TC Electronic LM 2n, LM 6n Loudness Meter Manual
Below you will find brief information for Loudness Meter LM 2n, Loudness Meter LM 6n. The TC Electronic LM2n / LM6n is a loudness meter that can be used for both real-time and offline loudness measurements. It is compatible with a variety of audio formats and standards, including ITU-R BS.1770, EBU R128, and ATSC A/85. The plug-in features a Radar display that visualizes short-term loudness and loudness history, as well as a variety of statistical descriptors, making it easy to identify program material and measure loudness parameters. The LM2n/LM6n can be used in a variety of applications, including music production, audio post-production, and broadcast.
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English Manual
Introduction
System requirements and installation
Appendix:
Level versus loudness
Using LM2n / LM6n
Universal Descriptors and Dolby LM100 13
Universal descriptors and AC3 Meta-data 13
Interface and feature reference
Presets
Product
Product version
Document
Document version / date
LM2n / LM6n
1.0
Manual
2014-04-24
LM2n / LM6n Manual a
Introduction
LM2n / LM6n Manual 1
About this manual
This manual will help you learn understanding and operating your TC Electronic software.
This manual is only available as a PDF download from the TC Electronic website.
You can print this manual, but we encourage you to use the PDF version, which has both internal and external hyperlinks. E.g., clicking the TC
Electronic logo in the upper left corner of each page will take you to the table of contents.
To get the most from this manual, please read it from start to finish, or you may miss important information.
To download the most current version of this manual, visit the web page tcelectronic.com/support/manuals/
Getting support
If you still have questions about the product after reading this manual, please get in touch with
TC Support: tcelectronic.com/support/
LM2n / LM6n Manual 2
System requirements and installation
System requirements and installation
LM2n / LM6n Manual 3
System requirements
System requirements for Mac OS X
– Intel CPU (min. 2 GHz recommended)
– 2 GB RAM
– Mac OS 10.6.8 or higher
– Pro Tools 10 or higher or a VST/AU-compatible host
– Plug-in Formats
– VST2.4 32/64 bit
– VST3 32/64 bit
– Audio Units 32/64 bit
– AudioSuite 32 bit
– AAX Native 32 bit
– AAX Native 64 bit
System requirements for
Microsoft Windows
– Intel-compatible CPU (min. 2 GHz recommended)
– 2 GB RAM
– Windows XP or higher
– Pro Tools 10 or higher or a VST-compatible host
– Plug-in Formats
– VST2.4 32/64 bit
– VST3 32/64 bit
– AudioSuite 32 bit
– AAX Native 32 bit
– AAX Native 64 bit
Hosts
You can use this plug-in with all host supporting the plug-in formats listed under System requirements. It has specifically been tested with:
– Avid Pro Tools 10 & 11 (Mac/PC)
– Apple Logic Pro X (Mac)
– Apple Final Cut Pro X (Mac)
– Steinberg Nuendo (Mac/PC)
– Steinberg Wavelab (PC)
– Steinberg Cubase (Mac/PC)
– Ableton Live (Mac/PC)
– Adobe Audition CC (Mac/PC)
– Adobe Premiere CC (Mac/PC)
– Reaper (Mac/PC)
System requirements and installation
Installation
You may be familiar with software licensing and authorization based on the iLok hardware.
LM2n / LM6n uses a new license management concept/technology that allows you to authorize your plug-ins without a physical iLok key.
Instead of the iLok key, you can use your computer as a “key”. All you need is a (free)
iLok ID,
and the license(s) you purchase will be associated with this ID.
You then install the
iLok License Manager
software on your computer and use your iLok ID to activate the plug-in(s) you have purchased on this computer. Licenses can later be deactivated and then activated on another computer, allowing you to easily use your LM2n / LM6n wherever you need it. No key to lose – one less thing to worry about.
Of course, you can still use an iLok 2 device to store your licenses if this is what you prefer.
LM2n / LM6n Manual 4
System requirements and installation
Obtaining an iLok ID
Please note that you will only need to create one account for all your PACE-based software licenses. If you already have an iLok ID, proceed
with “Obtaining and installing the iLok License
– Go to the iLok website: http://www.ilok.com/
– Click on “Create Free Account”.
– Fill the Free Account Setup form and click
“Create Account”.
After finishing the registration process, a confirmation message will be sent to the e-mail account you specified when registering. You can now use this account to log into the iLok website and activate software licenses on your computer using the
iLok License Manager
application.
Obtaining and installing the iLok License Manager
– Go to the iLok License Manager download page on the iLok website: http://www.ilok.com/ilm.html
– Download the iLok License Manager installer for your operating system.
– After downloading the iLok License Manager installer, unZIP it and run it.
– Follow the iLok License Manager installer’s instructions.
– After the installer is finished, launch the iLok
License Manager.
– Click on “Sign in” and provide the credentials
(your account name and your password) that you entered when you created your iLok ID.
Fig. 2.: iLok License Manager: Sign In dialog
Managing plug-in activation
– After signing in, the plug-ins that were registered to your iLok ID will be available for activation and deactivation.
– Select a plug-in in the license list.
– Click on “Show Details” to display additional information, including options to Activate and
Deactivate your plug-in(s).
Activating your plug-in from the iLok License Manager
If you want to activate a plug-in from the iLok License Manager, proceed as follows:
– Select a plug-in in the license list.
– Click on “Show Details”.
– Click on “Activate”.
– In the next dialog (“Select an activation location”), select the activation location (the computer or your iLok 2 device) and click “Next”.
Fig. 1.: The iLok License Manager
LM2n / LM6n Manual 5
Installing LM2n / LM6n
– Make sure your host software is not running.
– Run the installer for the LM2n / LM6n plugin. You may need an administrator account name and password to run the installer.
System requirements and installation
Activating your plug-in when launching the host application
– If you have not activated the recently installed plug-in as described in the previous section, you will now be presented with a dialog telling you that the plug-in needs to be activated.
Fig. 3.: Plug-in activation from iLok License Manager
Fig. 4.: The LM1n installer
– On OS X, you may see the following dialog when you try to open the installer by doubleclicking it:
– Review the plug-in name, make sure that this is the correct computer to activate and click on the “Activate” button.
