How loud is loud, how to measure it? Is THX calibration bad for your health?

[EEE272]

BS. The levels are adjustable in the Cinema. This video aptly demonstrates this. Pay attention to the commentary from 1:53 and on. They did (as I did) peak loudness measurements in the theaters in their area (just like I did), and the peak loudness was all over the place (just like they were in our measurement project on THX theaters and screening rooms). This my friend shows that any auditorium's master volume level can be adjusted so a manager can address any volume level complaint in any auditorium in real-time. This is regardless of the mix level, of which nobody knows except the mixers. Your statement is illogical, and shows total ignorance of how things work.

You can measure how loud the mix is, but that is completely different from how loud the mix is played back. sigh! Just like I have a volume control on my receiver, a theater has a volume control on its server. I can turn up or down the volume at will, and so can a movie theater, and the link above shows this.

Anyone who has watched a lot of movies on disc knows that there are movies that are mastered quite high, and others that are mastered quite low. If it is mastered too high, you reach over and turn it down if it is offensive (Transformer movies). If it is too low, you turn it up until you are comfortable (some Disney movies). Same in a movie theater. Mastering levels have nothing to do with playback levels when there is a volume control at the playback end. This is illogical to think otherwise.

Is there actually a reason why the information of the original mixing level is not provided in a file format? You gave this eye opening example with 79 mixes being 6 dB too loud on a calibrated system. The lower the mixing level, the more extreme the mismatch for a calibrated system. Why not just store this one extra number to avoid this problem? Or one could print it on the blu-ray box.

 

[Soundmixer]

My dear sir, you are funny, really funny. You are asking me a rhetorical question but the video you referred to says that when the volume turned down audience cannot hear the dialog

Volume turned down is not specific. Turned down how low? Cherry-picking a certain statement that requires a threshold to quantify shows how weak your position is. How much of the audience can not hear the dialog? It can't be everyone because everyone's hearing is different. Talk about being funny!

Really? Are you now going to tell me that the sound engineer mentioned at 4:15 who calls the situation as "audio abuse" is not the same as a sound designer?

Is he referring to the sound levels in the theater, or sound levels on the dubbing stage? He clearly said the "audio levels IN THEATERS are going to get worse, and that is audio abuse". He mentions nothing about mastering levels in post-production. This is a fail.

Sound engineers work on the recording and editing of the final stages of mixing the sound (which is usually three people), and the sound designers create the sound and performance aspects of the sound (which can be many people at the production stage). A sound engineer works on the dubbing stage; a sound designer works in Foley, and sound effect recording and mixing areas. These are two distinctly different jobs, even though the same people can do both.

For a person who pretends to know so much, I am surprised you don't know the distinction.

 

[AdamG]

Thread warning. I have been following this conversation and some of you are getting very close to getting a warning issued. So dial back the personal stuff. Snide remarks and backhand insults. If you can’t control yourself I will be forced to. Fair warning. Thus is just a forum. Quit taking everything so personally. I kindly ask for your cooperation, please and thank you!

 

[Soundmixer]

Is there actually a reason why the information of the original mixing level is not provided in a file format?

I cannot answer this question.

The lower the mixing level, the more extreme the mismatch for a calibrated system.

The mixing level has no relationship to the playback level when there is a volume control in the playback chain. Also, calibration levels also have no relationship to the playback level for that same reason. Ultimately, the end-user decides how loud they want to play back any content.

Or one could print it on the blu-ray box.

With soundbars, 5.1, 7.1, 5.1.2, 5.1.4, and 7.1.4 speaker setups out there, no one size could possibly fit all of these different reproduction sources. In the end, individuals will decide how loud they want to play their content.

 

[MKreroo]

(assume @ 1kHZ so easier to talk about when switching between dBA and dB SPL)
I have been wondering, those tables about noise level and hearing damage (things like chainsaw @ 100dBA etc), often have nightclub and live concert venue listed at the higher ends (>100dBA), and that dBA is mainly for noise

Wouldn't it be safe to assume that at places like nightclub/live venue etc, the main, and probably loudest, source of noise is the music being played?

 

[EEE272]

Also, calibration levels also have no relationship to the playback level for that same reason.

I fully got that but, in order to paint an entertaining picture: a friend of mine was very "moviephile" at some point. This meant for him that everything had to be as close to "perfect, authentic, and intended" as possible. Lowering the volume away from reference or using "bass or treble" would almost be an insult to the creator of the movie.

