Sound is energy that’s made from vibrations. When an object vibrates, such as a guitar string, it makes tiny air particles move around and these movements trigger bones in our ears that interoperate these vibrations as noises. The quicker these vibrations, the higher the frequency, which is what creates high-pitched noises. Humans can hear frequencies as low as 20 Hz, and as high as 20,000 Hz, but this ability changes as we age. In fact, as you grow older, we’ll struggle to hear these higher frequencies. This is why devices designed to stop children loitering deploy a high-pitched frequency as they can’t be heard by older people.
You would think that the speed of these waves would also affect how loud things are too; however, the speed of the vibration does not make it louder. In fact, loudness is due to something else entirely, known as amplitude.
What is Amplitude
Amplitude is the maximum extent of a vibration, measured from the position of equilibrium. If you imagine a sound wave looking very much like an ocean wave, then the amplitude is the highest point of a wave as it passes through the ocean. The bigger the amplitude of the wave — meaning the distance between the highest point and middle point — means a more intense sound, which is what determines volume.
To make something louder requires adding more force to it, and that’s why when we pluck a string more aggressively, the louder it becomes, as the string is oscillating between a long distance. This energy also helps make the air particles move for a longer time, which is also why the sound lingers for a longer period of time.
This is the case for natural sounds, or what is known as analog soundwaves, but things are a little different when we consider electronic audio. Here there are other things in place to help us control the volume and make things louder or quieter.
Digital potentiometers are usually used to create volume controls, and this is because they are a form of variable resistor that dictates how much current goes through a circuit and thus how powerful it is. This means that they can be used to select and manipulate volume. They are a widely used option because they offer great reliability and repeatability and are very precise. The only downfall to this type of equipment is that they can easily be affected by dust and other particles which can block the connections, meaning they will struggle to work properly. To avoid this, simply clean your devices regularly as this will help them last longer.
Sound in Electronic Devices
Electronics still use the same principles of air vibrations to make sound, however they do this by using magnets to push and manipulate the air. The set-up is pretty simple: speakers create a magnetic field by suspending a copper coil inside a magnet. It then creates an opposite magnetic charge that can either attract or push apart from each other, and it is this that creates the sound in most electronic devices.