How loud have Dublin cinemas gotten

On Wednesday afternoon, in the dark of the Odeon Blanchardstown’s IMAX theatre, the last few patrons potter to their seats, as the trailers roll.

Big chairs squeak as people settle in. There’s the unmistakable crunches of the first perfect handfuls of fresh, warm popcorn.

Suddenly, that sound is eclipsed by the sounds of the movie trailers.

A decibel meter app softly flickers. “The current decibel value is too high,” it warns.

The main show, Fantastic Four: First Steps, hasn’t even started yet – and readings as high as 109 dB flash on the meter.

Just before the film begins, patrons are reminded that it was filmed for IMAX screens, and features “earth shattering sound”.

How about ear shattering? Well, it depends, says audiologist Sally Jackson.

First off, the sound meter tested for dB, which is a bit different to dBA.

There are multiple scales for decibels, and they are all “weighted” differently, for different purposes, says Jackson.

DBA is to measure how loud sounds are to the average human ear, while dB is a general measure for sound pressure levels.

But, she says, if something is measuring over 90 dB, it’s likely bad for your ears whatever way you cut it.

The levels

While Fantastic Four on Wednesday peaked at 109 dB, it averaged out at 81.3 dB. But basically any action sequence registered in the 90s for most of its duration.

Anything over 85 dBA can be dangerous over time, says Jackson.

While 90 dBA is somewhere in between standing in heavy traffic, and operating a pneumatic drill in terms of sound intensity, she says.

That definitely has the capacity to damage your hearing, she says, but adds that it’s okay for levels to occasionally reach 90 dBA.

Jackson says that “safe” noise is calculated by sound pressure level multiplied by time.

So, are high levels safe in short doses like a cinema trip?

A two-hour film continuously reaching 91 dBA is “allegedly safe”, she says. But there are two caveats.

Firstly, exposure adds up, says Jackson.

If someone works amid 85 dBA noise all day, then goes to the cinema, then listens to music with headphones on the way home, she says, that person is not safe from hearing damage.

Secondly, she says, every 3 dBA increase in noise level halves the safe exposure time.

Warnings

While the ODEON’s IMAX screen prides itself on “earth shattering sound”, other standard screens in Dublin were also recently showing films at volumes that peaked over the 100 dB mark.

On Tuesday, in the city centre’s iconic Savoy Cinema – now owned by the IMC Cinema Group – levels during a screening for Superman reached 103 dB, a dozen times.

Paul Corcoran says he has stayed clear of the cinema since April last year after one film left his ears physically ringing.

He says he forgets what film it was that put him off finally. But he had noticed it as a growing issue in recent years, he says.

“I came out of Oppenheimer the same way. And the ads leading up to the movie seem even louder,” he says.

Garry Mulhall was at Wednesday’s screening of Fantastic Four in Blanchardstown with his two young sons. He wonders if they’ve just become accustomed to the noise at big films.

At Superman a few weeks prior, he says it was even louder.

At one point, he says, he noticed his youngest son had his hands over his ears. “We were going to leave but the boys wanted to hang on.”

Cinemas should warn that sound levels inside the theatre can average 85 dB and peak at over 100 dB, says Jackson, the audiologist.

Jackson compares those figures to the numbers within the European Union’s safe dosage limits for workplace safety.

Cinemas may say such numbers are under those limits, she says, but it’s not that straightforward.

There should be warnings, she says, that it can be uncomfortable for people with hyperacusis (abnormal sensitivity to sound) and tinnitus (which can be triggered by high sound pressure levels).

“At the very least they should invite you to come to the customer service desk if you are experiencing discomfort,” Jackson says.

Also, she notes, the EU safety limits relate to the maximum level an employer can subject their employees too. “They are not a target, as some cinemas seem to think.”

While 80 dBA and below is supposedly safe, she says every 3dB above this actually doubles the sound intensity and halves the exposure limit.

“You might think 80, 83, 86 – what’s the difference? The difference is a lot! 103 is safe for 7 minutes. 106 for 3.5 minutes. 109 – well I hope it was short!” she says.

Neither ODEON nor IMC have responded to questions asking how they calibrate the sound, and what average volume levels, or maximum levels, they permit.

Hidden hearing loss

Cinema users are consumers rather than employees of course. But regulations relating to noise levels at work are a useful reference point. In Ireland, they were last updated in 2007.

According to the Health and Safety Authority (HSA), where employees are exposed to noise about 85 dBA, an employer must take certain steps.

Displaying a warning sign, for one, and ensuring such workstations are protected from unauthorised access by barriers.

Since 2007, however, Jackson says there has been more research into hearing damage.

“We have known that the antibiotic gentamicin can damage hearing, now we know that if you have a certain gene, it will damage your hearing but you are safe if you do not have the gene,” she says.

There is also now an awareness of hidden hearing loss, or cochlear neuropathy, says Jackson.

This is damage that doesn’t register on a hearing test, she says. “You can still pass a hearing test but you cannot make sense of speech in the presence of background noise.”

Hidden hearing loss is strongly associated with noise exposure, she says.

However, she adds that it may take years before safe noise exposure guidelines catch up with the current research.

She says it is better to be overly cautious for the time being.

“I am seeing people in their 20s come through my door with trouble making out what their friends are saying when it’s noisy. That’s hidden hearing loss and I do not think it is adequately covered by today’s safe noise limits,” she says.

She warns that those with family members who suffered hearing loss in their early 50s should be particularly wary. “Your personal, genetic susceptibility is likely more than the average person.”

It’s still okay to have a good time!

Jackson encourages people to still go to things like concerts, but to just take precautions.

“Live music is an absolute joy,” she says.

However, human inner ears evolved to be sensitive to a breeze in a cornfield, she says, not to listen to drills, loud movies or music all day.

“It does not make sense that we can sit in an enclosed space such as a cinema for 2.5 hours listening to explosions,” she says.

While it may run you a couple of hundred euro, she says, custom made noise-filtering earplugs, from an audiologist, will keep you safe and things sounding great.

A rule of thumb, she says, is that if you’re exposed to noise that is causing discomfort or a headache, just get out of there.

“If your hearing goes temporarily dull afterwards, or you get ringing in your ears (tinnitus) for a day or so after, it has done damage that you cannot see,” she says.

“That damage, we now know, is not temporary, and adds up over time. So, err on the side of caution.”

Funded by the Local Democracy Reporting Scheme.