JP4279962B2 - Speaker system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a so-called trumpet type loudspeaker system used for wide-area sound amplification, and more particularly to a loudspeaker system in which a plurality of voice coils for driving a diaphragm are made independent.
[0002]
[Prior art]
Conventionally, a speaker system using this kind of trumpet type speaker has been widely spread and used in stadiums, schools, regional emergency broadcasts, in-car broadcasts for elections, and the like. This speaker system achieves a clear high sound pressure with a powerful driver unit and an efficient trumpet horn.
[0003]
[Problems to be solved by the invention]
However, in the conventional speaker system described above, an excessive input is applied to the speaker due to a user's operation to widen the sound expansion range, the voice coil is damaged, or the voice coil is removed from the diaphragm due to a temperature rise of the voice coil due to the excessive input. There were problems that caused accidents such as liberation.
[0004]
The present invention has been made to solve the problems of the prior art, and its purpose is to achieve optimum conditions even when an abnormality occurs due to severe conditions of a driver unit of a trumpet type speaker used for wide-range sound amplification. An object of the present invention is to provide a speaker system that can be used stably.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventor has found that the object can be achieved by providing a voice coil for occurrence of abnormality in addition to the conventional voice coil, and the present invention has been completed. It was.
[0006]
That is, the present invention is a speaker system in which a plurality of voice coils are installed on a voice coil bobbin of an electrodynamic driver unit having a single diaphragm, and the diaphragm is formed by the first voice coil among the plurality of voice coils. And a means for switching to another voice coil when an abnormality occurs in the first voice coil with the other voice coil in a standby state.
[0007]
In a preferred aspect of the speaker system of the present invention, the diaphragm is driven by the first voice coil, and when the first voice coil is disconnected during operation, the disconnection is detected by the detection system of the driving device, and the other voice is detected. Means for switching to the coil.
[0008]
In a preferred aspect of the speaker system of the present invention, the output of the amplification device is connected to a plurality of voice coils.
[0009]
In a preferred aspect of the speaker system of the present invention, the output of the amplifying device is connected in series to a plurality of voice coils, and when one voice coil is disconnected, means for switching to another voice coil is provided.
[0010]
In a preferred aspect of the speaker system of the present invention, an amplification device is connected to each of the plurality of voice coils independently.
[0011]
In a preferred aspect of the speaker system of the present invention, the first voice coil is connected to the amplifying device among a plurality of voice coils, and the other voice coil is used as temperature detection means for the first voice coil. Feedback control suitable for the temperature rise can be performed on the amplifying device, and a display means for displaying the temperature detection result as a temperature display or a danger display is provided.
[0012]
In a preferred aspect of the speaker system of the present invention, the first voice coil is connected to the amplifying device among the plurality of voice coils, and the other voice coil is used as temperature detection means for the first voice coil. When the coil temperature rises, another voice coil operates as a drive voice coil.
[0013]
In a preferred aspect of the speaker system of the present invention, a resistor is provided between the amplifier and the speaker of the speaker, and the power input to the speaker from the resistor is measured in units of time, and the temperature of the speaker is increased from the product of the power and time. And a means for estimating the load state of the speaker.
[0014]
In a preferred aspect of the speaker system of the present invention, there is provided means for connecting the outputs of the amplifying device to a plurality of voice coils and switching these voice coils periodically.
[0015]
In a preferred embodiment of the speaker system of the present invention, a plurality of voice coils are provided on a voice coil bobbin in parallel or in series, thereby having a plurality of impedances.
[0016]
In a preferred embodiment of the speaker system of the present invention, a temperature sensor is installed in an equalizer on the front surface of the diaphragm in the speaker, and the temperature of the speaker is detected in real time by this temperature sensor.
[0017]
In the speaker system of the present invention, since a plurality of voice coils are provided to the speaker driver as described above, the loudspeaker operator mistakenly inputs excessive power of the speaker, or the voice coil is heated by a long time operation. Even accidents can be minimized.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The speaker system of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto.
[0019]
FIG. 1A shows a typical structural example used as a driver unit of a trumpet speaker. A magnet 102, a center pole 106, and a top plate 105 are incorporated in a yoke 101, and a voice coil 104 is incorporated in a diaphragm 110. The voice coil 104 is installed in a magnetic circuit, the dust proof net 108 is installed in a driver throat 116 having an equalizer 109 and a throat 107, and the yoke 101 and the driver throat 116 are fixed together with screws 120. It is a thing.
