5 Common Myths About Loudness Metering Debunked

There are plenty of myths, rumors and misperceptions flying about when it comes to mixing, mastering and specifically, loudness, some of these myths need debunking. Shane Berry provides the facts.  

Myth #1: Loudness is Measured Using a Standard Called LKFS, LUFS and R128.

Fact #1: LUFS and LKFS are reference units: R128 is a standard.

As of this writing, the current loudness standards are based on a document called the ITU-R BS.1770-4 which is a recommendation by the International Telecommunications Union on the implementation of a series of algorithms that measure perceived loudness and true peak levels. 

The title of the paper is literally “Algorithms to measure audio program loudness and true-peak audio level”.

The EBU R128 is a document (among several others) outlining the European response to that recommendation. 

The ATSC A/85 in the US, and the TR-B32 in Japan are similar documents/standards and are all in close compliance with ITU-R BS.1770-4, with minor differences.

So, EBU R128 is not equivalent to LUFS or LKFS. It’s like saying decibels are the same as the manual explaining them.

LUFS and LKFS are a new reference unit of loudness measurement, but they are not the standard itself. 

Myth #2: LU, LKFS & LUFS Measure Different Things.

FACT #2: LUFS and LKFS are terms which mean Loudness Units referenced to Digital Full Scale (dBFS) with K-weighting. (For more on K-weighting see Myth #4). As of 2016, LKFS and LUFS are exactly the same thing.

The Loudness Unit (LU) is equivalent to 1dB—that is, an increase (or decrease) of one LU is the same as raising or lowering by 1dB.   

Here’s a bonus myth debunk: LU’s are NOT louder than dBs!

On an EBU R128 compliant loudness meter, a stereo -18dBFS sine tone at 1kHz measures -18 LUFS.

 

On an EBU R128 compliant loudness meter the scale can be absolute or relative meaning that on the meter itself you can set a specific target level to equal 0 LU or measure directly in LUFS. 

On an “EBU Mode” loudness meter 0 LU = -23 LUFS (relative scale) or you can set it so that -23 dBFS/LUFS = -23 LUFS (absolute scale). 

Here is a stereo -23 dBFS reference sine tone at 1kHz being measured by an EBU Mode meter on a relative scale reading -0.1 LU: 

Here is the same stereo -23 dBFS reference sine tone at 1kHz being measured by an EBU Mode meter on an absolute scale reading -23.1 LUFS. 

This is not as confusing as it first seems—on VU meters 0 can be calibrated to any desired reference level too, but typically 0VU is equal to +4dBu, which is equal to -20dBFS. 

Myth #3: The new loudness standards are only for TV and post production. 

Fact #3: Well, yes and no. It is true that the documents described above are primarily outlining broadcast standards (that’s what the “BS” in ITU-R BS.1770-4 refers to) but there is growing evidence that YouTube, iTunes and other major online music streamers are implementing some kind of loudness averaging.  

They are not necessarily adhering to any of the broadcast standards though, YouTube seems to be normalizing audio on some official videos to between -14 and -12 LUFS...

 

... and iTunes’ “soundcheck “ feature appears to be leveling audio to around -16 LUFS.  

Radio has yet to get on board with the standards, but when it does, the need for any musician, bedroom producer, mix engineer or mastering engineer to maximize loudness via brickwall limiting, or mix to arbitrary peak levels will come to an end. (See Myth #5 and Conclusion.)

Myth #4 Loudness Normalization will add more processing to my track and change it.

Fact #4: The loudness algorithms measure audio and adjust overall gain accordingly, they don’t process it.  

Loudness Normalization uses EQ curves (designated K weighting) that closely resemble how the human ear perceives loudness, it then measures the average peak to trough difference of the entire “program material”, ignoring levels below a certain threshold, and then calculates a value called an integrated loudness level. 

This Integrated level is then used to determine the overall loudness of the material and the levels of the whole program are turned up or down to comply with the various loudness standards mentioned above. 

Furthermore, don’t confuse Loudness Normalization with Peak Normalization.

With Peak Normalization an audio file’s total gain is raised to specified amount (usually to 0 dBFS), but only based on the highest measured peak in the audio.  

Here’s a plastic example; you have an audio file in which two characters are talking, and they are interrupted by loud gunshot. The gunshot nearly clips at -1 dBFS (i.e., the waveform nearly reaches 0dBFS) so peak normalizing the track will only raise the whole file by 1dB to 0dBFS, and leave the gain of the two characters talking perceptually unchanged —  remember, raising gain by 1dB is barely perceptible to the human ear. 

With loudness normalization the whole file is measured using the aforementioned set of algorithms and noise gates to determine the average or Integrated Loudness of the whole file. The algorithms and gates take into account the loud and quiet parts of the “program material” ignoring quiet parts (below a threshold of -70 LUFS as defined in the documents) and allowing for louder parts momentarily, and then spit out an Integrated Loudness value (I) after the whole file has been analyzed. 

