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How are the specs for level determined?
Old 28th January 2009
  #1
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How are the specs for level determined?

Can anyone tell me how the level specs are determined by the broadcaster, radio station etc.? I'd love to know because just about every client I ask for specs has no clue what I'm talking about (and I don't mean the ad firm, I'm talking the people right from the film production company). This is really just a curiosity thing more than ever, I would love to better understand how they come up with the magic number.

Thanks!

Paul
Old 28th January 2009
  #2
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I've seen specs that were literally photo copies of other network's specs. Half the time the people implementing the specs don't even know what they mean.

I'm not sure how the specs are determined for sure, but at least with the LM100 it was a fluke. Dolby delivered them with the dialnorm set at -27 just to have it set at something. The networks assumed this was what it was "supposed" to be and made that their spec. (This was told to me by a Dolby rep.)
Old 28th January 2009 | Show parent
  #3
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Quote:
Originally Posted by Frank S. ➑️
Dolby delivered them with the dialnorm set at -27 just to have it set at something. The networks assumed this was what it was "supposed" to be and made that their spec. (This was told to me by a Dolby rep.)
If that's true, that's hilarious!

Personally, I love mixing at -27. It keeps my Dialog a little lower so that I have more room for dynamics when I need a nice whiz-bang. When your slamming -10 at -16 dialnorm [spots... & totally slammed/square waved shows] you don't really have anywhere to go heh. I was always puzzled when I heard people complain about a lack of dynamic range with -27 dialnorm. If anything, [with -10 peak/-27 dialnorm] it's giving you tons more dynamic range than "normal" [-10 peak/-22ish dialnorm]. Especially since a lot of broadcast surround specs have no peak limitation.

oh crap... I think we just yanked this thread into LM100/Dialnorm territory in 1 post!

back to the original question.... standard specs in the US call for -10 peaks. (Even though my buddies that do spots tell me they mix at -6... shocking huh?!?) This goes back to analog land. I've seen a few good post about this in the past.. maybe on the DUC?
Old 28th January 2009 | Show parent
  #4
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The latest spec sheet to hit the streets is from NBC.

-8 peaks on all channels

-23 LKFS
Old 28th January 2009 | Show parent
  #5
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Quote:
Originally Posted by nathand ➑️
The latest spec sheet to hit the streets is from NBC.

-8 peaks on all channels

-23 LKFS

Yeah... it seems to average -8 peaks for Networks / -10 for Cable.

[When I mixed at G4, we peaked at -16!]
Old 28th January 2009 | Show parent
  #6
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I was under the impression that peak levels were originally transferred/adapted from analogue levels... analogue signals had to be broadcast at certain levels so as to actually work (I'm not very technical when it comes to over-the-air-transmission) - and when things went digital all the calibration and stuff roughly lined up to -8/-9/-10 depending on what country you're in.

I'm sure there's more to it (especially when it comes to the voodoo that is dialnorm) but someone once told me that this was the basic version of the story...
Old 29th January 2009 | Show parent
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Hi Have a look at this thread over at the DUC:
It's written by the Audio Post Supervisor at DCI

Dolby LM100 and Discovery deliverables - Digi User Conference
Old 29th January 2009 | Show parent
  #8
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Quote:
Originally Posted by nucelar ➑️
Hi Have a look at this thread over at the DUC:
It's written by the Audio Post Supervisor at DCI

Dolby LM100 and Discovery deliverables - Digi User Conference
This is fantastic, thanks for posting this.
Old 29th January 2009 | Show parent
  #9
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Some networks allow you to go to peak -3 for HD 5.1 shows. (W/ -24 dialnorm.) PBS is one.

Philip Perkins
Old 29th January 2009 | Show parent
  #10
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Quote:
Originally Posted by philper ➑️
Some networks allow ou to go to peak -3 for HD 5.1 shows. (W/ -24 dialnorm.) PBS is one.
I think (hope) with the full adoption of digital tv broadcasting peak levels will be replaced by DIAL NORM readings.

Of course peak readings may live on in deliverables for a while still.
Old 29th January 2009 | Show parent
  #11
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Quote:
Originally Posted by philper ➑️
Some networks allow ou to go to peak -3 for HD 5.1 shows. (W/ -24 dialnorm.) PBS is one.

