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LUFS vs SPL Monitor Controllers
Old 1 week ago
  #1
Here for the gear
 

LUFS vs SPL

Hello,

I know this is probably a newbie question but i am going to ask it anyway since it has been bothering me lately.

I am using a monitor controller that has a SPL meter inside of it (Grace m905 set to c-weighted, slow response).

The question is how does SPL level differ from LUFS. One thing that I have noticed that is puzzling me is when referencing released tracks to my mixes/masters, the released tracks are registering a higher SPL number than my mixes/masters but have a lower LUFS number. So even though my mixes/masters are "louder", the released tracks are making the SPL meter read higher numbers. I would love to figure out what is causing this so I can make my mixes hit loud (higher SPL) but be more dynamic (lower LUFS number). I feel like for my mixes to compete i have to pancake them much more than other peoples released mixes.

I hope that explanation makes since. Thanks in advance for helping!
Old 6 days ago
  #2
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Bart Nettle's Avatar
LUFS is related to full scale similar to the rms value but is the measured loundness of a track over the whole track.
If there are quite passages it lowers the overall LUFS and the louder parts can be louder, slightly and depends upon frequencies involved.
If no quiet passages LUFS will be the same but at a perceived lower loudness.

There is a more to this; some mixes are mixed to peak meters with little to no reference to average levels and the perceived volume is low even though it has elements peaking and sucking up the loudness range.

Checkout the K weighted frequency curve.

Record and mix to rms levels. Roll off the sub bass energy which will eat up your loudness range and some quick phase switching for the occasional digital over, but, mostly liberal corrective EQ cuts to optimize the dynamics within your peaks without ruining the mix.
Old 6 days ago
  #3
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jwh1192's Avatar
Amen !!! Average Volume is your Friend !!
Old 6 days ago
  #4
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Quote:
Originally Posted by DMagnus View Post
Hello,

I know this is probably a newbie question but i am going to ask it anyway since it has been bothering me lately.

I am using a monitor controller that has a SPL meter inside of it (Grace m905 set to c-weighted, slow response).

The question is how does SPL level differ from LUFS. One thing that I have noticed that is puzzling me is when referencing released tracks to my mixes/masters, the released tracks are registering a higher SPL number than my mixes/masters but have a lower LUFS number. So even though my mixes/masters are "louder", the released tracks are making the SPL meter read higher numbers. I would love to figure out what is causing this so I can make my mixes hit loud (higher SPL) but be more dynamic (lower LUFS number). I feel like for my mixes to compete i have to pancake them much more than other peoples released mixes.

I hope that explanation makes since. Thanks in advance for helping!
1 LUFS = 1db. LUFS is an absolute measurement. SPL is a logarithmic ratio, referenced against some relative value.

So, you worrying about matching a weighted SPL measurement to an LUFS measurement makes no sense. I suppose it could be done, at great mental expense and trouble, but why? LUFS is absolute for a reason. It makes matching up track levels quick and takes the reference brainwork out of the equation. Forget SPL. Use LUFS and your ears....
Old 6 days ago
  #5
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avare's Avatar
 

Another factor not mentioned yet is peaks removed from the tracks you are comparing to. If your tracks do not have peaks removed then naturally the peak reading on your tracks will be louder.

Andre
Old 6 days ago
  #6
SPL, describes sound pressure level in air, and is measured from the low threshold of human hearing. It is therefore generally seen as a positive value and measured using a logarithmic scale (in decibels/dB).

LUFS -- also known as LKFS (Loudness, K-weighted, relative to full scale) -- was designed to measure signal loudness relative to a maximum value over time (to get an averaged level) for broadcast and other purposes (also making it useful for talking about CD level, since the digital format has an absolute maximum). Because it is relative to a maximum level, it is typically seen as a negative numeric value. LUFS is also a logarithmic scale; one LUFS unit is equivalent to one dB.

Quote:
When measuring loudness, three terms are essential to be aware of: LKFS, LUFS and LU. What tends to create confusion is that these terms are very similar and basically aims at describing the exact same thing.

