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

[audio2920]

I disagree. 85dB is how you set your volume. It’s a calibration level. Once the volume is set you mix with your ears and with guidance of a loudness/peak meter. You mix to a feeling. You don’t mix to a level. The feeling is set with the calibration.

I don't disagree, I just think I'm not putting my point across and I don't really know how to because I'm tired.

I just mean, people, not you, seem to say things like "I played the mix and it measured 85dB and it seemed loud" - to which I'm like 'what?'

It's just a number. 85 is just a known calibration. It could have been 75 with 30 dB of headroom. The *number* they (Dolby) chose tells you nothing about how loud a mix is.

 

[sarumbear]

The *number* they (Dolby) chose tells you nothing about how loud a mix is.

I fully agree. However, your peers are putting out mixes that took advantage of the headroom and compress the sound, can’t find a better word, to the hilt. This means if you calibrate your home theatre as per THX guidance, the levels are dangerously high.

 

[audio2920]

This means if you calibrate your home theatre as per THX guidance, the levels are dangerously high.

Yes! This.

 

[Andysu]

I just leave it to video. JBL THX in my living room that I call THX cinema now. Well the local odeon bh2 isense atmos is sheer DEAFENING in the HF horns though to the side/back and overhead surrounds where I need to wear earplugs and the bass there is meh. It tries so hard to be THX. Atmos in my home way better than the isense even if they are running 64 channels? One of my CB radios has 200 channels. Atmos has to have its levels adjusted? To what and I don't care what Atmos cinemas SPL dB is, three times going and I had to put fingers in my ears or wear my earplugs.
Predator downmix from the 5.1 or 4.1 as it has original mono discrete surround, downmixed to MP 4.2.4 to my Dolby CP500/CP200 and monitored the levels on the THX crossover/monitor on AMP return. I can't use it while six-track or Atmos is playing I need to set-up the other computer monitor.

The bass cabs can easily reach 105dBC - HF horns can reach 120dBA but 85dBA peak is plenty sonic enough or often less around 80dBA depending on the film mix? The surround arrays can easily reach 105dBC.
Often at times I may ride the fader up and down.

Too bad there is no cinema using THX in the UK no longer. I wonder how many substandard ones would even adopt a baffle wall behind the screen? Does the VUE west end still use a baffle wall? I know the odoen bh2 isense doesn't seen pictures and maybe why the bass is just, meh.
I know the cineworld Leicester square doesn't use a baffle wall well I doubt Liemax could otherwise uncle George Lucas would drop a ton force bricks on them.

Two of the best THX cinemas was '89 CIC Empire Leicester Square and CIC High Wycombe, the new Warner West End 9 screen, was sort of but lacked bass? What is going on there? When it reopened I had to see what it was like? I measured in screen 7, with 'Maverick' 1992, Dolby Stereo SR, 90dBA peak and that was way too toppy. They only had single bass cab per LCR behind the screen I not totally sure if they had five screen for 70mm? Rare that be for prints that had Lc Rc.

I never thought of taking my SPL meter with at Empire or High Wycombe cos it was great, it was outstanding it was or once was out of this world.

There's a Dolby Loudness meter that measures, I just ordered the Dolby Leq 737 and 24v 500ma power supply. I should have this up and running, january 8th.

 

[Chromatischism]

OSHA 1910: https://www.osha.gov/laws-regs/regulations/standardnumber/1910#1910_Subpart_G
Specifically regarding noise exposure: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.95

Note OSHA is A-weighted to emulate the hearing sensitive of humans, and their guidance is basically to ensure (we hope) that in your old age you can follow conversations, not the nuances in full-range music. Recommendations I recall typically derate OSHA by 10~20 dB for more realistic levels. I personally find 80 dB (10 dB below the OSHA 8-hour spec) too loud for long listening sessions. Friends and articles/posts from those in the movie and music recording business tell me they rarely exceed 80 dB average during mixing and mastering.

When I run calibrations I usually leave the room.

YMMV - Don

Edit: Note these are average levels; peaks in music and movies can run 20 to 30 dB higher for brief peaks.

