Mastering Movie Audio for the Home - Page 18 - AVS Forum | Home Theater Discussions And Reviews
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post #511 of 568 Old 06-14-2019, 07:35 AM
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Originally Posted by Optimus_Fine View Post
1. AVRs test tones are -30 dBFS, thus the max level is identical to the cinema standard: 105 dBC.



2. At my home, I follow the cinema standard.



3. If you don't printmaster at Reference Level (105 dBC), all you're doing is fudging up the standard and your mix will make my ears bleed.

1. No ones disputing that conceit.

2. Good for you

3. Can you explain how changing the monitoring level in a mixing environment changes how much level you put in the recording?

One has nothing to do with the other.
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post #512 of 568 Old 06-14-2019, 09:57 AM
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Originally Posted by JonasHansen View Post
@FilmMixer : Did you mix Power Rangers? The sound was amazing in my home theater!

Sent from my SM-G960F using Tapatalk

Thanks for the comment. Very proud of that mix.


Sent from my iPhone using Tapatalk Pro
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post #513 of 568 Old 06-14-2019, 03:31 PM
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Monitoring Level for Home Mix

Probably I am misunderstanding something, but I don't understand why the monitoring level for the home theatre mix should be adjusted.

I am 100% on board with Brian Vessa's recommendations for a home theatre remix, but ISTM that any reduction in overall level should be simply done by the mixer bringing down the levels in their mix. If the reference level is brought down from 85 dB to 80 or 75 or 72 or whatever, all the that happens is that we, the end user (who don't *know* what the monitor reference was) are now forced to guess at the correct level.

Remember: reference level is not average level or dialogue level or any other aspect of the mix itself - it is simply a baseline that says an agreed upon test tone at -20 dB below full digital scale will measure at 85dB (and of course many home theatre devices use a lower-level test tone that assumes the tone, now -30dB below full digital scale will measure at a much more comfortable 75 dB, with the same end result).

The goal here is say that if I fix my home system at the reference level, I will hear the same level as the mixer on stage. If the reference level is itself now a moving target, then this is no longer possible. Am I missing something?
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post #514 of 568 Old 06-14-2019, 05:06 PM
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Probably I am misunderstanding something, but I don't understand why the monitoring level for the home theatre mix should be adjusted.
There are two independent reasons to adjust the monitoring level for home theater remixes.

First, adjustment is required to achieve comparable SPL and loudness to the cinema. I realize that this is probably very counter-intuitive to people here, but this is absolutely the case. Playing cinema tracks in a home theater calibrated like a cinema doesn't just sound a lot louder, it actually *is* louder in terms of measurable SPL. If people are curious as to the technical justification for this, I can elaborate on it in another post. In any case, to achieve even a comparable "reference level" for a near-field or small room system usually requires monitoring at a lower level.

Second, further adjustments down may be made to the monitor level in order to assess how well the mix behaves at playback levels that are more realistic in a home setting. A lot of people including myself in the past are flipping out about this, worrying that this is leading to mix decisions that substantially reduce dynamics from the theatrical version, etc, but that's not really what's going on here. The mixers *know* they are running below "reference". They know the dialog will sound a bit quieter than they mixed it for the cinema. They *know* that treble and bass seem a bit diminished due to Fletcher-Munson effects. They aren't going to go and boost the dialog a bunch and screw up the spectral balance (further than is done already for cinema mixes) in order to make up for that gap. What they *will* do is boost the quietest parts of the track that go missing at the lower level. Essentially that is all, as I understand it.

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Originally Posted by dschulz View Post
I am 100% on board with Brian Vessa's recommendations for a home theatre remix, but ISTM that any reduction in overall level should be simply done by the mixer bringing down the levels in their mix. If the reference level is brought down from 85 dB to 80 or 75 or 72 or whatever, all the that happens is that we, the end user (who don't *know* what the monitor reference was) are now forced to guess at the correct level.
I would argue that the real root of the SPL/loudness mismatch between cinema and home is the broken calibration standard. Thus, I am very much opposed to reductions of level within the track itself for the same of making a broken standard appear to work better.

As far as being "forced to guess" the correct level, I'm sorry (not sorry) to say that *there is no correct level*. Yup, you got that right! Apart from the fact that the standard calibration method is broken and doesn't give consistent levels vs. different speaker types, room sizes, and listener distances, both broad and finer aspects of spectral balance, which are unique to each pairing of soundtrack+playback system, have a big impact on perceived loudness.

At best, the pink noise calibration will get you into the rough ballpark in a large cinema.

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Originally Posted by dschulz View Post
Remember: reference level is not average level or dialogue level or any other aspect of the mix itself - it is simply a baseline that says an agreed upon test tone at -20 dB below full digital scale will measure at 85dB (and of course many home theatre devices use a lower-level test tone that assumes the tone, now -30dB below full digital scale will measure at a much more comfortable 75 dB, with the same end result).

The goal here is say that if I fix my home system at the reference level, I will hear the same level as the mixer on stage. If the reference level is itself now a moving target, then this is no longer possible. Am I missing something?
The goals are admirable, but for technical reasons, things just don't work out that way with the existing standards, except (as mentioned above) as a ballpark. And in terms of overall trends, near-field and small room systems almost always need reduction in monitoring level for comparability to cinemas in SPL and loudness.

Now, I guess people are going to want to know, how much monitor level reduction is necessary? How much should "I" reduce my playback level, relative to cinema standards, when playing back tracks? The most correct answer is "it depends", but if you are in a very high quality home theater room, you'll probably want to play things around "-6 db" lower than the cinema standard, on average, and give or take a couple dB.

I play content at "-5" on average in my room, but I do adjust for different content, anywhere from "0" to "-11" (the latter for stuff mixed like TV). I have a very clean and accurate system with 6-22000 Hz (+/- 0dB vs. target) and generous room-gain-enabled bass. The majority of speakers (and rooms too) have various spectral balance flaws and this can make "reference" levels quite unpleasant. So, it if sounds too loud, turn it down! If it sounds too quiet, turn it up!

