Protecting our ears from overcompression of sound

The dangers associated with overcompression of sound: an ingenious system which can be dangerous for hearing health during prolonged exposure. UNESCO Sound Week takes place from Monday January 15 to 28, in Paris and the regions.

If music softens morals and provides pleasure, it can also cause damage to the ears and the brain, and not only because of too much volume. Excessive sound compression would also have a significant impact on hearing health. Decryption with Martin Ducret, doctor and journalist at Doctor’s Daily.

franceinfo: First of all, explain to us what sound compression is?

Martin Ducret: To understand this, I asked Christian Hugonnet, acoustician and president of UNESCO Sound Week, an event to raise awareness among the general public about the quality of our sound environment, which begins tomorrow and runs until January 28, in Paris. and in around forty French cities. He explained to me that when we talk about sound compression, we are talking about dynamic sound compression, that is to say the fact of reducing the difference in levels between sounds at high decibels, and sounds at low decibels. decibels. Not to be confused with compressing the size of a sound file, which reduces its weight.

Dynamic compression allows – when listening to a concert, the radio, TV or a music platform – to have a more homogeneous, more linear sound, so as not to overwhelm the ears when the sound is very loud, or not to hear nothing when it is very weak. This ingenious, omnipresent system allows listening adapted to different media, without spending time adjusting the volume.

But be careful, when the compression is pushed to the extreme, what we call overcompression, it can be dangerous for hearing health during prolonged exposure.

Is this what recent work on the subject shows?

Yes exactly, the team of Professor Paul Avan, physiologist at the Hearing Institute in Paris, compared in guinea pigs – animals very similar to us in terms of hearing – the effects of listening during more than 4 hours, of overcompressed music compared to music without compression.

Results: overcompressed music caused harmful effects, not on the inner ear, but auditory fatigue on the hearing neurons. Professor Paul Avan explained to me that “overcompression in a way suffocates our hearing system, by eliminating microsilences, these small moments of auditory pauses, essential to make our ears breathe.” In another study, the professor also showed that other parameters, in addition to overcompression, can be harmful, such as generalization of low frequencies.

What perspectives does this work offer?

Thanks to its results, researchers and acousticians, during UNESCO Sound Week which begins tomorrow Monday January 15, will propose a sound quality label, a sort of nutriscore for sound, which will for example be affixed to albums or on music platforms.