The Integrated Loudness level is the value that will determine the perceived loudness of the whole track. 

When program material needs to be -23LUFs +/- 0.5 this is the value to check—it is important to understand that during playback parts of the material (music/dialog/EFX etc.) can be louder or softer than the target (I), but again, it’s the overall average loudness which is taken into account.

Referring to our plastic example above; as long as the gunshot peaks at or below a permitted momentary loudness level (EBU  R128 specifies a maximum short term loudness (3 seconds or less) of +/- 5LU or -18LUFS) the whole file will be raised (or lowered) in volume “x” amount of LU so that the dialog (average loudness) sits at -23 LUFS while the gunshot (outside the average) has heaps of headroom to play into. 

This will have more of an impact on the audience because the dialog is now audible and the gunshot has not been squashed down by a limiter or compression and thereby lessening the dynamics (and drama) between the two sonic elements.

The implications for more dynamics in music are also apparent.

Myth #5: dBFS peaks and RMS are more important to monitor than true peak or LUFS/LU readings. 

Fact #5: Peak metering is rapidly becoming unnecessary, and essentially never gave us useful information to begin with. Intersample peaks are not correctly registered by peak-sample meters. For example, a traditional sample-peak meter that displays a max of -0.2 dB could read as high as +3 dB on a true-peak meter.  

With the new Maximum True Peak Level of -1 dBTP, the previous PML (Permitted Maximum Level) -9 dBFS (as defined in ITU-R BS.645-2) is effectively obsolete and potentially replaces the previous music mixing standard for CD and online material of peaks no higher than -0.3 - 0.5 dBFS (once mastered).

As of this writing Logic X 10.2.2 has integrated True Peak measuring into all of its native meters and it is highly recommended to use true peak measurements from here on out. 

As for RMS—RMS is much more useful for gauging the actual, longer term, levels of a given waveform, but RMS is only a measurement (or display) of signal voltage, so it doesn't really give us an idea of perceived loudness. Two music tracks measuring the same RMS values may not necessarily have the same perceived loudness because RMS does not take into account the psychoacoustic nature of apparent loudness as heard by the human ear,  specifically that low, mid and high frequencies of the same level are not perceived as being the same loudness.  

The Integrated loudness measurement specifically takes into account this aspect of human hearing perception of loudness and adjusts accordingly. 

Conclusion

 So what does all this mean for music?  

In the EBU-R128 documentation it is explicitly suggested that no major changes to current mixing styles (as of 2016) are immediately necessary, but it is strongly recommended to consider the implications.

For music producers and engineers there are two choices:

  1. Mix as you always have, and have your music turned down later by loudness compliant playback systems
  2. Mix to the new loudness standard of -23 LUFS/-1 dBTP and utilize the large headroom and dynamic range it affords. 

When you mix/master your music track to the current standard of 16 bit 44.1kHz with peaks at between -0.3 and -0.5 dBFS with an average RMS of say -12dB to - 6dB (brickwall limited and loud) this track when measured with a EBU compliant meter will show levels way above -23 LUFs (and possibly true peaks upwards of +3dB) and thus will be turned down until it has an integrated loudness of -23 LUFS. 

No compression, no further processing, just literally turned down.

 

What this means is that pushing for high RMS values and squashing out dynamic range will  now actually work against your music when your “sausage” is played against music mixed to utilize the dynamic range afforded by the -23 LUFS mix headroom.

“Loud” over compressed and brickwall limited music - read: music with no dynamics -  really cannot compete sonically with more dynamic material in the new standards.

Learn all about audio production and concepts in The Ask.Audio Academy.

Shane is an SAE certified audio engineer, sound designer, composer, and audio consultant. Working with Tokyo based media agency Ultrasupernew and creative game agency Playbrain, he creates audio for TV, music and sound for product launch events, and web audio content for major multinational firms such as Red Bull, SuperCell, Heineke... Read More

Discussion

Andy
I'm stuck.. Help.. I've conducted research into loudness.. I use FL Studio and FabFilter plugins. I've read about the EBU R128 and would very much like to know if this is the target level to aim for whilst producing EDM..

These are my thoughts..

Gain staging..
Should I aim for -18 dbfs/lufs rms and not allow peaks to peak higher than -1 dbtp now that the -9 dbfs peak level safety celling is now gone?

Or.. Could I aim for -23 Lufs and go for a peak level no higher than -1 dbtp?

Master Track..
Aim for the EBU R128 recommended -23 Lufs and again not allow peaks over -1 dbtp?

I've looked at the loudness plugin videos and manuals and they seem to suggest a target level of -16 Lufs for mixing and -9 Lufs for mastering.

