CN1589065A - System capable of eliminating heat effect of speaker - Google Patents
System capable of eliminating heat effect of speaker Download PDFInfo
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- CN1589065A CN1589065A CN 200410053706 CN200410053706A CN1589065A CN 1589065 A CN1589065 A CN 1589065A CN 200410053706 CN200410053706 CN 200410053706 CN 200410053706 A CN200410053706 A CN 200410053706A CN 1589065 A CN1589065 A CN 1589065A
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- loud speaker
- frequency
- voice coil
- speaker
- power amplifier
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Abstract
This invention relates to a system capable of eliminating heat effect of the loud speaker including a power amplifier having a positive input, an inverted input end and an output end, a moving-coil loud speaker with one end connected with the output, the other connected with the inverse input end of the power amplifier, a compensation circuit including a resistor, a capacitor and an inductor in serial connection with the loud speaker, a voice coil impedance rectifier circuit including a resistor and a capacitor serially connected and parallel to the loud speaker, a degenerative resistor with one end connected to its inversed input end, the other to the earth.
Description
Technical field
The present invention relates to a kind of active speaker system, particularly relate to a kind of system that can eliminate the loud speaker thermal effect.
Background technology
In traditional passive type speaker system, comprise one or more coil-moving speakers and dividing network, when the electronic power amplifier promotes loudspeaker voice coil, voice coil loudspeaker voice coil can produce heat and the voice coil loudspeaker voice coil impedance increases accordingly, power output is big more, then the heat of voice coil loudspeaker voice coil generation is many more, and impedance increases just many more.Loud speaker is typically connected on the power amplifier of the very low voltage source of output impedance.If voice coil loudspeaker voice coil can not change impedance when being heated, the input voltage of then exporting acoustic pressure and power amplifier is proportional, and the electronic power amplifier output to acoustical power that power on the loud speaker and loud speaker produce all with square being directly proportional of input voltage.But when the voice coil loudspeaker voice coil impedance increases, the electronic power amplifier outputs to power the lacking than the quadratic growth of input voltage just on the loud speaker, also than the lacking of the quadratic growth of input voltage, this influence just is called as the thermal effect of coil-moving speaker to the acoustical power that loud speaker produces when high-power.Caused the dynamic range of loud speaker to be restricted from above thermal effect as can be seen.
Fig. 1 is the acoustic pressure (P) 103 of loud speaker when driving loud speaker by common amplifier such as voltage amplifier and the functional relation of input voltage (Vin) 104.Straight line 101 is illustrated in the acoustic pressure of the loud speaker that does not have the sound coil adstante febre, the acoustic pressure of the loud speaker that curve 102 expressions are actual.
A speaker system generally includes several loudspeaker monomers, and loud speaker is connected with external amplifier by the Passive network.In fact these dividing networks are exactly with the voltage divider of frequency dependence and are carried in the impedance of loud speaker, form the overall frequency response of desirable loud speaker.Owing to have functional relation between the impedance of moving-coil speaker and voice coil loudspeaker voice coil resistance, and the voice coil loudspeaker voice coil impedance has functional relation with input power, therefore the frequency response of whole loud speaker can distortion when high power.
Summary of the invention
The purpose of this invention is to provide a kind of system that can eliminate the loud speaker thermal effect, to eliminate the distortion phenomenon of loud speaker when the high power.
The present invention solves the problems of the technologies described above the technical scheme that is adopted:
A kind of system that can eliminate the loud speaker thermal effect, it comprises:
One power amplifier has positive input terminal, anti-input and an output;
One coil-moving speaker, the one end is connected to the output of described power amplifier, and the other end is connected to the anti-input of described power amplifier;
A compensating circuit such as gradeization, it comprises a resistance, an electric capacity, an inductance, series connection back and described loud speaker parallel connection;
A voice coil loudspeaker voice coil impedance correction circuit, it comprises resistance and electric capacity, series connection back and loud speaker parallel connection recited above;
A negative feedback resistor, one terminate to the anti-input of described power amplifier, other end ground connection.
Above-mentioned loud speaker, resistance, etc. change compensating circuit and voice coil loudspeaker voice coil correction circuit formed the negative feedback circuit of amplifier.Amplifier under this configuration formed loud speaker, etc. change the current source of circuit and compensating circuit.
