How does portable speakers work?

Have you ever thought about how does loudest portable speakers work? I started thinking about this problem when I was a kid, but when I watched the Beatles’ performance, my attention was drawn to the working principle of electric guitars.

Before I saw the actual electric guitar, I thought it needed to be connected to the wall AC power to work. So many years later, when I learned that it not only does not need to be plugged in, but also because it works by generating electricity, I was shocked. So how does it make a loud and strange sound? (Compared to the only classical guitar I have seen before watching the Beatles) This is the role of amplifiers and loudest portable speakers. They all belong to the same "ecosystem".

Let us change the order of the narrative, starting from the conclusion. It's simple: to produce or hear sound, you first need to vibrate the air. why? Because sound is the perception in our brain when moving air molecules interact with our eardrums. Yes, this also means that if there are no ears around the moving air molecules, there will be no sound. Until you hear it, the "sound" does not exist. Sound is actually a sensory perception. Perception requires cognitive processing. Our brain is such a processing plant. It brings subjective information and emotions in sound and music, but this is not what this article will discuss.

Letting the air move refers to the state in which the air changes from a static (or almost static) state to a moving state in the environment. How to do it? To cite a few examples in nature, changes in the temperature of the atmosphere create wind and will directly touch our eardrums, or hit other objects that will hinder the flow of the atmosphere, thus creating the sound of wind. For example, the ocean tide phenomenon formed by the gravitational pull of the moon is because the energy of gravitation moves the sea water, and the movement of the sea water causes the flow of air to make us hear the sound of the waves. Is this explanation easier to understand?

For most loudspeakers, the movement of air molecules comes from a vibrating surface. This thing is called "basin" in low-frequency loudspeakers, and "sound film" in compression unit. So what makes the sound film vibrate?

loudest portable speakers is actually a converter that converts energy from form A to form B. The most common loudest portable speakers is based on a movable coil. Its physical principle is to place a conductor in a magnetic field and apply a voltage to the conductor to make the conductor move. For loudest portable speakers, this conductor is the coil, and then the coil and the sound film are fixed together and placed in the magnetic field. When the voltage is applied, the coil will drive the sound membrane to move, so that the sound membrane pushes the air in front of it to move.

The pickup on an electric guitar is a converter that works in the opposite way. A conductor in the magnetic field generates a voltage to the coil inside it during movement. Specifically, in the pickup of an electric guitar, the plucked string breaks the magnetic field and generates a small amount of voltage in the coil surrounding the magnet. Then this small voltage will be transmitted to the power amplifier, and then the power amplifier will amplify it to a large amount of voltage to drive loudest portable speakers, loudest portable speakers then pushes the air, and finally produces sound. Until now I still like the whole cycle from plucking the strings to hearing the sound.

Back to loudest portable speakers itself. The speed at which the sound membrane moves back and forth depends entirely on the frequency of the voltage applied to its coil. But this can only explain the generation of single-frequency tones. How can a loudest portable speakers emit all the strange sounds produced by an electric guitar, or the sound of an entire orchestra?

Although we can see that loudest portable speakers moves forward and backward in a single direction, the surface of the sound film actually dances with thousands of frequencies at the same time. The interaction of these small movements of the sound film and the accompanying sound waves (cancel each other and combine) constitutes the multiple frequencies and tones we hear, such as the sound of the entire symphony orchestra playing at the same time, or the Jimi Hendrix guitar Solo sound. Surprisingly, you can actually observe this process in a loudest portable speakers laboratory with a signal generator and a flashlight. When the movement of the loudspeaker's sound film looks like an organized riot, the pattern is actually symmetrical and orderly, and this phenomenon has been studied for more than 200 years.