CN104768103B - A kind of subtraction formula electronics four divides acoustics circuit and method - Google Patents

Abstract

The present invention relates to the communication technology and electronic circuit, acoustics circuit and method are specifically divided using subtraction formula electronics four, this circuit has four high pitch, middle pitch, bass, subwoofer passages, midrange pathway and bass channel are all obtained using subtraction circuit, the part-frequency point of adjacency channel is set to connect automatically together, component parameters error allows to reach ± 10%, is adapted to produce in enormous quantities, meets consumer demand；Due to fully suitably being split to the working frequency range of each unit using circuit design simulation software, and reasonably successive bands, which are compensated, using the work transition frequency range of each unit by the docking of the round and smooth smooth-going of each frequency range, makes the overall reproduced of loudspeaker combination reach closest to ideal behavior effect；Copper foil resistance defect bigger than normal be present for circuit board on circuit production technique is realized, take the mode of special welding heavy gauge wire to give the several key points for influenceing signal ground connection resistance and make up, Static output AC noise is reduced into virtual value is not more than 1mV.

Description

A kind of subtraction formula electronics four divides acoustics circuit and method

[technical field]

The present invention relates to the sound system divided before the communication technology and electronic circuit and level, specifically using subtraction side The electronics four of formula design divides acoustics circuit and method.

[background technology]

People's oscillograph or simulation software observation, frequency phase-difference is up to 4 times of the identical sine wave for being equal to A of two amplitudes Signal, the amplitude after combination will be equal to 2A；If there is height frequency to differ identical up to 4 times of N number of amplitude respectively in composite signal A sine wave signal is equal to, NA will be equal to by combining the amplitude of superposition；And in conventional 20Hz~14KHz audio range, Can be divided into 4 sections according to 5 frequency multiplication relations, be followed successively by 20Hz~110Hz, 110Hz~550KHz, 550Hz~ 2750Hz, 2750Hz~14KHz；When sound signal is decomposed into above-mentioned 4 segments respectively with 1 power amplifier respectively by 4 Individual sound signal amplification output, if in the sound signal for respectively thering is a side frequency to differ by more than 4 times in this four sections, example As being 60Hz, 300Hz, 1500Hz, 7500Hz respectively, each power amplifier under each sound signal amplitude identical situation Power output be equal to P, share 4 amplifiers, total power output is equal to 4P；If only with 1 power amplifier amplitude 4 combination sound signal amplification outputs of identical, because composite signal amplitude has reached 4 times of single frequency signal amplitude, this The power output of individual amplifier must reach 16P, and 12P therein belongs to reactance capacity, not only seriously increases to power amplifier Demanded power output, also turn into hinder loudspeaker trouble free service hazard factor.So sound system is divided after level with full range list The playback status worst of loudspeaker work；Worked even with high, medium and low three loudspeaker combinations, must also use power output ratio The power amplifier of big 2 times total of power of frequency dividing before level, wherein 2/3 power output is connected in electric capacity and inductance point before loudspeaker Frequency circuit is accounted for, and its tonequality can just contend with three frequency division sound system before level reluctantly.

Actual contrast shows, even if being divided before level, electronics four divides sound system also substantially than electronics three frequency division sound Acoustic system shows more preferably, and reason is that the bass horn of electronics three frequency division will undertake the bass in four frequency dividings and subwoofer two The task that loudspeaker are shared.It should be clear that two acoustical vibrations that a loudspeaker reach frequency phase-difference more than 4 times restore Come, on the one hand high acoustic frequency vibration can prevent horn vibration basin from playing frequency in a low voice in a manner of smooth, on the other hand frequency vibration in a low voice Horn vibration basin is played high audio frequency in the case where deviateing the situation of equilbrium position again, high audio frequency occur larger non-linear distortion and Doppler effect frequency changes distortion caused by bass vibration modulation.Then it is the frequency in a low voice for making reduction is weak and feeble, it is high Audio frequency is impure in a jumble.Preferable bass dynamics is obtained, electronics three frequency division sound system need be relative by below 80Hz amount of bass 1~2 times is lifted in alt, resets out middle bass distortion because this can further be increased, can only be in the little situation of volume Under can receive.And electronics four divides sound system and had in the case where not lifting the situation of bass than electronics three frequency division sound system Preferably bass dynamics performance, while middle bass is also obvious clear clean, so the frequency dividing sound system of electronics four can be in entirety Volume ratio electronics three frequency division sound system receives in the case of substantially ringing two times.We using 2KHz as height sound separation, in The excursion of high audio frequency is only 10 times, in the excursion of frequency in a low voice be 100 times.In view of high audio frequency more than 14KHz into Split pole is few, and loud frequency division can meet good broadcast request into 2 sections in.But the frequency range in a low voice in, it is necessary to 20Hz~ 2KHz, which is divided into 3 sections, could meet good broadcast request.It can not be put in view of a large amount of practical applications large volume of Audio amplifier, to below 100Hz audio frequencies reduce it is less demanding, thus can according to demand in a low voice frequency division be 2 sections be fabricated to Four frequency dividing sound systems.In short, it is high-fidelity broadcast request at least that electronics four, which divides sound system,.But due to electronics Divide by four circuit is more much greater than the design difficulty of electronics Divide-by-3 circuit, and remain how power amplifier output background make an uproar Psophometric voltage virtual value does the small technical barrier in 1mV, just causes to have produced the popular sound equipment of listing so far almost Two divided-frequency state is all rested on, electronics three frequency division sound system, which all seldom can manufacture out, to be sold.