In my head, I see him sit with a -20=75 mix and believing that it is supposed to be played "as intended" at -0 dB, suffering through 10 dB too high volume levels on a calibrated system - with a forced smile on his face, trying to enjoy it.

If you look at the advertisement for the iMax sound with Disney plus, one major thing they talk about is: reference volume. Which, you (and others in this thread) taught me, is basically nonsense (or hand-wavy) because it cannot be known precisely. It is kind of funny that they advertise this particular aspect.

In my head, I always imagined that the last test is done at -20=85 in several real cinemas of differing sizes to check that all is "as intended". (Especially, when it comes to iMax, that I assumed to have building standards worldwide.) Then fine tweaking would be done in this environment. I was surprised this does not seem to always happen.

In the article about loudness, which was referenced above, it clearly shows that soundmixers have slightly different preferences, when it comes to mixing. Not all of them go to a cinema to hear the result. Fortunately, those that do, claim it mostly sounds as they intended in cinema and the levels that mixers use do not seem too far apart. People working on movies for cinema seem to stick to 79 to 85, as you also said, which gives us a good ballpark number. I hope that this will not change because, if someone mixes at 75 and makes it so loud that they can barely stand it, a cinema might play it too loud because they might never know that it was not intended for Dolby 7(85)...
IMax has this Godzilla trailer countdown that is just so extremely loud, I wonder if it was created that way...

I very much agree with your arguments!
I don't feel bad using the volume control during playback. Nevertheless, all loudness compensation functions, which we have in the receivers are based on a "reference" and this does frustrate me a bit. In the current situation, loudness compensation is always off, which is a bit of a shame. I do enjoy a nice rumbling sound but I hate it when people scream too much. Volume control alone does not help me with this and some loudness compensation would.

 

[MKreroo]

I think this study is quite worth the read.
here
It seems to be aligned with what discussed here, in that the standard used to determine dangerous listening level is not suitable for music/personal device, and how the standard is inconsistent across the globe, and how the standard for industrial/environmental noise is use (misuse?) to access recreational/music.

I wonder if there's any follow-up or improvement about the standards.

 

[kschmit2]

I always liked Marc Fishman's (https://www.emmys.com/bios/marc-fishman / https://www.imdb.com/name/nm0279892/) contributions on that topic on avsforum.com. He posts there as FilmMixer.
He shares a lot of insight.

 

[Aerith Gainsborough]

THX standard says that at reference level (-20dBFS, the broadcast/professional reference level) a Pink Noise should generate 85dBSPL at the audience position. As you can see from the simple chart below this means the theatre's sound system is expected to produce 115dBSPL without audible distortion.

Good post!

Yeah.... and then you have dialog in movies that is to stupidly quiet that it's a challenge to understand even when using headphones.
I get "dynamics" and all that jazz but at this point it just gets annoying. Having a human scream at the top of his lungs and the scream being ... well.. quiet, next to the deafening rumble and explosive effects just feels retarded to me. Sometimes I wish I could smack the darn audio engineers. :<

I absolutely agree on the point, that most people never think about exposition duration. I learned about that during my studies regarding workplace safety.

That being said: 85dB (Z) average is bloody loud indeed. I typically listen at 90dB (Z) peak level and already consider that quite a beefy volume. Then again, I never went to clubs and I hate cinemas for their loudness.

 

[AdamG]

I wish I could go back in time and Warn my younger self about how easy and quickly and Unkowningly you can cause irreversible damage to your hearing. You don’t really notice or demonstrate symptoms until the damage is done. 115db peaks would be fine if there were only a few moments in the movie that reached this level. But many Blockbuster Action movies drown you in hours of max SPL. The volume levels just keep creeping up in Movie Theaters it has become a very high possibility of hearing damage to pay to watch a movie.

It bears repeating this message, if only to save someone else from destroying their hearing. 115 dB peaks in my opinion are about 10 dB too high. It’s cumulative damage. Think of it like new tires on your car. Watching a loud movie is like doing burnouts and donuts. Do enough of them and…..except you can’t just go buy new ears/hearing. Calibrate to 75 dB and save your hearing.

 

[sarumbear]

Think of it like new tires on your car. Watching a loud movie is like doing burnouts and donuts. Do enough of them and…..except you can’t just go buy new ears/hearing. Calibrate to 75 dB and save your hearing.