Really, I think level calibration should probably be abandoned because it's essentially an impossible problem to solve. No one really needs a standard level for playback as that's best set by ear. For production, I'd argue that it should be set by ear too. As crazy as that sounds, I think it's actually better than trying to force a adherence to a standard that doesn't work.

Please let me know if you want me to elaborate on anything.
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post #515 of 568 Old 06-15-2019, 01:41 AM
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Originally Posted by awediophile View Post
Playing cinema tracks in a home theater calibrated like a cinema doesn't just sound a lot louder, it actually *is* louder in terms of measurable SPL.
This is completely false! It is actually a blasphemy!
85 dBC is 85 dBC no matter the distance of the source, as long as, at the listening position, the SPL meter reads 85 dBC.

Maybe, for small rooms, people should also try a calibration with band-limited noise, after the broadband one, and measure a -20 dBFS RMS white noise signal (equal energy per frequency) from 500-2000 Hz at 85 dBA, rather than dBC, and see if there's a measurable difference.

I did that and there was a large discrepancy of about 5 dB SPL.
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post #516 of 568 Old 06-15-2019, 02:26 AM
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Originally Posted by awediophile View Post
Really, I think level calibration should probably be abandoned because it's essentially an impossible problem to solve. No one really needs a standard level for playback as that's best set by ear. For production, I'd argue that it should be set by ear too. As crazy as that sounds, I think it's actually better than trying to force a adherence to a standard that doesn't work.
Wow!
That's even more blasphemous that the first sentence you wrote.
Setting playback level by ear?
We are not machines!
Our hearing varies in sensitivity from day to day!
What you suggest is exactly what brought the loudness war in the music industry and, recently, in the movie industry.
If Reference Level in your room is too harsh, either your gear sucks or your room treatment sucks.
Period!
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post #517 of 568 Old 06-15-2019, 02:39 AM
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FilmMixer, "3. Can you explain how changing the monitoring level in a mixing environment changes how much level you put in the recording?"
In the latest a few others post; "What they *will* do is boost the quietest parts of the track that go missing at the lower level". "Thus, I am very much opposed to reductions of level within the track itself".
I did listen a bit closer to Fury, Dark Tower, Power Rangers each separate loudness & dynamics in the tracks background effects and music in the more dialog oriented and action oriented scenes. Same time also analyzing the level of the surrounds. The dialog is in correct level on all this titles. I believe you have mix Fury in level 85 dB, Dark Tower in 80 and Power Rangers in 85 dB. Am I right?

"I play content at "-5" on average in my room, but I do adjust for different content, anywhere from "0" to "-11" (the latter for stuff mixed like TV). I have a very clean and accurate system with 6-22000 Hz (+/- 0dB vs. target)"
What type of volume adjuster is that? You listen to 0 which is 85 dB?
Your speakers freq. responce is from 6 Hz to 22 kHz +-0 dB?

"Really, I think level calibration should probably be abandoned because it's essentially an impossible problem to solve."
Did you mean SPL channel calibration? In dubbing stage and cinemas they have the same channel calibration. Equalizing all this this and a dedicated home systems have the same channel calibration.
300 miljon people use soundbars, matchstick size of speakers, tablets and mobile for broadcast/movies with late night viewing experience all the time without any calibration or correct volume levels. Of this 0.01% use dedicate home systems with everything in it place... Gess for whom the mixer will first target his mix for?
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post #518 of 568 Old 06-15-2019, 02:49 AM
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I think the problem lies on EQ-ing without knowing how much you're affecting current loads and THD on amplifiers and speakers.
Current loads can be already very heavy when we drive our gear as is, without any EQ.
But, then, if we start to measure frequency response and we see big spikes, we begin to turn some sliders down (which by the way, we can only do by affecting a full octave and not just the frequencies we want to target).
The end result is that we might lose a lot in average SPL, thus we raise the main level even harder than it was before, in order to reach 105 dB SPL, which brings us into distortion-fest territory.
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post #519 of 568 Old 06-15-2019, 04:03 AM
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Just to be more clear about the 5 dB SPL discrepancy between broadband noise and band-limited one with my audio chain: it's the band-limited noise which measured 5 dB louder than the broadband one, because if the main channels are not reproduced by ruler-flat speakers from 1 Hz to 24000 Hz, when playing an unfiltered broadband pink noise, a lot of the source signal energy in the bass, ultra-bass frequencies and ultra-high frequencies will be lost by the limited natural response of the speakers.

When playing a band-limited noise, instead, we are certain that our speakers are reproducing, more or less equally, all the frequencies of the source signal, which, then, will give a more accurate SPL reading, also in respect to dialogue-centric frequencies.

In other words, people at home calibrating with broadband noise were actually setting their gear above Reference Level.
That could be why it was too loud for them, considering that Reference Level can already be too loud for certain listeners.
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post #520 of 568 Old 06-15-2019, 06:48 AM
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One other thing:

I suspect that many AVRs, when calibrating with their proprietary systems, do not actually set Reference Level.
I tried with my Yamaha's YPAO and, after that, I measured a -20 dBFS RMS noise with my SPL meter, calibrated with a 1 KHz/94 dB calibrator, and I got 85 dBC at -13.0 dB at the AVR's output level.
So, just imagine how many people have been lead to believe that their AVRs at 0.0 dB outputs Reference Level, when they might be up to 20 dB above cinema reference.
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post #521 of 568 Old 06-15-2019, 07:43 AM
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This of course is the worst case but proven.
I would be more worried about a dubbing stage with a speaker system freq. response curve within +-10-15 dB where the cinema mix is happening and that print-master is transfer to near-field to blu-ray
...and the same with this https://seanolive.blogspot.com/2009/...confusion.html ...and on top of this the mixer decides to go with a blu-mix level -10 dB, tweak that here and there (1-2 dB EQ, new levels, new pan, 80 Hz bass-management, new loudness limiting etc.)...
What do you think the result is of all this...?

I do not have this that kind of problem in my calibration or freq. curve.

