Advantages of frequency division circuit

In a speaker system, people call the cabinet, frequency division circuit and speaker unit the three major parts of the speaker system, and the frequency division circuit plays an extremely important role in whether the speaker system can restore the electroacoustic signal with high quality. Especially in the mid- and high-frequency parts, the role of the frequency division circuit is more obvious.

Advantages of frequency division circuit

First of all, we need to understand the working principle of the speaker (it is not complicated in fact, and ordinary high school students should be able to understand it). The most basic theoretical basis of the speaker is the principle of electromagnetic induction. The energized solenoid coil of the speaker generates a magnetic field, which repels or attracts the magnetic field of the speaker to cause the diaphragm to vibrate. When an electrical signal completes its mission and disappears, the diaphragm still has inertia. Through inertial motion, the conductor cutting the magnetic flux lines will also generate an induced electromotive force. At this time, the magnetic field generated by the induced current will generate a torque opposite to the motion, pulling the speaker diaphragm back to its original position.

The above is the most ideal, simplest and most basic form for a loudspeaker to complete a signal cycle movement (in the most ideal state, people hope that the loudspeaker diaphragm can be completely controlled by electromagnetics, and given a current the diaphragm should reach the specified position without generating any unnecessary vibration). Although the movement of the loudspeaker is far from that simple, this is the basis for people to analyze the problem (even the simplest signal will generate secondary and tertiary induced electromotive forces after impacting the loudspeaker, and the principle is similar to that mentioned above).

Here, induced electromotive force is the key point of electronic frequency division technology, because the induced electromotive force generated is related to the final speed of the speaker after acceleration. After the induced electromotive force is generated, how much current can be generated depends on the loop impedance between the power amplifier and the speaker, which will be the key factor in generating torque. For a system with small impedance, the current will be relatively large, and the induced torque generated will also be greater. The speaker will return to its original position faster. So far, people can draw a clearer conclusion: the smaller the impedance between the power amplifier and the speaker, the better. In other words, the smaller the loop impedance from the power amplifier to the speaker (high damping coefficient, high braking), the stronger its control over the speaker, and the sound will be clean, the transient response will be good, and the speed will be fast. This is the first.

The problem of low-frequency overload is actually related to the above advantages. It can be said that the low-frequency overload possibility is one of the results or benefits of the narrowing of the operating frequency of a single amplifier. Since the mid- and low-frequency of the audio signal occupies most of the entire signal energy, the traditional amplifier (assuming that the same power amplifier IC is used) is likely to cause clipping distortion when playing back a signal with a large level if the full frequency is amplified first. However, it is possible to avoid this by dividing the frequency first and then amplifying. First, the high-frequency signal can be amplified separately without being affected by the mid- and low-frequency; second, after cutting off the high-frequency signal, the amplification bandwidth requirement is reduced, and the power amplifier IC has more redundancy when amplifying, which is indeed beneficial to improving the playback sound quality.

Electronic frequency division (or active frequency division) network has the following advantages: 1. Transient response is improved; 2. The working frequency band of each amplifier is narrowed; 3. The possibility of low-frequency overload is reduced; 4. The dynamic range is improved; 5. Intermodulation distortion is small; 6. The sensitivity of each unit is easy to control. People only discuss some of them based on the information they have mastered.

Frequency division circuit

1. Improved transient response

2. 
   

First of all, we need to understand the working principle of the speaker (it is not complicated in fact, and ordinary high school students should be able to understand it). The most basic theoretical basis of the speaker is the principle of electromagnetic induction. The energized solenoid coil of the speaker generates a magnetic field, which repels or attracts the magnetic field of the speaker to cause the diaphragm to vibrate. When an electrical signal completes its mission and disappears, the diaphragm still has inertia. Through inertial motion, the conductor cutting the magnetic flux lines will also generate an induced electromotive force. At this time, the magnetic field generated by the induced current will generate a torque opposite to the motion, pulling the speaker diaphragm back to its original position.

The above is the most ideal, simplest and most basic form for a loudspeaker to complete a signal cycle movement (in the most ideal state, people hope that the loudspeaker diaphragm can be completely controlled by electromagnetics, and given a current the diaphragm should reach the specified position without generating any unnecessary vibration). Although the movement of the loudspeaker is far from that simple, this is the basis for people to analyze the problem (even the simplest signal will generate secondary and tertiary induced electromotive forces after impacting the loudspeaker, and the principle is similar to that mentioned above).

Here, induced electromotive force is the key point of electronic frequency division technology, because the induced electromotive force generated is related to the final speed of the speaker after acceleration. After the induced electromotive force is generated, how much current can be generated depends on the loop impedance between the power amplifier and the speaker, which will be the key factor in generating torque. For a system with small impedance, the current will be relatively large, and the induced torque generated will also be greater. The speaker will return to its original position faster. So far, people can draw a clearer conclusion: the smaller the impedance between the power amplifier and the speaker, the better. In other words, the smaller the loop impedance from the power amplifier to the speaker (high damping coefficient, high braking performance), the stronger its control over the speaker, and the sound will be clean, the transient response will be good, and the speed will be fast. This is the first.

2. The operating frequency band of each amplifier becomes narrower

Since the circuit design of frequency division before amplification is adopted, the frequency band of the audio signal received by each group of amplifiers will be narrower than that of the traditional power frequency division circuit amplifier.

3. The possibility of low-frequency overload is reduced

The problem of low-frequency overload is actually related to the above advantages. It can be said that the low-frequency overload possibility is one of the results or benefits of the narrowing of the operating frequency of a single amplifier. Since the mid- and low-frequency of the audio signal occupies most of the entire signal energy, the traditional amplifier (assuming that the same power amplifier IC is used) is likely to cause clipping distortion when playing back a signal with a large level if the full frequency is amplified first. However, it is possible to avoid this by dividing the frequency first and then amplifying. First, the high-frequency signal can be amplified separately without being affected by the mid- and low-frequency; second, after cutting off the high-frequency signal, the amplification bandwidth requirement is reduced, and the power amplifier IC has more redundancy when amplifying, which is indeed beneficial to improving the playback sound quality.