Klangfreund Multimeter & LUFS Meter 2 by Sound-Guy
As you know, Loudness Standards are upon us. It’s no longer a simple matter to push your peak level to 0 dBFS - if you do, you’ll have your music level turned down by streaming and broadcast services, especially if you’ve compressed the dynamic range in an attempt to make your music "loud". Tailoring your songs to fit standards such as ITU-R BS.1770-4, EBU R 128 or ATSC A/85 requires new measurement tools. Luckily there are a lot of them available, some even built into recent DAW releases. But Klangfreund have designed some of the best meters around, and they include an automatic gain matching feature which puts them ahead of any other meter I’ve tried. The Multimeter is the newest Klangfreund tool and adds even more features that anyone from a mix or mastering engineer to a broadcast engineer will find valuable.
Bells are (Almost) Out
The new loudness standards bring us terms such as Loudness Units (LU) and LUFS (LU Full Scale), rather than dB. Except for True Peak measurements which are still expressed in dB (ain’t standards grand!). Although a one LU change in level is equal to a one dB change, measuring LU requires specific filtering of both frequency and time. The loudness standards for streaming and broadcasting include Integrated Loudness (I), which is the filtered average for anything from a single song to an entire program, and it’s not just an overall average, but ‘gates’ out lower levels so they don’t pull down the measured average. You cannot use your DAW’s peak meters or even an RMS meter to determine integrated loudness.
Another measure important to streaming and broadcasting is True-Peak (TP). While you may think your DAW’s peak meter measures TP, it’s unlikely unless it was designed to meet the new standards. TP is not the highest sample value in an audio data stream - it is actually higher. True-peaks occur when a digital audio data stream is transformed to analog in the D/A converter in your audio interface, where true-peaks occur due to the conversion process. True-peaks may be a dB or two, even three dB higher than the highest sample value you send to the converter. The new loudness standards specify an integrated loudness level that will be used, typically in the -12 to -24 LUFS range, and a maximum true-peak level (usually - 1 dBTP, which is 1 dB below full scale). You need to measure and adjust both loudness and TP levels so you can assure they will not exceed the broadcast or streaming requirements. Otherwise they will “turn down” the volume and your music may end up sounding dull.
These measurements are not easy to accomplish, and several “LUFS” measurement plug-ins I’ve tested fail to meet the standards. The Klangfreund meters fully meet the measurement requirements for all metrics, and for all musical styles I’ve tried, including highly (badly!) compressed songs that often confuse true peak measurements.
The Klangfreund LUFS Meter has been available since early 2015, and is the work of Samuel Gähwiler, a talented engineer/mathematician. He designed the LUFS Meter as a very efficient and accurate plug-in, with some beneficial ‘bells and whistles’. And he now has introduced the Multimeter, an expanded LUFS Meter with several new and helpful additions.
The LUFS Meter and Multimeter share a basic layout with both a graphical plot showing the history of loudness measures over time, and a panel showing the computed values of key measures and bar charts. The relative size and shape of the plots and tables can be adjusted freely, and the full window scaled from 50% to 400% of nominal size. Both meters compute Integrated Loudness Measurement (I), True-Peak measurement (TP), Momentary Loudness (M, measured over a 0.4 second moving average), Maximum Momentary Loudness (Mmax), Short Term Loudness (S, measured over a 3 second moving average), Maximum Short Term Loudness (Smax), and Loudness Range (LRA). Both also have presets to show measurements relative to a couple dozen standards and streaming platforms, including EBU R128, AES AGOTTVS TD1006 streaming, AGCOM 219/09/csp (Italy), ARIB TR-832 (Japan), ATC A/85 Pass (Calm Act - USA), OP-59 (Australia) and estimates for Spotify, Apple Music, and YouTube among others (these streaming services use their own proprietary loudness standards rather than using public standards - what do you expect!).
LUFS Meter 2 with Plots of Short Term Loudness and Integrated Loudness
Dynamic Range is a measure of the difference between the True-Peak value and the Integrated Loudness over a whole song or program. It essentially measures how well music “breathes”. In the loudness war of the past couple decades, dynamic range has often been reduced to only a few dB in order to raise the average level of sound as close to the digital maximum level as possible. This has resulted in many mixes sounding loud and dull at the same time.