That AVR thing was great that you prove it as I said earlier that all AVRs are rubbish with non calibrated volume adjusters . Isn't Yamaha volume knob 0 to 100?

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post #522 of 568 Old 06-15-2019, 08:48 AM
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Originally Posted by Optimus_Fine View Post
Wow!
If Reference Level in your room is too harsh, either your gear sucks or your room treatment sucks.
Period!
My experience tells me that in a smaller room reference level will be perceived louder than a larger room. Yes, they will both measure 75db (-30dbFS) when pink noise is generated, but there is indeed a difference between how loud it is perceived.

Reference level is not harsh in my room, but it is just so damn loud that I never listen to it. -5 or -10 sounds about right compared to how it is perceived in the cinema.

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post #523 of 568 Old 06-15-2019, 01:31 PM
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Originally Posted by JonasHansen View Post
Reference level is not harsh in my room, but it is just so damn loud that I never listen to it. -5 or -10 sounds about right compared to how it is perceived in the cinema.
Are you referring to dialogue level or maximum level?

In my setup, dialogues are at an acceptable level.

The effects, though, are much louder than what I can hear in cinemas, but that's probably because in cinemas, due to the distance from speakers to listeners, the load to the amplifiers and the speakers is so heavy that they're just driven into compression, thus they can't actually reach 105 dBC per channel.

Also, consider that many cinemas do not play at Reference Level, because of audience feedback.
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post #524 of 568 Old 06-15-2019, 04:04 PM
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Originally Posted by awediophile View Post
There are two independent reasons to adjust the monitoring level for home theater remixes.

First, adjustment is required to achieve comparable SPL and loudness to the cinema. I realize that this is probably very counter-intuitive to people here, but this is absolutely the case. Playing cinema tracks in a home theater calibrated like a cinema doesn't just sound a lot louder, it actually *is* louder in terms of measurable SPL. If people are curious as to the technical justification for this, I can elaborate on it in another post. In any case, to achieve even a comparable "reference level" for a near-field or small room system usually requires monitoring at a lower level.
*snip*

Quote:
I would argue that the real root of the SPL/loudness mismatch between cinema and home is the broken calibration standard. Thus, I am very much opposed to reductions of level within the track itself for the same of making a broken standard appear to work better.

Quote:
Really, I think level calibration should probably be abandoned because it's essentially an impossible problem to solve. No one really needs a standard level for playback as that's best set by ear. For production, I'd argue that it should be set by ear too. As crazy as that sounds, I think it's actually better than trying to force a adherence to a standard that doesn't work.

Please let me know if you want me to elaborate on anything.
Thank you for the lengthy reply - I appreciate the level of detail and thought that went in. I confess, though, to not being 100% convinced. Dolby's Dialogue Normalization, for example, is an attempt to achieve level matching between programs for broadcast/streaming, and ISTM that it is not too much to ask that all home media (streaming, broadcast, cable, physical media) conform to some agreed-upon standards for level. I totally get that the cinema mix would sound way too loud in a home environment, but that doesn't explain why the reference level should have to change - just that the home mix should not be as hot as the theatrical mix.

I do understand that there is likely no scenario in which a reference level for home can be set, as you would need agreement between content creators, distributors and equipment manufacturers, but ISTM this is a political problem and not necessarily a technical one. For me to hear the home mix at the same level as that heard on the mix stage should be eminently achievable.

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post #525 of 568 Old 06-15-2019, 09:44 PM
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Optimus_fine "The effects, though, are much louder than what I can hear in cinemas, but that's probably because in cinemas, due to the distance from speakers to listeners"
The effects are louder. It is done because your ear likes the idea of hearing equally loud sounds in the hole freq. response opposite to what Fletcher-Munson want you to believe. That is what the theatrical track is with equally loud sounds. That is exactly happening in the movie The Game/Criterion blu-discs theatrical track. It is a good example because it is a dialog oriented track and the background effects comes alive louder in the theatrical track. At least my ears like it
Means that we do not have any single problem of playing back a theatrical track at home. If it is too loud adjust the volume down.
When you refer to the distance, did you mean x-curve?

dschulz, dial. norm does not fix the loudness problem. Neither does it fix the differences between the contents. What it does is a silly 4 dB difference in level between the original.
"I totally get that the cinema mix would sound way too loud in a home environment, but that doesn't explain why the reference level should have to change - just that the home mix should not be as hot as the theatrical mix."
There are out a few others than the movie The Game. Try them out and you will realize that you do not have any single problem of playing back a theatrical track at home. It is a misled decision by some idiots.
Instead the blu mixers could go with a more simpler solution by adding the theatrical as it is with equally loud sounds in hole freq. response and just check that the high octave is not too bright. But if a dubbing stage mix is mix in a room with a curve of +-10-15 dB that kind of track need a totally NEW re-mix remaster which of course The Game do not need!
"I do understand that there is likely no scenario in which a reference level for home can be set"...first you need a good AVR with calibrated volume knob.
"For me to hear the home mix at the same level as that heard on the mix stage should be eminently achievable."...a tweaked blu-disc mix is not anymore a theatrical track.

By the way, nobody respond on the Dolby developer 79 dB/SUB +dB recommendation and on Roger Dressler comments on ITU channel calibration vs. 85 vs. 75. What is ITU channel calibration?

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post #526 of 568 Old 06-15-2019, 11:34 PM
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Originally Posted by OBJECT View Post
"I play content at "-5" on average in my room, but I do adjust for different content, anywhere from "0" to "-11" (the latter for stuff mixed like TV). I have a very clean and accurate system with 6-22000 Hz (+/- 0dB vs. target)"
What type of volume adjuster is that? You listen to 0 which is 85 dB?
Your speakers freq. responce is from 6 Hz to 22 kHz +-0 dB?
On my system, setting the master volume to "0" and sending -20 dBFS:rms pink noise that is band-limited to 500-2000 Hz to one of my front stage channels will deliver close to 85 dBC (+/- 0.5 dB-ish), considering multiple seats. It's not super-precise but roughly within 1 dB. So when I set the volume to "-5", I expect to read 80 dBC from the same pink noise. This pink noise test signal should read around 85 dBC in a big cinema.