Is -23 Lufs for music production?

Please help...

Thank you

Andy
Shane Berry
Hi Andy,

Thanks for taking the time to read the article and to post this question.

For EDM going online, I advise aiming for -16 LUFS with peaks no higher than -1 dB TP and for the dance floor between -12 to -9 LUFS. Although, I would argue that - 9 LUFS defeats the point of caring about levels to some degree, and -12 LUFS is still too loud, but even then neither are quite as crushed and obnoxious as CD standards and should be competitive loudness wise.

Headroom wise even several tracks at -18 dB RMS will start to clip the master bus when summed, so use the -18 RMS per track as a guide rather than a rule.

Happy mixing.
Sam
Hello Shane, Thanks so much for an incredibly useful article. I have few questions in my web of confusion.

1. My HOFA metering plugin measures -18dBFS = -18 LUFS with a 1kHZ sine wave. So according to your recommendation mix peaking at -18 LUFS is same and equal as mix peaking at -18 dBFS. If that is, can i use my Pro Tools meter instead of LUFS meter, just to rule out this confusion ?
2. Many Audio Gurus are teaching about plugin sweet spot as -18 dBFS which is equal to 0VU. If i am aiming to mix at -23 LUFS for maximum dynamics, my individual tracks will average below -18dBFS/0VU i.e much below the plugin sweet spot which is counter productive.

I am completely stuck in this web of confusion. Please kindly help me.

Till now i am peaking my Mix at -6dBFS and averaging my individual tracks at 0VU (using Bomb factory VU meter plugin). Thanks for your help.

Blessings
Sam.
Shane Berry
Sam

Comment:

Hello Shane, Thanks so much for an incredibly useful article.

Reply:

No problem, glad to be shedding some light on this grey area of audio.

Comment:

I have few questions in my web of confusion.

Reply:

Let’s do it.

Question:

1. My HOFA metering plugin measures -18dBFS = -18 LUFS with a 1kHZ sine wave.

Answer:

It’s cool that you have taken the time to check your plug-ins and see for yourself.

A sine wave is great way to test and calibrate systems; however, a sine tone in no way mimics the behaviour of “real” sound, or how the human ear perceives loudness.

Rather, run -18 dB PINK NOISE into your Hofa Meter and see what happens.

It will read around -24 LUFS, and because it is a relatively steady signal it will measure around -24 dB RMS too. Now check your peak meter. It’s probably hovering around -16 dBFS. On a VU meter calibrated to -18 the reading will hover around -6 dB.

The key difference to understand about dBFS, RMS, and LUFS measurements is that LUFS measurements explicitly account for how the human ear perceives loudness.

Two sounds might measure the same RMS (or dBFS peaks) but they are not necessarily the same perceived loudness.

Question:

So according to your recommendation mix peaking at -18 LUFS is same and equal as mix peaking at -18 dBFS.

Answer:

NO, the concept of “peaking” at or near a given dBFS level is largely moot with loudness standards. You are aiming for an average integrated measurement of a desired target loudness level at the end of the mix.

How you get there is up to you. As mentioned in the article:

"For music producers and engineers there are two choices:

1. Mix as you always have, and have your music turned down later by loudness compliant playback systems
2. Mix to the new loudness standard of -23 LUFS/-1 dBTP and utilize the large headroom and dynamic range it affords."

For music not destined for broadcast -23/-24 LUFS is only a guideline during mixing.

The practice is that staying within these parameters will eliminate issues with headroom and peaks, and allow for you to work on the mix with a huge “safety margin”.

Question:

If that is, can i use my Pro Tools meter instead of LUFS meter, just to rule out this confusion ?

Answer:

Of course you can stick with the pro tools metering, but bear in mind that unless the meter applies the BS-1770 algorithm and meets the requirements of a loudness compliant meter, it is an old school peak/RMS meter and does not correlate to industry standards of loudness measurement.

But, as mentioned above a Peak/RMS measurement is not the same as a LUFS/True Peak measurement.

RMS does not account for perceived loudness and normal peak meters cannot measure intersample peaks.

Question:

2. Many Audio Gurus are teaching about plugin sweet spot as -18 dBFS which is equal to 0VU. If i am aiming to mix at -23 LUFS for maximum dynamics, my individual tracks will average below -18dBFS/0VU i.e much below the plugin sweet spot which is counter productive.

Answer:

The “sweet spot” of certain analog model plugins is certainly a factor to take into consideration when using them. Those kinds of plug-ins are expecting a certain gain level of input to do their job “properly”.

But, when using a -18 dB pink noise test signal, which is more closely aligned with how we hear than a sine wave, we can see that it correlates to -24 LUFS which actually measures around -16 dBFS.

Comment:

I am completely stuck in this web of confusion. Please kindly help me.