LKFS is an abbreviation of: Loudness K-weighted Full Scale, and one unit of LKFS is equal to one dB.The LKFS term is used in the ITU BS.1770 standard and the ATSC A/85 standard also operates with this term. Other organizations, such as The European Broadcast Union (EBU), uses the term LUFS, which is an abbreviation of Loudness Units Full Scale. Despite the different names, LF KS and LUFS are identical. Both terms describe the same phenomenon and just like LKFS, one unit of LUFS is equal to one dB.
However there are other important differences and aspects of the 'new' LUFS standard ... more at the source of the above, here:
Loudness Explained Page | MUSIC Group - TC Electronic)
Old 6 days ago
  #7
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Quote:
Originally Posted by theblue1 View Post
SPL, describes sound pressure level in air, and is measured from the low threshold of human hearing. It is therefore generally seen as a positive value and measured using a logarithmic scale (in decibels/dB).

LUFS -- also known as LKFS (Loudness, K-weighted, relative to full scale) -- was designed to measure signal loudness relative to a maximum value over time (to get an averaged level) for broadcast and other purposes (also making it useful for talking about CD level, since the digital format has an absolute maximum). Because it is relative to a maximum level, it is typically seen as a negative numeric value. LUFS is also a logarithmic scale; one LUFS unit is equivalent to one dB.



However there are other important differences and aspects of the 'new' LUFS standard ... more at the source of the above, here:
Loudness Explained Page | MUSIC Group - TC Electronic)
How can LUFS be logarithmic when it is an ABSOLUTE measure of loudness? A decibel is the LOGARITHM of a ratio. A dB also needs a referencing value in order for it to be meaningful, in watts or volts...

Just because 1dB is equal to 1 LUFS, does not mean it is Logarithmic.

A dB quantifies the air molecules displaced by a soundwave.
LUFS upholds the consistency of the resulting volume from the source audio.
A dB uses air pressure as a reference for measuring sound intensity.
LUFS does not require a reference to measure the same loudness...
Old 6 days ago
  #8
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Sigma's Avatar
Simple...LUFS is percieved/apparent loudness taking into account the fletcher munson ear sensitivity curve in it's calculations
Old 5 days ago
  #9
Which loudness values are you comparing to SPL? Integrated, short term, or momentary?

Bottom line is that while both loudness and spl units tell you something about volume, they tell you different things.

Mix with your ears, then use Loudness measurements to normalize.
Old 5 days ago
  #10
Quote:
Originally Posted by UKMK00 View Post
How can LUFS be logarithmic when it is an ABSOLUTE measure of loudness? A decibel is a LOGARITHM of a ratio. A dB also needs a referencing value in order for it to be meaningful, in watts or volts...

Just because 1dB is equal to 1 LUFS, does not mean it is Logarithmic.

A dB quantifies the air molecules displaced by a soundwave.
LUFS upholds the consistency of the resulting volume from the source audio.
A dB uses air pressure as a reference for measuring sound intensity.
LUFS does not require a reference to measure the same loudness...
I suspect you're confusing absolute measure (a measure against a specific standard in this case) with the concept of numeric values plotted on a linear scale, rather than a logarithmic scale.

A logarithm is not something squishy or ill-defined. It is a scale which can be as precise as a linear scale.

If we have a defined, absolute value for x, then if we specify a value, for instance, 30 dB below x, that defined value, too, represents an absolute value, even though we use a logarithmic scale in defining it.


My 'explanation' is necessarily simplified. I strongly suggest that folks who are unclear on it all read the TC Electronics explainer to which I linked.
Old 5 days ago
  #11
Quote:
Originally Posted by Sigma View Post
Simple...LUFS is percieved/apparent loudness taking into account the fletcher munson ear sensitivity curve in it's calculations
More on how Fletcher Munson's research and earlier loudness scale specifications relate to LUFS...

dB(A), dB(C), LUFS…. – Refined Audiometrics Laboratory
Old 5 days ago
  #12
Quote:
Originally Posted by UKMK00 View Post
How can LUFS be logarithmic when it is an ABSOLUTE measure of loudness? A decibel is a LOGARITHM of a ratio. A dB also needs a referencing value in order for it to be meaningful, in watts or volts...

Just because 1dB is equal to 1 LUFS, does not mean it is Logarithmic.