Note that cinemas calibrate using full-band pink noise, but this gives wildly inconsistent results unless the spectral balance is also "calibrated" to a consistent target using pink noise measurements, as is done for X-curve cinemas. This is not recommended for home and will not necessarily duplicate a cinema environment if performed. The standard test signal used for calibration in homes is band-limited to 500-2000 Hz.

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"Really, I think level calibration should probably be abandoned because it's essentially an impossible problem to solve."
Did you mean SPL channel calibration? In dubbing stage and cinemas they have the same channel calibration. Equalizing all this this and a dedicated home systems have the same channel calibration.
I mean you can use -20 dBFS:rms pink noise and target 85 dBC for all your front channels (and 82 dBC for surrounds), but this doesn't really guarantee loudness consistency, even in the same room. Typically it works OK if the speakers are all the same type and are close to the same distance. Otherwise, you are likely to get an unbalanced result. This is likely true in cinemas too, which is interesting given that the surround beds (arrays) are often closer and are very different kinds of acoustic sources than front stage speakers are.

Using the same pink noise signals, my surrounds run about -2 dB (IIRC) vs. my fronts. I chose these levels by listening to a wide variety of content, including examples of both discrete panning effects and active room ambiance. I plan to upgrade my surrounds and add Atmos some day and won't be surprised if I have to cal the new stuff to new different levels.
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post #527 of 568 Old 06-16-2019, 01:01 AM
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The effects are louder. It is done because your ear likes the idea of hearing equally loud sounds in the hole freq. response opposite to what Fletcher-Munson want you to believe. That is what the theatrical track is with equally loud sounds. That is exactly happening in the movie The Game/Criterion blu-discs theatrical track. It is a good example because it is a dialog oriented track and the background effects comes alive louder in the theatrical track. At least my ears like it
Means that we do not have any single problem of playing back a theatrical track at home. If it is too loud adjust the volume down.
When you refer to the distance, did you mean x-curve?
You completely missed my point.
I was referring to people experiencing Reference Level louder at home than in cinemas and I wrote that either it could be because some cinemas audio chains don't actually reach 105 dBC due to technical limitations (amplifiers clipping, speakers compressing, etc.), or because some cinemas are actually playing below Reference Level due to audience complaints.

----------------------------------------------------------------------------------------------------------------------------------

Anyway, it's not that hard going from Dolby 79 dB recommendation for the home to Reference Level 85.
I tried both at my home and the difference is negligible.
You just need to get accustomed to it and not be influenced by other people's bias or useless white papers like ATSC 3.0 or mixing engineers who do not follow standards because they have 30 years experience, so they can do whatever they want.

Just try raising your AVR 1 dB for each movie you play and you'll notice, in the end, it's not that much louder than Dolby 79.

Considering that, depending on which 4K Ultra HD or Blu-ray you pick up, there's either a theatrical mix or a nearfield remix, with either Dialnorm -31 or -27, we might as well set our audio chain at Cinema Reference Level with Dialnorm -31 and let the decoder drop by 4 dB when there's a track flagged that way.
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post #528 of 568 Old 06-16-2019, 02:19 AM
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Yeah Optimus Prime , I will stick with 85/82/91. 82 is a bit weak

awediophile:

"On my system, setting the master volume to "0"..."
Have you calibrate you AVR volume adjuster meaning 0 is 85 dB. Is it 85 dB?

"...and sending -20 dBFS:rms pink noise that is band-limited to 500-2000 Hz to one of my front stage channels will deliver close to 85 dBC (+/- 0.5 dB-ish)..."
500 to 2000 is dBA. dBA is closer to human hearing and all other octaves are missing. Do not use that use instead the standard full-range pink -20 dBC Slow.
It is impossible that you have a speaker freq. response curve within +-0,5-1 dB 20Hz-20kHz even measured from 1 m. distance...my Earthworks M30 measurement mic is 0,5.

"..., considering multiple seats..."
You use 1, 4 or 8 Earthworks type of measurement mics? Do you measure 1x place, then place 2, then 3 etc. Sounds like you are using a room-correction?

"...It's not super-precise but roughly within 1 dB. So when I set the volume to "-5", I expect to read 80 dBC from the same pink noise. This pink noise test signal should read around 85 dBC in a big cinema."
Super precise is a speaker curve +-0,5 dB measured from 3-4 m. distance which is actually impossible.
So your AVR volume adjuster at -5 is 80 dB? How much is it when it is 85 dB?

"Note that cinemas calibrate using full-band pink noise, but this gives wildly inconsistent results unless the spectral balance is also "calibrated to a consistent target using pink noise measurements, as is done for X-curve cinemas. This is not recommended for home and will not necessarily duplicate a cinema environment if performed. The standard test signal used for calibration in homes is band-limited to 500-2000 Hz."
It is not a standard anywhere to calibrate channels with dBA.
If you would have a speaker withing the response of +-0,5 dB 20Hz-20kHz you do not miss anything in that spectrum, so why would you still calibrate it with limited dBA?

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post #529 of 568 Old 06-16-2019, 02:36 AM
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@OBJECT : Please learn how to use the quote functionality... And for the sake of the other readers in the thread, instead of slicing every single sentence from every single post, try and summarize your points and follow-up questions. Much easier to have a constructive dialogue going that way and context is not lost.

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post #530 of 568 Old 06-16-2019, 05:04 AM
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Originally Posted by Optimus_Fine View Post
This is completely false! It is actually a blasphemy!
85 dBC is 85 dBC no matter the distance of the source, as long as, at the listening position, the SPL meter reads 85 dBC.
I see I am now an heretical enthusiast.

That 85 dBC is with a particular pink noise test sample playing. Just because two systems hit 85 dBC with a particular pink noise test signal doesn't mean they'll hit the same SPL with on other test signals or on real-world content.