The LUFS Meter does not compute or plot dynamic range, but the new Multimeter calculates both short term and overall program dynamic ranges (termed PSR and PLR respectively). Program Dynamic Range (PLR) is well defined in the new standards as I just noted, but the short term value is a rather complex computation that displays dynamic range moment to moment with a three second ‘window’. In fact the definition of PSR is not yet finalized by standards groups, so Samuel has provided four variations of the PSR ranging from the most precise (and most difficult to implement) to simplified methods proposed by various organizations. Note that you can have PLR greater, or less than LRA, they do not track each other. One ‘funk’ song I recently mixed has a PLR of 14.9 and an LRA of only 3.5 LU. So its dynamic range is excellent even though its loudest passages are only a few dB louder than the quiet sections.
The Multimeter also plots PSR, with its values set to a color range of your choice. This is a convenient way to view how the short term dynamic range varies throughout a song. I have the plot change from orange to red if PSR falls below 8, and run from yellow through green tones for PSR from 10 to 14, and blue through purple as the PSR goes over 16. Although you certainly don’t want your music to be crushed to a low overall PLR, short periods of lower dynamics can add to musical variation.
Multimeter Time Plot and Data Display with Colorful and Useful PSR Indication
The Multimeter also adds a visual True-Peak warning system to the history plot - any true-peak exceeding a specified level (user set from -0.1 to -5 dB, or auto mode) can be shown as a spike on the history plot where it occurred (note that all measurements and display modes can be individually shown or hidden). The EBU R128 standard specifies no true-peak should be higher than -1 dBFS, and if you see any violations and expect your work to be broadcast or streamed, you need to adjust the overall level and/or the dynamics to meet this.
The Multimeter includes surround-sound measurement capability. Loudness for surround-sound, like stereo, is measured with a weighted average of the channels, so there is only a single calculated value for each loudness parameter that characterizes all audio channels. With the Multimeter operating in a DAW, the name of each channel can be set automatically - the DAW channel names will be used for the surround channel names. In standalone mode, meta-data in a file can be used to supply names. In either case the Multimeter sets the weighting according to the text strings of the names, but if the names or weighting are not what you want, you can manually set both. A DAW like REAPER that can have up to 64 audio channels in a track works directly with a single Multimeter in a multi-channel track. DAWs without multi-channel ability would be a challenge, but are not really the best choice for editing surround sound anyway.
In addition, the Multimeter has a standalone option to analyze audio files at high speed, a hundred times normal or higher, and this mode yields exactly the same results as running a real-time analysis, including plotting all bar charts and history plots if they are enabled. This allows you to quickly verify compliance of several files to any broadcast or streaming requirements, such as preparing a full music program with multiple songs for web use. This works with wav, flac, mp3, mp4 and other audio formats.
The Multimeter also has a list display that shows data in columns, including song time, I, LRA, S, M, sample Peak (last 100 msec), TP (last 100 msec), PSR and PLR. Data is listed for each 100 msec for the entire file length. And you can quickly sort a list by any of these metrics (just like a spreadsheet) so you can sort by TP, Momentary loudness, etc. Very handy if you need to find detailed loudness and dynamics information. In addition, you can save a .csv file (comma separated values format) which replicates the list data for use in other programs like EXCEL to view/analyze metrics offline. Very comprehensive!
With both the original LUFS Meter and new Multimeter, the built-in gain control enables a number of useful actions. After a full mix is analyzed, the gain can be manually changed and the resulting Integrated Loudness and True-Peak measurements will immediately change to match, so you can instantly see what loudness correction is needed to meet any integrated loudness or true peak requirements. If you render the audio files through the Klangfreund meters, the adjusted level can be recorded without having to make any other loudness adjustments. The gain adjustment range is from -60 to +60 dB, which should cover anything practical, and the meters add no distortion to audio they process.
