【 Weak current College 】 divider using problem---Power By 【 China power house network 】

Divider is a sound signal can be divided into several frequency bands of sound equipment. We know that the sound frequency range is in between 20Hz — 20kHz, jumbo, use only one speaker is able to guarantee broadcasting, 20Hz — 20kHz such wide frequency sound is difficult, because this will technically there all kinds of problems and difficulties. Therefore, in General, high-quality playback system, in order to ensure the reproduction of the sound frequency response and band width, most of the professional context using high bass separation type speaker playback while using high bass separation type speaker provides sound, they are bound to use the divider.
Bass separation type speaker using divider causes
The so-called high bass separation type speaker is the voice of the high frequency part consists of a treble speaker playback, low frequency part by a bass speaker playback of sound, rather than by a complete audio frequency loudspeaker playback tasks. In professional speakers, treble unit typically Horn-speaker, bass unit has direct-and air-and so many forms. Whether outside or within the crossover frequency, high bass separation type speaker must adopt frequency playback scenarios, the main reasons are the following three aspects.
1. make a variety of speakers are working in the most suitable audio segments
Vibrating dimensions and materials of different speakers, its best operating frequency is different. Diameter larger speaker, the better low-frequency characteristics. Therefore, other things being equal, the 18-inch bass and certainly better than the 15-inch bass.
Diaphragm material rigidity and crisp, the better, the more light, the quality of playback of high-frequency characteristics for the better. Many treble speakers using titanium coating or Indium films as diaphragm material, to improve its high-frequency characteristics; and bass speaker diaphragm generally use paper, carbon fiber, bullet-proof fabric and rubber (edge), and other materials in order to facilitate the bass reproduction.
Use the divider can be high-frequency signals sent to treble speakers, low frequency signal sent to the subwoofer speakers, high-and low-frequency signal prevails, as the Earth using their speakers working band advantages, to ensure that the different work band speakers fully play its role, the frequency of playback characteristics more balanced.
2. Overcome the different frequencies of sound speaker diaphragm vibration amplitude different cut-distortion caused by the
The speakers sound, its vibration touch bass vibration amplitude, high vibration amplitude. In theory, the speaker cone of the vibration amplitude and reproduce sound frequency is inversely proportional to the square, that is, the same speaker diaphragm, in the same range of signal voltage, the lower the frequency, amplitude, that is, if the frequency increase 10 times the amplitude will be reduced by 10 times, that is, the square of 100 times.
If we use a speaker produce very wide frequency range of sound, as the diaphragm, the mechanical properties of the existence of vibration amplitudes very wide variation is very difficult, and this will certainly happen sound cut distortion of the phenomenon, the reproduction of the sound quality is affected.
The study found that cut distortion effects on bass, when most MBS bass woofer, as long as there are high-pitched components exist, it will inevitably result in incising distortion, the bass is trembling and shaking phenomenon. Of course, the treble speakers appear cut distortion would make a hoarse sound treble, bass, affecting not just large. [fenye]
3. reduce the same speakers of different speakers sound interference between phenomena
For high-isolation-speaker, bass, in treble speakers and subwoofer speakers, although the work of the band, but if the full-frequency signal frequency is not added to give the treble speakers and woofer, surely there will be high, woofer also issued the same sounds, when the same sound of different speakers meet, it is possible to produce Sonic mutual interference.
A little knowledge of Acoustics knows that once the sound interference phenomenon, a comb filter effects, standing waves, and a series of problems that will be varying degrees of impact sound good reproduction.
Setting the crossover circuit, treble and bass speakers get their best work respectively band sound signal, they sound frequency range almost does not overwrite, in addition to the speaker frequency and frequency crossover region also exist a small number of interference, the remaining frequency sound interference phenomena are simply no longer exists.
Crossover points and frequency crossover region exists sound interference phenomenon, the reason is very simple, because the divider frequency attenuation rate cannot be infinite, in frequency crossover region, particularly in the crossover point, treble speakers and subwoofer speakers will present the other band's sound, sound interference appears inevitable. So, divider-n decay rate is higher, the more color separation cross-area small, the speaker asked the less sound interference.
Divider class
Divider: there are two broad categories: one category is passive divider (PassiVeCrossover), also known as power divider; active divider (ActiveCrossover), also known as electronic dividers.
1. passive divider
Passive divider is a speaker built-in divider, the capacitor and inductor filtering network, its characteristics are crossover network settings in the power amplifier and speakers. The divider from the amplifier directly out of full-spectrum audio power signal into the bass and treble or bass, tenor and treble, the frequency of the signal at different frequency bands allocated to the band speakers. In the full-frequency is high, the bass or high, mid, bass active frequency speakers, by passive crossover circuit complete frequency tasks.
