Sound science

How noise can become toxic

Inside your inner ear, tiny sensory cells called stereocilia convert sound waves into electrical signals for your brain to interpret. These cells are incredibly delicate - and they’re what allow every drop, kick and vocal on the dance floor to feel alive.

Like anything biological, though, they have limits.

A helpful way to picture them is as blades of grass in a field:

• If one person walks across the grass, it bends but springs back.
  In the same way, after a loud night out you may notice temporary muffling or ringing that settles within 24–48 hours.

• If hundreds of people trample the same patch repeatedly, some blades don’t recover.
  Similarly, repeated loud sound exposure can lead to permanent changes, because these hair cells don’t regenerate once lost.

Noise exposure builds up like a dose - the louder the sound or the longer you’re exposed, the more “energy” those hair cells have to absorb. What matters is total sound energy, not just how many times you go out.

This is known as the equal-energy principle:
the ear receives the same total “load” whether that sound energy is delivered all at once or spread across multiple exposures.

For example:
If 100 people walked across the grass in a single night or 100 people walked across it slowly over a year, the total wear on the grass is comparable.

Beyond mechanical stress, loud sound can trigger a cascade inside the inner ear, including:

• oxidative stress and free-radical formation

• excitotoxicity (overstimulation of auditory nerve pathways)

• temporary reduction in blood flow to the cochlea

• structural stress to the hair cells themselvesThese biological processes are the reason noise can become “toxic” when exposure goes beyond what the ear can comfortably handle.

Decibels work differently to how you think

Sound levels in clubs often exceed 90–100 dB, and some peak higher. Understanding what those numbers mean helps you stay in control of your exposure.

Decibels (dB) measure sound intensity, and the scale is logarithmic:

• a 10 dB increase = 10× more sound energy

• a 20 dB increase = 100× more sound energy

So:

• 100 dB is 10× more intense than 90 dB

• 110 dB is 100× more intense than 90 dB

Even though the risk increases dramatically, our ears don’t perceive loudness in a linear way. A sound that carries 10× more energy only feels about twice as loud. That’s why very small changes in measured sound level can have a big impact on your ears - even if they don’t feel huge.

This also matters when choosing earplugs:

• A –10 dB filter reduces sound energy by a factor of 10

• A –20 dB filter reduces it by a factor of 100

To your ears, –20 dB sounds roughly half as loud as –10 dB.
That’s a huge difference in experience. Choosing a filter that’s too strong can make the music feel distant or muted; choosing one too weak leaves you unprotected.

Your noise dose gives you a personalised way to judge what you actually need - helping you balance protection with a sound that stays detailed, clear and enjoyable.