A dB quantifies the air molecules displaced by a soundwave.
LUFS upholds the consistency of the resulting volume from the source audio.
A dB uses air pressure as a reference for measuring sound intensity.
LUFS does not require a reference to measure the same loudness...
dB is just a ratio. dB has nothing to do with air pressure; you’re thinking of dBSPL or similar.

dBu, dBV, dBVU - nothing to do with air.

a dB is a simple gain change, but otherwise meaningless. You can add 30dB of gain, or say one signal is 30dB louder than another, but you can’t set something to 30dB. You need the reference point - which is where the SPL, u, V or whatever comes in.

Technically I’m not sure that LUFS shouldn’t correctly be called dB(LUFS).
Old 5 days ago
  #13
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Quote:
Originally Posted by theblue1 View Post
I suspect you're confusing absolute measure (a measure against a specific standard in this case) with the concept of numeric values plotted on a linear scale, rather than a logarithmic scale.

A logarithm is not something squishy or ill-defined. It is a scale which can be as precise as a linear scale.

If we have a defined, absolute value for x, then if we specify a value, for instance, 30 dB below x, that defined value, too, represents an absolute value, even though we use a logarithmic scale in defining it.


My 'explanation' is necessarily simplified. I strongly suggest that folks who are unclear on it all read the TC Electronics explainer to which I linked.
Im not confused. You are. If a value is measured on a logarithmic scale,it can include values along the number line below the value "0", as well as values "between" an "ABSOLUTE" value of 0 or 1 . LUFS STARTS at "0". LUFS is a scientific standard measurement that "DOES NOT" include logarithmic values , its pretty specific about being an "ABSOLUTE" value.

Im just trying to provide some clarity. You are trying to prove how smart you are. Additionally, the TC electronic info DOES NOT SAY ANYTHING about LUFS being Logarithmic. You added that....
Old 5 days ago
  #14
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Quote:
Originally Posted by psycho_monkey View Post
dB is just a ratio. dB has nothing to do with air pressure; you’re thinking of dBSPL or similar.

dBu, dBV, dBVU - nothing to do with air.

a dB is a simple gain change, but otherwise meaningless. You can add 30dB of gain, or say one signal is 30dB louder than another, but you can’t set something to 30dB. You need the reference point - which is where the SPL, u, V or whatever comes in.

Technically I’m not sure that LUFS shouldn’t correctly be called dB(LUFS).

A dB is NOT "just a ratio".. Its the Log of a ratio. A dB has EVERYTHING to do with air pressure, "when" its referenced against SPL. Which is what the original poster asked for.

Why are you trying to mansplain the different dB references to me when I clearly already know that the dB is meaningless by itself?

Thanks Captain Obvious!!

Why are you trying to Explain LUFS when you clearly dont even know what it Means? Or what its "NOT" referenced to?
Old 5 days ago
  #15
Quote:
Originally Posted by UKMK00 View Post
Im not confused. You are. If a value is measured on a logarithmic scale,it can include values along the number line below the value "0", as well as values "between" an "ABSOLUTE" value of 0 or 1 . LUFS STARTS at "0". LUFS is a scientific standard measurement that "DOES NOT" include logarithmic values , its pretty specific about being an "ABSOLUTE" value.

Im just trying to provide some clarity. You are trying to prove how smart you are. Additionally, the TC electronic info DOES NOT SAY ANYTHING about LUFS being Logarithmic. You added that....
I quoted the pertinent TC Electronics info in the post that you, yourself quoted.

But, hey, I can do it again:

Quote:
When measuring loudness, three terms are essential to be aware of: LKFS, LUFS and LU. What tends to create confusion is that these terms are very similar and basically aims at describing the exact same thing.

LKFS is an abbreviation of: Loudness K-weighted Full Scale, and one unit of LKFS is equal to one dB.The LKFS term is used in the ITU BS.1770 standard and the ATSC A/85 standard also operates with this term. Other organizations, such as The European Broadcast Union (EBU), uses the term LUFS, which is an abbreviation of Loudness Units Full Scale. Despite the different names, LF KS and LUFS are identical. Both terms describe the same phenomenon and just like LKFS, one unit of LUFS is equal to one dB.
[bold added] Loudness Explained Page | MUSIC Group - TC Electronic)

You're correct that the TC explainer does not use the word logarithmic -- but I'm not sure that should really be necessary when addressing experienced recordists. Any basic definition of decibel (including standard dictionaries) provides that info.

With regard to use here of the term absolute scale: Absolute scale - Wikipedia. It's worth noting that the common use of 'absolute' to describe LUFS/LKFS may be confusing things, here, since in normal definition an absolute scale has only positive values (an absolute value, for instance, is independent of 'sign').