Substantial SPL differences can arise for two mains reasons: First, the spectral balance of the speakers may be very different. Second, the acoustics of the rooms may be different.

There is pretty good evidence that X-curve calibrated dub-stages have diminished output in the treble *and* bass compared to an accurate studio monitor or an "average" top-tier home theater. So if a home theater and cinema calibrate to equal SPL over the 500-2000 Hz (midrange) band, the accurate monitor will be putting out a lot more bass and treble than the cinema will be for the same content. That extra content will increase SPL and may have other side-effects via Fletcher-Munsen effects, which could account for the apparent exaggeration of dynamics when cinema mixes are viewed on a more neutral system.

The acoustics of the rooms and relative placement of speaker(s) and listener(s) are also important. Larger rooms often have longer decay time, which increases the contribution of late arriving sound. Greater distances between speakers and listener(s) also increases the proportion of late arriving sound vs. direct and early arriving sound.

The consequences of these factors on SPL depend substantially on the content. Real-world movie content is dynamic. The sounds which determine our perception of the loudness of the track are likely to be momentary and dispersed as opposed to a pink noise signal, which is continuous. If we use medium-term SPL (i.e., an SPL meter operating in "fast" mode) to assess approximate loudness, we are likely to observed that the momentary dynamics are not enhanced much by late reflections; however, the SPL of continuous sounds like pink noise will be enhanced substantially by late reflections.

So basically what's happening with calibration and acoustics is that cinemas, where listening distances are higher, have a much higher proportion of late arriving energy, than small rooms, and that energy inflates the SPL of the pink noise measurement but not the SPL of the sounds that affect loudness in real-world content. So if a home theater calibrates to the same pink noise SPL target, the SPL of the momentary sounds will actually be louder from acoustics alone. And to re-iterate, the spectral balance differences are likely to contribute even more to SPL.

Quote:
Originally Posted by Optimus_Fine View Post
Maybe, for small rooms, people should also try a calibration with band-limited noise, after the broadband one, and measure a -20 dBFS RMS white noise signal (equal energy per frequency) from 500-2000 Hz at 85 dBA, rather than dBC, and see if there's a measurable difference.

I did that and there was a large discrepancy of about 5 dB SPL.
I would argue that *no one* should be using broadband pink noise to calibrate level in a home theater. The broadband signal only really works as consistently as it does for cinemas (which isn't saying much) because the cinema is *also* being calibrated to the X-curve target using the same signal. The X-curve target is rolled-off at both extremes, and this effectively "band-limits" the full-band signal consistently between venues.

Technically speaking, a finite duration full-band pink noise signal does not exist! Pink noise signals contain equal energy in each octave, and there are an infinite number of octaves down to DC. In digital audio, pink noise must also be band-limited to below the Nyquist frequency to avoid aliasing, but the Nyquist frequency can vary between systems, depending on chosen sample rate. So really, "full-band pink noise" must always be band-limited at some high and low limits, and the choices aren't arbitrary. They affect the distribution of energy between the mid-bands and the extremes.

If anyone insists upon working around this limitation by performing X-curve spectral balance calibration, realize that you are not following any known standard. X-curve is expressly intended for cinema and even specifies different target curves and levels for different size rooms. To my knowledge, X-curve doesn't specify what to do for "tiny" home theater rooms, and even if it did, I still wouldn't recommend using it if the best sound quality is desired.

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Originally Posted by Optimus_Fine View Post
Wow!
That's even more blasphemous that the first sentence you wrote.
Setting playback level by ear?
We are not machines!
Our hearing varies in sensitivity from day to day!
What you suggest is exactly what brought the loudness war in the music industry and, recently, in the movie industry.
If Reference Level in your room is too harsh, either your gear sucks or your room treatment sucks.
Period!
You are right that we are not machines. And likewise, machines are not people, and at the end of the day, audio is for people not machines to enjoy. Machines cannot tell how good or how loud something sounds. At best, machines can guess on the basis of physical and/or psychoacoustic models applied to whatever data is available. The level calibration methods we are discussing here rely on poor quality data with no phase or time-domain information and typically poor frequency resolution as well. They also completely ignore physical and psychoacoustic concerns, which they can't address anyway without time-domain information. We also haven't even discussed spatial variations and what to do about them. (Average them? How? How do we fairly sample the seating area? Where trade-offs exist, how do we prioritize sound quality vs. different seats? Etc.)

Psyho-acoustics is another major dimension that I haven't addressed yet. My experiments with thousands of different EQ configurations indicate to me that various spectral balance characteristics of both the playback system and the soundtrack have a profound impact on perceived loudness. For example I can make a small EQ change, and afterwards, one movie might sound a lot louder (i.e., a few dB) but another sound a lot quieter. I suspect that even environmental changes like increased humidity can have an impact. Every soundtrack has nuances which combine with the nuances of the playback system, all of which interacts in complex and unpredictable ways. And let me not forget to mention individual listener differences too!

On the other hand, practically every playback system has a volume control that is usually very easy to operate. I set it by ear, usually based on how the dialog sounds. Often all it takes is one spoken line for me to get it right for the rest of the film.

Dialog is often called the "anchor" element, because its loudness is often used by the mixers as a kind of reference for everything else. So if you can find the right level for the dialog, chances are the rest of the mix will sound close to right.

Dialog mixing styles do vary. Some movies mix dialog at a fairly constant loudness, usually very prominently. I like to imagine that this style makes the voices sound as big as they look close up on a big screen. Other films go for a more "realistic" style, which tends to be a lot quieter on average but varies a lot more in general. For me, most films seem to fall in one of these three categories, though there are always exceptions.

For people doing audio production, a good method for calibration may be to set the monitor level by ear while listening to a dialog clip with a standardized loudness. For example, the ATSC provides the following sample to use as a reference for TV mixing:

http://www.atsc.org/refs/a85/Speech_sample.wav

The sample is standardized to -24 LKFS, which is the standard specified loudness for broadcast TV. (Note: computing LKFS involves a sophisticated analysis of the content, taking into account various spectral balance and temporal characteristics to estimate how loud something will sound.)