– In the next dialog, select the plug-in you wish to activate and click “Next”.
– If you see this dialog, close it, then, right-click the installer’s icon and select “Open” from the context menu. This will open another dialog, allowing you to confirm that you want to install this plug-in and continue with the installation process.
– Read and accept the Software License Agreement presented by the installer.
– Finish the installation of the LM2n / LM6n plug-in and quit the installer.
– Launch your host software.
LM2n / LM6n Manual 6
– In the next dialog, select the activation location (the computer or your iLok 2 device) and click “Next”.
Fig. 5.: Plug-in activation during host software startup
System requirements and installation
Fig. 6.: Plug-in Activation confirmation
– When your host software has finished launching, the newly activated plug-in(s) will be available.
LM2n / LM6n Manual 7
Using LM2n / LM6n
Using LM2n / LM6n
LM2n / LM6n Manual 8
LM2n / LM6n features
– Loudness meter fully compliant with
– EBU R128
– BS.1770-3
– ATSC A/85 2013
– ITU-R BS.1770
– Universal Descriptors
– Presets for use in broadcast, music, post production and film
– Offline measurements
– Supports mono and stereo sources
– Supports 5.1 sources (LM6n only)
– Advanced logging functionality (LM6n only).
Using LM2n / LM6n
Differences between
LM1n, LM2n and LM6n
This table shows the differences between the three versions of this product: LM1n, LM2n and
LM6n.
Function LM1n
Audio channels 1.0 and
PPM Meter
2.0
No
LM2n
1.0 and
2.0
1.0 and
2.0
Interface size Very small Medium
Radar
Logfile
No
No and big
Yes
No
LM6n
1.0, 2.0 and 5.1
1.0, 2.0 and 5.1
Medium and big
Yes
Yes
LM2n / LM6n vs. LM2 and LM6
If you have been using the original TC Electronic
LM2 /LM6 plug-ins, you will find the following major differences between these plug-ins and
LM2n / LM6n:
– Installation is possible without a physical iLok
device (see “Installation” on page 4).
– The Radar display is available in two sizes
(medium and big).
– Offline processing capabilities have been improved.
– There is a new “Surround channel order” feature.
– The interface colors can be desaturated.
– The log file format has been updated.
– There are now dedicated Max Momentary
Loudness and Max Short Term Loudness descriptors.
LM2n / LM6n Manual 9
Welcome!
LM2n / LM6n represents a quantum leap away from simply measuring audio level to measuring perceived loudness.
The old level method is responsible for unacceptable level jumps in television, for music CDs getting increasingly distorted, and for different audio formats and program genres becoming incompatible: Pristine music tracks from the past don’t coexist with new recordings, TV commercials don’t fit drama, classical music or film and broadcast don’t match. The most fundamental audio issue of all –
control of loudness
– every day makes millions of people adjust the volume control over and over again.
LM2n / LM6n is part of a universal and ITUstandardized loudness control concept, whereby audio may easily and consistently be measured and controlled at various stages of production and distribution. LM2n / LM6n works coherently together with other TC equipment, or with equipment of other brands adhering to the same global standard. Follow the guidelines given to allow audio produced for different purposes to be mixed – without low dynamic range material such as commercials or pop CD’s always emerging the loudest.
Using LM2n / LM6n
Understanding LM2n / LM6n
Since 1998, TC has performed listening tests and evaluation of loudness models and therefore holds an extensive
Universal Database of loudness,
based on ten thousands of assessments.
This database covers all sorts of broadcast material, music, commercials, feature film and experimental sounds, and is verified against other independent studies.
Fig. 7.: Left: Dynamic Range Tolerance (DRT) for consumers under different listening situations.
Right: Peak level normalization means that material targeted low dynamic range platforms gets loud.
The Universal Database is authoritative from an academic as well as a practical point of view.
It has been indispensable when designing the
LM2n / LM6n meters, because it provided the missing link between short-term and long-term loudness, and enabled the statistically founded
Universal Descriptors of LM2n / LM6n.
The chart of Dynamic Range Tolerance in Fig. 7
is a side-effect of the studies mentioned: Consumers were found to have a distinct
Dynamic
Range Tolerance
(DRT) specific to their listening environment. The DRT is defined as a Preferred Average window with a certain peak level
Headroom above it. The average sound pressure level – which obviously is different from one listening condition to another – has to be kept within certain boundaries in order to maintain speech intelligibility, and to avoid music or effects from getting annoyingly loud or soft.
Audio engineers instinctively target a certain
DRT profile when mixing, but because level normalization in broadcast and music production is based on peak level measures, low dynamic range signatures end up the loudest as shown
by the red line in Fig. 7. Audio production is
therefore trapped in a downwards spiral, going for ever decreasing dynamic range. By now, the pop music industry is “right of” In Flight Entertainment in the illustration.
LM2n / LM6n Manual 10
LM2n / LM6n offers a standardized option: The
visualization of loudness history and Dynamic Range Tolerance
in combination with longterm descriptors from production onwards is a transparent and well-sounding alternative to our current peak level obsession.
This is relevant not only for music, but also in production for broadcast or film. The engineer, who may not be an audio expert, should be able to identify and consciously work with loudness developments within the limits of a target distribution platform, and with predictable results when the program is transcoded to another platform.
LM2n / LM6n therefore color-codes loudness so it’s easy to identify
– target level (green),
– below the noise floor level (blue), or
– loud events (yellow) – see Fig. 8.
Fig. 8.: Color coding and target loudness for selected broadcast platforms based on a consumer’s Dynamic Range Tolerance (DRT). The aim is to center dynamic range restriction around average loudness, in this case the -20 dB line, thereby automatically avoiding to wash out differences between foreground and background elements of a mix.
Note how different broadcast requirements are from those of cinema.
Using LM2n / LM6n
When production engineers realize the boundaries they should generally stay within, less dynamics processing is automatically needed during distribution, and the requirement for maintaining time-consuming metadata at a broadcast station is minimized.