With regard to this...
Quote:
Originally Posted by UKMK00 View Post
[...] You are trying to prove how smart you are. [...]
Since I knew next to nothing about LUFS before I started this thread (I'm retired and not in the EU) but did know a bit about LKFS, I wouldn't say I was particularly informed on the topic at all.

But I can read. If I've posted something incorrect above, I'm more than happy to be corrected with supporting facts from authoritative sources -- and I'll gladly admit my error in such a case. I'd rather admit to being wrong than incorrectly perceived as being right.*

* Oh, geez... and now having said that, someone is sure to accuse me of 'virtue signalling' or whatever that alt-right term is.


PS... I think you're going to find that psycho_monkey has a pretty good grounding in the technology and science of audio. Just an FYI.

Last edited by theblue1; 5 days ago at 07:39 PM..
Old 5 days ago
  #16
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Quote:
Originally Posted by theblue1 View Post
I quoted the pertinent TC Electronics info in the post that you, yourself quoted.

But, hey, I can do it again:

[bold added] Loudness Explained Page | MUSIC Group - TC Electronic)

You're correct that the TC explainer does not use the word logarithmic -- but I'm not sure that should really be necessary when addressing experienced recordists. Any basic definition of decibel (including standard dictionaries) provides that info.

With regard to use here of the term absolute scale: Absolute scale - Wikipedia. It's worth noting that the common use of 'absolute' to describe LUFS/LKFS may be confusing things, here, since in normal definition an absolute scale has only positive values (an absolute value, for instance, is independent of 'sign').

PS... I think you're going to find that psycho_monkey has a pretty good grounding in the technology and science of audio. Just an FYI.
Clearly, the person who started the thread was less than experienced. I tried to make it as simple as possible. You tried to show how smart you are. Im not intimidated by anyones credentials.

Im as smart as any of the doubletalking selfserving jackasses on GS....

Absolute values are indeed positive. LUFS are defined as Absolute, not by me, but by the standard itself. Absolute values are a different measurement than logarithmic. Yes, thanks for mansplaining that for me. dB is a log of a ratio. Yes, also fully understood. Your Mansplaining prowess knows no bounds.
Old 5 days ago
  #17
Seems to me this thread has gotten off on a tangent; few posters have addressed the OP's original question.

Why is it that his masters measure louder than reference releases on the LUFS scale but less loud on the SPL scale? The heart of what he seems to what to know is this: what was done to the reference releases that made them measure higher (louder) on the SPL meter but lower on the LUFS meter?
Old 5 days ago
  #18
Quote:
Originally Posted by UKMK00 View Post
A dB is NOT "just a ratio".. Its the Log of a ratio. A dB has EVERYTHING to do with air pressure, "when" its referenced against SPL. Which is what the original poster asked for.

Why are you trying to mansplain the different dB references to me when I clearly already know that the dB is meaningless by itself?

Thanks Captain Obvious!!

Why are you trying to Explain LUFS when you clearly dont even know what it Means? Or what its "NOT" referenced to?
Sorry - you referenced “dB” on its own - which has nothing to do with air pressure. If that’s just a typo/lazy referencing fine - but it’s also confusing as you can see (and possibly deserves a bit of mansplaining). If you’d written dBSPL I wouldn’t have said anything...

yes, the log of a ratio. But still just a ratio between 2 things. Without a reference point, it’s meaningless as absolute.

My post was not meant specifically to correct YOU - more to clarify what you said, so don’t take it personally. What you wrote wasn’t clear, and as you’d at the OP already isn’t clear about things.
Old 4 days ago
  #19
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Quote:
Originally Posted by theblue1 View Post
SPL, describes sound pressure level in air, and is measured from the low threshold of human hearing. It is therefore generally seen as a positive value and measured using a logarithmic scale (in decibels/dB).

LUFS -- also known as LKFS (Loudness, K-weighted, relative to full scale) -- was designed to measure signal loudness relative to a maximum value over time (to get an averaged level) for broadcast and other purposes (also making it useful for talking about CD level, since the digital format has an absolute maximum). Because it is relative to a maximum level, it is typically seen as a negative numeric value. LUFS is also a logarithmic scale; one LUFS unit is equivalent to one dB.