I hope it's okay to post this small excerpt from Toole, Floyd E.. Sound Reproduction (Audio Engineering Society Presents) (p. 63). Taylor and Francis. Kindle Edition:

"The occupational hearing conservation guidelines are important, but are often misinterpreted in that it is assumed that they prevent hearing loss. As discussed in more detail in Chapter 17, that is not the case. They permit hearing loss to occur, aiming only to conserve enough at the end of a working life to permit carrying on a generally intelligible conversation at a distance of 1 m. Appreciating the subtleties of live or reproduced sounds would be a pleasure long gone."

Later adding: "These are guidelines created for factory workers, not audio engineers."

 

[Chromatischism]

I've never seen Dune, but if that's the theatrical cinema release that measures -11LUFS, that does sound like it would be utterly brutal in a cinema at full level.

I saw it in the theater. It was a louder movie, clearly trying to be so, but I didn't find it unbearable. It's possible the theater didn't run it full bore, I have no idea.

 

[Descartes]

For those who prefer to read science, here are a couple of websites on noise & health

Loud Noise Dangers

Loud noise can cause permanent hearing loss. There are ways to protect your hearing. Audiologists can help.

www.asha.org

What Noises Cause Hearing Loss? | NCEH | CDC

Noise is a significant source of hearing loss, but you can protect your hearing. An important first step is to understand how noise causes hearing loss.

www.cdc.gov

 

[Chromatischism]

This is an often repeated but unsubstantiated myth. In fact, due to the physiology of the cochlea, loud bass frequencies may actually be more damaging than high frequencies:

https://www.reddit.com/r/headphones/comments/6tmg44/_/dln3q0e

Do not use A filtering. That is for measuring environmental noise. Music does not require weighing as unlike noise, music is a full spectrum sound. Filtering will skew your measurements.

This will be worth a read regarding low frequency hearing loss and, separately, A-weighting. PDF attached.

From: Loudness and the Risk of Hearing Loss: Two Different Criteria
Floyd Toole

 

[sarumbear]

This will be worth a read regarding low frequency hearing loss and, separately, A-weighting. PDF attached.

From: Loudness and the Risk of Hearing Loss: Two Different Criteria
Floyd Toole

All due and well deserved respect to Dr. Toole he wrote this in his book originally published in 2008. He used a model based on the pioneering work done in the 70s by R Plomp about hearing loss and effect of hearing aids.

If you think that the medical science have not improved during the last quarter of a century, by all means ignore my original post. It is your life, your decision.

 

[thewas]

Dr. Toole recently added a new chapter on hearing loss in the latest edition of his book quoting there newer literature up to 2016.

 

[sarumbear]

Dr. Toole recently added a new chapter on hearing loss in the latest edition of his book quoting there newer literature up to 2016.

The research he refers to was from the 70s, a quarter century ago. That is what I am pointing out.

 

[thewas]

The research he refers to was from the 70s, a quarter century ago. That is what I am pointing out.

And I am pointing out that newer research he refers can be found in the latest edition of his book.

 

[sarumbear]

And I am pointing out that newer research he refers can be found in the latest edition of his book.

I apologise. I thought the post above is from the new edition. If you have access to the new edition I like to read the revised text or at least learn what research Dr Toole is referring on the new edition?

 

[thewas]

I apologise. I thought the post above is from the new edition. If you have access to the new edition I like to read the revised text or at least learn what research Dr Toole is referring on the new edition?

I have the book but please have the understanding that due to copyright reasons I won't upload here any scans of it (and also too lazy to write a summary ). But here he shortly refers to this chapter https://www.audiosciencereview.com/...iew-powered-monitor.28039/page-59#post-987547

 

[sarumbear]

I have the book but please have the understanding that due to copyright reasons I won't upload here any scans of it (and also too lazy to write a summary ). But here he shortly refers to this chapter https://www.audiosciencereview.com/...iew-powered-monitor.28039/page-59#post-987547

Thank you for the link to Dr Toole’s posts. I’m glad to read that he points to the dangers of high SPL listening as well.

Meanwhile, copying a single snippet of a book does not break copyright. It’s fair use as I was interested only on what research the author has based a section of his book on.