In broadcast, the goal is to use the same loudness measure for production, ingest, linking, master control processing and logging – thereby ensuring better audio quality not only in DTV audio, but across all broadcast platforms.
LM2n / LM6n and TC signal processing can coexist with PPM meters, VU meters or Dolby’s LM100 meter.
LM2n / LM6n greatly increases the usability of LM100 in production environments because it provides running status and gives a standardized and intuitive indication of both dialog and non-dialog program.
LM2n / LM6n Manual 11
Using LM2n / LM6n
Basic use of LM2n / LM6n
LM2n and LM6n make use of a unique way of visualizing short-term loudness, loudness history, and long-term statistical descriptors for any type of program material.
LM2n supports analysis of mono and stereo signals, while LM6n supports mono, stereo and 5.1.
Select LM2n or LM6n in your host to bring up the
Radar page.
This page will be used most of the time.
Reading the Radar display
The parameter values shown in the left and right bottom corners of the Radar page in yellow are called
Descriptors.
The default descriptors are
Loudness Range (left) and Program Loudness
(right).
The Outer ring surrounding the actual Radar display shows
Momentary Loudness.
The value shown at the 12 o’clock position is the
Target
Loudness
.
The Radar measures loudness over the time. The time represented by one Radar revolution is set using the Radar Speed parameter on the Settings page.
Resetting measurements
Click the Reset button (the “X” in the upper right corner of the interface) to reset the Radar display and the Descriptors.
Logging (LM6n only)
When logging has been activated (using the Create Log File parameter on the Settings page) and the plug-in is opened or reset, a log file is created in the log file folder specified on the Settings page.
This log file includes information such as:
– when LM6n was opened and closed
– how long LM6n has been measuring material since it was opened last
– Loudness Range and Program loudness data logged since LM6n was opened.
– Use the Create Log File parameter on the
Settings page to activate logging functional-
ity. See “Create Log File parameter” on page
– Use the Log File Folder parameter on the Settings page to define the folder where log files
should be stored. See “Log File Folder parameter (LM6n only)” on page 24.
– Use the Reset on Play parameter on the Settings page to specify wether measurements should be reset when activating Play mode.
See “Reset on Play parameter” on page 25
Presets (storing/recalling settings)
Presets are handled via your host. Please refer to the description of the host software’s features for storing and recalling plug-in settings.
Log file name and content
The format of the log file name is
“LM6n-Log-YYYY-MM-DD-hh-mm-ss.log”.
E.g.,“LM6n-Log-2014-04-02-14-23-00.log” means that this log file was created April 2nd,
2014 at 2:23 pm.
Fig. 9.: LM6n Radar page
LM2n / LM6n Manual 12
Each LM6n log file is a simple text document that can be opened in any text editor. You can easily copy and paste the information from a log file into other applications – e.g., into your e-mail client.
Fig. 10.: A sample LM6 log file, opened in a text editor
An LM6n log file will contain…
–
plug-in version information
in the header section
–
overall statistics
(including start and end time and Descriptor data as seen on the Stats page)
– the actual
Loudness log
with one line per measurement in the following format, with data separated by tabs:
– Date
– Time
– Loudness value.
Universal Descriptors and Dolby LM100
Unlike methods that measure dialog only, LM2n /
LM6n may be used with any type of audio – which includes dialog, of course. If you wish to measure dialog, it is recommended to do a manual spot check of a program or a film. Find 10 to
30 seconds of regular dialog and measure it with
LM2n / LM6n. Where dialog may be soft, regular or loud, and shift by more than 15 dB inside a film, regular dialog tends to be less ambiguous and more consistent across a program.
For compatibility with a proprietary measure such as Dolby LM100, only some of these meters are updated to use ITU-R BS.1770 and Leq(K) while others are locked at Leq(A). The software version of LM100 should be 1.3.1.5 or higher in order for it to comply with BS.1770, and to have its average loudness reading be compatible with
Center of Gravity in LM5 or Program Loudness in
LM2n / LM6n . Even used just on speech, Leq(A) is not a precise approximation to perceived loudness, so please update the unit to BS.1770 to obtain similar readings and predictable results.
To measure dialog with LM2n / LM6n the same way Dolby LM100 is sometimes used, solo the
Center channel during a spot check to momentarily disable the channel weighting specified in
BS.1770, if you’re working on a 5.1 stem.
Using LM2n / LM6n
Universal descriptors and AC3 Meta-data
The “Dialnorm” parameter in AC3 metadata should indicate the average loudness of a program. Basic dynamic range and level control that rely on this parameter may take place in the consumer’s receiver. Therefore, its value should not be far off target, or the consumer results become highly unpredictable.
Program Loudness in LM2n / LM6n is directly compatible with Dialnorm in AC3. Most broadcast stations work with a fixed dialnorm setting, for instance -23 LUFS. This would be the Program Loudness target level for any program.
If your station is more music than speech, better inter-channel leveling may be obtained with dialnorm permanently set 1 or 2 LU lower than the
Program Loudness target level.
LM2n / LM6n Manual 13
Offline measurements
In Avid Pro Tools, LM2n / LM6n cannot only be used for real-time loudness measurements, but also for offline processing. This means that you can select a track or the section of a recording and measure loudness parameters without having to run this track in real-time.
To perform offline measurements in Avid Pro
Tools, proceed as follows:
– Select the track or audio part that you want to measure.
– From the Pro Tools AudioSuite menu, select
Sound Field / LM2n or Sound Field / LM6n – depending on the plug-in license(s) you have purchased and activated and the track(s) you need to measure.
LM2n / LM6n will measure the loudness of the selected track or audio part and present you with the results.
Fig. 11.: LM2n after measuring an audio signal offline.
Using LM2n / LM6n
– Click the “Analyze” button in the lower right corner of the plug-in window.
LM2n / LM6n Manual 14
Interface and feature reference
Interface and feature reference
LM2n / LM6n Manual 15
LM2n / LM6n tabs / screens:
Radar, PPM, Stats, Settings
Main controls
Fig. 12.: Tabs
Use the four tabs on top of the LM2n / LM6n interface to navigate to the four pages that make up the plug-in’s interface:
–
Radar:
Main Radar display.