Philip Perkins
I don't deal much with specs, 95% of my current client base looks at me funny when I ask for them, so I'm not as up to speed on all of this as I'd like to be (going entirely by ears and guess work here).

A peak of -3 and dialnorm of -24, why would you want to have peaks at -3 if you're dialog is only at -24. I understand the whole concept of loud SFX for dynamic and shocking effect, but a difference like that would give someone a heart attack. I just imagine having someone talking away, they stop and then BANG gunshot or something peaking at the -3. Maybe I'm crazy and missing something here - I openly admit to not exactly knowing much about post and specs etc.
Old 29th January 2009 | Show parent
  #12
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Quote:
Originally Posted by pbell ➑️
I don't deal much with specs, 95% of my current client base looks at me funny when I ask for them, so I'm not as up to speed on all of this as I'd like to be (going entirely by ears and guess work here).

A peak of -3 and dialnorm of -24, why would you want to have peaks at -3 if you're dialog is only at -24. I understand the whole concept of loud SFX for dynamic and shocking effect, but a difference like that would give someone a heart attack. I just imagine having someone talking away, they stop and then BANG gunshot or something peaking at the -3. Maybe I'm crazy and missing something here - I openly admit to not exactly knowing much about post and specs etc.
Yes, you are missing something here. Dialnorm when quoted this way is a long-term average of the dialog level of the whole film. This level is part of each network's spec now, and shows what level they want to see the average dialog of all their shows on that channel to be at, mostly so that viewers do not have to constantly adjust their TV set volume. (I'm not arguing that this is true or works in practice, this is just what the networks say when you ask them why they require that the dialog hit their standard.) The peak level is a different animal entirely, and it is possible to have huge peak levels and a fairly low dialnorm level if only because dialnorm only measures dialog and peak level measures everything. Shows that are speced to have a -24 dialnorm and -3 peak max level can have a lot more dynamic range in the music and SFX than a show with the same -24 dialnorm and a peak spec of -10 (PBS SD shows). The former gives the viewer an experience more like a theatrical feature (where levels can be wherever the director wants within the limits of the equipment and the tolerance of the audience and theatre owner), the latter is what TV mixes have more or less become these days, esp. when those same mixes must be able to be repurposed for web and cel-phone playback.

Philip Perkins
Old 29th January 2009 | Show parent
  #13
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Quote:
Originally Posted by philper ➑️
Yes, you are missing something here. Dialnorm when quoted this way is a long-term average of the dialog level of the whole film. This level is part of each network's spec now, and shows what level they want to see the average dialog of all their shows on that channel to be at, mostly so that viewers do not have to constantly adjust their TV set volume. (I'm not arguing that this is true or works in practice, this is just what the networks say when you ask them why they require that the dialog hit their standard.) The peak level is a different animal entirely, and it is possible to have huge peak levels and a fairly low dialnorm level if only because dialnorm only measures dialog and peak level measures everything. Shows that are speced to have a -24 dialnorm and -3 peak max level can have a lot more dynamic range in the music and SFX than a show with the same -24 dialnorm and a peak spec of -10 (PBS SD shows). The former gives the viewer an experience more like a theatrical feature (where levels can be wherever the director wants within the limits of the equipment and the tolerance of the audience and theatre owner), the latter is what TV mixes have more or less become these days, esp. when those same mixes must be able to be repurposed for web and cel-phone playback.

Philip Perkins
Thanks Philip, I think I understood it more than I thought. So just to clarify, dialnorm is more about average level of dialog than it is about the dialog peak levels?
Old 30th January 2009 | Show parent
  #14
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Quote:
Originally Posted by pbell ➑️
Thanks Philip, I think I understood it more than I thought. So just to clarify, dialnorm is more about average level of dialog than it is about the dialog peak levels?
I'm new to this topic, but if I understood Philip correctly, Dialnorm is exclusively about the average level of dialog.

Can someone please explain what LKFS means? It's the first time I hear about that scale, and I couldn't find its meaning in google. Thanks.