 

[thewas]

Feel free to ask him if he is ok with it, than he would do it himself. Also please mind a short snipet is not that helpful as his literature quotes are spread all over the text. Also please bare with me, as for me his book, despite already owning the 2nd edition too, is THE must have audio literature, so I will do anything to promote and support its sale.

 

[sarumbear]

Feel free to ask him if he is ok with it, than he would do it himself. Also please mind a short snipet is not that helpful as his literature quotes are spread all over the text. Also please bare with me, as for me his book, despite already owning the 2nd edition too, is THE must have audio literature, so I will do anything to promote and support its sale.

I have a copy of the original edition, which I bought upon its publication. I couldn’t justify to buy every edition though.

 

[thewas]

I have a copy of the original edition, which I bought upon its publication. I couldn’t justify to buy every edition though.

The current 3rd edition has so many additions and changes that its imho (and many others share that opinion too) really worth an additional buy, I also have both and didn't regret a second buying it, the best money I ever spent on audio, even more considering its peanut 40€ price.

 

[Descartes]

Fir those who want scientific literature; here you are:

Common loud noises cause fluid buildup in the inner ear, study finds

A new study reveals that common loud noises cause fluid buildup in the inner ear and suggests a simple possible treatment for noise-induced hearing loss.

www.sciencedaily.com

Understanding hearing loss from noise damage through gene expression changes

A team led by researchers has published an online interactive atlas representing the changes in the levels of RNA made in the different cell types of ears of mice, after damage due to loud noise. From this analysis, the research teams identified a handful of drug candidates that may be able to...

www.sciencedaily.com

Also there maybe hope:

Hearing Loss

Seventeen percent of Americans have some degree of irreversible hearing loss. Harvard Stem Cell Institute scientists want to bring it back.

hsci.harvard.edu

 

[GaryH]

This will be worth a read regarding low frequency hearing loss and, separately, A-weighting. PDF attached.

From: Loudness and the Risk of Hearing Loss: Two Different Criteria
Floyd Toole

View attachment 174836

That paper Toole references was on temporary threshold shifts (TTS), not permanent hearing damage. It's an assumption that the same frequency dependence will hold for the latter. In fact, Toole goes on to say in that article:

It has also been suggested that: “caution should be used in exposing human subjects to schedules of noise that may, in fact, be hazardous, but that produce little or no TTS” (Clark, W.W. JASA, pp.175-181, 1991).

The 3rd edition of his book that @thewas mentioned actually expands on and offers more supporting evidence for this 'hidden hearing loss' that can manifest in impaired binaural / spatial discrimination. He quotes Kujawa and Liberman (2009):

It is sobering to consider that normal threshold sensitivity can mask ongoing and dramatic neural degeneration in noise-exposed ears, yet threshold sensitivity represents the gold standard for quantifying noise damage in humans. Federal exposure guidelines (OSHA, 1974; NIOSH, 1998) aim to protect against permanent threshold shifts, an approach that assumes that reversible threshold shifts are associated with benign levels of exposure. Moreover, lack of delayed threshold shifts after noise has been taken as evidence that delayed effects of noise do not occur. The present results contradict these fundamental assumptions by showing that reversibility of noise-induced threshold shifts masks progressive underlying neuropathology that likely has profound long-term consequences on auditory processing. The clear conclusion is that noise exposure is more dangerous than has been assumed.

And Bernstein and Trahiotis (2016):

listeners whose high-frequency monaural hearing status would be classified audiometrically as being normal or ‘slight loss’ may exhibit substantial and perceptually meaningful losses of binaural processing

As well as referencing Srinivasan et al.'s (2016) study on soundstage image separation discrimination, who concluded that young normal-hearing listeners could discriminate ~2° angular separation between a sound and a masker, older normal-hearing listeners could discriminate ~6°, and older hearing-impaired listeners only managing ~30°. (I suspect this could be a possible contributing cause to some, usually older, reviewers reporting that they can't really hear or distinguish that well the soundstage differences many others perceive between for example different headphones).

Finally, a quick Google search reveals this study actually on permanent hearing loss, in which the authors conclude:

We did not notice any association among frequency bands carrying intense noise levels and the hearing damage frequency.

So, I stand by my, and the qualified audiologist's I quoted, assertion that "any frequency at a loud enough intensity can damage your ears", including bass frequencies.