When you disassemble the speaker, in addition to the materials used by the manufacturer for tuning, there will also be a circuit board sandwiched between the output terminal and the sound unit, and this circuit board is the frequency divider. Its function is equivalent to the "brain" in the speaker, which separates the analog signal into different parts such as high, medium, and bass and sends it to the corresponding sound unit, so as to achieve a better playback effect.
Crossovers are generally used in speakers with treble and bass units, or speakers with midrange units. If there is no crossover, a multi-unit speaker can not play back sounds in different frequency bands. And the difference in the type and quality of the crossover also affects whether the speaker can play back a better sound performance.
What is the use of a divider?
Whether it is a tweeter or a woofer, their frequency response curve is not flat. The tweeter and woofer will be attenuated at both ends, so that the upper attenuation part of the low-frequency sound may be the same as the lower-limit attenuation part of the high-frequency sound. Coincidence or even interleaving occurs, causing the frequency bands to overlap and fail to form a straight curve, so the sound will not be of good sound quality.
If you want them to work together in a coordinated manner, it does not mean simply docking. The function of the crossover is to complete this combination of frequency response between the various speakers to achieve better results. The frequency divider processes the music signal output by the power amplifier through the original filter to allow the specific frequency signals of each unit to pass. Simply put, the original signal is divided into several frequency bands, and the frequency divider selects the most suitable unit for playback. The frequency band is allocated to it to realize the cooperative work of multiple speakers.
The need of the frequency divider is determined by the design of the speaker itself. The double frequency divider is divided into two sections, and the three frequency divider is divided into three sections. This is what we often call "two-way" and "three-way". Divided according to the working principle of the frequency divider, it has a variety of implementation methods, which are divided into different types of designs, but we often see two major categories of power dividers and electronic dividers, which are also common The concept of being able to hear.
Power divider with electronic parts as the core
The power divider is designed after the power amplifier, mainly composed of capacitors and inductance components, so it is also called a capacitive divider. Because inductors and capacitors have a filtering effect, low-pass and high-pass can be achieved through inductors and capacitors, and finally achieve the purpose of dividing the frequency. This type of frequency divider is set inside the speaker, through the LC filter network, the audio signal output by the power amplifier is divided into high, medium, and low, and then sent to each sound unit.
The simplest power frequency division is capacitor frequency division, which is to achieve frequency division by connecting a capacitor in series behind the tweeter. For a slightly more complicated one, capacitors and inductors can be used in each channel to achieve a more precise frequency division effect. But in any case, the power divider installation is still very simple, both active and passive speakers can be applied. The power frequency division also has attenuation in the frequency band after frequency division. The slope of the attenuation curve is generally related to the number of filtering.
However, the shortcomings of the power divider are also more obvious. It consumes power itself, audio valley points will appear and crossover distortion will occur. In addition, the parameters of the power divider have a direct relationship with the impedance of the speaker unit itself, because the impedance of the unit is a function of frequency, which deviates greatly from the nominal value, so the error is large, which is not conducive to tuning, and sufficient experience may be required And technology can make the power frequency division achieve good results.
Electronic frequency divider working with audio signal
Unlike the power divider, the electronic divider is located before the power amplifier. After the electronic frequency divider divides the weak audio signal, the signal of each frequency band is amplified by its independent power amplifier and then sent to the speaker unit to achieve the frequency division effect. For example, if a two-way (two-way) speaker uses electronic crossover, the two-channel signal will be divided into four channels, so the back-end power amplifier needs four channels to be fully output.
Electronic frequency division has obvious advantages in technology. First of all, it does not have power loss like a power divider. Its current is small and can be achieved with a smaller power electronic active filter. Its power loss is not Not obvious or even negligible. The interference between the speaker units of the electronic crossover will be smaller, the signal loss will be smaller, and the sound quality will be slightly better. Of course, its tuning is more intuitive and convenient.
Of course, electronic frequency dividers also have shortcomings. Due to the operating principle, each electronic frequency divider needs to use an independent power amplifier. The cost is high, and the circuit structure design is more complicated. However, compared with the current power frequency division From the perspective of high-priced brass, it still has a cost advantage. And because the electronic crossover is generally integrated with the power amplifier system, for DIY speaker players, the playability of the electronic crossover is not so high.