Reply:

A man with one watch knows what time it is, a man with two watches is never quite sure… ;)

I feel your pain, there are just too many metering plug-ins to get to the same goal.

Comment:

Till now i am peaking my Mix at -6dBFS and averaging my individual tracks at 0VU (using Bomb factory VU meter plugin).

Reply:

My first recommendation is to find a less confusing loudness compliant meter, especially if you are using the free Hofa 4U Meter Fader. That GUI is very confusing.

Try the free Youlean Loudness Meter, much easier to use and read, or try the Loudness Analyzer in the Melda Free Bundle.

Hands down the best VU meter is the Klanghelm VUMT. It is only 15 Euros and it’s a staple in many mixer’s toolbox. It’s far more flexible than the BF Essential Meter Bridge (I wouldn’t use the BF Essential Noise Meter).

If money is tight, then at the very least calibrate your BF Essential Meter Bridge to -18 Peak/RMS.

If you’re levelling individual tracks to 0VU and 0VU is calibrated to -18 dB RMS that is a fine place to start.

Just remember, meters are guides not handcuffs.

Your ears take precedence over all.

If it sounds good, but the meter values are not ”right”, ignore them and trust your ears.

The only technical barrier to consider is no intersample peaks over -1dbTP, don’t ignore those!

Comment:

Thanks for your help.

Reply:

No problem at all, I hope this answer clears up some info for you.

Blessings

And to you Sam, all the best.
Sam
Hello Shane, Thank you very much for taking time to answer all my questions very detailedly. You removed the layer of confusion that was creating a lot of frustration. I leave no time but will incorporate the LUFS measurement into my workflow immediately, very excited about that. Thank you once again for caring to recommend some great plugins and thereby pointing me in the right direction. Will definitely contact you if i have any more questions about metering. I am very thankful to you Sir.

God Bless.
Sam.
Sam
Hello Shane, i've got a feedback. As you have suggested, i used a Pro Tools Pink noise generator with -18dBFS set to Peak and the following are the readings on different plugins

-18dBFS Pink noise (set to Peak) in Pro Tools.

TB ProAudio dpMeter ii = -20.6 LUFS Integrated / Peak meters show -15.9 dBFS
HOFA 4U Meter = -20.6 LUFS Integrated
TB ProAudio dpMeter ii = -24.0 RMS / Peak meters show -18 dBFS
Bombfactory Meter Bridge VU meter hovering around -0.5 VU (when in Peak Mode)
Bombfactory Meter Bridge VU meter hovering around -6.5 to -7 (When in RMS Mode)
PSP VU 3 VU Meter hovering around -3.5VU
Pro Tools meters = -18dBFS

Sorry for troubling you. I am looking forward to clear off my confusions before even i press play on my next project. I am using my old Mac mini with OSX 6.8 and Pro Tools LE 8 and Digidesign 003 R.
Please kindly help.

Thanks a lot for all your efforts to help me.

Blessings
Sam.
Shane Berry
Hi Sam,

A few things.

Try setting the Pink Noise Generator to RMS and see what happens.

It may seem counterintuitive, but we are using the meters to check the pink noise, not the other way around.

Furthermore, not all signal generators are equal. For example the MNoiseGenerator by Melda has to be set at -13.8 dB to measure -23 LUFS on the dpMeter2. The mda noise generator has to be set at -22.5 to measure -23 LUFS. Logic's Test Osc measures -24 LUFS when pink noise is output at -18dB.

So, use the dpMeter2 as your main loudness meter for now.

Set the gain of the ProTools pink noise so it that reads -23 LUFS (Integrated) on the dpMeter2. (The signal generator will not necessarily end up at -18 dB on its GUI, as I said, it varies from plug-in to plug-in.)

Check this calibrated signal with your VU meter of choice. Make sure its “reference level” is set to -18 dBFS.

(Also, make sure to switch the PSP VU to true peak detection.)

Finally, don’t overthink a plate of beans!

The key concept here is that all these reference levels relate in some way.

If you meter with RMS keep average levels within -18dB to -24dB.

If you mix with VU (on a meter referenced/calibrated to -18dB) keep average levels within -6dB

If you meter with LUFS keep average levels within -23 LUFS.

The main difference between these measurements is that loudness compliant measurements are also accounting for perceived loudness.

But, these are not absolute figures! Some mix elements will have to be louder or softer than these recommended levels.

Meters are not there to dictate which levels “must be used”. They are there to warn us when we are going too close to the digital edge.

Another thing.

Metering on individual tracks can be quite distracting. I would recommend using meters strictly on the whole mix (master bus) and loosely on each track. This frees up space for creative levelling and processing. You can work freely as long as the whole mix doesn’t go over the target levels, and each track can do what it needs to do in the context of the entire song.

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