. Measurements are made continuously from start to
stop.
• Single Block 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 time interval defined by the single block
timer.
4-10 Measurement Settings Tabs LxT Manual
• 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 selected. Press
shown in Figure 4-10.
FIGURE 4-10 Run Mode Menu
5 to open the Run Mode Menu, as
Navigate to select the desired mode and press
the selection. The screen then appears as one of those shown
in Figure 4-11, depending upon the mode selected. For the
Timed Stop and Stop When Stable modes, further
information must be entered.
Manual, Timed Stop, or Stop When Stable Modes
When the run mode used is Manual, Timed Stop or Stop
When Stable, a single measurement runs continuously from
start time to end time. The selection and setting of
parameters for these run modes is shown in FIGURE 4-11.
5 to make
FIGURE 4-11 Setup of Manual Stop, Timed Stop, and Stop When Stable Run Modes
LxT Manual Measurement Settings Tabs 4-11
Entering Run Time for the Timed Stop Mode
To enter the Run Time, navigate to select the Time data field
and press
digit positions in the data field using the 4 and 6 keys, as
shown in Figure 4-12.
FIGURE 4-12 Entering Time in Timed Stop
Stop When Stable Mode
The Stop When Stable run mode contains the data fields
Delta and Time, as shown in Figure 4-13.
FIGURE 4-13 Stop When Stable Run Mode
5. You can then move left and right to different
Run Mode
Delta Level
The Delta level is the maximum one minute change in
overall average level (i.e. L
) allowed for the
Aeq
measurement to be considered stable.
Time
The Time is the duration that the measurement must run
before the measurement can stop.
If the time were set to 0, the measurement would run until
the stability condition was met.
Once duration is set, the measurement runs for the duration
specified and then continues until the stability condition is
met.
Run Modes Without Measurement History
All Run Modes include check box options to enable the
Measurement History feature. The descriptions presented in
4-12 Measurement Settings Tabs LxT Manual
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 Overall and Current tabs is identical.
Continuous
The Continuous run mode is similar to the Manual Stop
mode, except that Daily Auto-Store can also be enabled, in
which case daily measurement reports for 24-hour time
periods are automatically stored. The user specifies a
beginning time for such periods. This also presumes that the
measurement time period encompasses at least one 24-hour
time period as programmed. The parameter Time defines the
start time for the 24-hour time period to be used for the
report.
Single Block Time or Daily Timer
When the run mode is Single Block Timer or Daily Timer,
the single measurement consists of data measured over
different blocks of time between the start date and time and
the end date and time.
LxT Manual Measurement Settings Tabs 4-13
The selection and setting of appropriate parameters for the
Click to open data
fields for blocks 2 and
3.
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
4-14 Measurement Settings Tabs LxT Manual
For each run mode option, select the corresponding data
field and press the
5. To enter the desired values, press the
5 again.
For the Continuous mode, when the Auto-Store checking
the box in the Daily tab results in the following: daily
measurement reports for 24-hour time periods are
automatically stored, beginning at a user-specified time
(assuming that the measurement time period encompasses at
least one 24-hour time period as programmed).
When the option is checked, a data field opens to define the
start time for the 24-hour time period to be used for the
report, as shown in FIGURE 4-15.
FIGURE 4-15 Auto-Store Report Start Time
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.
Triggers Tab
Note that the default values for these
parameters are as shown in
FIGURE 4-16.
To measure and store sequences of measurements using the
same setup, either manually or automatically, you can use
the Measurement History feature, which is described in
detail in "Measurement History".
FIGURE 4-16 shows the Triggers tab.
FIGURE 4-16 Triggers Tab
The Triggers tab is used to define trigger levels that can
than be used to detect when the measured sound level (SPL
or Peak) exceeds one of these trigger levels.
Day/Night
The Day/Night parameters are used in conjunction with
Community Noise Measurements that require the optional
firmware LXT-CN to be enabled.
The default values for these
parameters are as shown in
FIGURE 4-17.
LxT Manual Measurement Settings Tabs 4-15
Among the parameters measured and displayed as part of a
basic sound level measurement are the community noise
descriptors L
DN
and L
. The Day/Night tab defines the
DEN
times and penalties to be used.
FIGURE 4-17 shows the Day/Night tab.
Ldn10Log
10
1
24
------
10
Li10+10
0000
0700
10
Li10
0700
2200
10
Li10+10
2200
2400
++
=
DEN
L =
10
10
10
5
10
10*810*410*12
24
1
lg10
LnightLeveningLday
FIGURE 4-17 Day/Evening/Night Definition
L
DN
The day-night level LDN defined by the following formula:
L
DEN
The day-evening-night level L
following formula:
In the default form, the day has twelve hours, the evening
has four hours and the night has eight hours, as can be seen
in the equation. The default times for these periods are as
follows:
4-16 Measurement Settings Tabs LxT Manual
is defined by the
DEN
CNEL
CNEL 10log
10
1
24
------
10
Li10+10
0000
0700
10
Li10
0700
1900
10
Li5+10
1900
2200
10
Li10+10
2200
2400
++ +
=
• 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 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 the Council of 25 June 2002, relating to the assessment of
environmental noise permits member states to shorten the
evening period by one or two hours and lengthen the day
and/or the night accordingly and also to choose the time for
the start of the day.