Andres.
Old 30th January 2009 | Show parent
  #15
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Quote:
Originally Posted by pbell ➑️
Thanks Philip, I think I understood it more than I thought. So just to clarify, dialnorm is more about average level of dialog than it is about the dialog peak levels?
Dialnorm is exclusively about average levels OF DIALOG only. The whole basis of Dolby's patents is that an LM100 can (somehow) discriminate between what is dialog in a full mono, stereo or 5.1 mix and what is not. The LM100 can look at a short "sliding window" of time (about 10 sec) and tell you the short term average as it goes (very useful during dialog cutting and premixing) and also has an "infinite" mode which will average over as long a time as the audio stays running (useful for getting the dialnorm of a whole show). This latter figure is mostly what networks are interested in, and what is being referred to around here when people talk about dialnorm. Peak levels as talked about here are peak levels of the whole mix (which an LM100 will show you as well). BOTH are part of network specs, and are looked at in the QC process.

Philip Perkins
Old 30th January 2009 | Show parent
  #16
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Quote:
Originally Posted by Elephant_Talk ➑️
Can someone please explain what LKFS means? It's the first time I hear about that scale, and I couldn't find its meaning in google. Thanks.


Andres.
It's another way of saying ITU-R BS.1770-1.

Does that clear it up?

It's the measurement algorithm in the Dolby Media Meter and an up-to-date LM100.

Here's the definition:

"This designation signifies: Loudness, K weighted, relative to nominal full scale. The LKFS unit is equivalent to a decibel in that an increase in the level of a signal by 1 dB will cause the loudness reading to increase by 1 LKFS."
Old 31st January 2009 | Show parent
  #17
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Quote:
Originally Posted by nathand ➑️
It's another way of saying ITU-R BS.1770-1.

Does that clear it up?

It's the measurement algorithm in the Dolby Media Meter and an up-to-date LM100.

Here's the definition:

"This designation signifies: Loudness, K weighted, relative to nominal full scale. The LKFS unit is equivalent to a decibel in that an increase in the level of a signal by 1 dB will cause the loudness reading to increase by 1 LKFS."
Thanks nathand.

It's actually a bit confusing, but you gave me some good pointers to research more.

Regards,

Andres.
Old 1st February 2009 | Show parent
  #18
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i posted a whole bunch of stuff about dialnorm in my thread...

cheers
geo
Old 1st February 2009 | Show parent
  #19
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Quote:
Originally Posted by georgia ➑️
i posted a whole bunch of stuff about dialnorm in my thread...

cheers
geo
Yes, these posts are just an intro--read thru Georgia's stickies @ the top of the forum and the dialnorm threads on the DUC for a post-graduate course.

Philip Perkins
Old 1st February 2009 | Show parent
  #20
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Paul,
The various reasons why the levels vary form Broadcaster to Broadcaster and medium to medium is because of delivery requirements. By that I mean that some TV networks have to satellite their material from East Coast to West Coast. The different satellites that the networks use have various limitations on the overall level they can be "hit " with.
That is why you see specs such as no more than +10 peaks etc for a Stereo signal.
I had a Chief Engineer at a Major network discuss this with me and it was very interesting. I think as we transition to total digital HD delivery you will see as some have already posted much higher levels for 5.1 material ( in the peaks).
Old 2nd February 2009 | Show parent
  #21
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Quote:
Originally Posted by dr.sound ➑️
Paul,
The various reasons why the levels vary form Broadcaster to Broadcaster and medium to medium is because of delivery requirements. By that I mean that some TV networks have to satellite their material from East Coast to West Coast. The different satellites that the networks use have various limitations on the overall level they can be "hit " with.
That is why you see specs such as no more than +10 peaks etc for a Stereo signal.
I had a Chief Engineer at a Major network discuss this with me and it was very interesting. I think as we transition to total digital HD delivery you will see as some have already posted much higher levels for 5.1 material ( in the peaks).
Well that makes sense. How does this apply to film, or is film fairly standard (never done anything for film)? Now for thread topic 2, methods for acquiring these seemingly sacred specs. Why are some of these companies so unwilling to hand these out to the people supplying them with material. And why do so many people who I'm delivering audio too have absolutely NO IDEA WHAT I'm talking about?!
Old 2nd February 2009 | Show parent
  #22
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Quote:
Originally Posted by pbell ➑️
Why are some of these companies so unwilling to hand these out to the people supplying them with material. And why do so many people who I'm delivering audio too have absolutely NO IDEA WHAT I'm talking about?!
They shouldn't be unwilling to hand out specs to a content provider. It is the producer's responsibility to get them to you. Why that is so hard I cannot fathom. I suppose its easier for them to rebuff you than to admit they have no clue what you're asking for.
Old 2nd February 2009 | Show parent
  #23
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Quote:
Originally Posted by smurfyou ➑️
They shouldn't be unwilling to hand out specs to a content provider. It is the producer's responsibility to get them to you. Why that is so hard I cannot fathom. I suppose its easier for them to rebuff you than to admit they have no clue what you're asking for.
Well exactly. I think you're right though, easier to rebuff me rather than admit they have no idea whats going on. Oh well. No complaints yet. If I hear my stuff on TV and I go "What the Hell was that?" I know I need to start changing things.
Old 5th March 2009 | Show parent
  #24
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Quote:
Originally Posted by nathand ➑️
The latest spec sheet to hit the streets is from NBC.