Passive crossover advantage is:first, simple structure, low cost, together with the sound installation, without the need of adjustment, easy to use; Secondly, the system connection easier, just give power amplifier input frequency signal, the power amplifier and speakers connected together can achieve full-frequency playback; third, the need for power amplifier, generally a power amplifier can take two full-frequency passive frequency speaker, so the system is less expensive.
Passive crossover deficiencies are: first, the crossover network to add to the speakers on the great workRate and the current, so you want to use a larger volume of inductance, and since the inductance of the parameters and have a direct relationship between the speaker impedance, and speaker impedance is the frequency of the function, and the nominal value deviates from the larger, so the error is large, computing more difficult; Secondly, the power amplifier output power audio signal through the electrical capacitance and inductance filter, inevitably since capacitance and inductance of the nonlinear distortion, caused by the sound distortion and then the inevitable; the third, from audio power amplifier output power signal, after a capacitive and inductive devices will result in the loss of power signals, so passive crossover of larger power signal loss; and, finally, frequency attenuation rate cannot be too high, generally the largest 12dB/octaves, frequency crossover area of interference on the high side, this is because passive dividers enhance frequency attenuation rate approach is to increase the capacitor and inductor, filtering, but the order of increase capacitor or inductor of numbers, that means increased signal distortion and power loss, improve the frequency attenuation rate result is brought more problems.
As the name implies, passive crossover is a "helpless": the way of frequency, power amplifier output full-frequency power signal had to be a fractional-n PLL, leads to a series of questions, it willbe forced to deal with the power of the signal frequency. Civil speakers in order to reduce the system cost, all adopt a passive crossover. Professional speaker since and civil speaker in the request, use the main listening and personnel, there are very different, so in addition to passive crossover way speaker system, there are active crossover way speakers.
2. active divider
Active divider is a full-spectrum audio weak signal frequency devices, General electronic circuit by active crossover system, its characteristics are located color separation system power amplifier, full-spectrum audio weak fractional frequency, bass, treble or bass, tenor and treble signal sent to the respective power amplifier and amplifier are output to the bass, treble or bass, tenor and treble speakers, this method is called active crossover, for work in weak signal, so the available low-power electronic filter implements frequency.
Passive crossover of speaker's speaker units are equipped with their own power and signal interface, some high-speaker, bass separation can have active crossover and a passive crossover two connection methods, behind such speakers are installed with active crossover (Active) and a passive crossover (Passive) switch, some speakers of this switch is also equipped with a locking mechanism to prevent accidental pull. When using active crossover mode, be sure to call the crossover mode switch to "Active" side, will treble amp add treble (Hi2h) input, Bass Amplifier received the bass (Low) input.
Active frequency of the advantages are many: one is due to weak signal circuit signal frequency processing, so the sound signal loss, low distortion, the reproduction of the sound quality is good; the second is a fractional frequency attenuation rate can be more passive crossover, 24dB/octaves very easy, cross-regional relatively passive crossover frequency much frequency crossover area of high and bass modules sound interference between basically be overcome; three is adjustable, electro-acoustic indicators.
Active crossover of no one is involved in sound quality, its main problem is that a high investment costs. Due to the way active crossover, bass each separately with separate power amplifier, so use power amplifier, such as a speaker on the second distribution to use two power amplifier driven; the second is to increase a e divider, which makes the connection and adjustment increase use difficult.
Divider using
As already described, the divider has active crossover and passive crossover. Passive divider for fixed installation inside the speaker, and do not need audio make adjustments to it in the active presence of crossover is an electronic way divider for the correct use, reasonable connection and adjustment, and other aspects of the problem, so this article only on active divider in use should be noted that several major issues to be addressed.
1. Panel and function keys
E-divider is Panel as shown in Figure 1, the following describes the various function keys, buttons and interfaces.
(1) INPUTGAIN
Input gain. Input signal level adjustment, normally on the rib B location.
(2) LFDELAY
Bass delay. On bass for O-2ms (maximum 60cm) delay.
(3) LF/HFGAIN
Low-frequency/high-frequency gain. On the low frequency band, high-frequency band level.
(4) MUTE
Mute the sound. Blocking a certain frequency band signal.
(5)x-0VERPREQ
Crossover frequency (frequency division). Second frequency, only a crossover point; three points, two crossover point.
(6) RANGE
Frequency range-o-n frequency in the range of 90-900Hz or choose between 900Hz — 9kHz.
(7) MODE
Frequency. Dual mono two different frequency or Mono three frequency selection.
(8) MONOBASS
Monophonic bass. In two-channel stereo mode, you can select single acoustic bass output.
(9) CDEQ
Equilibrium constant to point to the Horn. When using a constant pointer to Horn (United States Patent EV company), you can make high-frequency characteristics for the better.