Compared with prior art, the invention has the advantages that: in speaker system,, can eliminate the thermal effect of speaker system by increasing compensating circuit such as gradeization, voice coil loudspeaker voice coil impedance correction circuit and negative feedback resistor.In addition, the present invention also provides a kind of system that forms desirable whole frequency response, and has improved the reproduction of loudspeaker sound.
Description of drawings
The functional arrangement of Fig. 1 acoustic pressure and input voltage for the time with traditional power amplifier such as driven loud speaker;
The functional arrangement of Fig. 2 acoustic pressure and input voltage when driving loud speaker with the present invention;
Fig. 3 is the typical impedance curve of mono speaker, frequency response curve when being driven by traditional amplifier and the frequency response curve during by driven with current sources;
Fig. 4 is the circuit diagram of the preferential embodiment of the present invention of mono speaker;
Fig. 5 is the circuit diagram of the preferential embodiment of the present invention of multi-channel loudspeaker;
Frequency response curve that the amplifier that Fig. 6 serves as reasons traditional drives and the frequency response curve that drives with existing current source amplifier, the load curve of the multi-channel loudspeaker of a plurality of moving-coil speakers and frequency dividing circuit.
Embodiment
Following according to various aspects of the present invention, embodiment describes in further detail the present invention in conjunction with the accompanying drawings.Although the present invention adopts these figures and example to describe, it is not to limit the invention among these disclosed embodiment.On the contrary, its objective is and to cover by all changes of determined essence of the present invention of described claim and protection range, improve and be equal to replacement.
When adding power, the heating of the voice coil loudspeaker voice coil of moving-coil speaker, the impedance of voice coil loudspeaker voice coil also increases accordingly.Added power is big more, and then the resistance of Zeng Jiaing is big more.Loud speaker is driven by the amplifier with lower output impedance, so it adopts driven.
If adstante febre, voice coil loudspeaker voice coil do not change resistance, sound pressure level can be directly proportional with amplifier output voltage, and the electrical power and the consequent actual power that are applied to loud speaker are directly proportional with the square value of the input voltage of amplifier.But,, be added to the square value that its added value of electrical power on the loud speaker but is lower than the input voltage of amplifier, and when higher-wattage, the increase of acoustic pressure also is lower than the increase of input voltage square value along with the voice coil loudspeaker voice coil impedance increases.This effect is called the thermal effect of moving-coil speaker, and thermal effect has caused the limited of above-mentioned dynamic change scope.
Fig. 1 is the acoustic pressure (P) 103 of loud speaker when driving loud speaker by common amplifier such as voltage amplifier and the functional relation of input voltage (Vin) 104.Straight line 101 is illustrated in the acoustic pressure of the loud speaker that does not have the sound coil adstante febre, the acoustic pressure of the loud speaker that curve 102 expressions are actual.Be the thermal effect zone to the right from frequency 105.
In fact the difference of thermal effect is very little when different acoustic pressures.
The present invention has provided a kind of system that can eliminate the loud speaker thermal effect.
If loud speaker is not to be driven by the amplifier of traditional low output impedance such as voltage source, but driven by amplifier such as the current source more high than the impedance of loud speaker, the output current of such amplifier is just by input voltage vin
460 decisions and and load impedance irrelevant.Therefore output current and voice coil temperature are irrelevant.If voice coil temperature rises, and the impedance rising, even Vin fixes, the electric current that is applied to sound coil also can rise.This effect is thermal effect.
Fig. 2 is the acoustic pressure of loud speaker (P) 103 when driving loud speaker by the current source power amplifier and the functional relation of input voltage (Vin) 104.Straight line 201 is illustrated in the acoustic pressure of the loud speaker that does not have the voice coil loudspeaker voice coil adstante febre, the acoustic pressure of the loud speaker that curve 202 expressions are actual.Be the thermal effect zone to the right from frequency 105 among the figure.