When the structure of the diaphragm 110 is shown in more detail in the perspective view 114 of the diaphragm in FIG. 1B, the diaphragm 110 has a voice coil 112 mounted on a voice coil bobbin 119 and lead wires 113 and 115 of the voice coil 112 are mounted. The vibration part 111 and the fixed part 117 have a round front surface.
[0020]
When the sound output from the amplification device is applied to the voice coil 104, the diaphragm 110 vibrates back and forth due to interference between the magnetic field of the strong magnet 102 and the magnetic field generated by the voice coil 104, and the sound is corrected by the equalizer 109. And output as acoustic vibration to the trumpet horn, and amplify the acoustic input input to the amplifier.
[0021]
If the input from the loudspeaker is excessive, the voice coil 112 installed on the voice coil bobbin 119 shown in FIG. 1 (b) is cut, or the adhesive that fixes the voice coil 112 to the voice coil bobbin 119 is released. , Sound may stop during use.
[0022]
The voice coil of the conventional speaker system has a single winding structure of a diaphragm 201 and a voice coil 202 as shown in FIG. 2, and the voice coil 202 is usually placed on the voice coil bobbin 203 of the diaphragm 201 as an impedance adapted to the output impedance of the speaker. By specifying and winding the impedance from 2-16Ω used, it is matched with the loudspeaker and vibrated with the output from the loudspeaker.
[0023]
However, as a loudspeaker application, when the background noise of the usage environment increases from the normal use, power that is not normally considered beyond the specification may be continuously input to the speaker. That is, an excessive load is applied to the voice coil of the speaker, and disconnection and other accidents may occur.
[0024]
On the other hand, in order to solve such a problem, the speaker system of the present invention is provided with a second voice coil 303 in addition to the first voice coil 302 installed on the voice coil bobbin 304 of the diaphragm 301 as shown in FIG. A diaphragm driver is completed by constituting the diaphragm 301. As for the winding method of the first voice coil and the second voice coil, a conventionally known method can be appropriately employed depending on the loudspeaking application or purpose of use. For example, the first voice coil 302 and the second voice coil 303 are overlapped. Or a method of winding a plurality of voice coils side by side in parallel.
[0025]
When the first voice coil 302 is used as a loudspeaker, the second voice coil can be operated when the voice coil is cut or becomes inoperable due to excessive input in the above situation. The connection can be changed to 303 and the loudspeaker operation can be continued.
[0026]
In addition, by using the first voice coil 302 and the second voice coil 303 in parallel or in series, or by using the second voice coil 303 for detection purposes to prevent an accident from occurring in advance, It is possible to construct a speaker system that can be used continuously even if the function as a speaker is in an over-input state.
[0027]
In the speaker system of the present invention, the diaphragm is driven by the first voice coil, and when the first voice coil is disconnected during operation, the disconnection is detected by the detection system of the driving device, and the second voice coil, etc. There may be means for switching to another voice coil. For example, when driving a loudspeaker by installing a plurality of voice coils on a diaphragm, an input 401 is connected to an amplifier circuit 402 as shown in FIG. The switch 406 that can select the use of either the first voice coil 407 or the second voice coil 408 is connected to the output, and the first voice coil 407 and the second voice coil 408 are connected to the output. The output of the abnormality detection 403 is connected to the switch control 404 and controls the switching 406.
[0028]
Since the abnormality detection 403 is provided on the output side of the amplifier circuit, if the speaker is disconnected and the load on the speaker is open, the load on the output terminal of the amplifier circuit 402 is open compared to the normal load state. An abnormality that the output current stops flowing can be recognized by the abnormality detection 403. On the contrary, if the first voice coil 407 is short-circuited, the output current of the amplifier circuit 402 is extremely increased, so that the abnormality detection 403 recognizes that an abnormal state has occurred in the first voice coil 407.
[0029]
When the abnormality detection 403 constantly monitors the disconnection of the first voice coil 407 by detecting the current, if the excessive input is continuously input to the first voice coil 407 and the voice coil is disconnected, the amplifier circuit 402 Since the current for driving the voice coil does not flow to the first voice coil 407, the abnormality detection 403 determines that the first voice coil 407 is disconnected, and the abnormality detection 403 outputs a switching signal to the switch control 404, A signal for switching to the second voice coil 408 is output to the switch 406, and the operation of switching from the first voice coil 407 to the second voice coil 408 enables continuous operation as a speaker.
