Car audio modification, play active or passive

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Those who have a certain understanding of car audio modification may know the concept of active crossover and passive crossover, but it is not very clear. What is the active crossover and passive crossover?

The active and passive in the car audio modification is of course inseparable from the crossover. When we install the car audio set speaker, we often touch a device called the electronic crossover, which is sometimes hidden under the instrument panel, sometimes It was hidden inside us by the trim of the door. What does the electronic crossover do? Can there be no electronic crossover? Let's analyze it together. First of all, what is an electronic crossover?

Literally, the electronic crossover means “differentiation of frequency equipment”, which divides the weak signal of the audio, then transmits it to the power amplifier, and then amplifies the audio signal, and finally transmits it to each speaker.

The role of the electronic crossover:

A weak audio signal is received from the car host and then differentiated, which signal is required for the tweeter. These need to be differentiated by it, and then transmitted to the power amplifier, so that the amplifier will amplify the signal and transmit it to the speakers of each part. The advantage is signal interference, improve the dynamic range, and also have a certain amplification effect, so that each Can better display its sound quality.

What is the active crossover, what is the passive crossover? The difference between the active crossover and the passive crossover in the car audio is that the crossover process is before or after the power amplification, and the crossover is called the active crossover before the power amplification. The output of the output is divided into a passive crossover. Both active and passive have their own advantages. Sound quality also has their own advantages and disadvantages. You need to make choices according to your own needs, instead of letting others take the initiative to play active. Let's take a look at the advantages of active crossover and passive crossover. Disadvantages.

Advantages of passive crossover: Firstly, the structure is simple, the cost is low, it is installed with the speaker, no adjustment is needed, and it is easy to use. Secondly, it is easier to connect the system. Just input the full-frequency signal to the power amplifier, and connect the amplifier to the speaker. Together, full-range playback can be achieved. Third, there is less power amplifier required. Generally, one power amplifier can carry two full-frequency passive crossover speakers, so the system cost is low.

Disadvantages of passive crossover: First, the crossover network has to bear a lot of power and current applied to the speaker, so a larger volume of inductance is used, and since the inductance parameter has a direct relationship with the speaker impedance, the impedance of the speaker is Is a function of frequency, which deviates greatly from the nominal value, so the error is large and the calculation is difficult;

Secondly, after the power audio signal output by the power amplifier passes through the capacitor and the inductive filter, it will inevitably cause distortion due to the nonlinearity of the capacitor and the inductor, and the sound distortion is inevitable. Third, the audio power signal output from the power amplifier passes through each Capacitance and inductance devices will cause loss of power signal, so the power signal loss of passive frequency division is large;

Finally, the frequency division attenuation rate cannot be made too high, generally up to 12dB/octave, and the interference in the crossover crossover area is too large. This is because the way to improve the frequency division attenuation rate of the passive frequency divider is to increase the capacitor or inductor. That is, the order of filtering, but increasing the number of capacitors or inductors means that the signal distortion and power loss are increased, and the result of increasing the frequency division attenuation rate brings other problems.

The advantages of active frequency division are many: First, due to the use of weak signal electronic line signals for frequency division processing, the sound signal loss is small, the distortion is small, and the reproduction sound quality is good; second, the frequency division attenuation rate can be made higher than the passive frequency division. It is easy to reach 24dB/octave, the crossover crossover area is much smaller than the passive crossover, and the interference between the high and low volume sounds in the crossover crossover area is basically overcome; the third is good adjustability, electricity The sound index is high.

Insufficient active frequency division: No one is related to sound quality. The main problems are: First, high cost and large investment. Since the active crossover mode is high and the bass is used separately with separate power amplifiers, there are many power amplifiers, such as one-to-two distributed speakers to be driven by two amplifiers; the second is to add an electronic crossover, which makes Connection and adjustment aspects increase the difficulty of use.

If the quality of the system equipment is not good enough to play the active crossover, it is a waste of money. Many people use the speakers that are very cheap and not very good to take the initiative. The sound is not as good as the same brand of power amplifiers when the whole set of audio is matched. And the speaker crossover sound is good. What do you think?