To accommodate these and other possible modifications, the
Day/Night tab permits the user to modify the times for the
beginning of the Day, Evening and Night periods and the
penalties to be utilized when calculating 24-hour integrated
values.
In the state of California, a commonly used community
noise descriptor is Community Noise Equivalent Level
(CNEL), defined by the following formula:
This is essentially the same as the L
values, with the exception that the evening period begins at
22.00 instead of 23.00. Thus, by making this change in the
LxT Manual Measurement Settings Tabs 4-17
L
DEN
settings, the measured value represents CNEL.
using default
DEN
4-18 Measurement Settings Tabs LxT Manual
CHAPTER
Data Display
5
Data Labels
Tabbed Display
This chapter describes how data is displayed for basic
sound level measurements.
The LxT sound metrics labels are designated by
international standards. For many displayed values, the
frequency and time weighting are indicated in the name of
the metric. Example: L
level measured using the Slow detector. Sound pressure
level is often referred to as SPL.
Measured data are displayed using a number of tabs
arranged horizontally across the screen, as shown in Figure
5-1. Depending on the firmware options loaded in the LxT,
multiple tabs appear in the Data Display, each identified by a
title at the top.
is the A-weighted sound pressure
AS
FIGURE 5-1 Tabbed Display
Navigating through Tabs
Not all of the tabs can be seen at one time on the display. To
see tabs on the right, use the Right Softkey beneath the
display. To navigate to the left, use the Left Softkey beneath
the display.
Navigating within Tabs
Each tab contains multiple pages. To navigate between
pages, use the 8 or 2 keys.
The 4 and 6 keys can be used move the cursor left and
right, respectively, to select a specific filter or record,
depending on the data being displayed.
LxT Manual Data Display 5-1
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
On some tabs, you can also select check box options by
highlighting them and pressing
5 (ENTER).
Specifying Values for Settings within Tabs
Sometimes the 4 and 6 keys or the 8 or 2 keys may be
used to increase or decrease the scaling or level of some
settings within pages of the tabs, once the setting is selected.
In these cases, once the desired value is specified, press
Under Range Condition
When a measured level is in an under range condition, its
displayed level appears in gray rather than black.
Graph Scale Adjustment
The default amplitude (dB) settings for the graphic display
of sound pressure level versus time and frequency spectra
(1/1 and 1/3 octave) are as indicated below:
5.
5.
• Level vs. Time Graph: 20 dB to 140 dB
• Frequency Spectra, Normal Range: 20 dB to 140 dB
• Frequency Spectra, Low Range: -10 dB to 110 dB
To change the scaling of any one of these graphs, press the
Menu softkey to obtain the display shown in FIGURE 5-2.
FIGURE 5-2 Menu
5-2 Tabbed Display LxT Manual
Live Tab
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 icons indicate
which arrow key adjusts which value. Press
implement the change.
Once the scaling on one or more graphic displays has
changed, it remains that way until changed again or until the
defaults settings are restored.
When changing range between normal and low, the scale is
automatically adjusted.
This sections describes the pages on the Live tab. The Live
tab contains the following pages:
• Profile
• Digital
• 1/1 Octave (optional with separate license)
• 1/3 Octave (optional with separate license)
• Triggering
•Power
Upon turning on the LxT, the Live tab is displayed. The
measurements displayed on the Live tab are active, real-time
measurements. The displayed values are not controlled by
the
9 (RUN/ PAUSE) key. This allows you to view the
current SPL without disrupting any measured data. For
example, suppose you are making a measurement and an
unwanted event takes place, causing you to stop the
measurement. With the measurement stopped, you can
monitor the actual level on the Live tab to be certain that the
residual effects of the unexpected event have finished before
beginning a new measurement.
5 to
LxT Manual Live Tab 5-3
Profile Page
Profile of 1 Sec Leq using selected Frequency
Weighting from Setup
Current Value of 1 Sec Leq using selected
Frequency Weighting from Setup
Current SPL using selected Frequency
Weighting and Detector
Value of L
Peak
using selected Frequency
Weighting, Reset Every Second
Date and Time Measurement Began
The Profile page presents recent graphic history of Leq,
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
5-4 Live Tab LxT Manual
The time at the bottom of the page is the date and time that
the measurement started.