–
PPM:
PPM page, also displaying a smaller version of the Radar.
–
Stats:
Statistical information.
–
Settings:
Units and other basic settings affecting the Radar display, and access to logging features.
See “Settings page” on page 23.
If you should also use the LM1n plug-in, please note that the LM1n interface has no tabs.
Fig. 13.: Status indicator, Pause button, Reset button
Reset button
To clear all current measurements and restart meter revolution from the 12 o’clock position, click the Reset button.
Make it a habit to click the Reset button before a new measurement.
This resets the Descriptors, the Radar and the true-peak meters.
Run the audio, and watch the radar and descriptor fields update accordingly. It is normal that the descriptors wait five seconds into the program before showing the first readings, while the radar updates instantly. The first five seconds of a program are included in the descriptor calculations, even though they are not shown instantly.
In LM6n, resetting measurements will also create a new log file when the Create Log File parameter on the Settings page has been set to On.
Pausing measurements
Click the Pause button to the left of the Reset button to temporarily pause metering and measurements.
Interface and feature reference
LM2n / LM6n Manual 16
Radar page
Momentary loudness
Radar display Peak Indicator
Left Descriptor Right Descriptor
Plug-in running time
Fig. 14.: The LM2n / LM6n Radar page
Interface and feature reference
The LM2n / LM6n Radar measures loudness over time.
The Radar display is a visualization of Short Term
Loudness. The time represented by one Radar revolution is set using the Radar Speed parameter on the Settings page.
In the
Radar display,
Target Loudness is represented by the border between green and yellow, while the Low Level point is marked by the border between green and blue.
You should keep the outer ring in the green area, and around 12 o’clock on the average. Excursions into the blue or the yellow area should be balanced, and not only go in one direction.
The numbers associated with the outer ring may be referenced at either maximum loudness
(LUFS selected), or have a zero point set at the
12 o’clock position (LU selected). Set the Loudness Unit parameter on the Settings page to
“LUFS” or “LU/LUFS” accordingly. Either way of looking at loudness is valid. LUFS reading is in line with how peak level is typically measured in a digital system, and compatible with Dolby AC3 and E metadata, while the LU approach calls for a certain target Loudness to have been predetermined.
For the Loudness Unit parameter and the differ-
ence between “LUFS” and “LKFS”, see “Loudness Unit parameter” on page 24.
The Outer ring surrounding the actual Radar display shows
Momentary Loudness.
The value shown at the 12 o’clock position is the
Target
Loudness
. The range is defined using the Momentary Range parameter on the Settings page.
Please note that LM2n / LM6n incorporates an intelligent gate, which discriminates between foreground and background material of a program. Consequently, a measure doesn’t start before audio has been identified. It also pauses the measurement during periods of only background noise, and in the fade-out of a music track.
Peak Indicator
In the upper right corner of the page is a Peak indicator. Use the Peak indicator parameter on the
Settings page to define at which level the peak indicator should light up.
Plug-in running time
The
plug-in running time
displayed on the right edge will be reset when you click the Reset button.
LM2n / LM6n Manual 17
Descriptors
The parameter values shown in the left and right bottom corners of the LM2n /LM6n Radar page in yellow are called
Descriptors.
Universal descriptors may be used to make program-duration measurements, or you may “spotcheck” regular dialog or individual scenes as required. It is recommended not to measure programs of a shorter duration than approximately
10 seconds, while the maximum duration may be
24 hours or longer.
The default descriptors are
Loudness Range
(left) and
Program Loudness
(right).
Use the Settings page to select Descriptors. See
Interface and feature reference
Prog. Loudness (I) descriptor
Program Loudness (I) returns one loudness number for an entire program, film or music track. Its unit is LUFS. Some vendors and countries use the unit “LKFS” or “LUFS”, but they are identical:
An absolute measure of loudness in the digital domain, where the region around “0” is overly loud and not relevant for measuring anything but test signals. Expect readings of broadcast programs in the range between -28 and -20 LUFS.
Program Loudness is used as a production guideline, for transparent normalizing of programs and commercials, and to set loudness metadata in delivery if so required. For delivery or transmission of AC3 format, the metadata parameter “dialnorm” should reflect Program
Loudness. The easiest way to handle multiple broadcast platforms is to normalize programs at the station to a certain value, thereby being able to take advantage of the normalization benefits across platforms, at the same time enabling static metadata.
Loudness measurements in LM2n / LM6n are all rooted in ITU-R BS.1770. However, subtle differences exist between different regions of the world. Therefore LM2n / LM6n also includes the
“Loudness Standard” parameter. Be sure to set this parameter correctly for compliance in your region.
The Program Loudness target is more or less the same for broadcasters around the world, especially when taking the measurement differences into account. Target numbers range between -24 and -22 LUFS.
As with Loudness Range and Loudness Max, the meter should be reset before measuring Program Loudness.
LM2n / LM6n Manual 18
Sliding Loudness descriptor
Sliding Loudness – unlike Program Loudness,
Loudness Range and Loudness Max – is a continuously updated measure that doesn’t need to be reset. This type of descriptor is especially useful when “mixing by numbers”, i.e. when there is no access to the extremely informative radar display. When mixing by numbers, having
Program Loudness as one descriptor and Sliding Loudness as the other displays simultaneous information about the full program side by side with the most recent loudness history.
Because the Sliding Loudness measurement is completely ungated, it may also be used to spot-check sections of a program complying to “raw” ITU-R BS.1770 and the first revision of
ATSC A/85.
LM2n / LM6n makes use of optimized statistics processing in order to display a sliding loudness value (a prognosis) as quickly as possible after a reset.
Loudness Range (LRA) descriptor
Loudness Range, standardized in EBU R128 and abbreviated “LRA”, displays the loudness range of a program, a film or a music track. The unit is
LU, which can be thought of as “dB on the average”.
The Loudness Range descriptor quantifies the variation of the loudness measurement of a program. It is based on the statistical distribution of loudness within a program, thereby excluding the extremes. Thus, for example, a single gunshot is not able to bias the LRA number.