[content of the invention]

The purpose of the present invention is exactly the difficult design that solve electronics divide by four circuit, and overcomes the background of power amplifier output to make an uproar Psophometric voltage virtual value does the small technical barrier in 1mV, and spy obtains two middle pitch, bass passages using subtractive way, made once Popularized through allowing people to feel that the forbidding frequency dividing sound system of electronics four can design and produce out easily.

To achieve these goals, design a kind of subtraction formula electronics four and divide acoustics circuit, input signal input is passed through first Cross C1, R1 and enter the amplifier being made up of IC1 and C2, R2, R3, R4, wherein：C1 plays isolated DC by AC signal, Must use polarity free capacitor, capacity is the μ of 4.7 μ~10；R1 and C2 forms simple R C first-order low-pass wave circuits, and C2, which will be inputted, to be believed Supersonic frequency signal attenuation in number is fallen, and R1 values are 470 Ω, and C2 values are 1000P；R2 is to connect IC1 positive input terminals to midpoint Resistance, value about 47K；R3 is to connect IC1 negative input ends to the resistance at midpoint, and value is 1K~2.2K；R4 is to be connected to IC1 Output end is to the negative feedback resistor between negative input end, and value is in 15K；IC1 amplification is determined by R4 and R3 ratio Multiple, be set in as needed between 5~15 times, through IC1 amplify output signal be divided into three tunnels, enter all the way by IC2 and C3, The second order high pass active filter circuit output that C4, R5, R6 are formed is high pitch H channel signals；Enter all the way by IC4 and C5, C6, The step low-pass active filter circuit that R7, R8 are formed；Enter all the way by R11 and be made up of IC3 and R9, R10, R11, R12, R29 Differential amplifier circuit negative input end, with entering respectively by R9, R10 into the IC3 signal of positive input terminal from IC2, IC4 output Row subtraction, so as to obtain middle pitch output M channel signals；Wherein R12 is to be connected to IC3 output ends between negative input end Negative feedback resistor, the M channel signal amplitudes exported from IC3 can be changed by changing its resistance；R29 is connection IC4 positive input terminals in The resistance of point, value is identical with R11 to be all taken as 10K；R9 and R10 resistance, is taken as 3.3k, is further divided into from the signal of IC4 outputs Three tunnels, enter IC3 positive input terminal by R10 all the way, enter the step low-pass being made up of IC5 and R13, R14, C7, C8 all the way Active filter circuit, enter the differential amplifier circuit positive input terminal being made up of IC6 and R16, R17, R30 by R15 all the way；From The signal of IC5 outputs is divided into two tunnels, is entering IC6 just with passing through R15 from IC4 outputs by R16 into IC6 negative input end all the way The signal of input carries out subtraction so as to obtain bass output L * channel signal；First passed through from the another way signal of IC5 outputs The figure that the attenuation being made up of IC7 and R18, R19, R20, R21, R22, C9, C10 is 12dB, attenuation center frequency is about 2kHz Formula attenuator circuit, then pass through the lifting centre frequency being made up of IC8 and R23, R24, R25, R26, R27, R28, C11, C12 and be 20Hz~30Hz schema lifting circuit, exports subwoofer W and passes through signal afterwards；The two of fixed attenuation amount or lifting capacity herein In segment standard schema circuit, R18, R19, R23, R24 value are that 1M Ω, R20, R25, R28 value are 10k, and R21 values are 100K, R22 value are to be determined according to specific needs no more than 100 Ω, R26 and R27 values, it is desirable to which R26 and R27 sums are equal to 100K, R26 are less than R27, and C9 takes 470P, C10 to take 4700P, and C11 values are the μ of 0.022 μ~0.047, and C12 values are the 10 of C11 Times, and in the second order high pass active filter circuit that IC2 and C3, C4, R5, R6 are formed, IC2 negative input ends connect with output end, C3 connects with C4 is connected to IC2 positive input terminals, and R5 is connected to C3 and C4 connection end from IC2 negative input ends, and R6 terminates from IC2 positive inputs To midpoint, in the step low-pass active filter circuit that IC4 and C5, C6, R7, R8 are formed, IC4 negative input ends connect with output end Logical, R7 connects with R8 is connected to IC4 positive input terminals, and C5 is connected to R7 and R8 connection end from IC4 negative input ends, and C6 is from IC4 positive inputs Midpoint is terminated to, in the step low-pass active filter circuit that IC5 and R13, R14, C7, C8 are formed, IC5 negative input ends and output end Connection, R13 connects with R14 is connected to IC5 positive input terminals, and C7 is connected to R13 and R14 connection end from IC5 negative input ends, and C8 is from IC5 Positive input terminal is connected to midpoint, can be by the handing-over of treble pathways and midrange pathway according to the horn frequency characteristic range of actual use Frequency is between 4.5kHz~7.5kHz, and between 1kHz~2kHz, bass leads to the handing-over frequency of midrange pathway and bass channel The handing-over frequency of road and sub-bass channel is between 150Hz~300Hz, and the handing-over frequency of adjacency channel is not according to a same frequency Rate determines, but is determined according to frequent subsequences curve overall after four channel signals synthesis.