But the really powerful application of these gain controls comes with using the Group mode. With this you can instantly set any number of tracks to a given Integrated Loudness value, even if they all initially have different loudness levels - increasing some track levels while decreasing others. And a new synchronised undo control will return all LUFS Meters and/or Multimeters in a group to their last gain setting, which is extremely handy. You can specify up to 32 groups, use as many LUFS Meters or Multimeters per group as your computer can handle (and with a CPU load at a tiny fraction of a percent per meter; with the true-peak calculation turned off, less than 0.05% per instance on my system).
Used in a multi-track mixing session the automated “Adjust to” function can be used to set any number of tracks to a desired level, and using different Groups, you can set one kind of audio (such as vocals) to one target level, and another type (drums) to another in order to optimize the relative levels based on the genre of music. This facilitates faders-up mixing by enabling you to set up an initial rough static balance for many tracks at once, without having to adjust any faders manually. I find I can have a good rough mix with any practical number of audio tracks in a couple minutes, without touching a fader or channel trim. It doesn’t finish the mix for me, but certainly saves time setting up.
The Klangfreund LUFS Meter and Multimeter provide an excellent set of loudness measurement tools useful for mixing and mastering to meet current and future loudness standards. And beyond just measuring loudness and dynamics, their unique synchronization mode, along with the automatic level adjustment, sets them apart from other loudness meters, and truly streamlines setting up a mix project. The extra features of the Multimeter will satisfy any and all loudness measurements that I can think of, while the LUFS Meter covers all the basic requirements and includes the synchronized automatic gain system. You can buy one or both meters, and if you already have the original LUFS Meter, version 2 is free and the Multimeter is only a few extra dollars or Euros. Definitely worth a look and listen.
Metrics and Specifications
The Klangfreund LUFS Meter and Multimeter are compliant with many standards including ITU-R BS.1770-4, AES AGOTTVS TD1006 streaming, AGCOM 219/09/CSP (Italy), ARIB TR-B32 (Japan), ATSC A/85 / PRSS / CALM Act (US), EBU R 128 (Europe), and OP-59 (Australia).
macOS: AAX and AAX Audio Suite (Pro Tools 10.3.5 or later), Audio Unit, VST2 and VST3 (32 and 64 bit on all plugin formats).
Windows: AAX and AAX Audio Suite (Pro Tools 10.3.5 or later), VST2 and VST3 (32 and 64 bit on all plugin formats).
Linux: VST2 (32 and 64 bit)
Can be authorized both online and offline. No iLok required.
Both meters: Integrated Loudness Measurement (ITU-R BS.1770-4), True-peak measurement, Momentary Loudness (EBU R128), Maximum Momentary Loudness (EBU R128 s1), Short Term Loudness (EBU R128), Maximum Short Term Loudness (EBU R128 s1), Loudness Range ((EBU R128), and plots a Loudness history graph.
Multimeter: adds short term and overall program dynamic ranges (termed PSR and PLR respectively) both plotted and shown numerically, a visual True-Peak warning system on the history plot, surround-sound measurements, a list display with export feature, and a standalone mode for fast analysis of program material.
Gain adjustment range: -60 LU to + 60 LU
Groups: up to 32 groups with the full LUFS Meter version, one group in the discounted LUFS Meter. The Multimeter is available only in a full version.
Maximum synchronization: unlimited meters in full version, 6 meters in discounted version.
PC Audio Labs Rok Box with Intel Core i7-4770K CPU @ 3.5 GHz, 16 MB RAM running Windows 7 64 bit.
Compliant with a wide range of standards.
Plots loudness history as well as displaying numerical values.
Can automatically adjust loudness of a track to a target value.
Group mode enables control across many tracks, with up to 32 groups.
Low CPU load, especially with True-Peak calculation switched off for use in a faders-up configurartion.
Can automatically adjust multiple tracks to a target value in group mode.
Continuously scalable interface (50% to 400%) with Retina display support.
Excellent interactive Help system.
Low cost compared to similar professional loudness meters.
Not anything I could find!
See: Klangfreund - Multimeter