EBU R128 does not specify a maximum permitted LRA. R128 does, however, strongly encourage the use of LRA to determine if dynamic treatment of an audio signal is needed and to match the signal with the requirements of a particular transmission channel or platform.
Consequently, if a program has LRA measured at 10 LU, you would need to move the master fader ±5 dB to make loudness stay generally the same over the duration of the program. (Not that you would want that).
In production, Loudness Range may serve as a guide to how well balancing has been performed, and if too much or too little compression has been applied. If a journalist or video editor isn’t capable of arriving at a suitable LRA, he could be instructed to call an audio expert for help.
Interface and feature reference
The following may be regarded as initial production guidelines:
–
HDTV and digital radio:
Stay below LRA of
20 LU.
–
SDTV:
Stay below LRA of 12 LU.
–
Mobile TV and car radio:
Stay below LRA of 8 LU.
Remember to use LRA the other way around too: If there is an ideal for a certain genre, check its LRA measure, and don’t try go below it. LRA should not be used for Limbo. Allow programs or music tracks the loudness range they need, but not more than they need.
Loudness Range may also be measured on a broadcast server to predict if a program is suitable for broadcast without further processing.
LRA is even a fingerprint of a program and stays the same downstream of production if no dynamics processing has been applied. You may even check the number out of a consumer’s settop box to verify that distribution processing and
Dolby DRC has been disabled.
As with Program Loudness and Loudness Max, the meter should be reset before measuring
LRA.
LM2n / LM6n Manual 19
Max Momentary (M) descriptor
Max Momentary is the maximum momentary value through the entire program. This is the same descriptor that is also displayed by the
Outer ring of the Radar display in LM2n and
LM6n (see “Radar page” on page 17.
While Program Loudness concerns the entire, full-length program, Momentary loudness is measured in a window of 400 ms.
Max Short Term (S) descriptor
Max Short Term is the maximum momentary value through the entire program. This is the same descriptor that is also displayed by the Radar
display in LM2n and LM6n (see “Radar page” on page 17.
While Program Loudness concerns the entire, full-length program, Max Short Term is measured in a window of 3 seconds.
Max True Peak (TP) descriptor
Max True-peak is the maximum true-peak value seen over the entire program.
Peak/Loudness Ratio
(PLR) descriptor
Peak/Loudness Ratio is the distance between
Program Loudness (see “Prog. Loudness (I) descriptor” on page 18) and Max True-Peak (see
“Max True Peak (TP) descriptor” on page 20).
Loudness Range (LRA) quantifies loudness variations inside a program or a music track. But
LRA isn’t very sensitive to transient-limiting and clipping happening as a result of the loudness war in commercials and music production.
Peak to Loudness Ratio (PLR)
is a more appropriate measure of such squashing, which has an adverse effect on clarity, intelligibility and audio quality at large. In addition to its “educational” value, PLR is also relevant when tailoring a track or a program to a certain amount of downstream headroom. For instance, ATSC A/85 and EBU
R128 provide 23 dB of headroom, while Sound
Check in iTunes offers 16 dB of headroom.
Lowering PLR further only destroys audio quality without gaining loudness on any modern platform. Accordingly, keeping an eye on this crucial reading can save your next recording for generations to come.
Interface and feature reference
LM2n / LM6n Manual 20
PPM page
Fig. 15.: LM2n PPM page
Interface and feature reference
The PPM page shows…
– a
peak programme meter
(PPM) for the signal currently being measured by the plug-in
– a smaller version of the
Radar display
as seen on the plug-in’s Radar page and
– the two
Descriptors
selected on the Settings page using the Left Descriptor and Right Descriptor parameters.
The peak meters of LM2n and LM6n display true-peak as specified in ITU-R BS.1770. Truepeak meters give a better indication of headroom and risk of distortion in downstream equipment such as sample rate converters, data reduction systems and consumer electronics than digital sample meters used e.g. in CD mastering. Note that the standard level meters in most digital workstations and mixers are only sample peak
(Final Cut, Avid, ProTools, Yamaha etc.) and should only be used as a rough guideline of the headroom.
Note that the meter scale is extended above 0 dBFS. Most consumer equipment distorts if you see readings above 0. It’s not a problem to have true-peak level going to -1 dBFS in production, but legacy platforms (analog, NICAM etc.) and some data-reduction codecs may distort unless true-peak level is kept lower. With Dolby AC3 and with low bit rate codecs, -3 dBFS should be considered the limit, while legacy platforms requiring emphasis may need even further restriction. As described in EBU R128, it is recommended to make full use of the headroom with true-peaks going to -1 dBFS in production, and to only restrict peak level further during distribution/transmission.
LM2n / LM6n Manual 21
Stats page
Fig. 16.: LM6n Stats page
The Stats page gives an overview of essential descriptors, as described in this section.
Please note that clicking the Reset button will re-
set the meters and the log file. See “Reset button” on page 16.
Statistics
This is the time (given in days, hours, minutes and seconds) since the plug-in has been instantiated or since the Reset button has been clicked for the last time.
Program Loudness (I)
This is the Program Loudness. Use the Loudness Units parameter on the Settings page to define the unit for this display.
Max Momentary Loudness (M) or
Max Short Term Loudness (S)
The parameter displayed in this line depends on the setting of the
Max Loud. Time
parameter on the Settings page.
– If you set the Max Loud. Time parameter on the Settings page to “0.4 sec (M)”, the parameter is displayed as “Max Momentary Loudness (M)”.
– If you set the Max Loud. Time parameter on the Settings page to “3 sec (S)”, the parameter is displayed as “Max Short Term Loudness (S)”.
Use the Loudness Units parameter on the Settings page to define the unit for this display.
Interface and feature reference
Loudness Range (LRA)
This is the Loudness Range, measured in LU.
True-Peak Max
This is the True-peak Max parameter, measured in dBFS.
Sliding Loudness [n] seconds
Use the Sliding Loudness Time parameter on the
Settings page to define [n].