The designing and manufacturing method of described circuit comprises the following steps：

A) frequency dividing circuit described in is that the sound signal of each section passage output is all mutually added up with add circuit, From high audio channel to low audio channel or on the contrary, the phase of output signal of successive bands differ by more than 90 ° closer to 180 ° when, Both are connected to before add circuit input first makees anti-phase processing one of them, and it is defeated then to watch entire combination with baud graphic instrument The frequency width resonse characteristic gone out should meet deviation no more than ± 2dB requirements, due to being superimposed from the sound wave that more loudspeaker are sent After combination, middle segment signal can be strengthened by the same sound signal that two neighboring frequency dividing circuit exports, the height in overall both ends Sound signal and low sound signal will correspondingly give to be lifted, hereby because the high audio frequency pickup electrode for exceeding 14KHz in sound source is low, as long as One section of equalizing circuit is specifically added into lower end low pass road correspondingly to lift the low sound signal less than 80Hz, lifts center Frequency is in 30Hz or so；

B) frequency dividing circuit described in is except the rectifying circuit, power amplifier output ground wire and power amplifier input ground that pass through high current Line separates cabling and convergeed to again a bit, it is necessary to amplifier power supply on a printed circuit, to prescale unit circuit power supply Voltage-stabilized power supply between external input signal ground the special upper heavy gauge wire of welding, by quiescent current herein three crucially between shape Into noise voltage drop eliminate, when being powered using monostable voltage source, also by power amplifier voltage-stabilized power supply with rectification energy storage bulky capacitor Ground is connected with heavy gauge wire, eliminates static AC noise.

The invention compared with the existing technology, midrange pathway and bass channel is all obtained using subtraction circuit, made Obtaining the part-frequency point of adjacency channel can connect together automatically, and component parameters error allows to reach ± 10%, be adapted to produce in enormous quantities, meet to consume Person's demand；Due to fully suitably being split to the working frequency range of each unit using circuit design simulation software, and reasonable land productivity Successive bands are compensated the docking of the round and smooth smooth-going of each frequency range with the work transition frequency range of each unit, so that loudspeaker The overall reproduced of combination reaches closest to ideal behavior effect.Copper be present for circuit board on circuit production technique is realized simultaneously Paper tinsel resistance defect bigger than normal, the mode for taking special welding heavy gauge wire to the several key points for influenceing signal ground connection resistance are given Make up, Static output AC noise is reduced to index of the virtual value no more than 1mV, this causes the multi-channel active electricity produced Son frequency dividing sound system has reached high-grade requirement.