[0030]
Further, if the first voice coil 407 is short-circuited, an excessive current flows in the abnormality detection 403 as compared with the normal state, so that a short-circuit abnormality of the first voice coil 407 can be detected.
[0031]
As described above, the abnormality detection 403 that detects the disconnection or short circuit of the voice coil inputs the detection data to the switch control 404 and causes the switching 406 to perform the switching operation from the first voice coil 407 to the second voice coil 408. . Similarly, when the second voice coil 408 is initially driven and the second voice coil is disconnected or short-circuited, an operation of switching from the second voice coil 408 to the first voice coil 407 is performed. In addition, when a plurality of three or more voice coils are installed, the voice coil can be switched one after another by the same method, and the speaker can be continuously operated.
[0032]
If a plurality of voice coils are installed on the diaphragm 409 as described above, even if a failure occurs due to excessive input or severe continuous use, the voice coils are switched one after another according to the detection result of the abnormality detection 403. Therefore, the durability of the speaker system can be improved.
[0033]
The speaker system of the present invention can connect the output of the amplifier to a plurality of voice coils (two in the figure) as shown in FIG.
FIG. 5A shows an example in which the input 501 is connected to the amplifier circuit 502, the output is connected in series to the first voice coil 503 and the second voice coil 504, and the diaphragm 505 is vibrated to squeeze out. FIG. 5B shows an example in which the input 506 is connected to the amplifier circuit 507, the output is connected in parallel to the first voice coil 508 and the second voice coil 509, and the diaphragm 510 is vibrated to make a loud sound.
[0034]
In this case, if the first voice coil 503 and the second voice coil 504 installed on the diaphragm 505 are each 8Ω, they can be connected in series to the 16Ω amplifier circuit 502 as shown in FIG.
If the first voice coil 508 and the second voice coil 509 provided on the diaphragm 510 are each 8Ω, it is possible to correspond to a 4Ω amplifying device in parallel connection as shown in FIG.
[0035]
As described above, the impedance of the speaker and the amplification device can be adjusted by a plurality of voice coil impedances, and the first voice coil and the second voice coil are independent voice coils, and the external connection terminal of the voice coil is installed, The speaker system can be flexibly adapted to the construction of the site where the speaker is installed.
[0036]
The speaker system of the present invention can have means for connecting the output of the amplifying device in series to a plurality of voice coils and switching to another voice coil when one voice coil is disconnected.
For example, as shown in FIG. 6, an audio input 601 is input to an amplifier circuit 602, and the output is connected in series to a first voice coil 607 and a second voice coil 606. The detection 603 is connected to the output of the amplifier circuit 602, the output of the detection 603 is connected to the switching control 604, the output is connected to the switching circuit 605, and the switching circuit 605 switches the speakers.
[0037]
When the first voice coil 607 and the second voice coil 606 installed on the diaphragm 608 are used as a serial connection from the amplification device, and the first or second voice coil is disconnected, the amplification circuit is opened. The output voltage of 602 increases.
When the switch position of the switching circuit 605 is set to neutral and the voltage is detected, the voltage is switched to the first voice coil 607 or the second voice coil 606, and the output voltage of the amplifier circuit decreases to about one half or greatly. If the switch circuit 605 is switched to any of the positions, the switch position of the switching circuit 605 is connected to a normally operating voice coil. When the switching circuit 605 enters any position, the voltage of the amplifier circuit 602 does not decrease. It is detected that the voice coil is connected to the cut voice coil, and the voice coil that operates normally by switching to another position is connected as a load of the amplifier circuit 602.
[0038]
In the speaker system of the present invention, an amplifier can be connected to each of a plurality of voice coils independently. For example, as shown in FIG. 7, a voice input 701 is connected to a preamplifier 702, the output is connected to an amplifier circuit 703 and an amplifier circuit 704, and a first voice coil 705 and a second voice coil 706 are connected to each of the outputs. It is connected and driven, and the diaphragm 707 is vibrated to make a loud sound. In this case, the audio signal input 701 is output from the preamplifier 702 in the same phase and level, and is output from the amplifier circuit 703 and the amplifier circuit 704 to the first voice coil 705 and the second voice coil 706, respectively.
[0039]
When configured as described above, the diaphragm 707 can be driven by different voice coils, and if the phase and output are the same, the driving force of the diaphragm applied twice as much input to one voice coil. Even if the first or second voice coil is disconnected due to excessive input, the sound pressure level from the speaker will decrease, but any voice coil is operating, so the loudspeaker operation will continue. be able to.