Before doing a TV mix, a mixer can use the reference to adjust the monitor level until it sounds comfortable to them and then *just mix* everything relative to that level. Because it already sounds "right", the mixer won't be tempted to mix something too loud or too soft, and the final mix is more likely to comply with broadcast standards without the need for normalization and other unwanted processing.

For cinema and home theater tracks, -24 LKFS is usually too loud, and mixers need not adhere to a single, standardized loudness. The test sample can be attenuated by (e.g.) between -3 dB and -7 dB in order to calibrate for a film that follows one particular dialog style or another. Then everything could be mixed relative to that anchor loudness.

A likely counter-argument to my suggestion to set levels by-ear is that it's too subjective. What if people don't really agree on how loud is "right"? And "what about Fletcher-Munson effects"?

To answer the first question, let me turn it around. Why should we listen at a volume level other than what sounds best to our ears? Why should mixers work at a level other than what is most effective for them? The main thing we want to avoid is inconsistency in loudness between tracks, apart from that which arises due to stylistic difference. Hence, if we create a "Speech Sample" with standardized loudness for each kind of style, mixers can do the rest themselves. I really doubt a mixer will have trouble deciding whether the "prominent" or "realistic" is best for their work. It's all based on *precedent*. Do I want my mix to sound like those with louder, flatter dialog or those with quieter, more dynamic dialog? Choose the appropriate "Speech Sample" and then just mix naturally.

What about Fletcher-Munson effects? I think they are overblown. Even the most extreme level differences we're talking about are like +/- 5 dB, and FM effects are pretty subtle between those differences and near "reference level". In fact, the differences in broad spectral balance between different systems calibrated with X-curve and between the wide variety of home systems is likely far, far more important. General differences in treble+bass vs. mids balance in X-curve stages compared to accurate near-field monitors may be the primary reason for the need for home remixes.
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post #531 of 568 Old 06-16-2019, 10:52 AM
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Again, perception should not be used in place of a standard based on instrumental measurement.
Sound Pressure Level is scientifically measurable.
Perceived Loudness cannot be measured, because it varies from person to person.
85 dB SPL at the listening position with a source from 1 m or from 10 m is the same and can be replicated because it is measureable.
Period.

If someone hates Reference Level, he's free to not use it.
If a mixer hates Reference Level, he should do another job.
I play at 85 in my small room and dialogues are at an acceptable level, some times are louder and others are lower, depending on if the mixer follows the standard or not (Skywalker Sound does).

The difference between Flat and X-Curve in theaters is 2 dB.
I know that because I was able to calculate it thanks to that fantastic website called sengpielaudio.
Now, I seriously doubt a 2 dB difference makes people in small room run away covering their ears, but rather that some mixers work below Reference and, thus, their average level will be higher.
That also leads to theaters playing below Reference.

Or, again, the average theater is unable to technically reach Reference and, thus, the max levels will clip/compress below 105 dBC per main channel, but when we listen to the same soundtrack again, in a smaller environment, we experience the full dynamic range and it simply overwhelms us.
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post #532 of 568 Old 06-16-2019, 11:45 AM
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Quote:
Originally Posted by Optimus_Fine View Post
Again, perception should not be used in place of a standard based on instrumental measurement.

Sound Pressure Level is scientifically measurable.

Perceived Loudness cannot be measured, because it varies from person to person.

85 dB SPL at the listening position with a source from 1 m or from 10 m is the same and can be replicated because it is measureable.

Period.



If someone hates Reference Level, he's free to not use it.

If a mixer hates Reference Level, he should do another job.

I play at 85 in my small room and dialogues are at an acceptable level, some times are louder and others are lower, depending on if the mixer follows the standard or not (Skywalker Sound does).



The difference between Flat and X-Curve in theaters is 2 dB.

I know that because I was able to calculate it thanks to that fantastic website called sengpielaudio.

Now, I seriously doubt a 2 dB difference makes people in small room run away covering their ears, but rather that some mixers work below Reference and, thus, their average level will be higher.

That also leads to theaters playing below Reference.



Or, again, the average theater is unable to technically reach Reference and, thus, the max levels will clip/compress below 105 dBC per main channel, but when we listen to the same soundtrack again, in a smaller environment, we experience the full dynamic range and it simply overwhelms us.

I’ve never mixed a film at anything by reference level.

I don’t know of anyone else who does or has.

Skywalker Sound isn’t some magical place that works any differently than any other studio.

The dialog level on almost al of my films varies... and they are all mixed to the “standard...”. Every project is different, production sound quality varies, music varies, the amount of relaxed dialog varies, how the film was shot (how close does the camera get to the actors, how wide is the lens, etc...). Those all factor into average dialog level. The idea is to the dialog to sound like its coming from the actors, not to make it match some arbitrary idea you have in your head.

Again, when you’re talking about doing a home theater mix, turning down the monitoring level doesn’t change the recorded level of a mix UNLESS YOU PUSH THE STEMS UP AS YOU RE-RECORD THEM. As I have mentioned many times, I don’t know any mixer that starts with a near field and pushes their stems up to match the attenuation of the monitor level.

You can mock my comments and make disparaging remakes about me personally.

What I do for my home theater mixes matches 90% of what my peers also do.

It’s really shocking that anyone in this thread would think they care more about how a mix translates or comes home than someone who does this for a living....

I’ve dedicated my life to my craft... to say I wouldn’t want the home listener, the person listening to the soundtrack as it will live on forever, to hear what we, as a team created with the director to satisfy their vision, is just asinine.

You know what films I’ve mixed. If you want to tell me which ones are near field mixes, which ones I’ve “ruined” by not following your advice, or which ones are the theatrical print master I am all ears.... they certainly all vary, especially as I’ve grown as a professional over all these years.
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Optimus, again you are right. Tell me more about that 2 dB experience between flat and x-curve you had. What is sengpielaudio?