[brief description of the drawings]

Fig. 1 is the schematic diagram that electronics four divides acoustics circuit in the present invention；

Fig. 2 is that the electronics four powered using single supply divides power amplifier example circuit diagram；

Fig. 3 is to divide power amplifier example circuit diagram first half using the electronics four of dual power supply；

Fig. 4 is to divide power amplifier example circuit diagram latter half using the electronics four of dual power supply；

Specify Figure of abstract of the Fig. 1 as the present invention.

[embodiment]

The invention will be further described below in conjunction with the accompanying drawings, is to be perfectly clear for the circuit theory people professional to this 's.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not intended to limit the present invention.

The present invention be the component parameters in electronic sub-frequency circuit are made by circuit design simulation software Multisim it is pre- Adjustment, in the case where meeting the substantially requirement of each frequency dividing section bound frequency range, the signal that each frequency dividing section exports is set to exist After reconfiguring, overall total frequency width response curve can reach the requirement that deviation is not more than ± 2dB.Specific design step is, first Draw circuit diagram with circuit design simulation software, according to active filter circuit calculation formula calculate resistance capacitance parameter and by it Be modified as the element standard series parameter that actual energy is purchased, then watch the frequency that each frequency-division section exports with baud graphic instrument Whether width resonse characteristic reaches requirement.At the same time, the output signal of each frequency-division section is all added with add circuit Get up, when noticing that the phase of output signal of successive bands differs by more than 90 ° closer to 180 °, both are connected to add circuit input One of them is first made anti-phase processing before, the frequency width response characteristic then exported with baud graphic instrument viewing entire combination is bent Whether line meets deviation no more than ± 2dB requirements, and it is to judge more frequency dividing circuits either with or without the foundation for designing parameter, if whole The frequency width resonse characteristic of body combination output has excessive concavo-convex change, just need be to the member on corresponding audio frequency range frequency dividing circuit Part parameter adjusts.Because the same sound signal that the middle segment signal after combination can be exported by two neighboring frequency dividing circuit adds By force, the high sound signal in overall both ends and low sound signal need may be lifted suitably, but because exceeding 14KHz's in sound source Its is few for high audio frequency pickup electrode, the low sound signal less than 80Hz need only be lifted correspondingly.

Due to coating foil too it is thin make on pcb board walk resistance it is bigger than normal, quiescent current flowed through on PCB ground wires will produce milli Level pulsating volage drop is lied prostrate, the signal input part that it enters power amplification system can be exaggerated, and virtual value is output into from power amplifier The serious noise voltage for exceeding 1mV, so amplifier power supply that must be on a printed circuit, to the power supply of prescale unit circuit A heavy gauge wire is specially welded to voltage-stabilized power supply between external input signal ground, by quiescent current herein three crucially it Between formed noise voltage drop eliminate.Certainly, rectifying circuit, the power amplifier while also passed through high current exports ground wire and power amplifier Input ground wire separates cabling and finally convergeed to a bit, and otherwise the ampere level pulsating current on rectifying circuit is slightly led what is welded in addition The pulsating volage drop formed on line can still reach more than the 0.1 millivolt order of magnitude, and it enters power amplifier input can be by power amplifier Amplification is output into the AC noise voltage that virtual value seriously exceedes 1mV.Specialty Design is generally known that this requirement below, no Previous main points are known, as long as takeing for being supplied to prescale unit circuit with the independent current source completely isolated with amplifier power supply in addition Electricity, flow through with regard to quiescent current can be eliminated on PCB ground wires caused by thermal noise voltage drop, be this transformer production factory also in work( Put and independent double 12V windings are specially laid out on matching used annular power transformer.

It is demonstrated experimentally that in above three, crucially the noise voltage formed between them does not drop in heavy gauge wire in welding in addition Eliminate, give prescale unit circuit to power even with the independent voltage-stabilized power supply completely isolated with amplifier power supply, still can not be The ambient noise voltage of power amplifier output is reduced to the good condition that virtual value is less than 1mV.It must be incited somebody to action in the way of telling about here Quiescent current three crucially between the noise voltage drop that is formed eliminate, it can be prevented to be amplified to output as effective Value reaches several millivolts to tens millivolts of background AC noise voltage.

