The volume adjustment on our devices is not linear: it depends on our hearing

When you adjust the volume of your smartphone, computer or headphones, you might think that 50% sound is exactly half of what you would feel by setting it 100%. In reality it is not so. Our way of perceiving sounds is not linear, but logarithmic. Put simply, a sound that we perceive how double the volume of another actually has a sound power in terms of Decibel (DB) Ten times higher, and not simply double! This principle is the basis of the Decibel scale (DB), which does not grow evenly but exponentially.

If the volume checks worked in linearly, the adjustment would be anything but intuitive: small movements of the bar would seem irrelevant, while the last increases would be exaggerated. To solve this problem, many manufacturers of software devices and developers adopt Logarithmic curves to make the more natural volume adjustment experience. It must be said, however, that not all platforms apply this principle in the same way, and some interfaces are uncomfortable to use. This explains, for example, because some volume sliders seem ineffective up to a certain point and then change drastically in the latest values.

How the perception of sound for the human ear works

Human hearing follows a logarithmic scale: to perceive a sound like twice stronger, its real intensity must increase by ten times. This biological feature has been studied for a long time and is the reason why The decibel scale is built in a non -linear way. A sound of 60 dB is not simply twice a sound of 30 dB, but a thousand times more powerful in terms of sound energy. If the engineers designed the volume based on a linear progression, we would have a system in which the first half of the regulation would seem almost imperceptible, while the second would have extremely impactful changes.

Volume adjustment in electronic devices such as the smartphone

To solve this problem, Volume control is implemented with logarithmic curves. In practice, the value set by the user is followed to adapt to human auditory perception. If you set the volume at 50%, the exit will not have half of the sound power compared to 100%, but an intermediate value calibrated to be as natural as possible. This approach is widely adopted in mobile operating systems, such as Android and iOS, which regulate the volume in order to avoid too abrupt jumps or changes almost totally imperceptible. But as we said at the beginning, not all software adopts adequate curves: a very famous example is represented by YouTube on desktop, where volume control appears not very reactive in the first part of the slider, while in the last increases the sound grows disproportionately.

Another complication derives from the diversity of output devices. Headphones and speakers respond differently to volume variations. Some devices emphasize certain sound frequencies more than others, further influencing the perception of the variation of the volume. This brings manufacturers to develop specific profiles to adapt the control behavior based on the device in use. Many of the wireless headphones on the market, for example, have customized volume curves to improve the perception of audio with low volumes.

The adjustment of the volume may seem a negligible detail, but behind this apparently trivial function there is a hidden Intimate balance between sound engineering, human perception and user interface design. Now that you know these mechanisms a little better, you can not only better understand the functioning of the devices you use every day, but also note those small inconsistencies that make certain experiences of less intuitive use than others.