FilmMixer, your dialog is right in level in Fury, Dark Tower, Power Rangers so I did not have to increase my pre-pro volume level to achieve that. You could anywayput a bit louder the background effects and the surrounds, please.
But on same system the list I provided with huge amount of Remasters with almost all I had to increase the volume level hugely to achieve each title with proper dialog in level. The flaw is not in the sound design it is a decision what your colleges did which was a huge mistake.
And there will anyway be a new Remaster after 3-5 years and here FilmMixer you could be the one to make them right!
Could you please provide more titles you have done because you are in the right direction.

awediophile, I do not know where you got the idea of measuring a loudspeakers freq. response curve with 500-2000 dBA. Nobody use that in a dubbing stage, cinema and in a dedicated home system. 500-2000 and dBA is only in use within the government employee who track for too loud things, places, venues, traffic etc. in daily use to make laws/standards to protect our hearing.
What comes to the x-curve you point out, you already have it in your own use IF if you have a flat speaker response in heights measured from 1 meter distance
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post #534 of 568 Old 06-17-2019, 03:57 AM
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Originally Posted by OBJECT View Post
Yeah Optimus Prime , I will stick with 85/82/91. 82 is a bit weak

awediophile:

"On my system, setting the master volume to "0"..."
Have you calibrate you AVR volume adjuster meaning 0 is 85 dB. Is it 85 dB?
Sorry, I should have stated that the calibration is done with MV set to "0". Technically I do it completely via software now. The 500-2000 Hz range is brick-wall band-passed. It all traces back to a calibrated SPL meter and mic though.

Quote:
Originally Posted by OBJECT View Post
"...and sending -20 dBFS:rms pink noise that is band-limited to 500-2000 Hz to one of my front stage channels will deliver close to 85 dBC (+/- 0.5 dB-ish)..."
500 to 2000 is dBA. dBA is closer to human hearing and all other octaves are missing. Do not use that use instead the standard full-range pink -20 dBC Slow.
Do you realize that an A-weighting curve looks very different from a 500-2000 Hz bandpass response curve?

Calibrating my levels using e.g., the Dolby full-band pink noise sample doesn't make much sense because I don't calibrate my spectral balance using pink noise measurement, nor do I calibrate to the X-curve target (which would be needed for any measure of consistency against cinemas). My system playing full-band pink noise will have substantially more output in the bass, which will tend to make my readings much higher than another system with similar midrange response but a lot less bass output and extension.

So why bother? I guess I can run and record the Dolby test signal, for curiosity sake. I wouldn't be surprised if I was over "90 dBC", FWIW.

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Originally Posted by OBJECT View Post
It is impossible that you have a speaker freq. response curve within +-0,5-1 dB 20Hz-20kHz even measured from 1 m. distance...my Earthworks M30 measurement mic is 0,5.

"..., considering multiple seats..."
You use 1, 4 or 8 Earthworks type of measurement mics? Do you measure 1x place, then place 2, then 3 etc. Sounds like you are using a room-correction?
My mic may suffer inaccuracy of up to 0.5 dB, but it is probably very precise and may also be very accurate with regards to characteristics that matter the most for optimization. This is definitely something that deserves more careful study though.

Even ignoring mic inaccuracy, I'm not hitting my target *exactly*, but it is still very close. By 6-22000 Hz +/- 0 dB, I meant that I extend to those extremes without any roll-off, spectrally speaking. Technically, SPL output around 6 Hz is quite a bit higher than around 22000 Hz, but that's not the point.

I do not use room correction in the usual sense. I do speaker optimization using in-room measurements at multiple locations. I optimize for room effects, in so far as they affect the speaker (which includes room resonances), but I don't "correct" reflections or natural room gain.

Quote:
Originally Posted by OBJECT View Post
"Note that cinemas calibrate using full-band pink noise, but this gives wildly inconsistent results unless the spectral balance is also "calibrated to a consistent target using pink noise measurements, as is done for X-curve cinemas. This is not recommended for home and will not necessarily duplicate a cinema environment if performed. The standard test signal used for calibration in homes is band-limited to 500-2000 Hz."
It is not a standard anywhere to calibrate channels with dBA.
If you would have a speaker withing the response of +-0,5 dB 20Hz-20kHz you do not miss anything in that spectrum, so why would you still calibrate it with limited dBA?
See above about 500-2000 Hz band-limiting vs. A-weighting. They are totally different.

Last edited by awediophile; 06-17-2019 at 04:38 AM.
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post #535 of 568 Old 06-17-2019, 04:30 AM
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Quote:
Originally Posted by Optimus_Fine View Post
Again, perception should not be used in place of a standard based on instrumental measurement.
Sound Pressure Level is scientifically measurable.
Perceived Loudness cannot be measured, because it varies from person to person.
Just because there is a standard that involves measurement using instruments doesn't mean that it's correct or even scientific.

Quote:
Originally Posted by Optimus_Fine View Post
85 dB SPL at the listening position with a source from 1 m or from 10 m is the same and can be replicated because it is measureable.
Period.
Yes, if only movie soundtracks were all pink noise all the time. You are assuming that if SPL between rooms is the same for pink noise then the SPL will be the same between rooms for any other signal. That is not correct and this point is fundamentally important.

Please re-read my post on this point. If you want clarification on anything, please ask for it. If you disagree with anything, please explain specifically why you disagree.

Quote:
Originally Posted by Optimus_Fine View Post
The difference between Flat and X-Curve in theaters is 2 dB.
I know that because I was able to calculate it thanks to that fantastic website called sengpielaudio.
Now, I seriously doubt a 2 dB difference makes people in small room run away covering their ears, but rather that some mixers work below Reference and, thus, their average level will be higher.
That also leads to theaters playing below Reference.
I have no idea what you saying here with regard to "Flat" vs. "X-curve". What kind of difference are you talking about? You need to be specific about these things or else they are too ambiguous.
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post #536 of 568 Old 06-17-2019, 12:21 PM
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Nobody use 500-2000 Hz band-pass response curve for anything.
A dBA measurement will give a different result compared to dBC because of the included low end.