[0040]
In the speaker system of the present invention, the first voice coil among a plurality of voice coils is connected to the amplifying device, and the other voice coil is used as temperature detection means for the first voice coil to increase the temperature of the voice coil. Appropriate feedback control can be performed on the amplifier.
For example, as shown in FIG. 8A, the first voice coil 805 is normally connected, that is, the voice input 801 is amplified by the preamplifier 802 and the amplifier circuit 803 and supplied to the first voice coil 805, and the diaphragm 807 is vibrated to make a loud sound.
However, if the first voice coil 805 is continuously operated in an over-input state, the second voice coil 806 that is overlapped or in close proximity is also heated by the first voice coil 805 and the temperature rises.
In this case, the second voice coil 806 is connected to the temperature detection 804 for temperature detection, and the temperature detection result is connected to the preamplifier 802 for control. The temperature detection 804 is connected to a temperature display 810 that displays the temperature increase of the first voice coil 805.
[0041]
In the temperature detection 804, a current is passed through the resistance of the second voice coil 806, and the temperature of the second voice coil 806 can be known from the change in the current value. Since the voice coil is generally made of copper, it approximates the temperature characteristic of copper, and the resistance of the voice coil increases in proportion to the increase in temperature, as shown by the temperature characteristic 808 in FIG. 8B. Therefore, the temperature can be detected from the voice coil resistance change 809. Since the second voice coil 806 is installed close to the first voice coil 805, the temperature is the same.
Since the resistance value of the second voice coil 806 is detected as described above, an increase in the temperature of the first voice coil 805 can be detected.
[0042]
When a change in resistance of the second voice coil 806 is detected by a change in current and the voice coil becomes hot and it is dangerous if excessive input continues further, a voice input 801 is input from the temperature detection data to the preamplifier 802. , The input to the first voice coil 805 is limited to suppress over-input to the first voice coil 805. When a dangerous temperature rise is suppressed by excessive input to the first voice coil 805, the restriction on the preamplifier 802 is released.
By controlling the excessive input to the first voice coil 805 as described above, a stable operation for a long time can be realized.
[0043]
In the speaker system of the present invention, as described above, a change in the resistance value of the voice coil that occurs due to an increase in temperature due to excessive input of the voice coil of the second voice coil 806 is detected as a temperature change. When it is detected that it is in a dangerous state that causes its own disconnection or adhesive deterioration, the temperature detection 804 performs temperature display or danger display with the temperature display 810. The display can also display the cause of the decrease in volume, for example.
Further, since the temperature and state are displayed by the temperature display 810, the operator can adjust the sound volume by looking at the display, thereby preventing an excessive input to the driver unit.
[0044]
The speaker system of the present invention is connected to each speaker line in which an output circuit 905 is connected to a plurality of voice coils (first voice coil 906, second voice coil 907) installed on a speaker diaphragm 908 as shown in FIG. A detection resistor r 909 and a detection resistor r 910 that are negligible with respect to the impedance of the speaker are provided, and the speaker is operated by voice input, and flows into the first voice coil 906 and the second voice coil 907 per unit time. The power is fed back to the detection 903 and the detection 904 as over-input information, and the preamplification 902 is controlled to reduce the amplification of the voice of the input 901 to input the first voice coil 906 and the second voice coil 907. The power consumption can be lowered to a safe level. In this method, the input to the speaker is controlled by detecting the degree of danger based on the power consumption per fixed time, instead of reacting to the excessive input flowing into the voice coil with an instantaneous peak.
[0045]
According to the speaker system of the present invention, the output of the amplifying device can be connected to a plurality of voice coils, and the voice coils can be switched periodically to reduce the stress of the voice coils.
[0046]
For example, as shown in FIG. 10, the amplifier circuit 1002 that drives the speaker is connected to the first voice coil 1007 and the second voice coil 1008 via the switch 1006. The switch 1006 is a signal from the timer 1004 and is switched at regular intervals. The switch 1006 is switched between the first voice coil 1007 and the second voice coil 1008.
In addition, when the input 1001 of the voice is higher than the rated value and is clearly recognized as being overloaded to the voice coil, the overload detection 1003 is notified, and the switching speed of the timer 1004 is increased with respect to the timer 1004 than before. Thus, it operates to lighten the load on the voice coil at regular intervals.
[0047]
By doing as described above, a specific voice coil does not receive stress in a long-time overinput state, and can respond while resting. Therefore, a speaker system that can withstand long-time overinput can be constructed as a system. .