Digital Page
Indication of Current Exceedance
of SPL1 Trigger Level
Current SPL using selected Frequency
Weighting and Detector, Updated Once per
Second
SPL1 Trigger Level
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 indicate current of the SPL1 trigger
level, which are user-defined, as described in page "Triggers
Tab” on page 4-15.
LxT Manual Live Tab 5-5
1/1 Octave Page (Optional)
Frequency Weighting and Time
Averaging for Spectrum Measurement
Frequency Spectrum Bandwidth
Measured Level at Cursor Position
Broadband Sound Pressure Level
The 1/1 Octave Band Analyzer
appears only when the sound level
meter is loaded with the optional
LxT-OB1 or LxT-OB3 firmware.
FIGURE 5-6 Live Tab, 1/1 Octave Page
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
most bar on the graph is the selected broadband SPL value
(in this instance, L
AS
).
The spectrum frequency weighting is selected independently
from that of the sound level measurement, as described in
“OBA Frequency Weighting”. The detector is the same as
that of the sound level measurement.
5-6 Live Tab LxT Manual
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.
Triggering
For a description of the setup of
these trigger values, see “Triggers
Tab”.
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 Figure 5-7.
FIGURE 5-7 Live Page, 1/3 Octave Page
The Triggering page displays the sound level and peak level
with their associated trigger points, as shown in Figure 5-8.
Exceedances of these trigger points are indicated by check
marks appearing to the right of each. Check marks appear
only as long as the measured level remains above the trigger
point.
FIGURE 5-8 Live Tab, Trigger Page
LxT Manual Live Tab 5-7
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
number of stored data files is also indicated.
Figure 5-9 shows the Power page.
FIGURE 5-9 Live Tab, Power Page
Overall Tab
This section describes the pages of the Overall tab
associated with basic sound level measurements. The
Overall tab includes the following pages:
•Profile
•Digital
•Leq
• 1/1 Octave (optional with separate license)
• 1/3 Octave (optional with separate license)
• Dose 1
• Dose 2
•SEL
•SEA
5-8 Overall Tab LxT Manual
Profile (with Overall Leq)
Leq using Frequency Weighting
and Detector from Setup
Sound Level for Currently
Selected Weighting and Detector
Leq using selected
Frequency Weighting and
Detector from Setup
SPL1 Trigger Level
Maximum Level using
selected Frequency
Weighting and Detector
Percent Of Time Measured
Level is Above SPL1
Trigger Level
Measurement Duration
Peak Level using selected
Frequency Weighting
• Percentiles
• Exceedances
• Overloads
• Community Noise
• Miscellaneous
• Memory
Figure 5-10 shows the Profile page of the Overall tab.
Digital
LxT Manual Overall Tab 5-9
FIGURE 5-10 Overall Tab, Profile Page
Figure 5-11shows the Digital page of the Overall tab.
Leq
L
Peak
using selected
Frequency Weighting
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 average
sound level is updated approximately four times per second.
The Leq Page presents the maximum, minimum, and peak
sound levels, as shown in Figure 5-12. On this page, you can
view the current sound levels and instantaneous peak values
to note their effect on the maximum and minimum sound
levels, and the maximum peak level.
5-10 Overall Tab LxT Manual
FIGURE 5-12 Overall Tab, Leq Page
The L
Zpeak(max)
is the highest level the peak detector has
measured during the run time of the measurement. The date
and time of occurrence is recorded with this event.
The L
Zpeak(max)
is also considered the peak hold. Whenever
data is reset, this parameter is cleared. To reset data, press
the
1 (RESET) key.
The L
is the highest level the RMS detector has
ASmax
measured during the run time of the measurement. The date
and time of occurrence is recorded with this event.
The L
is also considered the max hold. Whenever data
ASmax
is reset, this parameter is cleared. To reset data, press the
(RESET) key.
The L
is the lowest level the RMS detector has
ASmin
measured during the run time of the measurement. The date
and time of occurrence is recorded with this event.
1
1/1 Octave (Optional)
Frequency Spectrum Bandwidth
Lmax Values
Leq Values
Lmin Values
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.
FIGURE 5-13 Overall Tab, 1/1 Octave Page
Leq
Lmin
Lmax
The 1/1 Octave page displays bar graphs of sound level in 1/
1 octave frequency bands, as shown in Figure 5-13.
L
is the energy average sound level of the frequency band
eq
for the duration of the measurement.
L
is the minimum sound level of the frequency band for
min
the duration of the measurement.
The value of Lmax for each frequency band is the maximum
value that occurred in that band during the entire
measurement period. Since individual frequency bands may
reach their maximum levels at different times, this spectrum
might be one that never occurred at any instant during the
measurement period.
1/3 Octave Band Analyzer (Optional)
The 1/3 Octave Band Analyzer page
appears only when the sound level
meter is loaded with the optional
LxT-OB3 firmware and this
measurement mode has been
selected in the setup.