Are you trying to duplicate Hidley & Kino rooms http://www.hidley-design.com/. They go to 10 Hz
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post #537 of 568 Old 06-17-2019, 04:11 PM
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Nobody use 500-2000 Hz band-pass response curve for anything.
A dBA measurement will give a different result compared to dBC because of the included low end.
For the last time: A-weighting as in "dBA" is very different from applying band limiting to 500 to 2000 Hz.

Pink noise that is band-limited to 500-2000 Hz is used to calibrate levels for music (see e.g. Bob Katz K-system), TV program in both US and Europe (ATSC and EBU recommendations), and home theaters (I believe originally recommended by THX).

Out of curiosity, I measured the "full-band Dolby Pink Noise" sample as-is on my front-stage speakers with a calibrated Galaxy Pro SPL meter set to "slow". I get very close to 85 dBC at "0". Note that this test sample is actually around -18.2 dBFS:rms, so if -20 dBFS:rms is the standard that counts, then I may be technically a bit under "reference" at "0". OTOH, if one first processes this pink noise sample using the X-curve target, it comes out exactly to -20 dBFS:rms. (This may be purely a coincidence.)

I was a bit surprised that I didn't come in a lot higher, but I guess my generous bass response does not affect things too much. The C-weight curve is already starting to roll off at 100 Hz and 4 kHz, so contribution from sub-bass and treble are definitely de-emphasized. Bass in my system also builds and decays very fast (small room with multiple subs and tight DSP optimization), and so there is very little late energy build-up contributing down there.

FWIW, as calibrated I can hit well into the mid-to-upper 120s dB SPL (raw with no weighting) with real-world content and playback at "-5" (80 dBC?). For example, in "Oz: The Great and Powerful" in the scene with the lightning attacks, I used the above SPL meter in "fast" mode (still C-weight) and measured ~122 dBC. However, the effect is centered in the mid 20s Hz where C-weighting is down by about -5 dB, so one can do the math to figure out roughly where the SPL was really at. The effect was very clean and not that "loud" BTW (even though it heavily clips the LFE channel on the track), it just felt like I had a shaker attached directly to my chest.

Quote:
Originally Posted by OBJECT View Post
Are you trying to duplicate Hidley & Kino rooms http://www.hidley-design.com/. They go to 10 Hz
Nope. I'm just trying to reproduce all audible content in a neutral and accurate manner. I can't describe in words how good it sounds to anyone who has not experienced this level of accuracy and performance before.
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post #538 of 568 Old 06-18-2019, 05:13 AM
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All right, so, I just remembered that we all forgot dBC is not a flat reading.
C-weighting has roll-offs too in the lower end and upper end.
Thus, I went back to sengpielaudio and made some calculations.

If I take a broadband pink noise brick-wall filtered at 20 Hz and 20 KHz and play it at 85 dBZ (unweighted), then, each of the 10 octaves will be 75 dBZ.
At that point, I apply C-weighting filtering to the geometric mean-frequency of each octave.
For example, from 20 KHz to 10 KHz, the geometric mean frequency is 14142.13562373095 Hz.
After that, I obtain the C-weighting gain difference at that frequency, which is -7.336303536454145 dB.
I, then, subtract it from the 75 dBZ energy of that octave.

After all octaves are done, I get the following, in order, from 20 Hz to 20 KHz:

71.2203988 dBC
73.9307807 dBC
74.7643123 dBC
74.9838362 dBC
75.0316052 dBC
75.0116581 dBC
74.8801895 dBC
74.3611045 dBC
72.5460916 dBC
67.6636965 dBC

Which give a total energy of 83.87 dBC.

But I aim for 85 dBC, so I add the difference (1.13 dB) at every octave.

72.3503988 dBC
75.0607807 dBC
75.8943123 dBC
76.1138362 dBC
76.1616052 dBC
76.1416581 dBC
76.0101895 dBC
75.4911045 dBC
73.6760916 dBC
68.7936965 dBC

Total energy: 85 dBC or 86.13 dBZ

Now, I want to know how much is the maximum dBC available around 1000 Hz throughout the 6th and 7th octaves.
Each octave has an headroom of 28.2 dB (1/10th of -18.2 dBFS RMS of Dolby's noise), which, when divided by 2, gives 25.19 dB.
Adding 25.19 dB to the energy sum of the 6th and 7th octaves of 79.08 dBC gives 104.27 dBC.

So, if one wants to calibrate with a band-limited pink noise, from 625-2500 Hz, at -20 dBFS RMS, he should not actually aim for 83 dBC, but 84 dBC.

I'll look into this further and update if I come up with some errors I made.

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post #539 of 568 Old 06-18-2019, 08:14 PM
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...And equalizing a speaker system in ATSC, dubbing stage, cinema and home

Optimus, seams to be you are using X-curve even you have not apply EQ for that (?).
The measurement of dB per each octave can not be done because the octave effects the one next to it in level vs. You can not calibrate nor equalize each octave separately!

awediophile, I still do not believe that you are having a speaker freq. response curve 6Hz to 22kHz +-0.0 dB even +-1.0 run through a dedicated FFT app. speakers at 4 m. distance, in a room which do not have a acoustic treatment. There does not even exist a loudspeaker capable of that.

I mighr have seen one in a anechoic chamber. It was a completely round speaker. That one did in that completely dead room a flat response as a measurement mic.

How did you capture this 6 Hz from the freq. response?

You use same DSP optimization as Bag End which goes to 8 Hz?
Is your room tuned to 6 Hz?

sengpielaudio?

Last edited by OBJECT; 06-18-2019 at 08:56 PM.
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Sengpielaudio is a deutch website which is pretty much an encyclopedia on the science of sound and has pages and pages with calculators, unit converters and so on.
For me, it's a gold mine.

The calculations and estimations I made in my previous post do not take into account the attenuation performed with the large room X-Curve.
Those are meant to be dBC levels with a flat loudspeaker response.
Anyway, I can also do that, but it's meant to taken with a grain of salt, because the X-Curve varies depending on room size.
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