How to protect yourself from rapid volume fluctuations

On several websites, hyperacusis is defined as the “loss of the ear’s dynamic range, understood as the auditory system’s ability to handle rapid increases in sound volume.” At first, I didn’t take this definition very seriously because hyperacusis is, above all, a reduction of the maximum tolerable intensity. Clearly, my problem was excessively loud sounds, which previously were no issue and now were intolerable, and I didn’t notice any particular difficulty with rapid volume changes.

However, over time I realized that this definition is incomplete. In hyperacusis, the limitation is not only the maximum tolerable sound intensity but also sudden variations in volume. This means that sounds with an intensity clearly within our comfortable range can still be incomprehensibly difficult to tolerate. For example, a person with hyperacusis might tolerate the noise of a bus at 75–80 dB without difficulty, yet a door slamming at only 65 dB—if heard in a very quiet environment—can leave the ear somewhat sore and more sensitive.

How is this possible? In my view, it is because the ear perceives not only absolute intensity but also relative intensity. Ears with hyperacusis are limited by these two variables: a given sound elicits a response both from its absolute intensity and from its relative intensity. You can think of relative intensity as the difference between the absolute intensity and the ambient sound or background noise. Therefore, as you might imagine, relative intensity is higher in a quiet environment, meaning that even a moderately intense, otherwise tolerable sound can feel overwhelming.

One typical sound that is difficult to manage for this reason is human speech, which generally has many intensity fluctuations. Bus noise, although relatively loud, is constant, with minimal variations. Even with people conversing around you, the fluctuations are minor because the background noise of the bus dampens them. In a very quiet environment, however, the same conversation at the same volume will be perceived as much louder, because the background is almost nonexistent, giving the impression that people are speaking excessively loudly. This perception of moderate sounds as “too loud” is caused by the lack of background noise, which acts as a volume multiplier: everything sounds louder than it would under normal conditions. Even if your sound meter shows a level you know to be tolerable, silence can make the sound exceed your threshold.

So, how can we cope with rapid volume changes? The answer is simple: provide the ears with continuous background noise that reduces the relative intensity of sounds. Hyperacusis treatment using sound therapy—which involves listening to broadband noise for hours and enriching the sound environment to avoid silence—has validated this approach for managing rapid volume changes or unexpected sounds in overly quiet environments. I’ve observed how certain sounds stress my ears in silence but become harmless when a constant background noise is present to lower the perceived intensity.

Obviously, the background noise must be tolerable; otherwise, it would have the opposite effect. As the bus example shows, the background noise doesn’t need to be the same as the sound used in therapy; it can be any constant, tolerable ambient sound that prevents excessive silence and buffers rapid volume changes. Sound therapy can be especially useful in quiet environments where natural background noise is insufficient—for example, in a relatively silent office where people intermittently start conversations that create rapid intensity fluctuations relative to the background.