Fig. 3 is the typical impedance curve 301 of single channel loud speaker, and the frequency response curve 302 when being driven by common amplifier, the frequency response curve 303 when being driven by the conventional voltage amplifier.Impedance curve has a peak value when loudspeaker monomer resonates, and is higher than in frequency the rising that is caused by the voice coil loudspeaker voice coil induction was arranged in 305 o'clock.Frequency response is linear in lower frequency 304 and higher 306 of cut-off frequencies.
If loud speaker is driven by existing current source amplifier, then its response curve is having a peak value near driver resonance frequency place, and 307 risings from frequency 305 to peak frequency, thus its response curve 303 have one with load curve 301 similar shapes.In order to reach the curve balance, special circuit described below is adopted in suggestion.
Fig. 4 is the preferential embodiment of single channel loud speaker of the present invention.Loud speaker 405 1 ends 406 connect the output 404 of amplifier 401, and the other end 407 connects the anti-input 403 and the resistance 408 of amplifier 401.The other end ground connection 409 of resistance 408.Loud speaker 405 and resistance 408 have been formed the negative-feedback circuit of amplifier 401, simultaneously also as the load of amplifier.
Input voltage vin 460 acts on the positive input terminal 402 of amplifier 401.Under this structure, amplifier 401 has formed the current source of loud speaker 405.Current source amplifier has been eliminated thermal effect, but speaker frequency response plot 303 is similar to the shape of load curve 301, and this also is unacceptable.
For obtaining the shape of desirable frequency response, in loud speaker and di-kind circuit: first-classization compensating circuit 410, comprise a resistance 413, an electric capacity 412 and a coil 411, these electric elements are connected; One voice coil loudspeaker voice coil compensating circuit 420 comprises resistance 421 and an electric capacity 422 series connection.Circuit 410 and 420 also forms the negative-feedback circuit of amplifier 401 with loud speaker 405 and resistance 409.
Because the centre frequency and the Q value of circuit 410 equate with the resonance frequency and the Q value of loud speaker respectively, so circuit 410 reduced the whole resistance value at the amplifier 401 at loud speaker 405 resonance frequencys 304 places, and eliminated near the peak value of this frequency.If necessary, the Q value of circuit 410 can change by changing capacitance and induction coefficient, therefore can obtain peak value or offset near the frequency response at frequency 304 places.
Circuit 420 compensates the rising of the increase of the impedance that is caused by loudspeaker monomer voice coil loudspeaker voice coil self-induction and the correspondent frequency response that frequency is higher than 305 places.
If loudspeaker response has one to duplicate when high frequency, then can or not use circuit 420 to compensate by the undercompensation of sound coil impedance.Even like this, described preferred embodiment still has the character of the thermal effect of eliminating loud speaker.
If the frequency response of loudspeaker has its oneself peak value and irrelevant with impedance, several compensating circuits that resemble circuit 410 can be in parallel with loud speaker, and the centre frequency of these circuit is corresponding with the centre frequency and the Q value of these peak values with the Q value.
Because the part of output current Iout470 has been diverted to circuit 410 and 420, therefore the compensation of Impedance Peak will appear.Whole electric current output Iout470 is directly proportional with the input voltage vin 460 of amplifier, and the total impedance of its impedance and loud speaker 405 and circuit 410 and 420 is irrelevant.
Fig. 5 is second preferred embodiment of the present invention, adopts multichannel loudspeaker.One No. three loud speaker 550 comprises moving-coil speaker 551,552 and 553, and frequency dividing circuit 554,555 and 556, sees among the figure.Each loud speaker produces the frequency range of oneself.
One end 557 of loud speaker 550 connects the output 504 of amplifier 501, and the other end 558 is connected to the anti-input 503 and the resistance 508 of amplifier 501, the other end ground connection 509 of resistance 508.
The loudspeaker monomer of each frequency dividing circuit and its oneself is connected: circuit 554 links to each other with loud speaker 551, and circuit 555 links to each other with loud speaker 552, and circuit 556 links to each other with loud speaker 553.Second end of loud speaker links to each other with the incoming end 558 of loud speaker 550.
Deng change compensating circuit 510, etc. change compensating circuit 520, etc. change compensating circuit 530 and voice coil loudspeaker voice coil compensating circuit 540 in parallel with 557 ends and 558 ends of loud speaker 550.
