When we were kids, we often took apart broken speakers just to play with the magnet inside. Did anyone else do that? I noticed something interesting: whether we were dismantling a massive woofer or a tiny tweeter, there was always a magnet inside. Naturally, the size of the magnet corresponds to the size of the speaker. But what exactly is the connection between the magnet and the speaker?
Today, the editor from Dongguan Shengqun will explain the relationship between the speaker and that magnet. First and foremost, the magnet is the core component of a loudspeaker. Its size determines the speaker's acoustic output. Its working principle relies on interacting with the voice coil to convert electrical signals into mechanical vibrations, thereby producing sound. To transform electrical energy into sound using a magnet, three key conditions must be met:
Let’s break down these key operational steps:
1. Establishing a Stable Magnetic Field
The magnet generates a powerful and stable magnetic field within the voice coil gap. Think of this as the foundation of a building. If the materials or craftsmanship fall short at this stage, the sound quality and audio reproduction will never reach perfection.
The magnet generates a powerful and stable magnetic field within the voice coil gap. Think of this as the foundation of a building. If the materials or craftsmanship fall short at this stage, the sound quality and audio reproduction will never reach perfection.
2. Generating Electromagnetic Thrust
This is also known as the Lorentz force. When an alternating current flows through the voice coil, it creates a continuously changing electromagnetic field. This field interacts with the permanent magnetic field of the magnet, generating a pushing force known as the Lorentz force.
This is also known as the Lorentz force. When an alternating current flows through the voice coil, it creates a continuously changing electromagnetic field. This field interacts with the permanent magnetic field of the magnet, generating a pushing force known as the Lorentz force.
3. Driving the Diaphragm to Vibrate
As the direction and intensity of the audio signal current constantly change, the direction and magnitude of the force applied to the voice coil change accordingly. This causes the voice coil to move rapidly back and forth within the magnetic field. Since the voice coil is attached to the speaker diaphragm, the diaphragm vibrates in tandem, pushing the surrounding air to create the sound waves we hear.
As the direction and intensity of the audio signal current constantly change, the direction and magnitude of the force applied to the voice coil change accordingly. This causes the voice coil to move rapidly back and forth within the magnetic field. Since the voice coil is attached to the speaker diaphragm, the diaphragm vibrates in tandem, pushing the surrounding air to create the sound waves we hear.
It is also worth noting that magnets come in different types. Generally, the stronger the magnetism, the higher the speaker's strength and sensitivity. For example, neodymium magnets (rare-earth strong magnets) are widely used for this purpose.