In the electronics divide by four circuit figure shown in Fig. 1, midrange pathway and bass channel are all obtained using subtraction circuit, Being characterized in the part-frequency point of adjacency channel can connect together automatically, and component parameters error allows to reach ± 10%, be adapted to produce in enormous quantities.Figure Four high pitch, middle pitch, bass, subwoofer passages are represented using alphabetical H, M, L, W respectively in 1.

Embodiment 1

Shown in Fig. 2 single supply power supply electronics four divide power amplifier figure in, specially using two encapsulation with The power amplifier TDA7379 of TDA7294 identicals four forms the work of the BTL way of outputs, and it can be under the power supply of 17.5V voltage-stabilized power supplies to four 4 Europe loudspeaker continuously export four sine waves of the 25W without slicing for a long time, to four 8 Europe loudspeaker length under the power supply of 19.5V voltage-stabilized power supplies Phase continuously exports four sine waves of the 20W without slicing；Four total power outputs of cell power amplifier can reach 80W~ 100W, it is sufficient to meet the broadcast request of home audio-visual sound equipment.The circuit is easy to make, and lime light is exactly on a printed circuit Be welded after element, it is necessary in rectifier power source (10000 μ bulky capacitor negative poles position), power amplifier voltage-stabilized power supply (TL431 be grounded End position), front end circuit voltage-stabilized power supply (78L12 be grounded end position), in four spot weldings of signal input socket earthing position One heavy gauge wire, static background AC noise is reduced to minimum situation.

Embodiment 2

In the frequency dividing power amplifier figure of electronics four of the negative and positive dual power power supply shown in Fig. 3, Fig. 4, it is desirable to using TDA7294 As unit power amplifier, if access is positive and negative 24V voltage-stabilized power supplies, TDA7295 or TDA7296 can also be used instead Serve as unit power amplifier and obtain identical power output.According to power discharging IC cooling requirements, unit power When the total power output of amplifier is not more than 100W, prescale unit circuit and four power discharging ICs can be all arranged in one piece of PCB On plate；And when the total power output of unit power amplifier adds up to 200W, it is necessary to prescale unit circuit and power amplifier Rectification circuit is made on one piece of pcb board, and four power discharging ICs respectively make a small pcb board respectively, so as to which four power discharging ICs are scattered Uniformly it is placed on the several positions of radiator.To latter separate structure, the signal input part and prescale unit of four power discharging ICs It must be attached on circuit board between corresponding signal output part using shielding line, power amplifier output ground is directly from prescale unit electricity Draw power amplifier rectification circuit and be connected on loudspeaker on the plate of road.Either integral version still separated version, is welded on a printed circuit After good element, all should in rectifier power source (the positive and negative connection point midways of 2 10000 μ bulky capacitors), front end circuit voltage stabilizing electricity Source (78L12 and 79L12 common ground end position) and upper one of the spot welding of signal input socket earthing position three slightly lead Line.There is good Ripple Suppression performance based on TDA7294 series power discharging ICs, need not be upper when being powered using positive and negative voltage-stabilized power supply Weld heavy gauge wire with stating at 3 points.If but the external alternating current for being no more than double 20V, be in above three crucially position Static AC noise could be down in 1mV by heavy gauge wire in welding.Paying attention to the power discharging IC of not other models has such property Can, for example TDA7292 must on above three is crucially welded heavy gauge wire, and powered using positive and negative voltage-stabilized power supply Situation under background hum could be eliminated.