LxT Manual Overall Tab 5-11
The data displayed in the 1/3 Octave page is similar to that
displayed for 1/1 octave spectrum measurements, except that
it represents 1/3 octave data. Figure 5-14 shows the 1/3
Octave page.
Dosimeter 1 and 2
FIGURE 5-14 Overall Tab, 1/3 Octave Page
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 Pages
TWA(8)
The value of TWA(8) (Time Weighted Average for 8 hours)
is based on data measured during the run time and calculated
for the user-defined Criterion Time, in this case 8 hours. The
5-12 Overall Tab LxT Manual
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 TWA(8) would be
the same as the TWA measured over an eight hour period if
there were no other sound exposure other than that which
occurred during that ten minute period.
ProjTWA
The ProjTWA (Projected Time Weighted Average) is
calculated from data measured during the measurement run
time and calculated for the user-defined Criterion Time, in
this case 8 hours. Continuing with the example in the
previous paragraph, the ProjTWA for that ten minute
measurement represents the value of TWA that would be
measured if the noise measured during the ten minute period
had continued for eight hours.
L
ep,d
The Daily Personal Noise Exposure, L
is calculated from
ep,d
data measured during the run time of the measurement.
DOSE
Dose is based on data measured during the run time
calculated for the user-defined Criterion Time and Criterion
Level (100% definition). For example, suppose a
measurement was performed over a time period of ten
minutes. The value of Dose would be the same as the Dose
measured over an eight hour period if there were no other
sound exposure other than that which occurred during that
ten minute period.
ProjDOSE
Projected Dose is based on data measured during the run
time and calculated for the user-defined Criterion Time and
Criterion Level (100% definition). Continuing with the
example in the above paragraph, the Projected Dose for that
ten minute measurement represents the value of Dose that
would be measured if the noise measured during the ten
minute period had continued for eight hours.
The remainder of the display shows the parameters used for
the measurement: Frequency Weighting, Exchange Rate,
Threshold and Criterion (time and level).
LxT Manual Overall Tab 5-13
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
is the sound exposure level (previously known as
ASE
SEL). The Sound Exposure metrics indicate the actual and
extrapolated (8 and 40 hours) exposure accumulated in
terms of hours and seconds. These are discussed in “Sound
Exposure (SE)” and “Sound Exposure Level (SEL, LE)”.
5-14 Overall Tab LxT Manual
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 Glossary for a detailed
description.
FIGURE 5-17 Overall Tab, SEA Page
LxT Manual Overall Tab 5-15
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 Tab, Percentiles Page
5-16 Overall Tab LxT Manual
Exceedances
The exceedances count and time
shown on this page, as well as those
exported in data files, are computed
according to your current weighting
and detector settings. An exceedance
begins when the measured level is
greater than the specified threshold
and ends when the level is less than
or equal to -2 dB of the measured
threshold. This prevents excessive
exceedance counts when the
measured level is at or near the
threshold.
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 threshold levels of the RMS
detector and three for the peak detector, as shown in Figure
5-19.
FIGURE 5-19 Overall Tab, Exceedances Page
LxT Manual Overall Tab 5-17
Overloads
Community Noise
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
The times intervals associated with
the Day, Evening and Night periods
are set as described in “Triggers
Tab ”.
5-18 Overall Tab LxT Manual
The Community Noise page displays three equivalent
levels calculated for the total measurement time, as shown in
Figure 5-21.
FIGURE 5-21 Community Noise Page
The Community Noise page appears only when the optional
firmware LXT-CN has been loaded on the sound level meter
and this measurement mode has been selected in the setup.
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
are always calculated using
Aeq
the linear detector, regardless of the value selected in the
SLM Setup. The LAIeq value is from the impulse detector.
L
CSeq
and L
are equivalent levels measured using Slow
ASeq
RMS averaging and using frequency weightings of C and A,
respectively. The difference between them, L
CSeq - LASeq,
often used as an indicator of the amount of low frequency
content in sounds.
It is also used as a parameter for the selection of hearing
protectors, since noise fields having large amounts of low
frequency sound can require more effective hearing
protectors than would otherwise be indicated by the
measured L
level alone.
ASeq
The parameter LAFTMS only appears when Takt M ax i ma l
Data has been selected on the Preferences tab.
is
LxT Manual Overall Tab 5-19
Memory
Session Log Tab
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
The Session Log is a record of sound measurement actions,
as shown in Figure 5-24.
Select the icon and press the
Enter key to play a recording.
FIGURE 5-24 Session Log Tab
5-20 Session Log Tab LxT Manual
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 of memory
• Preamplifier disconnect
The icons in the left column of the display indicate the
action: Run, Pause, Voice Recording, etc. The date and time
of the action is displayed next to the icon.