However there are other important differences and aspects of the 'new' LUFS standard ... more at the source of the above, here:
Loudness Explained Page | MUSIC Group - TC Electronic)

Thank you for your response. You said, “SPL, describes sound pressure level in air...”. My question is why are my mixes not moving as much “air” (SPL) even when I am matching or exceeding the LUFS values of the songs I am comparing it to. What is causing that?
Old 4 days ago
  #20
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Quote:
Originally Posted by TMetzinger View Post
Bottom line is that while both loudness and spl units tell you something about volume, they tell you different things.
Can you elaborate on what different things they tell you? Is there anything in the frequency balance? Like do they read the entire frequency range the same way? I’m just trying to understand why I can seem to match LUFS values of other songs but my songs SPL level is lower compared to the other songs. It’s like my songs don’t want to “Pop out of the speakers,” and instead are “tilted back inside the speakers” regardless how loud I make it.
Old 4 days ago
  #21
Quote:
Originally Posted by DMagnus View Post
Hello,

I know this is probably a newbie question but i am going to ask it anyway since it has been bothering me lately.

I am using a monitor controller that has a SPL meter inside of it (Grace m905 set to c-weighted, slow response).

The question is how does SPL level differ from LUFS. One thing that I have noticed that is puzzling me is when referencing released tracks to my mixes/masters, the released tracks are registering a higher SPL number than my mixes/masters but have a lower LUFS number. So even though my mixes/masters are "louder", the released tracks are making the SPL meter read higher numbers. I would love to figure out what is causing this so I can make my mixes hit loud (higher SPL) but be more dynamic (lower LUFS number). I feel like for my mixes to compete i have to pancake them much more than other peoples released mixes.

I hope that explanation makes since. Thanks in advance for helping!

Quote:
Originally Posted by DMagnus View Post
Thank you for your response. You said, “SPL, describes sound pressure level in air...”. My question is why are my mixes not moving as much “air” (SPL) even when I am matching or exceeding the LUFS values of the songs I am comparing it to. What is causing that?
I'm not familiar with that monitor controller, but I note this from the SOS review of it:
Quote:
The actual monitoring SPL, as detected by the built-in talkback mic, is also permanently displayed below the speaker volume setting, while the digital input source parameters are revealed below the headphone volume setting (word-length, sample rate, clock source, and s-Lock status).
I'm assuming you're making your comparisons with a fixed control room volume (so that the SPL readings from your talkback mic will be consistent across all your program material, the mixes and references you're using for this comparison).

While differences in weighting (discussed in attached articles above) might account for a certain 'disconnect' in expected results, I suppose we would expect to see something of an inverse relationship overall.

One thing I could see that might be at work is that, since the SPL meter is measuring the SPL in your specific room as you play your commercially released references vis a vis your own tracks, maybe differences in the tonal balance between how your reference tracks and your own tracks interact with your room (with regard to standing wave cancellation, etc) are at play in the unexpected 'disconnect' between expected meter readings.


Consider this: the reference tracks are presumably mixed/mastered in high end studios/rooms, but your tracks are mixed (and self-mastered if you're doing that) in your room. It's probably treated, and may sound pretty good -- but it may well have some 'room response' anomalies across the frequency spectrum that the monitor controller talkback mic being used to feed the SPL meter is subject to.

So, continuing in this line of thinking, the commercial reference tracks may be exciting room resonances that skew their response in the room, making some frequency ranges boom out. (And the SPL meter to go high on those resonances.)

But YOUR tracks, mixed/mastered in your own CR -- with any possible room response imbalances that may exist -- were likely mixed in such a way to sound 'good' in your room, unconsciously EQ shaping the mix in such a way that it sounds 'even' in the room.

Such a scenario might well result in seemingly anomalous divergence between the two quite different measures -- the electronic signal of the mixes -- vis a vis the sound of the mix in the room picked up by the talkback mic.


Finally, also worth considering, perhaps in addition to the above possible explanation: the talkback mic on your monitor controller may simply not be designed for super-accurate SPL reading across the entire frequency range.

After all, it's not an expensive reference mic -- it's a talkback mic built into a CR monitor controller -- and the SPL metering is provided to help engineers maintain a constant level in the control room (for all the reasons Bob Katz and others have explained), not for super-accurate acoustic analysis.


Wish I could be more help.
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