How does a speaker really work?
Speakers come in many different sizes and shapes. Just think of the speakers in your mobile phone, for example, and compare them to the speakers in a movie theater. Same principle, but a huge difference in performance and results. The main functionality of speakers is that they produce sound, in short, it can be said that speakers process and translate electronic signals/pulses into sound.
Fixed permanent magnet in the speaker
Inside the speaker, there is a permanent magnet mounted. This permanent magnet is mounted so that its position is fixed against a fixed suspension device. This fixed mounting device is in turn fixed against the outer casing of the speaker. The suspension device should be as stable and stable as possible.
Speaker diaphragm and electromagnetic coil
In the suspension device, there is then mounted a speaker membrane, as well as an electromagnetic coil. The coil is mounted so that it can move towards the suspension device, and therefore also towards the permanent magnet. The speaker membrane usually consists of a flexible material, such as paper or space, which gives it great freedom to both move and vibrate.
Electromagnetic vibrations create sound waves
By then sending electrical signals/pulses through the coil, one can induce a magnetic field that will run around the coil. Depending on which direction you send these electrical pulses, you will also be able to induce magnetic fields with field lines in different directions around the coil. This magnetic field induced around the coil will then interact with the magnetic field of the fixture mounted permanent magnet.
The current direction induces different magnetic fields
When the current is sent through the coil in one direction, a magnetic field will be induced around the coil so that the coil is repelled by the magnet. The coil is pushed away from the magnet and presses the diaphragm, the air in front of the diaphragm is rapidly compressed and pushed away as a sound wave.
When current is then sent in the other direction, a magnetic field will be induced in the other direction so that the coil is instead attracted by the magnet. The coil is then pulled toward the magnet and retracted the diaphragm, ready to be pushed forward again.
Test yourself with refrigerator magnets
You can easily explore this effect yourself by using two very common refrigerator magnets. Magnets have a south and a north pole, and the magnetic field goes from the north pole to the south pole. If you take two magnets and bring them together so that their north poles or south poles are facing each other, you cannot make them sit together.
They will push, or repel, each other. But if instead of merging a north pole with a south pole, the magnets will be pulled toward each other, or attracted, and sit together. It is this phenomenon that is used with the help of the coil and permanent magnet in the speaker.
By then utilizing these rapid shifts in the current direction, continuous vibration of the speaker membrane can then be achieved. It is then these vibrations that create the sound waves that are set in motion and travel through the air in all directions out of the speaker membrane.
How to influence the sound produced
The frequency of the movement of the electromagnet, ie how fast it moves, determines the pitch of the sound produced. The amplitude of the movement of the electromagnet, ie how far it moves, determines the volume of sound produced. So simply, one can say that what happens when you turn up the volume of your stereo is that you increase the amplitude of the current flowing through the coil.
The speaker membrane also affects
The choice of the diaphragm in a speaker also has a major impact on what sound the speaker will produce. For example, If you have a decent and heavy bass sound you use a large and cone-shaped diaphragm, instead, you want a nice chirping treble you use a small dome-shaped diaphragm instead.