Introduction to electric loudspeaker

Electric speakers are divided into paper basin type, horn type and ball top type. The electric loudspeaker has the characteristics of soft sound and high power. The significance of measuring (or calibrating) the large linear sound pressure level splmax of the electric loudspeaker monomer under the large signal working state is proposed, and the corresponding large linear displacement xmax is calculated. The production is organized by imported software materials, which has the characteristics of super power, good bass effect, wide frequency response and so on.

working principle

The current carrying conductor will be affected by the magnetic field force in the magnetic field. Suppose we put a current carrying conductor in a uniform magnetic field, and the direction of the conductor is perpendicular to the direction of the magnetic force line in the magnetic field; The coil of alternating current signal moves in the magnetic field to vibrate the diaphragm connected with the voice coil, which involves the vibration of the paper basin, and then transmits the sound wave through the air medium.

classification

Electric loudspeaker is widely used. It is divided into paper basin type, horn type and ball top type.

1. Paper basin loudspeaker paper basin loudspeaker is also called moving coil loudspeaker.

It consists of three parts:

(1) Vibration system: drum paper, voice coil, centering support (elastic wave)

(2) Magnetic circuit system: magnet, yoke (T iron), magnetic guide plate (Huasi)

(3) Auxiliary system, including basin frame, terminal block, conductor, blank holder, dust cover, etc.

When an audio current passes through the voice coil in the magnetic field, a magnetic field varying with the audio current will be generated. This magnetic field interacts with the magnetic field of the permanent magnet to make the voice coil vibrate along the axial direction. Due to the simple structure, plump bass, soft sound quality and wide frequency band, the efficiency is low.

According to Faraday's law, when the current carrying conductor passes through the magnetic field, it will receive an electric force, and its direction conforms to Fleming's left-hand rule. The force is perpendicular to the direction of current and magnetic field, and the force is directly proportional to the current, conductor length and magnetic flux density. When the voice coil inputs alternating audio current, the voice coil receives an alternating driving force to produce alternating motion, which drives the paper basin to vibrate and repeatedly pushes the air to make sound. The force that causes the diaphragm of the electric loudspeaker to vibrate is the force of the magnetic field on the current carrying conductor. This effect is called the force effect of the electric transducer, Its size is specified by the following formula: F = B, l, where: B is the magnetic induction density (intensity) in the magnetic gap, and its unit is Tesla (T); L is the length of the voice coil conductor, and its unit is meter; I is the current flowing through the voice coil, and its unit is ampere; F is the force of the magnetic field on the voice coil, and its unit is Newton.

However, when the energized voice coil is forced to move, the induced electromotive force will be generated in the voice coil due to the cutting of the magnetic force line in the magnetic gap. This effect is called the electrical effect of the electromotive transducer. The magnitude of the induced electromotive force is: е=В l ν， Where: V is the vibration speed of voice coil, and its unit is m / s, е Is the induced electromotive force in the voice coil, in volts. The force effect and electrical effect of electric loudspeaker exist at the same time.

2. Horn speaker structure of horn speaker, It is composed of a vibration system (tweeter) and a horn. The vibration system is similar to the paper basin loudspeaker, except that its diaphragm is not a paper basin, but a spherical top diaphragm. The vibration of the diaphragm radiates sound waves into the air through the horn (after twice reflection). It has high frequency and high volume, and is often used for outdoor and square sound reinforcement.