Each measurement segment (from Run to Stop) is
numbered, as is each voice message.
Navigate through the list and expand each item. The number
in the upper right corner of the expanded item indicates
which item is being viewed out of how many total items are
in the list.
View Spectrum Normalized (Optional)
The Live Spectrum continues to
change in time following the
normalization, whereas the
Reference spectrum remains the
same.
LxT Manual View Spectrum Normalized (Optional) 5-21
The View Normalized function permits the display of the
difference between two spectra by subtracting a userselected reference spectrum from the measured spectrum.
This function can be used with both 1/1 and 1/3 octave
spectra, although the measured spectrum and the reference
spectrum must have the same bandwidth: 1/1 or 1/3 octave.
View Spectrum Normalization is context sensitive and
displays the normalized spectrum for the data from the tab
where it was activated, whether Live, Overall,
Measurement History, or others.
A and C frequency weighting curves can also be used for
references, as described in "Normalizing using Frequency
Weighting” on page 5-24.
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 octave data.
FIGURE 5-26 Menu
5-22 View Spectrum Normalized (Optional) LxT Manual
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 1 has not been
previously defined, the display shows the actual live SPL
spectrum.
Selecting the Spectrum Type
In the live display, it is not necessary to select a spectrum
type since only SPL is available.
Selecting the Reference Spectrum
Select the field referenced in Figure 5-27 and press
open the menu shown in FIGURE 5-28.
FIGURE 5-28 Spectrum Type Menu
Select from the three spectrum types: Leq, Lmax and Lmin.
LxT Manual View Spectrum Normalized (Optional) 5-23
5 to
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 define four reference
spectra.
The last four items permit the user to use add positive or
negative A or C frequency weightings to the displayed
spectrum.
Setting a Reference Spectrum
By pressing the Set softkey, the current spectrum is set as the
reference spectrum for the selected reference (1, 2, 3 or 4).
Following this procedure, reference spectra 1, 2, 3 and 4 can
be defined. Once defined, the user can choose to display the
live SPL spectrum normalized to any one of these four
reference spectra.
Normalizing using Frequency Weighting
The A and C reference spectrum represent the A and C
frequency ratings sampled at the center frequency of the
selected filter.
Selecting A or C approximates an A or C weighted spectrum
when the original data is unweighted, z weighted. Using -A
and -C removes the effects of A or C frequency weighting.
5-24 View Spectrum Normalized (Optional) LxT Manual
FIGURE 5-30 shows an -A reference display for an Aweighted version of a spectrum.
Graph Relative
FIGURE 5-30 Normalized Spectrum with -A
Weighting
Selecting Graph Relative changes the graph to show the
difference between the current data and the reference, with
the center of the graph being 0dB. This feature can be used
to easily determine if a reference has been exceeded.
LxT Manual View Spectrum Normalized (Optional) 5-25
5-26 View Spectrum Normalized (Optional) LxT Manual
CHAPTER
Making Measurements
6
Preparation
Positioning the LxT
Observer Position
This chapter describes how to make and store accurate
sound level measurements.
Before making a measurement, make sure of the following:
• The instrument hardware has been properly assembled as
described in "Preparing for First Use".
• The instrument has been calibrated as described in
Chapter 7 "Calibration”.
• The measurement has been configured as described in
"Basic Measurement Setup".
This section describes how to position the LxT for optimal
sound level measurements.
In order to avoid the effect of sound reflections from the
body of the operator interfering with the measurement, the
meter should be located as far as possible from the body.
Thus, when actually performing the measurement, the
operator should place himself at a distance behind the
tripod-mounted meter, or extend the hand-held meter as far
from the body as is comfortable.
Microphone Extension Cable
If desired, a microphone extension cable may be placed
between the meter and the preamplifier/microphone. No
correction is required when using Larson Davis Model
EXC<xxx> shielded microphone extension cables in
combined lengths up to 200 feet. (The variable <xxx>
represents the length in feet of the cable.)
LxT Manual Making Measurements 6-1
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 that a windscreen be placed over the
microphone. Larson Davis provides the WS001 windscreen,
a 3 1/2” diameter ball made of open cell foam which can be
placed over the microphone and preamplifier as shown in
FIGURE 6-1.
FIGURE 6-1 Position of Windscreen
Performing Measurements
This section describes the steps for performing basic sound
level measurements.
Starting the Measurement
The LxT uses a single range for
sound level measurements, so there
is no need to select a range. as part
of making a measurement.
6-2 Performing Measurements LxT Manual
The Live tab displays current acoustic data that is not being
recorded or stored. Pressing the 9
causes the LxT to begin storing data, which is displayed on
the Overall tab.
(RUN/PAUSE) key
Measurement Range
Under Range
Not Under Range
Overload Indication
Under Range Indication
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 not be considered accurate.
