2024-02-13 18:00:00
The YouGov Institute reveals the results of a study on the listening habits of the French and their hearing health.
According to this survey, carried out for the streaming platform Qobuz, 73% of 18-24 year olds report having risky, “prolonged and high volume” listening – this is 62% in the general population.
The youngest, however, seem more aware than their elders of the impact of sound quality on hearing health: 66% recognize the cause and effect link when only 54% of the general average is aware of it.
According to the WHO, more than a billion young people (aged 12 to 35) are at risk of hearing loss due to exposure to leisure noise at concerts, in nightclubs or while listening to music at home. helmet. The sound volume is obviously in question but the compression of the sound also plays a part.
What is sound compression?
“This is dynamic compression – the difference between the loudest sound and the quietest sound – not file compression. This compression is inherited from the advent of amplified music and recording (sound fixation, microphone, electric instruments, editor’s note)”, explains Professor Paul Avan, professor of biophysics at the University of Clermont-Auvergne who studied the impact of this compressed music on the auditory system.
“This practice then made it possible to increase the range of radio waves. Today useless with digital music, compressed sound is still used to prevent extraneous sounds from interfering with relevant sounds,” explains the biophysicist, director of the Center for Research and Innovation in Human Audiology (Ceriah) at the ‘Pastor Institute.
By videoconference, on platforms, on radio, television
The music alternates between quiet and louder sounds. When it comes to low sounds, these can be covered by extraneous noises, such as traffic, a crowd, a car engine, etc.
“Broadcasters and engineers then had the idea of raising sounds when they are below a certain decibel level. So, the deliberate choice is to remove all the silences so that the surrounding noise can no longer infiltrate the moments of silence,” explains Paul Avan. The sound is also more homogeneous: no more very loud sounds and very low ones.
We find this process in advertisements, on the radio, using your smartphone, on certain streaming music platforms. Among the recently compressed sounds: speech.
“In videoconferencing, most platforms compress the sound, so that when you speak, all you hear is you. The level of speech is amplified but also breathing, mouth noises, and all surrounding noises,” explains Professor Avan.
The problem for hearing health with this compression? “By removing silence, even for extremely short periods of time, the hearing system can no longer recover,” adds the specialist.
Damaged auditory neurons
To find out the impact of compressed music, he and his team exposed guinea pigs – which have a hearing system similar to that of humans – to supercompressed music, at the sound level permitted in nightclubs (102 dB), for 4 hours. Another group was exposed to the same song, at the same decibels, but uncompressed.
Results: in the group exposed to supercompressed music, hearing abilities were not affected but the auditory neurons permanently lost efficiency; the other group regained these abilities in just a few hours.
“The capacity of the acoustic reflex (which protects the inner ear from noise, editor’s note), directed by the brain, had halved for an entire week. A week without recovering these abilities for only 4 hours of exposure means that it might be damage and not simply hearing fatigue,” says the scientist. “Other neurons might also have been damaged, but we do not know how to measure them all.”
Certain types of music more than others
The majority of us do not realize that we are subjected to compressed sound, when listening to music or during a video conference. “But we sometimes have this feeling of exhaustion, this impression of being overworked, overloaded. », Describes the scientist.
A new study, also led by Paul Avan and his team, shows that in addition to compression, certain types of music cause exhaustion of the auditory system while others do not. Nothing to do with whether it’s a classical, rock, metal, jazz or rap song.
“It is the richness of the spectral palette which comes into play this time. And in particular the pieces where we find a lot of mids, bass and treble on various sound tracks. »
It remains to be determined precisely what a partition contains that might damage the hearing system.
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