Speakers are devices that convert electrical signals into sound waves, allowing us to hear audio. They work based on the principle of electromagnetism and utilize the interaction between a permanent magnet and an electromagnet to produce sound.
Here's a simplified explanation of how speakers work:
Electrical Signal: An audio signal, representing the desired sound, is sent to the speaker. This signal is typically an alternating current (AC) electrical signal that varies in amplitude and frequency.
Coil and Magnet: Inside the speaker, there is a coil of wire (voice coil) attached to a diaphragm or cone-shaped membrane. The coil is positioned within the magnetic field of a permanent magnet. When the audio signal passes through the coil, it generates a changing magnetic field around it.
Electromagnetic Interaction: The changing magnetic field produced by the coil interacts with the fixed magnetic field of the permanent magnet. According to the principles of electromagnetism, this interaction causes the coil to move back and forth rapidly.
Diaphragm Motion: As the coil moves, it transfers the motion to the attached diaphragm or cone. The diaphragm is typically made of a lightweight material, such as paper or plastic, and its movement creates variations in air pressure.
Sound Waves: The variations in air pressure produced by the diaphragm create compressions and rarefactions in the surrounding air. These compressions and rarefactions travel through the air as sound waves, reproducing the original audio signal.
By changing the electrical signal driving the speaker, the diaphragm's motion and, consequently, the generated sound waves can be adjusted. This allows speakers to produce a wide range of frequencies, covering the entire audible spectrum.
To reproduce the complete sound spectrum, speakers utilize a combination of multiple drivers (individual speakers) designed to handle specific frequency ranges. For example, a speaker system may include separate drivers for low frequencies (woofers), mid-range frequencies (mid-range drivers), and high frequencies (tweeters). These drivers work together to produce a balanced and full-range audio experience.
So, while a single speaker can generate sound waves across a broad frequency spectrum, it achieves this by using multiple drivers within the same speaker unit, each responsible for reproducing a specific range of frequencies.