When input signals exceed the input range of the LxT, the
Input Overload Icon appears at the top of the display.
If a measurement is running and an overload occurs, the icon
flashes on and off for as long as the overload condition
exists, or one second minimum. When the overload has been
removed, the icon remains present (not flashing) to indicate
that an overload has occurred during the measurement. A
reset clears the icon from the display.
When input signals drop below the level that the LxT can
measure within specified tolerances, an under range
condition exists. When this happens the Under Range Icon
appears.
LxT Manual Performing Measurements 6-3
As long as the under range condition exists, the icon flashes.
When the measured level no longer produces an under range
condition, the icon is removed from the display.
At any time when a measured parameter is in an under range
condition, it’s numeric display appears in gray rather than
the usual black, as shown FIGURE 6-2.
FIGURE 6-2 Normal vs. Under Range Data Display
Pausing Measurements
5 Second Back Erase Label
Measurements may be paused and
then run again multiple times.
Back Erase
At any time the measurement of overall data can be
temporarily suspended by pressing the 9
run clock also pauses. However, instantaneous data
continues to be displayed on the Live tab.
Pressing the 9 key one more time starts the measurement
again; overall data continues to accumulate. The run clock
also begins again from the time indicated when the pause
occurred. The overall data is not affected by any acoustic
events occurring during the time period that the LxT is
paused.
key. Note that the
Back Erase is disabled when
Measurement History has been
enabled in the LxT setup, as
described in Chapter 10
"Measurement History”.
The back erase function permits the user to rapidly delete
from the measurement the effects of acoustical events that
have occurred during the previous five or ten seconds. The
back erase can be implemented when the measurement is
paused, as described in the preceding section. When the
measurement is paused, the center softkey is labeled Back-
5s, as shown in FIGURE 6-3.
FIGURE 6-3 Five Second Back Erase Label
The Back-5s label does not indicate
the state of the instrument but that an
action can now be taken to delete the
last five second segment.
6-4 Performing Measurements LxT Manual
Press the center softkey to implement a five second back
erase.
> Ten Seconds Since Last Stop or Pause
Ten Second Back Erase Label
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 FIGURE 6-4.
FIGURE 6-4 Ten Second Back Erase Label
The Back-10 label does not indicate
the state of the instrument but that an
action can now be taken to delete the
last ten second segment.
LxT Manual Performing Measurements 6-5
The user can take one of the following actions:
• Press the 9 key to accept the five second back erase
and continue the measurement.
• Press the center softkey to extend the back erase to ten
seconds. The center softkey is then labeled Undo, as
shown in FIGURE 6-5.
< Ten Seconds Since Last Stop or Pause
Back Erase Undo Indication
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
Time History Records
6-6 Performing Measurements LxT Manual
The user can take one of the following actions:
•Press the 9
five second segment removed.
Press the center softkey to implement the Undo action and
then press the 9 key to continue the measurement without
removing the previous five second time segment.
The time history records from the point that data was
restored to the last record are marked as back erase records
in the marker field.
key to continue the measurement with the
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
for resetting.
Starting a New Measurement
Stopping Measurements
The LxT can be stopped when either
running or paused.
Storing Measurements
Measurements can only be stored
when they have been stopped.
To reset a measurement in progress, press the
key. This erases all data previously measured and resets the
run time clock to zero. A reset does not reset stored data
files.
A reset can be initiated when the LxT is running, paused or
stopped. However, it must be stopped for the reset operation
to be performed.
The 9
Press the 7 (STOP) key to suspend the overall
measurement.
Pressing the 9
measurement which had been stopped.
To store the measurement, press the 7 key one more time.
The Save File menu is then displayed, as shown in FIGURE
6-6 "Save File Menu” .
key must be pressed to start a new measurement.
key afterwards continues the overall
1 (RESET)
FIGURE 6-6 Save File Menu
LxT Manual Storing Measurements 6-7
After a file has been successfully
stored, the LxT automatically resets
when the
another measurement.
Overwriting a Saved File
9
key is pressed to begin
The data is stored under the file name defined in the section
"General Tab" along with a file number. The file number
automatically begins at 000 for the first measurement stored.
The file number is also indexed so that whenever a
measurement is stored, the file number assigned is the next
in sequence following the measurement previously stored.
If you wish to use this data to replace a data file already
saved in the LxT, select the box with the title “...” and press
5 (ENTER). This opens a window listing all the data files
already saved in the LxT, as shown in FIGURE 6-7.
FIGURE 6-7 Saved Data Files
Select the file that is to be overwritten. This replaces the file
name and number that previously appeared with the one
shown on the display, as shown in FIGURE 6-8.
FIGURE 6-8 Overwriting a Saved File
6-8 Storing Measurements LxT Manual
To continue with the overwrite operation, select Ye s 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 upon the setup
being used at the time of the measurement. This section
describes two cases.