It is described above using electronics divide by four circuit schematic diagram 1 as the application side that sound system front end circuit is divided before level Formula.Single supply power supply can be divided by the use of TDA7379 as each unit amplifier using the battery-powered small-power electronic four of 12V storing up electricities Frequency sound system can also be used as four Unit Amplifiers by the use of TDA7388 and same type power amplifier；Dual power supply recommendation TDA7294 Serial power discharging IC is as each unit amplifier, actual if serving as unit power amplifier using the power discharging IC of other models Performance indications wait designer and assemble checking.The power amplifier powered using single supply, it is necessary to can be kept away using voltage-stabilized power supply Power-free mains ripple has an impact to power amplifier output midpoint potential makes output hum be less than the limit value that can be tolerated；It is and right The power amplifier powered with negative and positive dual power, in order that power discharging IC safely can give play to whole abilities by reliably working, also must It must be powered using positive and negative voltage-stabilized power supply to them.With most representational TDA7294, TDA7295, TDA7296 series power discharging IC For, they can load long-term continuous output sines of the 50W without slicing under using the power supply of positive and negative 24V voltage-stabilized power supplies to 4 Europe Ripple, difference are only that the ceiling voltage that power supply can be born is different.The ceiling voltage that TDA7294 can be born is positive and negative 40V, if with double 24V alternating currents give it to power by full-wave rectification, and the voltage for being added to amplifier power supply end reached positive and negative 32V, when civil power is from 220V The secondary double 24V winding output voltages of power transformer would rise to 29.5V when being increased to 270V, and power amplifier is added to by full-wave rectification The voltage of power end reaches positive and negative 39.7V.Once more than 270V, being added to the voltage at amplifier power supply end will exceed most city's electro-mechanical wave Ceiling value is by its punch through damage.Therefore, manufactory produces the TDA7293 that can bear the positive and negative 50V voltages of highest again, this is Reach the ic manufacturing process limit, although it can be reduced by the probability of over-voltage breakdown, because the radiating speed of power discharging IC Degree also can only be in use ± 24V voltage stabilizings electricity with TDA7294 identicals TDA7293 by actual package structures shape, encapsulating structure Under the power supply of source 4 Europe are loaded with long-term continuous output sine waves of the 50W without slicing.The hair of power discharging IC can only be increased by improving operating voltage Heat, power discharging IC inside thermal protection circuit are had to just carry out automatic protection closing when power amplifier power output not yet reaches rated value Output, so as to cause power discharging IC to be worked in the case where exporting the situation less than 50W.So powered using positive and negative bistable voltage source Mainly it is to ensure that power discharging IC is operated in safe and reliable state and has given play to whole abilities.The power discharging IC of other models also in this way, and Suppression of the power discharging IC of most of model to power supply ripple is simultaneously not strong enough, and the performance indications write out on product technology data can be endured Height, actual so not good, they more need use voltage-stabilized power supply power supply to obtain good behaviour.

Claims (2)