[0048]
The speaker system of the present invention can realize a speaker that can cope with various input impedances by installing a plurality of voice coils in parallel or in series on a voice coil bobbin.
For example, as shown in FIG. 11, a plurality of voice coils, that is, a first voice coil 1105, a second voice coil 1106, a third voice coil 1107, and a fourth voice coil 1108 are provided on the diaphragm 1109, and the impedance of the voice coil is set. Z1 1001, Z2 1102, Z3 1103, and Z4 1104 are installed on the diaphragm 1109.
[0049]
When the impedance of each voice coil is Z1, Z2, Z3, Z4, and each impedance is 2Ω
Z1 + Z2 + Z3 + Z4 = 8Ω
Z1 // Z2 + Z3 // Z4 = 2Ω (// means parallel)
Z1 + Z2 = 4Ω
As described above, a speaker that can cope with various impedances can be realized by a connection method. If necessary, one of the plurality of voice coils may be used for temperature detection.
[0050]
In the speaker system of the present invention, a temperature sensor is installed in an equalizer on the front surface of the diaphragm in the speaker, and the temperature of the speaker can be detected in real time by this temperature sensor.
For example, as shown in FIG. 12, the voice is input to the input 1201 and the preamplifier 1202, connected to the output 1203 and the output 1204, and each output is connected to the first voice coil 1205 and the second voice coil 1206. The temperature sensor 1209 is installed in a part of the equalizer 1208 that oscillates the diaphragm 1207 and corrects the sound of the diaphragm 1207. The output of the temperature sensor 1209 is converted into an electric signal by the temperature detection 1210 and input to the preamplifier 1202. The speaker input is controlled by the temperature rise of the speaker. Further, the sensor position is not limited to the equalizer, and may be installed anywhere as long as it can sense the temperature of the voice coil.
[0051]
In the loudspeaker system, an accident such as a disconnection may occur due to a rise in the temperature of the voice coil due to an excessive input operation for a long time or an input of sound far exceeding the rating in a short time due to the above-described loudspeaker application.
Therefore, by measuring the temperature of the temperature sensor 1209 installed on the front surface of the diaphragm, the temperature of the voice coil is predicted from the temperature in the speaker driver, and the temperature detection 1210 is corrected to the temperature of the voice coil by a prediction coefficient. When it is predicted that a temperature rise has occurred in the voice coil, the amplification level of the preamplifier 1202 is forcibly lowered to lower the temperature of the voice coil, avoiding dangers such as disconnection in advance, Judging from the result of the temperature detection 1210 when the voice coil is in a safe temperature state by operating, the gain of the preamplifier 1202 is returned to the conventional state and the loudspeaking operation is performed.
[0052]
【The invention's effect】
As described above, a driver unit of a trumpet speaker intended for wide-area loudspeaking is applied with excessive input from the usage environment, which is a severe usage condition. According to the speaker system of the present invention, the diaphragm is driven. Since a plurality of voice coils are prepared and controlled by various methods, the life of the driver unit can be extended and a more stable loudspeaker system can be supplied.
[Brief description of the drawings]
FIG. 1A is an explanatory diagram of a basic speaker driver structure.
(B) Perspective view of diaphragm
FIG. 2 is an explanatory diagram of a conventional voice coil installation example.
FIG. 3 is an explanatory diagram of an example of a voice coil device according to the present invention.
FIG. 4 is an explanatory diagram of a device example of the speaker system of the present invention.
FIG. 5A is an explanatory diagram of an example of a speaker system according to the present invention (a voice coil is connected in series to an amplifier circuit).
(B) An explanatory diagram of an example of a speaker system according to the present invention (a voice coil is connected in parallel to an amplifier circuit).
FIG. 6 is an explanatory diagram of an apparatus example of the speaker system of the present invention.
FIG. 7 is an explanatory diagram of an apparatus example of the speaker system of the present invention.
FIG. 8A is an explanatory diagram of an example of the apparatus of the speaker system of the present invention.
(B) Graph of temperature characteristics of voice coil resistance
FIG. 9 is an explanatory diagram of a device example of the speaker system of the present invention.
FIG. 10 is an explanatory diagram of an apparatus example of the speaker system of the present invention.
FIG. 11 is an explanatory diagram of a device example of the speaker system of the present invention.
FIG. 12 is an explanatory diagram of a device example of the speaker system of the present invention.