What a brilliant analogy! Exactly right!

 

[Aerith Gainsborough]

115 dB peaks in my opinion are about 10 dB too high. It’s cumulative damage.

It's not just about damage though. At that volume, the human ear also goes into "protective mode", meaning: not only do you risk permanent injury, you also lose out on sonic details because your ear and body are totally stressed out.

May not be much of an issue with crappy cinema systems but if you spend big bucks to build a highend home system....

 

[Chromatischism]

IME 115 dB of low bass isn't bad and can add a lot to the experience, while 115 dB of treble frequencies would end my enjoyment, run me out of the room, and leave me with temporary (hopefully) threshold shift.

 

[sarumbear]

IME 115 dB of low bass isn't bad and can add a lot to the experience, while 115 dB of treble frequencies would end my enjoyment, run me out of the room, and leave me with temporary (hopefully) threshold shift.

I'm not sure if you read the research where they show low frequencies are equally effective in causing hearing damage.

 

[Descartes]

Yep
Noise-induced hearing loss is very common. If you are continuously exposed to noise that exceeds 85 decibels, your hearing might be irreversibly damaged.

Noise-related hearing loss can be brought on by long-term subjection to extremely high levels of noise, which leads to a gradual deterioration of your hearing. It can also be caused by a single instance of a loud burst of noise that can immediately result in hearing loss due to hair cells inside of your inner ear that get permanently destroyed by noise or to high volume.

Unfortunately many of us who love rock concerts probably

 

[Descartes]

I'm not sure if you read the research where they show low frequencies are equally effective in causing hearing damage.

LOW FREQUENCY SENSORINEURAL HEARING LOSS

Low frequency sensorineural hearing loss is often caused by Meniere's disease. This page reviews the causes

dizziness-and-balance.com

 

[Aerith Gainsborough]

IME 115 dB of low bass isn't bad and can add a lot to the experience, while 115 dB of treble frequencies would end my enjoyment, run me out of the room, and leave me with temporary (hopefully) threshold shift.

Well, having high frequencies scream at me @105dB THX levels isn't that much better. Probably a little safer but it would still make me reach for the volume knob immediately.

 

[Andysu]

I wish I could go back in time and Warn my younger self about how easy and quickly and Unkowningly you can cause irreversible damage to your hearing. You don’t really notice or demonstrate symptoms until the damage is done. 115db peaks would be fine if there were only a few moments in the movie that reached this level. But many Blockbuster Action movies drown you in hours of max SPL. The volume levels just keep creeping up in Movie Theaters it has become a very high possibility of hearing damage to pay to watch a movie.

It bears repeating this message, if only to save someone else from destroying their hearing. 115 dB peaks in my opinion are about 10 dB too high. It’s cumulative damage. Think of it like new tires on your car. Watching a loud movie is like doing burnouts and donuts. Do enough of them and…..except you can’t just go buy new ears/hearing. Calibrate to 75 dB and save your hearing.

i wish i can warn myself of the dangers of universal pictures sensurround that was unhealthy with non-stop 120dB for 120mins on battlestar galatica at the bournemouth abc screen 1, september 1979, that resulted in strange hissing noise i can hear most evenings in bed and later in 1990's asked my doctor and knew right away. "sounds like tinnitus" . and i'm stuck with it day and night on and off most days and off other days. but always comes back to haunting me with hisssssssssssssss. now anyone that moans about some rubbish hi-fi with signal to noise ratio, please.
< that is me and F you sound mixers and sound people at universal pictures for causing me hearing damage.

 

[AdamG]

i wish i can warn myself of the dangers of universal pictures sensurround that was unhealthy with non-stop 120dB for 120mins on battlestar galatica at the bournemouth abc screen 1, september 1979, that resulted in strange hissing noise i can hear most evenings in bed and later in 1990's asked my doctor and knew right away. "sounds like tinnitus" . and i'm stuck with it day and night on and off most days and off other days. but always comes back to haunting me with hisssssssssssssss. now anyone that moans about some rubbish hi-fi with signal to noise ratio, please.
< that is me and F you sound mixers and sound people at universal pictures for causing me hearing damage.

Cheers Mate!

 

[Andysu]

Cheers Mate!

yeah we both, been, everyone been F by the deafening unnecessarily of it all. i need not type another word.