What is a headphone crossover and what does a crossover do?

The crossover arranges the sound signals "into categories" for their respective jobs.

If the full-band signal is directly input into the high, mid and bass drivers without "shunting", the part of the "redundant signal" outside the range of the frequency signal reproduced by the unit will adversely affect the signal restoration in the normal frequency band (the term is called "modulation distortion"), the sound will be chaotic and chaotic, and this is only a relatively minor consequence, the more serious consequence is that the high-power bass signal escapes into the tweeter and midrange driver, beyond the power carrying range of such units, and then directly damages the unit.

The headphone crossover is a unique component (circuit, circuit board) of multi-unit headphones, and like the speaker, the headphone crossover can be divided into power crossover and electronic crossover.

1. Power crossover: Through the combination of resistors, capacitors and inductive components, the analog audio electrical signals output by the power amplifier headphone jack are separated into high, bass or high, medium and low tones and transmitted to the relevant high, bass or high, medium and low speaker units respectively.

<>2. Electronic frequency division:

The electronic circuit is used to separate the analog audio electrical signal (or digital audio signal through decoding) output by the power amplifier headphone jack into high, bass or high, middle and low tones respectively and transmit them to the relevant high, bass or high, medium and bass power amplifier circuits, and then transmit them to the high, bass or high, medium and low woofer units respectively. Electronic crossover requires headphones to have their own sound card or power amplifier, which is relatively rare due to complex structure and high cost.

Advantages and disadvantages of headphone crossovers:

The full-range (single-unit) design does not need to divide the frequency, the sound is more natural, and there is no problem of connection, while the crossover design has the problem of the crossover point, if it is not handled properly, it is not natural to connect with each other near the crossover point, resulting in peaks or valleys, then the sound is also easy to lose the real feeling. Multi-unit headphones make it easier to get a wide vocal range.

Hello, the crossover is generally found in multi-unit headphones and speakers, which is to allocate signals from different frequency bands to different speakers, for example, the tweeter only emits the high-frequency part above a certain frequency, and the mid-woofer only emits the middle and low frequency below a certain frequency.

Usually multi-unit speakers have crossover lines, and in recent years, some in-ear earbuds have also launched a relatively high-end multi-unit multi-division design, such as the current high-end non-custom moving iron earbuds can reach a three-unit three-way design, and custom headphones can even reach as many as eight units on each side.

The higher the number of sound generators, the better the restoration and dynamics of the sound field, but it will also bring problems with the design of the frequency division, the different design of the frequency division point may be completely different, and the connection between the various frequency bands will also have problems.

There are two types of crossovers: active crossovers and passive crossovers.

In summary, his principle of frequency division is:

The capacitor has the function of resisting high frequency and passing low frequency, the larger the capacitor capacity and the smaller the capacitive reactance, the smaller the resistance of the high-frequency signal to pass.

The inductance coil has the effect of resisting low frequency to high frequency, and the larger the inductance, the greater the resistance to the low frequency signal.

Reasonable selection of the capacitance of the capacitor and the capacity of the inductor can make the selected (crossover) tone signal split into two ways. That's where the crossover comes in.

The crossover distinguishes the sound signals of different frequency bands, amplifies them separately, and then sends them to the speakers in the corresponding frequency bands for replay. In the case of high-quality sound reproduction, electronic crossover processing is required.

The crossover is the "brain" of the speaker and is crucial to the quality of the sound. The ** signal output by the power amplifier must be processed by the filter element in the frequency divider to let the signal of a specific frequency of each unit pass through. It is necessary to scientifically, reasonably and rigorously design the crossover of the speaker, in order to effectively modify the different characteristics of the speaker unit, optimize the combination, make each unit develop its strengths and avoid weaknesses, and give full play to its due potential, so that the frequency response of each frequency band becomes smooth, and the sound image phase is accurate, so that the high, medium and low tones can be clearly layered, coordinated, comfortable, wide and natural sound quality effect.

Principle: From the perspective of circuit structure, the frequency divider is essentially an LC filter network composed of capacitors and inductance coils, and the treble channel is a high-pass filter, which only allows high-frequency signals to pass through and blocks low-frequency signals; The bass channel is the opposite, which only lets the low-frequency signal pass through and blocks the high-frequency signal.

The midrange channel is a bandpass filter, and the frequency between the two crossover points, one low and one high, can be passed, and the high-frequency component and low will be blocked. In the actual crossover, sometimes an attenuation resistor is added to balance the sensitivity difference between the tweeter and the woofer; In addition, some crossovers are also added to the impedance compensation network composed of resistance and capacitors, the purpose of which is to make the impedance curve of the speaker flatter, so as to facilitate the power amplifier drive.

From the perspective of circuit structure, the crossover is essentially an LC filter network composed of capacitors and inductance coils, and the tweeter channel is a high-pass filter, which only allows high-frequency signals to pass through and blocks low-frequency signals; The bass channel is the opposite, it only lets the bass pass through and blocks the high-frequency signal; The midrange channel is a bandpass filter, except for the frequency between the two crossover points, one low and one high, the high-frequency component and the low-frequency component will be blocked. In the actual crossover, sometimes an attenuation resistor is added to balance the sensitivity difference between the tweeter and the woofer; In addition, some crossovers are also added to the impedance compensation network composed of resistance and capacitor, the purpose of which is to make the impedance curve of the speaker psychologically flat, so as to facilitate the power amplifier drive.