Use the Loudness Units parameter on the Settings page to define the unit for this display.
PLR
This is the Peak-to-Loudness Range (PLR), measured in dB.
LM2n / LM6n Manual 22
Interface and feature reference
Settings page
Left Descriptor parameter
Parameter settings:
– Off
– Program Loudness (I)
– Sliding Loudness
– Loudness Range (LRA)
– Max Momentary (M)
– Max Short Term (S)
– Max True Peak (TP)
– Peak/Loudness Ratio (PLR)
Target Loudness parameter
Parameter range: -6 to -36 LUFS (or LKFS, depending on name setting) in 0.5 steps
The Target Loudness parameter specifies the loudness level to generally aim at. It affects a number of functions and displays in LM2n /
LM6n, and must be set according to the standard you need to comply with.
Use this parameter to define what Descriptor should be shown in the lower left corner of the
Radar page and the Stats page. See “Descriptors” on page 18.
Current broadcast standards require Target
Loudness to be in the range between -26 and
-20 LUFS. For instance, EBU R128 calls for -23
LUFS while ATSC A/85 specifies -24 LUFS.
Fig. 17.: LM6n Settings page
Selecting Max Momentary (M) or Max Short
Term (S) will automatically set the Max Loudness
Time parameter to 0.4 sec or 3 sec.
Right Descriptor parameter
Parameter settings:
– Off
– Program Loudness (I)
– Sliding Loudness Sliding L.
– Loudness Range (LRA)
– Max True Peak (TP)
– Peak/Loudness Ratio (PLR)
The Target Loudness parameter affects these functions and displays:
– It sets the
reference point for loudness measurements
in LU. If the Loudness Unit parameter is set to LU, Program Loudness,
Sliding Loudness and Loudness Max will be shown in LU relative to LU Reference. Consequently, measurements that a on precisely on target will consequently read “0.0 LU”.
– It defines the
“12 o’clock” value of the Radar meter.
Radar Speed parameter
Parameter settings: 1, 4, 12, 30 min,1, 2, 4, 12,
24 hours Use this parameter to define what Descriptor should be shown in the lower right corner of the
Radar page and the Stats page. See “Descriptors” on page 18.
Radar Speed controls how long each radar revolution takes. Select from 1 minute to 24 hours.
You may “zoom” between the settings without loosing data as long as the history isn’t reset.
The radar remembers up to 24 hours. Clicking
LM2n / LM6n Manual 23
Interface and feature reference the Reset button will reset the meter and descriptor history.
Low Level Below parameter
Parameter settings: -6 LU to -30 LU in 1 LU steps
Loudness Unit parameter
Parameter settings: LUFS / LKFS / LU/LUFS /
LU/LKFS
Radar Resolution parameter
Parameter settings: 3, 4, 6, 8, 10, 12 dB/div
Use the Low Level Below parameter to set the transition between the colors blue and green on the momentary ring. It indicates that the level is at the risk of being below the noise floor.
Use the Loudness Unit parameter to choose between LKFS and LUFS depending on preference and region.
Use the Radar Resolution parameter to set the difference in loudness between each concentric circle in the Radar between 3 and 12 dB.
Choose low numbers when targeting a platform with a low dynamic range tolerance. You may
“zoom” between the settings, as long as the history isn’t reset.
Create Log File parameter
Parameter settings: On, Off
Set the Create Log File parameter to On to start creating log files in the folder defined with the
Log File Folder parameter.
– LKFS is the unit for loudness according to the
International Telecommunication Union (ITU).
– LUFS is the unit for loudness according to the
European Broadcasting Union (EBU).
– LU is the unit for loudness relative to the target value according to the ITU and the EBU.
Momentary Range parameter
Parameter settings: EBU +9, EBU +18
Use the Momentary Range parameter to set the range of the radar meter.
Log File Folder parameter
(LM6n only)
Use the Log file folder parameter to set the folder on your computer’s hard disk where LM6n log files should be stored.
If you use the LU/LUFS or the LU/LKFS setting, the Radar will show LU values, while for instance
Target Loudness will be displayed as LUFS or
LKFS respectively.
Loud(ness) Standard parameter
Parameter settings: BS.1770-3, Leq(K)
EBU mode meters can to display two different momentary displays: One with a narrow loudness range intended for normal broadcast and denoted “EBU +9”, and one with a wide loudness range intended for film, drama and wide range music denoted “EBU +18”.
– Click the Choose button.
– Select a folder.
– Click OK to confirm.
The selected folder will be displayed at the bottom of the Settings page.
Use the Loud(ness) Standard parameter to set the loudness standard that measurements should adhere to.
– The “EBU +9” setting gives a momentary meter range from -18 to +9 LU.
– The “EBU +18” setting gives a momentary range from -36 to 18 LU.
Reveal in Windows Explorer /
Reveal in Finder (LM6n only)
Click this button to reveal (open) the folder defined with the Log file folder parameter.
Sliding Loudness Time (Slid.
Loud. Time) parameter
Parameter settings: 3, 6, 10, 15, 30 sec, 1, 2, 4,
8 min
When Sliding Loudness is selected as Descriptor
1 or 2, use the Sliding Loudness Time parameter to set the window for analysis. E.g. if 6 seconds
LM2n / LM6n Manual 24
Interface and feature reference is selected, the loudness range for the past 6 seconds is displayed.
Max Loudness Time (Max
Loud. Time) parameter
Parameter settings:
0.4 sec – Momentary (M),
3 sec – Short Term (S)
Use the Max Loudness Time parameter to set the time window used for measuring Maximum
Loudness.
This parameter can only be edited if the Left Descriptor parameter is set to another value than
Max Momentary or Max Short Term.
If Left Descriptor is set to Max Momentary, this value is set to 0.4, and this setting is grayed out.
If Left Descriptor is set to Max Short Term, this value is set to 3 sec., and this setting is grayed out.
Peak Indicator parameter
Parameter range: -12 to +3 dBTP in 0.5 dBTP steps
Use the Peak indicator parameter to define at which level the red peak indicator in the top right corner of the Radar page and the PPM page should light up.