Case 1
If the Run Mode is:
Continuous
or
Single Block Timer
or
Daily
and
Daily Autostore is enabled
Normal Operation
Under normal operation the stored data files are stored with
the following name format:
yymmdd00.LD0
where yymmdd is the date the file was stored.
Improper Shutdown
Following an improper shutdown, when the instrument is
next turned On, the data is automatically stored using the
following name format:
yymmddxx.LD0
where yymmdd is the date the data is stored and xx is a
number, beginning at 01, which is automatically
incremented for subsequent instances of improper shutdown.
Case 2
This case covers all setups other than those described in
Case 1.
LxT Manual Data Storage After Improper Shutdown 6-9
Improper Shutdown
When present, the user must
eventually select to store the data,
reset the instrument, or take no
action, in which case the instrument
is automatically reset.
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 is no user response to the prompt within ten
seconds, the instrument is reset
• If the user responds by selecting not to store the data, the
sequence moves to Step 2.
Step 2 The user is prompted to reset the instrument
• If the user responds by selecting to reset the instrument,
the instrument is reset.
• If there is no user response to the prompt within ten
seconds, the instrument is reset.
• If the user responds by selecting not to reset the
instrument, the sequence moves back to Step 1.
This sequence is diagramed below
6-10 Data Storage After Improper Shutdown LxT Manual
FIGURE 6-9 Improper Shutdown Sequence, Case 2
Instrument Reset
No Response for 10 seconds
No
Reset Instrument prompt
Ye s
No
No Response for 10 seconds
Save Data prompt
Data Saved
Ye s
LxT Manual Data Storage After Improper Shutdown 6-11
6-12 Data Storage After Improper Shutdown LxT Manual
CHAPTER
Calibration
7
Calibration Overview
Sensitivity Determination
Overload/Under Range Conditions
This chapter describes both the purposes and steps for
calibrating the SoundTrack LxT
LxT.
The primary role of sound level meter calibration is to
establish a numerical relationship between the sound level at
the diaphragm of the microphone and the voltage measured
by the meter so that the sound pressure level can be read
directly from the display of the meter in units of dB. The
result of a calibration is the determination of the sensitivity
of the meter, including microphone and preamplifier,
typically in units of dB re 1V/Pa or mV/Pa.
A secondary role of calibration is to determine the sound
level that would overload the instrument and the minimum
sound level that can be accurately measured, referred to as
the under range level. This requires a knowledge of the
electrical noise levels of the microphone, preamplifier, and
the instrument circuitry.
and SoundExpert
Calibration Stability
The LxT should maintain a stable value of sensitivity over
long periods of time. Significant changes in sensitivity, or a
pattern of small but regular sensitivity changes, are
indicative of problems with the measurement system, calling
for laboratory calibration and possibly service. To assist the
user in identifying these situations, the LxT provides two
notifications:
Calibration History
Data and date/time of the most recent ten calibrations.
LxT Manual Calibration 7-1
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 exceed 3 dB.
Control Panel - Calibrate
To activate the Calibration function, press the 3 (TOOLS)
key and select the Calibrate icon as shown in Figure 7-1.
FIGURE 7-1 Control Panel
Press
5 (ENTER) to open the Calibrate tabs.
7-2 Control Panel - Calibrate LxT Manual
The four Calibration tabs are shown in FIGURE 7-2.
Calibrate Tab
History Tab
Sensitivity Tab Certification Tab
FIGURE 7-2 Calibration Tabs
Calibrate Tab
LxT Manual Control Panel - Calibrate 7-3
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
calibration procedure.
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.
Sensitivity Tab
Certification Tab
Exiting from the Calibration Function
The History tab lists the results, along with the date and
time, of the ten most recent calibrations performed using the
same type of preamplifier as presently connected to the LxT.
The preamplifier name appears at the top of the tab
(PRMLxT1 in this example). The preamplifier type is read
automatically when the instrument is booted up, or
following a change in preamplifier. The value of sensitivity
in dB re. 1 V/Pa and the variation of the sensitivity
determined from that calibration relative to the calibration
prior to that,
When performing an acoustic calibration, the Sensitivity tab
is used to select the microphone being used.
The Certification tab shows the date of the last certification,
the due date for the next certification, and information about
the calibration facility. You can also enter your certification
interval and certification reminder from this tab.
Press the Close Softkey to exit from any of the calibration
tabs to the Control Panel.
dB, are presented for each calibration.
Acoustic Calibration
This is the most commonly used calibration method, and the
one required by most national and international standards
prior to performing a measurement. A sound level calibrator
is used to apply an acoustical signal of a known amplitude
and frequency to the microphone. From the voltage level
measured by the meter, the sensitivity can be determined.