(10) LIMITER
Restrictions button. Output signal gain limit regulation that limits a strong signal to protect the power amplifier speakers.
(11) THRESHOLD
Threshold selection keys. Select limit threshold range,-6dB and + 18dBu two choices.
E-modulus prescaler back panel generally dominated by various interface, as shown in Figure 2, the following describes the various interfaces and the role of function keys.
(12) FUSE
Insurance and the power outlet.
(13) SERIALNUMBER
Product series number.
(14) HIGH/MID/LOWOUTPUT
> HF/MF/LF output interface. Dual mono two different frequency output, press interface above band indicates the output high-frequency and low frequency: Mono three frequency, press the interface the following band indicates the output high-frequency, medium-frequency and low frequency.
(15) POLARITY
Polarity (phase) key. Use this key can be reversed.
(16) INPUT
Signal input interface. From this interface enter full-frequency signal, three-way Mono frequency, from the left channel input signal.
2. the frequency of some typical connection methods
For the different requirements of electronic sound reinforcement systems, prescalers connection varies in practice, specific select which connection method should look different.
(1) high/low-frequency-division 2
Bass 2 frequency of connections as shown in Figure 3. Bass-active frequency speakers generally used to high-pitched-sized playback, power amplifier and subwoofer amplifier power ratio of 3: 7 or 4: 6.
(2) high/medium/low-frequency
High frequency low three connection as shown in Figure 4. High school bass separation type active frequency speaker typically used by large playback, high-pitched power amplifier, audio amplifier and subwoofer amplifier power ratio of roughly 2: 3: 5.
(3) full-frequency/low-
Full-frequency/low mode in connection than other crossover connection easier, the full-frequency channel of connection and non-active crossover is exactly the same way, left and right channels from the mixer (primary output) output signal to sound reinforcement system main channel, the master channel peripheral equipment connected to the order and method and general sound reinforcement system main channel of connection method and sequence, only the output from the groups a mixer and then sent out a signal received divider (full-frequency/low processor), dividers (full-frequency/low processor) low frequency (ultra low) output interface out ultra-low signals to the ultra low power amplifier and speakers, divider crossover point generally installed in 100Hz following.
In addition to the above connection method, there is also a direct use of full-frequency/low processor connection let spectrum ultra low system method, as shown in Figure 6.
According to the author. The first connection method is superior to the second connection method, the following analysis of the full-frequency/low connection scenarios unique advantages, from analysis to know whether two connection methods which better.
Full-frequency/low system is the application of the broader system that addresses from several aspects of sound reinforcement system often encounter problems.
First of all, a solution to the human voice and music compatible playback problems. We all know, voice pitch and lower frequency about 130Hz, if the voice of bass components too much, will lead to turbidity, directly affect the sound speech intelligibility and intelligibility, it provides the human voice, should generally be appropriate for bass components, to ensure that listen to hear clear language and vocal content; while the lower frequency of bass music can reach 20Hz, if music is not enough bass components will cause the fullness. bass When a system item p to broadcasting the human voice and the hottest music, there is a conflict in the bass side, full-spectrum low scenario can resolve this contradiction. Provides voice, you can use a mixer to group output faders down, Ulf is lost; the hottest music, will be teaming up, Ulf faders to push and wide-band at the same time, appropriate regulation exists, full-frequency and low frequency ratio, can be satisfied with the effect of music. Thus, Figure 5 shows the connection scheme proved in the regulation.
Second, to some extent resolves the passive crossover inefficiencies. Full-spectrum low system of ultra low part adopts active crossover mode, because the low frequency sound energy accounted for more than half, sometimes even can reach 70 per cent of the full-frequency sound Ulf part adopts active frequency processing, means that more than half of the sound energy, efficiency is improved, the treble section even with passive crossover would be a loss or harm in trying.
Some people use the equalizer in place of scalers, received the equalizer in the ultra low channel Equalizer 100Hz attenuate above that can replace the divider. In fact, this kind of connection of bass and certainly not better because, that is, using the Equalizer will treble section attenuation to bottom, or just have the treble attenuation 12dB, still have some high-frequency components by equalizer and sent to the amplifier, and the divider is a low-pass filter, high frequency of the sound part cannot pass. From Equalizer leaked treble constituents through the amplifier is enlarged to the woofer, as mentioned earlier, the Woofer and treble constituents in once there will be result in incising distortion, bass shaking, effects of variation.
Third, active crossover way subwoofer with good effect, adjustable. Ultra-low system uses active crossover approach not only improves efficiency of transmission, the bass also makes bass distortion is minimized, more rich, deep bass. Due to the low proportion of the full-frequency can be adjusted according to actual needs, bass and full-frequency part of the interface can also be controlled by the soundengineer, bass room for a great play, sound adjustable resistance.