Surround Channel Order (Surr.Ch.
Order) parameter (LM6n only)
Parameter settings:
– L C R – Ls Rs – LFE (Film)
– L R – C – LFE – Ls Rs (SMPTE/ITU)
– L R – Ls Rs – C LFE (DTS)
Use the Surround Channel Order parameter to choose in which order the surround channels should be shown in the PPM view.
Radar Color parameter
Parameter settings: Normal, Desaturated
Use the Radar Color parameter to set the color scheme for the Radar.
The desaturated color scheme is particularly useful for users working in film applications (who usually don’t want a colorful interface to distract them from the film they are working on).
Fig. 18.: LM2n Radar in desaturated mode
Follow Transport parameter
Parameter settings: On, Off
Use the Follow Transport parameter to define if measurements should follow the transport controls (Start / Stop / Pause) of your host application, or run continuously.
– Off setting: The Radar runs all the time, except if manually set to PAUSE mode.
– On: The Radar runs depending on the state of the host applications transport controls.
Reset on Play parameter
Parameter settings: On, Off
When you set this parameter to On, measurements will be reset when going into Play mode.
LM2n / LM6n Manual 25
Presets
LM2n / LM6n Manual 26
LM2n / LM6n
Preset name and target loudness
Parameter
Target Loudness
Radar Speed
Radar Resolution
Momentary range
Low Level below
Loudness Unit
Loudness Standard
Sliding Loudness Time
Peak Indicator
Follow Transport
Yellow Upper Limit
Yellow Lower Limit
Red Upper Limit
Red Lower Limit
-24
4
-24
4
-24
4
-24
4
-24
4
-23
4
-23
4
-24
4
-24
4
-15
4
-24
4
-27
4
-31
4
-16
4
6 6 6 6 6 6 6 6 6 6 10 10 10 6
EBU +18 EBU +18 EBU +18 EBU +18 EBU +18 EBU +9 EBU +9 EBU +18 EBU +18 EBU +18 EBU +18 EBU +18 EBU +18 EBU +9
-9
LKFS
-18
LKFS/LU
-18
LKFS
-18
LKFS/LU
-18
LKFS
-9
LUFS/LU
-9
LUFS
-18
LKFS/LU
-18
LKFS
-18
LKFS
-18
LKFS
-18
LKFS
-18
LKFS
-9
LKFS
BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3 BS.1770-3
10 sec
-2
On
+1
-1
+2
-2
10 sec
-2
On
+1
-1
+2
-2
10 sec
-2
On
+1
-1
+2
-2
10 sec
-2
On
+1
-1
+2
-2
10 sec
-2
On
+1
-1
+2
-2
10 sec
-1
On
+0.5
-0.5
+1
-1
10 sec
-1
On
+0.5
-0.5
+1
-1
10 sec
-2
On
+1
-1
+2
-2
10 sec
-2
On
+1
-1
+2
-2
10 sec
0
On
+2
-2
+4
-4
10 sec
0
On
+3
-3
+7
-7
10 sec
0
On
+3
-3
+7
-7
10 sec
0
On
+3
-3
+7
-7
10 sec
0
On
+1
-1
+2
-2
LM2n / LM6n Manual 27
Appendix: Level versus loudness
Appendix:
Level versus loudness
LM2n / LM6n Manual 28
The path to BS.1770
When level normalization in audio distribution is based on a peak level measures, it favors low dy-
namic range signatures as shown in Fig. 7. This is
what has happened to the CD format.
Quasi-peak level meters
have this effect. They tell little about loudness, and also require a headroom in order to stay clear of distortion. Using IEC 268-18 meters, the headroom needed is typically 8-9 dB.
Sample based meters
are also widely used, but tell even less about loudness. Max sample detection is the general rule in digital mixers and
DAWs. The side effect of using such a simplistic measure has become clear over the last decade, and CD music production stands as a monument over its deficiency. In numerous TC papers, it has been demonstrated how sample-based peak meters require a headroom of at least 3 dB in order to prevent distortion and listener fatigue.
The only type of standard level instrument that does not display some sort of peak level is the
VU meter.
Though developed for another era, this kind of meter is arguably better at presenting an audio segment’s center of gravity. However, a
VU meter is not perceptually optimized, or ideal for looking at audio with markedly different dynamic range signatures.
Appendix: Level versus loudness
Unlike electrical level,
loudness is subjective,
and listeners weigh its most important factors
–
SPL, frequency contents and duration
– differently. In search of an “objective” loudness measure, a certain
Between Listener Variability (BLV)
and
Within Listener Variability (WLV)
must be accepted – meaning that even loudness assessments by the same person are only consistent to some extent, and depends on the time of day, her mood etc. BLV adds further to the blur, when sex, culture, age etc. are introduced as variables.
Because of the variations, a generic loudness measure is only meaningful when it is based on large subjective reference tests and solid statistics. Together with McGill University in Montreal,
TC Electronic has undertaken extensive loudness model investigation and evaluation.
The results denounce a couple of Leq measures, namely A and M weighted, as generic loudness measures. In fact, a quasi-peak meter showed better judgement of loudness than Leq(A) or
Leq(M). Even when used just for speech, Leq(A) is a poor pick, and it performs worse on music and effects. An appropriate choice for a low-complexity, generic measurement algorithm which works for listening levels used domestically has been known as Leq(RLB).
Combined loudness and peak level meters exist already, for instance the ones from Dorroughs, but BS.1770 now offers a standardized way of measuring these parameters.
In 2006, ITU-R Working Party 6J drafted a new loudness and peak level measure, BS.1770, and the standard has subsequently come into effect. It has been debated if the loudness part is robust enough, because it will obviously get exploited where possible. However, with a variety of program material, Leq(RLB) has been verified in independent studies to be a relatively accurate measure, and correlate well with human test panels. It therefore seems justified to use
Leq(RLB) as a baseline measure for loudness, especially because room for improvement is also built into the standard. The final BS.1770 standard included a multichannel annex with a revised weighting filter, R2LB – now known as “K” weighting – and a channel weighting scheme.
