A speaker is an electroacoustic device that converts electrical signals into sound signals. Its working principle is mainly to convert audio electrical power signals into audible sound with low distortion and sufficient sound pressure level through energy conversion. The following is a detailed explanation of the working principle of the speaker:

1. Electromagnetic effect

The speaker contains a magnet, a coil, and a diaphragm inside. When an electrical signal passes through the coil of a speaker, it generates an alternating magnetic field under the action of a magnet, causing the coil to vibrate and driving the diaphragm to produce sound. Specifically, when current passes through the coil of a speaker, the coil generates a force in the magnetic field, and the magnitude and direction of this force are proportional to the current. Because electrical signals are AC, the coil will continuously vibrate up and down with changes in current. The vibrating coil will drive the diaphragm connected to it, which in turn drives the air to form sound waves of the same frequency, thus emitting sound.

2. Materials and Structure

There are many types of speakers, and the prices vary greatly. Audio electrical energy produces sound through electromagnetic, piezoelectric, or electrostatic effects, causing the paper tray or film to vibrate and resonate with the surrounding air. Low end plastic speakers have no sound quality due to their thin casing and inability to overcome resonance; Wooden speakers reduce the sound distortion caused by box resonance, and the sound quality is generally better than plastic speakers.

3. Working process

The working process of a speaker can be divided into the following steps:

When current passes through the coil of the speaker, an alternating magnetic field is generated.

This alternating magnetic field acts on the permanent magnet, causing the coil to move perpendicular to the direction of the voice coil current under the action of the magnetic field.

Due to the connection between the voice coil and the paper tray, the movement of the voice coil drives the front and rear vibrations of the paper tray.

The vibration of the paper basin drives the vibration of the air, and the human ear can feel the vibration of the air and produce sound.

4. Electrical characteristics

The electrical characteristics of speakers include impedance, sensitivity, and frequency response. Impedance refers to the resistance of a speaker to changes in current at a specific frequency; Sensitivity refers to the sound output of a speaker at a unit voltage; Frequency response refers to the sound output capability of a speaker at different frequencies.

In general, the working principle of a speaker is to convert electrical signals into sound signals through electromagnetic effects, and then through the design of materials and structures, enable sound to propagate better.