-8 peaks on all channels

-23 LKFS
The latest CBS HD specs call for -24 +- 2 LKFS referenced at -20dBFS. Dialogue peaks between -14 and
-8dBFS, with no peaks to exceed -2dBFS.
Measured on ALL channels.
That's both the 5.1, and Lo/Ro or Lt/Rt programming.
Old 6th March 2009 | Show parent
  #25
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Quote:
Originally Posted by TVPostSound ➑️
The latest CBS HD specs call for -24 +- 2 LKFS referenced at -20dBFS. Dialogue peaks between -14 and
-8dBFS, with no peaks to exceed -2dBFS.
Measured on ALL channels.
That's both the 5.1, and Lo/Ro or Lt/Rt programming.


Why can't they just all agree.....
Old 6th March 2009 | Show parent
  #26
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Quote:
Originally Posted by nathand ➑️


Why can't they just all agree.....
Just like us audio mixers allllways agree & hear things the same way, right heh
Old 6th March 2009 | Show parent
  #27
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Quote:
Originally Posted by Dallas Taylor ➑️
Just like us audio mixers allllways agree & hear things the same way, right heh
Good one.

But in all honesty, I believe there are some thing we can allll agree on. If a spec is reasonable and more importantly required then mixers will abide. Not to offend the spec creators from other networks, but from what I can tell that new CBS spec provides a fair amount of wiggle room so that not everybody would have to agree but everybody could be in spec.

Maybe what you are really saying is that politics and ego won't allow broadcasters, like us, to get on the same page.

Let me be the first to say...Tell me the size of space I can play in and I'll play in there.
Old 6th March 2009 | Show parent
  #28
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Natan,

The CBS specs I received were "HD" specs, as the next CBS show I'm mixing won't air until July/August.
The specs allow us a little more room as there will no longer be analog broadcast limiters in the equation!!!
Old 7th March 2009 | Show parent
  #29
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Quote:
Originally Posted by nathand ➑️
Good one.

But in all honesty, I believe there are some thing we can allll agree on. If a spec is reasonable and more importantly required then mixers will abide. Not to offend the spec creators from other networks, but from what I can tell that new CBS spec provides a fair amount of wiggle room so that not everybody would have to agree but everybody could be in spec.

.
For those of us who do promos that air on multiple network and cable channels, things get really weird. The other day I heard a spot I had mixed on USA and it sounded soft and dull. The same spot on CBS sounded like it should have and on Fox it sounded loud. It sounded like USA had a giant de-esser set to stun working overtime.
Old 7th March 2009 | Show parent
  #30
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Quote:
Originally Posted by Dallas Taylor ➑️
oh crap... I think we just yanked this thread into LM100/Dialnorm territory in 1 post!

Nooooooooooooo!!!!!!!

Not Dialnorm!!! NO!!!

(as she runs and hides under the bed... not wanting to grab her soapbox and start ranting again...)




cheers
geo
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