Fig. 6 has shown the impedance curve 601 of multichannel loudspeaker 550, the frequency response curve 603 under traditional amplifier drives, and the frequency response curve 602 under the driving of the amplifier (for example electric current) of big output impedance.This frequency response can not have circuit to obtain for 510,520,530,540 times yet.The actual overall response frequency curve image curve 603 of the system among Fig. 5.Impedance curve 601 has three peak dots: woofer 553 resonance frequencys 605, and bass and middle pitch part-frequency point 606, middle pitch and high pitch part-frequency point 607, frequency is higher than the rising that is caused by the sound coil induction in 608 o'clock.Frequency response curve 602 have three frequency 605,606 and 607 places with corresponding three peak values of impedance curve.
If the frequency response of loud speaker or single loud speaker has a peak value at certain frequency place, it can by one resemble circuit 510, circuit 520 and circuit 530 such centre frequencies equal this frequency etc. the change compensating circuit compensated, so can comprise numerous compensating circuit in this system.
Although the embodiment that can imitate of the present invention lists in the above and describes in detail, obviously, those people that grasp prior art can do some change, improvement or replacement to the present invention, but these variations all do not break away from essence of the present invention.For example, can adopt multichannel loudspeaker, and said in the foregoing description of the present invention be three the tunnel; Two or more driver can be arranged, many different passive type compensating circuits (the frequency division compensating circuit of for example connecting) also can be arranged.Loud speaker also can use different box bodys (as sealing with bending).All these variations, improvement and replacement all should be counted as within the scope of the invention.
Claims (3)
1, a kind of system that can eliminate the loud speaker thermal effect, it is characterized in that: it comprises:
One power amplifier has positive input terminal, anti-input and an output;
One coil-moving speaker, the one end is connected to the output of described power amplifier, and the other end is connected to the anti-input of described power amplifier;
A compensating circuit such as gradeization, it comprises a resistance, an electric capacity, an inductance, series connection back and described loud speaker parallel connection;
A voice coil loudspeaker voice coil impedance correction circuit, it comprises resistance and electric capacity, series connection back and described loud speaker parallel connection;
A negative feedback resistor, one terminate to the anti-input of described power amplifier, other end ground connection.
2, the system that can eliminate the loud speaker thermal effect as claimed in claim 1, it is characterized in that: described coil-moving speaker comprises 2 coil-moving speakers and 2 dividing networks at least, one of described each loud speaker terminates to an end of dividing network, and the other end is received the anti-input of described power amplifier.
3, the system that can eliminate the loud speaker thermal effect as claimed in claim 2, it is characterized in that: comprise two compensating circuits such as gradeization at least, described each etc. its resonance frequency of change compensating circuit equal the impedance peak of described loud speaker or the frequency of frequency response peak correspondence.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200410053706A CN100592824C (en) | 2004-08-13 | 2004-08-13 | System capable of eliminating heat effect of speaker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200410053706A CN100592824C (en) | 2004-08-13 | 2004-08-13 | System capable of eliminating heat effect of speaker |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1589065A true CN1589065A (en) | 2005-03-02 |
| CN100592824C CN100592824C (en) | 2010-02-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200410053706A Expired - Fee Related CN100592824C (en) | 2004-08-13 | 2004-08-13 | System capable of eliminating heat effect of speaker |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101394688B (en) * | 2008-09-09 | 2012-05-09 | 南京大学 | Non-thermal resistance prediction method for power compression of coil driven loudspeaker |
| CN103543310A (en) * | 2012-07-10 | 2014-01-29 | 北京普源精电科技有限公司 | Oscillograph with frequency response compensation circuit |
-
2004
- 2004-08-13 CN CN200410053706A patent/CN100592824C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101394688B (en) * | 2008-09-09 | 2012-05-09 | 南京大学 | Non-thermal resistance prediction method for power compression of coil driven loudspeaker |
| CN103543310A (en) * | 2012-07-10 | 2014-01-29 | 北京普源精电科技有限公司 | Oscillograph with frequency response compensation circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100592824C (en) | 2010-02-24 |
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Granted publication date: 20100224 Termination date: 20100813 |