Car speakers are divided into air speakers and electric speakers according to the power of sound.
Air speakers
Air speakers are mostly used on large and medium-sized trucks and large buses equipped with air brakes. The volume of air speakers is high and it is forbidden to use them in urban areas. Therefore, whether the car has an air speaker or not, an electric speaker must be installed. The sound of the electric speaker is crisp and pleasant, and its volume does not exceed 105dB. It is widely used in various types of cars.
Electric speakers
Electric speakers are divided into ordinary electric speakers and electronic electric speakers according to whether they have contacts or not. Ordinary electric speakers mainly rely on the closing and opening of contacts to control the electromagnetic coil to excite the diaphragm to vibrate and produce sound; electronic electric speakers have no contacts and use transistor circuits to excite the diaphragm to vibrate and produce sound. The structure and principle of electric speakers: Electric speakers are constantly powered on and off by electromagnetic coils, causing the metal diaphragm to vibrate and produce sound, and the sound is pleasant.
The shape of electric speakers is mostly spiral and basin-shaped, and they are widely used in various cars. Light vehicles all use electric speakers. Air speakers use the airflow of compressed air to make the metal diaphragm vibrate. The shape is mostly long trumpet-shaped (cylindrical), with loud sound and high pitch, and long transmission distance. They are mostly used in large and medium-sized cars running long distances, and are prohibited in cities. Spiral car electric speakers are equipped with loudspeakers, which are rolled into a spiral shape to compress the volume, and the sound quality is beautiful and loud. Basin-shaped car electric speakers do not have loudspeakers, are flat in shape and small in volume, light in weight and easy to install, with slightly inferior sound quality but widely used.
Introduction to the principle of car speakers
The basic working principle of the spiral and basin-shaped speakers is the same, which are composed of an iron core 1, a magnetic coil 2, a diaphragm 3, a resonance plate 4, an armature 5, etc. The figure shows the working principle of the basin-shaped speaker. When the driver presses the button 7, the current passes through the coil through the contacts, and the coil generates a magnetic force to attract the armature 5 to force the diaphragm to move. The armature moves to disconnect the contacts, and the current is interrupted and the magnetic force disappears. The diaphragm returns to its original position together with the armature under the action of its own elasticity and the spring sheet. The contact is closed and the circuit is connected. The current flows through the coil through the contacts to generate magnetic force. The above actions are repeated. In this way, the diaphragm vibrates continuously, thereby emitting sound. The resonance plate 4 is rigidly connected to the diaphragm, which can make the vibration smooth and the sound emitted more pleasant.