It is located behind the power amplifier and is arranged in the speaker, and the power audio signal output by the power amplifier is divided into bass, midrange and treble through the LC filtering network, and sent to their respective speakers respectively. The connection is simple, easy to use, but the power consumption, the audio valley, the production of cross distortion, its parameters and the speaker impedance has a direct relationship, and the speaker impedance is a function of frequency, and the nominal value deviates greatly, so the error is also large, is not conducive to adjustment.

The equipment that divides the weak audio signal is located in front of the power amplifier, and then uses its own independent power amplifier to amplify the signal of each audio frequency band, and then sends it to the corresponding speaker unit respectively. Due to the low current, it can be achieved with a small power electronic active filter, which is easier to adjust, reducing power loss and interference between the speaker units. It makes the signal loss small and the sound quality is good.

However, this method requires an independent power amplifier for each channel, which is costly and complex in circuit structure, and is used in professional sound reinforcement systems.

Speaker crossover.

A loudspeaker crossover can divide the sound signal into several frequency bands. For example, a two-way filter consists of a high-pass filter and a low-pass filter. The three-way frequency adds a band-pass filter. The crossover is the "brain" of the speaker and is crucial to the quality of the sound.

The speaker crossover adopts the following structure, specific analysis: the circuit connecting the tweeter: let the current flow through the capacitor first, block the low frequency, let the high frequency pass, and the speaker is connected in parallel with a coil, so that the coil produces a negative voltage, then this voltage is just a voltage compensation for the tweeter, so the sound current can be approximately realistically restored.

Connect the woofer circuit: the current flows through the coil first, so that the high-frequency part is blocked, and the low-frequency band passes smoothly because the coil basically has no obstruction effect, similarly, the woofer is connected with a capacitor in parallel, that is, the capacitor is used to generate a voltage at the high frequency to compensate for the loss of voltage, the reason is the same as the tweeter end.

It can be seen that the characteristics of the capacitor and coil that the divider makes full use of to achieve the crossover. However, the coil and capacitor still consume voltage in the frequency band that they are obstructed by, so the circuit divider will lose a certain amount of sound, and there are many compensation measures, which is difficult to explain clearly due to the author's lack of knowledge. The electronic frequency division solves this problem, when the sound is input to the power amplifier before the frequency is divided, and then the different frequency bands are amplified by special amplification circuits, so that the sound distortion is small and the restoration is realistic.

However, the circuit is complex and expensive.

There are two interpretations of the crossover.

One is the processing of analog signals. It is achieved using a bandpass filter. For example, in the audio power amplifier, the audio signals of different frequency bands are separated, and then amplified and transmitted to different speakers to restore the sound of different frequency bands.

This type of crossover usually uses the different impedances of the inductor capacitor to the high and low frequency signals to distinguish the signal.

The other type is to divide the pulse signal by 2 to the nth power, for example, to turn the pulse signal of 32768 Hz into a second signal of 1 Hz. This kind of crossover is usually implemented by using a t-flip-flop, the flip-flop state changes once after each pulse, and after being processed by n t-flip-flops, you can get a crossover signal of 2 to the nth power.

The crossover arranges the sound signals "into categories" for their respective jobs.

If the full-band signal is directly input into the high, medium and low woofer without "shunting", the part of the "redundant signal" outside the range of the frequency signal reproduced by the unit will adversely affect the signal restoration in the normal frequency band (the term is called "modulation distortion"), the sound will be chaotic and chaotic, and this is only a relatively minor consequence, the more serious consequence is that the high-power bass signal runs into the treble and talk cancelling midrange unit, beyond the power carrying range of this type of unit, and then directly damages the unit.

If there is a woofer and a tweeter in a speaker, it needs to be connected with a crossover. If the output power of the amplifier is relatively small, and the caliber of the woofer is not large, even if the crossover is used, the effect is not large. Use the frequency divider to drive the horn, the output power of the power amplifier should be at least 10 watts, and the woofer caliber should also be more than seven inches.

The two-way circuit diagram is as follows:

The l in the figure can be wound into an air punch side accompaniment coil 150 200 turns. C in the figure can be replaced by an electrolytic capacitor with 3 10 microfarthics, regardless of positive and negative electrodes.

Frequency. It is also another important part of the loudspeaker, and its main responsibility is to divide the sound signal into several different frequency bands.

Redistribution. Give each accordingly.

Horn unit. At the same time, it can also play a role in correcting between units.

Phase. and inconsistent sensitivity. Hence the crossover.

The quality of the design directly affects the sound reproduction quality of the speaker. At present, power division (LC division network) and electronic division are the most commonly used frequency division methods. The former is the use of capacitors, inductors to form a filter network, which is characterized by relatively simple circuits and convenient use, so most of the civilian speakers now use this way to divide the frequency, for example.

Maibo. FC280, PURE100,

Edifier R1900TII06

Huiwei M200 is a power crossover design.

Power crossover (LC divider network) and electronic crossover are the most commonly used crossovers, and crossovers are another important component of loudspeakers. At present, the quality of the crossover design directly affects the sound reproduction quality of the speaker. Therefore, it can also be used to correct problems such as phase differences between cells and sensitivity inconsistencies.

At the same time, its main responsibility is to divide the sound signal into several different frequency bands and then distribute them to each corresponding speaker unit.

Headphone speakers, pay attention to the factors are, the outer diameter of the speaker, generally the large one is used as a bass, the smallest one is used as a treble, and the three speakers can be full range of bass, the midrange is at 1kHz, and the treble is at 5kHz