With this technique, it is assumed that the calibrator is
functioning correctly; any variation in level results in an
improper calibration and an erroneous value of sensitivity.
For this reason, the user is advised to compare the newly
determined sensitivity with the previous sensitivity to ensure
that significant variations have not occurred.
7-4 Acoustic Calibration LxT Manual
Frequency Weighting
Calibrator
Recommended Calibrator
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.
After calibration, the LxT returns to the original frequency
and time weighting set by the user.
The Calibrator section of the Calibrate tab includes an
area to enter information about a calibrator and a list of
calibrators. The user may select a calibrator from the list or
enter new information about a calibrator.
Table 7-1 'Recommended Calibrators for Use with LxT1 and
LxT2' lists the sound level calibrators which Larson Davis
recommends for calibrating the LxT1 and LxT2.
When using a 1/4” microphone, the adaptor ADP024, a 1/4”
microphone adaptor for the 1/2” opening in the CAL150 and
CAL200 calibrators, is also required.
Calibrator Instrument
CAL200 LxT1, LxT2 Class 1 94/114 dB 1 kHz
CAL150 LxT2 Class 2 94/114 dB 1 kHz
Table 7-1 Recommended Calibrators for Use with LxT1 and LxT2
Calibrating the LxT1 and 377B02 microphone
The CAL200 provides a nominal pressure level of 94 dB or
114 dB. The exact levels are printed on the Larson Davis
calibration sheet that came with the calibrator. When using a
free-field microphone, the pressure level at the microphone
diaphragm is slightly different. Thus, a free field correction
of -0.12 dB (0.03 dB uncertainty at 95% confidence level)
should be applied to either of these levels. Pressure and
random incidence microphones do not require this
correction. If the calibrator and instrument are near room
LxT Manual Acoustic Calibration 7-5
Calibrator
Precision
Output Frequency
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 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 from Larson Davis with the
CAL200 to get these corrections. The corrections can be
added to the level obtained in the previous paragraph to get
the actual level of the CAL200.
The 377B02 microphone's sensitivity varies with static
pressure. If the instrument is calibrated in one environment
and moved to another, then the sensitivity changes (after
stabilization) depending on the change of temperature and
pressure. The coefficient of static pressure is -0.01 dB/kPa.
If the system is calibrated at 85 kPa for instance then it is
0.16 dB less sensitive at sea level (101.3 kPa). The
sensitivity of the 377B02 and LxT vary slightly with
temperature also. The coefficient of temperature is +0.009
dB/°C. If the system is calibrated at 18° C then it is 0.045 dB
more sensitive at 23° C.
The Larson Davis 3" Wind Screen has less than 0.05dB
effect on the system response at 1 kHz.
Set the CAL200 level switch to 94 or 114 dB.
Calibrating the LxT2 and 375B02 microphone
The CAL200 and CAL150 provide a nominal pressure level
of 94 dB or 114 dB. The exact levels are printed on the
Larson Davis calibration sheet that came with the calibrator.
When using a free-field microphone, the pressure level at the
microphone diaphragm is slightly different. Thus, a free
field correction of -0.12 dB (0.03 dB uncertainty at 95%
confidence level) should be applied to either of these levels.
If the calibrator and instrument are near room 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 or CAL150 indicates 113.98 dB for
it's level when set to 114 dB, then set the Cal Level in the
LxT to 113.86 dB and 1000 Hz.
7-6 Acoustic Calibration LxT Manual
Environmental Parameter Ranges
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 from Larson Davis with the
CAL200 or CAL150 to get these corrections. The
corrections can be added to the level obtained in the
previous paragraph to get the actual level of the CAL200 or
CAL150.
The 375B02 microphone's sensitivity varies with static
pressure. If the instrument is calibrated in one environment
and moved to another, then the sensitivity changes (after
stabilization) depending on the change of temperature and
pressure. The coefficient of static pressure is -0.01 dB/kPa.
If the system is calibrated at 85 kPa for instance then it is
0.16 dB less sensitive at sea level. The sensitivity of the
375A02 and LxT vary slightly with temperature also. The
coefficient of temperature is -0.015 dB/°C. If the system is
calibrated at 18° C then it is 0.07 dB less sensitive at 23° C.
The Larson Davis 3" Wind Screen has less than 0.05dB
effect on the system response at 1 kHz.
For proper calibration, the calibration procedure and the
correction values apply over the ranges presented in Table 7-
2.
Instrument Class Parameter Range
Static Pressure 65 kPa to 108 kPa
Class 1, LxT1 with 377B02
microphone
Table 7-2 Environmental Parameter Ranges for Calibration
LxT Manual Acoustic Calibration 7-7
Temperature - 10 C to + 50C
Relative Humidity 25 % to 90%, without condensation
9.4 psi to 15.7 psi
14 F to + 122F
from - 10 C to + 39C
(14 F to + 102F)
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