[Explanation of symbols]
101. yoke
102. magnet
104. Voice coil
105. Top plate
106. Center pole
107. Throat
108. Dustproof net
109. Equalizer
110. Diaphragm
111. Vibration part
112. Voice coil
113. Lead
114. Diaphragm perspective view
115. Lead
116. Driver throat
117. Fixed part
118. Voice coil packing
119. Voice coil bobbin
120. screw
201. Diaphragm
202. Voice coil
203. Voice coil bobbin
301. Diaphragm
302. 1st voice coil
303. Second voice coil
304. Voice coil bobbin
401. input
402. Amplifier circuit
403. Anomaly detection
404. Switch control
406. switching
407. 1st voice coil
408. Second voice coil
409. Diaphragm
501. input
502. Amplifier circuit
503. 1st voice coil
504. Second voice coil
505. Diaphragm
506. input
507. Amplifier circuit
508. 1st voice coil
509. Second voice coil
510. Diaphragm
601. input
602. Amplifier circuit
603. Detection
604. Switching control
605. Switching circuit
606. Second voice coil
607. 1st voice coil
608. Diaphragm
701. input
702. Preamplification
703. Amplifier circuit
704. Amplifier circuit
705. 1st voice coil
706. Second voice coil
707. Diaphragm
801. input
802. Preamplification
803. Amplifier circuit
804. Temperature detection
805. 1st voice coil
806. Second voice coil
807. Diaphragm
808. Temperature characteristics
809. Voice coil resistance change
810. Temperature display
901. input
902. Preamplification
903. Detection
904. Detection
905. Output circuit
906. 1st voice coil
907. Second voice coil
908. Diaphragm
909. Detection resistance r
910. Detection resistance r
1001. input
1002. Amplifier circuit
1003. Overload detection
1004. timer
1005. Switching control
1006. switching
1007. 1st voice coil
1008. Second voice coil
1009. Diaphragm
1101. Z1
1102. Z2
1103. Z3
1104. Z4
1105. 1st voice coil
1106. Second voice coil
1107. Third voice coil
1108. 4th voice coil
1109. Diaphragm
1201. input
1202. Preamplification
1203. output
1204. output
1205. 1st voice coil
1206. Second voice coil
1207. Diaphragm
1208. Equalizer
1209. Temperature sensor
1210. Temperature detection

Claims (12)

A speaker system in which a plurality of voice coils are installed on a voice coil bobbin of an electrodynamic driver unit having a single diaphragm, and the diaphragm is driven by the first voice coil among the plurality of voice coils. A speaker system comprising means for switching to another voice coil when an abnormality occurs in the first voice coil with the voice coil in a standby state. The diaphragm is driven by the first voice coil, and when the first voice coil is disconnected during operation, it has means for detecting the disconnection by the detection system of the driving device and switching to another voice coil. The speaker system according to claim 1. The speaker system according to claim 1, wherein the output of the amplifying device is connected to a plurality of voice coils. 2. The speaker system according to claim 1, further comprising means for connecting the output of the amplifying device in series to a plurality of voice coils and switching to another voice coil when one voice coil is disconnected. 2. The speaker system according to claim 1, wherein an amplifier is connected to each of the plurality of voice coils independently. Of the multiple voice coils, the first voice coil is connected to the amplifying device, and the other voice coil is used as the temperature detecting means for the first voice coil, and feedback control corresponding to the temperature rise of the voice coil is provided to the amplifying device. The speaker system according to claim 1, which can be performed. 7. The speaker system according to claim 6, further comprising display means for displaying the temperature detection result as a temperature display or a danger display. When the temperature of the first voice coil rises when the first voice coil is connected to the amplifying device and the other voice coil is used as the temperature detection means for the first voice coil, The speaker system according to claim 1, wherein the coil operates as a drive voice coil. A resistor is installed between the speaker amplifying device and the speaker, and the power input to the speaker from the resistor is measured in units of time, the temperature rise of the speaker is detected from the product of the power and time, and the load state of the speaker is estimated The speaker system according to claim 1, further comprising: 2. The speaker system according to claim 1, further comprising means for connecting the outputs of the amplifying device to a plurality of voice coils and periodically switching the voice coils. The speaker system according to claim 1, wherein a plurality of impedances are provided by arranging a plurality of voice coils in a voice coil bobbin in parallel or in series. The speaker system according to claim 1, wherein a temperature sensor is installed in an equalizer on a front surface of a diaphragm in the speaker, and the temperature of the speaker is detected in real time by the temperature sensor.

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