These two later additions have been less verified than the basic Leq(RLB) frequency weighting.
The other aspect of BS.1770, the algorithm to measure true-peak, is built on solid ground. Inconsistent peak meter readings, unexpected overloads, distortion in data-reduced delivery and conversion etc. have been extensively described, so in liaison with AES SC-02-01, an over-sampled true-peak level measure was included with BS.1770.
LM2n / LM6n Manual 29
In conclusion, BS.1770 is an honorable attempt at specifying loudness and peak level separately, instead of the simplistic (sample peak) and mixed up measures (quasi-peak) in use today.
The loudness and peak level measurement engine of LM2n / LM6n follows the standard precisely. Possible updates to the ITU standard may be released as updates to LM2n / LM6n
(provided that processing requirements doesn’t exhaust the system).
Technical papers from AES, SMPTE, NAB and
DAFX conferences with more information about loudness measurement, evaluation of loudness models, true-peak detection, consequences of
0 dBFS+ signals etc., are available from the TC website.
For details, visit the TC Tech Library at tcelectronic.com/tech-library/
Meter calibration
Because of the frequency and channel weighting, and of the way channels sum, only specific tones and input channels should be used for calibration.
The most transparent results are obtained using a 1 kHz sine tone for calibration. Other frequencies or types of signal may be used (square wave, noise etc.), but don’t expect similar results.
The beauty of the system lies in its RMS foundation, so this is a feature, not an error. The same feature enables the loudness measure to identify overly hot CDs or commercials, and to take outof-phase signals into account just as much as signals that are in phase.
If we stick to standard methods for measuring peak audio level in a digital system (where a sine wave asynchronous of the sample rate with digital peaks at 0 dBFS is regarded a 0 dBFS tone),
BS.1770 and LM2n / LM6n output these results:
– One front channel fed with a -20 dBFS, 1 kHz sine tone: Reading of -23.0 LUFS.
– Two front channels fed with a -20 dBFS,
1 kHz sine tone: Reading of -20.0 LUFS.
– All 5.1 channels fed with a -20 dBFS, 1 kHz sine tone: Reading of -15.4 LUFS.
Appendix: Level versus loudness
Display
LM2n / LM6n may use either the measurement unit of
LU (Loudness Units)
or
LUFS (Loudness Units Full Scale).
LU and LUFS are measurements in dB, reflecting the estimated gain offset to arrive at a certain
Reference Loudness (LU) or Maximum Loudness
(LUFS) as defined in BS.1770. Since a common reference point for LU has not been agreed on at the time of writing, LUFS (or “LKFS”, pointing specifically to the Leq(R2LB) weighting of
BS.1770), might be favored initially to avoid ambiguous use of the term LU.
The effectiveness of any loudness meter depends on both the graphical appearance and dynamic behavior of its display, as well as on its underlying measurement algorithms. A short-term loudness meter also relies on the measurement algorithm’s ability to output pertinent loudness information using different analysis windows, for instance, 200-800 ms for running real-time updates. It should be noted how the optimum size of this window varies from study to study, possibly because the objective of a running display hasn’t been fully agreed upon.
Formal evaluation of a visualization system is challenging: First of all, one or more metrics must be defined by which the display should be evaluated. The correspondence between the sound heard and the picture seen is one aspect to be evaluated. Another metric could characterize the speed of reading the meter reliably.
LM2n / LM6n Manual 30
In LM2n and LM6n, short-term, mid-term and long-term of loudness measurements are tied together coherently, and displayed in novel ways
(angular reading and radar) that were preferred in its development and test phases. However, we remain open to suggestions for further improvement of the visualization of loudness.
Appendix: Level versus loudness
Postscript
Control of loudness is the only audio issue that has made It to the political agenda. Political regulation is currently being put into effect in Europe to prevent hearing damage and disturbances from PA systems, and to avoid annoying level jumps during commercial breaks in television. In
Australia, something similar may happen.
Many years of research into loudness of not only dialog, but also of loudness relating to any type of audio programming, has brought TC to the forefront of companies in the world to perform real-time loudness measurement and control.
Therefore, TC has taken active part in loudness standardization efforts in Japan, the United
States, Europe and other areas.
In broadcast, digitization is driving the number of AV channels and platforms up, while the total number of viewers remains roughly the same. On the sound production side, it is therefore important that delivery criteria can be easily specified and met, even by people not primarily concerned with audio: Journalists, musicians, video editors, marketing professionals etc.
Using only dialog-based audio measurements in digital broadcast has led to ambiguous level management, more level jumps between programs, and extra time spent on audio production and management in general. Non-dialog based level jumps are currently creating havoc in digital TV, and LM2n / LM6n helps correct that situation.
LM2n / LM6n can be used to control level and improve sound
– not only in Dolby AC3-based transmissions, but also on other broadcast platforms, such as analog TV, mobile TV and IPTV.
To summarize:
LM2n / LM6n is part of a holistic and universal approach to loudness control, starting at the production or live engineer. When she realizes the dynamic range at her disposal, less processing is needed at later stages of a distribution chain. The chain ends with the capability of quality controlling everything upstream by applying the same loudness measure for logging purposes: A closed loop.
Welcome to a new, standardized world of audio leveling – across genres, across formats, across the globe.
LM2n / LM6n Manual 31
Appendix: Level versus loudness
LM2n / LM6n Manual 32
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Key Features
- Loudness meter fully compliant with EBU R128, BS.1770-3, ATSC A/85 2013, ITU-R BS.1770
- Universal Descriptors
- Presets for use in broadcast, music, post production and film
- Offline measurements
- Supports mono and stereo sources
- Supports 5.1 sources (LM6n only)
- Advanced logging functionality (LM6n only)
Frequently Answers and Questions
How does the LM2n/LM6n measure loudness?
What are the different descriptors available in the LM2n/LM6n?
How do the descriptors affect the Radar display?
What are the different loudness standards supported by the LM2n/LM6n?
How can I use the LM2n/LM6n for offline measurements?
How do I reset measurements in the LM2n/LM6n?
What is the purpose of the Pause button in the LM2n/LM6n?
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