1. a kind of subtraction formula electronics four divides acoustics circuit, it is characterised in that input signal input first pass around C1, R1 enter by The amplifier that IC1 and C2, R2, R3, R4 are formed, wherein：C1 plays isolated DC by AC signal, must use nonpolarity electricity Hold, capacity is the μ of 4.7 μ~10；R1 and C2 forms simple R C first-order low-pass wave circuits, and C2 believes the supersonic frequency in input signal Number attenuate, R1 values are 470 Ω, and C2 values are 1000P；R2 is to connect IC1 positive input terminals to the resistance at midpoint, and value is about 47K；R3 is to connect IC1 negative input ends to the resistance at midpoint, and value is 1K~2.2K；R4 is to be connected to IC1 output ends to negative defeated Enter the negative feedback resistor between end, value is in 15K；IC1 multiplication factor is determined by R4 and R3 ratio, as needed It is set between 5~15 times, the signal for amplifying output through IC1 is divided into three tunnels, enters be made up of IC2 and C3, C4, R5, R6 all the way Second order high pass active filter circuit output be high pitch H channel signals；Two be made up of IC4 and C5, C6, R7, R8 are entered all the way Rank low pass active filter circuit；Enter the differential amplifier circuit being made up of IC3 and R9, R10, R11, R12, R29 by R11 all the way Negative input end, with carrying out subtraction by the signal of R9, R10 into IC3 positive input terminal respectively from IC2, IC4 output, from And obtain middle pitch output M channel signals；Wherein R12 is to be connected to IC3 output ends to the negative feedback resistor between negative input end, is changed The M channel signal amplitudes exported from IC3 can be changed by becoming its resistance；R29 is to connect IC4 positive input terminals to the resistance at midpoint, value It is identical with R11 to be all taken as 10K；R9 and R10 resistance, is taken as 3.3k, is further divided into three tunnels from the signal of IC4 outputs, passes through all the way R10 enters IC3 positive input terminal, enters the step low-pass active filter circuit being made up of IC5 and R13, R14, C7, C8 all the way, Enter the differential amplifier circuit positive input terminal being made up of IC6 and R16, R17, R30 by R15 all the way；From the signal point of IC5 outputs For two tunnels, entered all the way by R16 into IC6 negative input end with entering the signal of IC6 positive input terminals by R15 from IC4 outputs Row subtraction exports L * channel signal so as to obtain bass；From IC5 output another way signal first pass through by IC7 and R18, The schema attenuator circuit that the attenuation that R19, R20, R21, R22, C9, C10 are formed is 12dB, attenuation center frequency is about 2kHz, It is again 20Hz~30Hz's by the lifting centre frequency being made up of IC8 and R23, R24, R25, R26, R27, R28, C11, C12 Schema lifts circuit, exports subwoofer W afterwards and passes through signal；Two segment standard schemas of fixed attenuation amount or lifting capacity are electric herein Lu Li, R18, R19, R23, R24 value are that 1M Ω, R20, R25, R28 value are 10k, and R21 values are 100K, and R22 values is not More than 100 Ω, R26 and R27 values determine according to specific needs, it is desirable to which R26 is less than R27, C9 with R27 sums equal to 100K, R26 Take 470P, C10 to take 4700P, C11 values are the μ of 0.022 μ~0.047, and C12 values are 10 times of C11, and IC2 and C3, C4, In the second order high pass active filter circuit that R5, R6 are formed, IC2 negative input ends connect with output end, and C3 connects with C4 is being connected to IC2 just Input, R5 are connected to C3 and C4 connection end from IC2 negative input ends, and R6 is connected to midpoint from IC2 positive input terminals, IC4 and C5, In the step low-pass active filter circuit that C6, R7, R8 are formed, IC4 negative input ends connect with output end, and R7 connects with R8 and is connected to IC4 positive input terminals, C5 are connected to R7 and R8 connection end from IC4 negative input ends, and C6 is connected to midpoint from IC4 positive input terminals, in IC5 and The step low-pass active filter circuit that R13, R14, C7, C8 are formed, IC5 negative input ends connect with output end, and R13 connects with R14 IC5 positive input terminals are connected to, C7 is connected to R13 and R14 connection end from IC5 negative input ends, and C8 is connected to midpoint from IC5 positive input terminals, According to the horn frequency characteristic range of actual use, can by the handing-over frequency of treble pathways and midrange pathway 4.5kHz~ Between 7.5kHz, the handing-over frequency of midrange pathway and bass channel is between 1kHz~2kHz, bass channel and sub-bass channel Handing-over frequency between 150Hz~300Hz, the handing-over frequency of adjacency channel does not determine according to an identical frequency, but root Determined according to frequent subsequences curve overall after four channel signals synthesis.

2. a kind of method that subtraction formula electronics four as claimed in claim 1 divides acoustics circuit, it is characterised in that described electricity Path method comprises the following steps：

A) frequency dividing circuit described in is that the sound signal of each section passage output is all mutually added up with add circuit, from height Audio channel to low audio channel or on the contrary, the phase of output signal of successive bands differ by more than 90 ° closer to 180 ° when, both It is connected to before add circuit input and one of them is first made anti-phase processing, is then exported with baud graphic instrument viewing entire combination Frequency width resonse characteristic should meet deviation no more than ± 2dB requirements, because the sound wave sent from more loudspeaker is in stack combinations Afterwards, middle segment signal can be strengthened by the same sound signal that two neighboring frequency dividing circuit exports, the high audio frequency in overall both ends Signal and low sound signal will correspondingly give to be lifted, hereby because the high audio frequency pickup electrode for exceeding 14KHz in sound source is low, as long as under End low pass road is specifically added into one section of equalizing circuit and the low sound signal less than 80Hz is correspondingly lifted, and lifts centre frequency In 30Hz or so；

B) frequency dividing circuit described in except the rectifying circuit, power amplifier output ground wire and the power amplifier that pass through high current input ground wire every The line that drives away converges to a bit again, it is necessary to amplifier power supply on a printed circuit, to prescale unit circuit power supply voltage stabilizing Power supply between external input signal ground the special upper heavy gauge wire of welding, by quiescent current herein three crucially between formed Noise voltage drop eliminates, and when being powered using monostable voltage source, also by power amplifier voltage-stabilized power supply is used with rectification energy storage bulky capacitor Heavy gauge wire connects, and eliminates static AC noise.