JP5908616B2 - Loudspeaker system and loudspeaker system controller - Google Patents

Description

  The present invention relates to a loudspeaker system having a plurality of speakers. The present invention also relates to a control device applied to a loudspeaker system.

  A loudspeaker system is known as an audio broadcasting system that provides information to the public or entertains the public in buildings and facilities. A typical loudspeaker system includes a plurality of speakers connected to an amplifier via speaker lines, and each controller that monitors the connection of the speaker lines. An example is disclosed in Patent Document 1. In an emergency, the loudspeaker system alerts the public in the building or facility.

  A loudspeaker system used in Europe must meet European Norm (EN) 60849, which requires the connection of speaker lines extending from the amplifier to its terminals and monitoring of accuracy. EN 60849 specifies the performance requirements for audio reinforcement systems used indoors and outdoors to broadcast to protect people in a given area in an emergency. The EN 60849 standard requires a redundant system that reliably maintains a warning function in the event of a line break.

US Patent Application Publication No. 2003/0063755

The loudspeaker system needs to maintain a broadcastable state even if the speaker line is partially disconnected.
One object of the invention disclosed herein is to realize a loudspeaker system with improved reliability and safety.

  According to one aspect of the present invention, a loudspeaker system including a loop-shaped transmission medium, a plurality of speakers connected to the transmission medium, and a first filter unit connected to the transmission medium is provided. The transmission medium transmits a transmission signal in a first direction and a second direction opposite to the first direction. The transmission signal includes a first signal having a predetermined frequency band and a second signal having a frequency band different from the first signal. The first filter unit filters the transmission signal so as to attenuate the first signal and output the second signal. The first filter unit is connected to the transmission medium so that the first signal is not transmitted in the first direction while the first signal and the second signal are transmitted in the second direction.

  According to the above one aspect of the present invention, it is possible to realize a loudspeaker system with improved reliability and safety.

Schematic of a loudspeaker system according to one embodiment Schematic of the control device of the loudspeaker system shown in FIG. Schematic of the filter unit used in the control device shown in FIG. Schematic of the monitoring device of the loudspeaker system shown in FIG. Schematic of isolator part of monitoring device shown in FIG. Flowchart of operation by the control device shown in FIG. Schematic of a monitoring device according to another embodiment

Selected embodiments of the present invention will be described with reference to the drawings. Those skilled in the art can now appreciate from the present disclosure that the following descriptions of the embodiments of the present invention are for illustrative purposes and are not intended to limit the invention as defined by the appended claims and their equivalents.
(Embodiment 1)
(Speaking system 1)
FIG. 1 schematically shows a loudspeaker system 1 (an example of a loudspeaker system) according to an embodiment of the present invention. The loudspeaker system 1 is used in a large-scale facility or building.

The loudspeaker system 1 includes an amplifier 2, a plurality of speakers 3, a speaker line 4 (an example of a transmission medium), a control device 5 (an example of a control device), and a plurality of monitoring devices 10 corresponding to each speaker 3 (of a communication control device). Example).
The amplifier 2 is connected to the speaker line 4. Although not shown, the amplifier 2 is connected to the speaker line 4 via a transformer.

The monitoring device 10 is connected in series with the speaker line 4. The speaker 3 is connected in parallel to the speaker line 4. The control device 5 is connected to the speaker line 4.
The speaker line 4 may be a two-wire wire or cable as shown in FIG. The speaker line 4 is configured in a loop so that a signal from the amplifier 2 or a signal generated by the control device 5 is transmitted to the speaker line 4 in both directions. The speaker line 4 may be a power supply line for the speaker 3. The power supply in this embodiment is a direct current (DC).

  In the loudspeaker system 1, the amplifier 2 outputs an audio signal (an example of a second signal) transmitted by the loudspeaker system 1. The audio signal may have a frequency of 20 kHz or less. The audio signal is superimposed on a direct current supplied from a power source (not shown) and transmitted through the speaker line 4. The control device 5 generates and outputs a communication signal (an example of a first signal). The communication signal may have a frequency exceeding 60 kHz. The communication signal is superimposed on the audio signal transmitted through the speaker line 4 and the direct current. The superimposed signal (an example of a transmission signal) is transmitted to the speaker line 4.

The communication signal is not transmitted in the first direction of the speaker line 4 when the voice and the communication signal that are superimposed signals are transmitted in the second direction of the speaker line 4. The second direction is the reverse direction of the first direction.
The monitoring device 10 is polled intermittently or continuously by the control device 5. The control device 5 generates a polling signal (an example of a communication signal) and transmits it to the designated monitoring device 10. The designated monitoring device 10 that has received the polling signal generates a response signal and transmits the response signal to the control device 5 via the speaker line 4. If no response signal is received, it is concluded that at least one of the connected monitoring devices 10 does not respond, and therefore it is concluded that there is some failure in the loudspeaker system 1. The possibility is a short circuit and / or disconnection that has occurred in the speaker line 4.

Each device connected to the speaker line 4 in the loudspeaker system 1 will be described in detail below.
(Control device 5)
FIG. 2 schematically shows a possible configuration of the control device 5. The control device 5 performs communication control on the speaker line 4 according to a predetermined communication protocol. For example, the control device 5 polls all the monitoring devices 10 to check the occurrence of a failure or disconnection in the loudspeaker system 1. The polling is an automatic and continuous inspection for checking the operation state of the monitoring device 10, the speaker 3, and the speaker line 4.

The control device 5 includes a first filter unit 51 (an example of a first filter unit), a second filter unit 52 (an example of a second filter unit), a switch 53, a reception unit 54a, a transmission unit 54b, and a CPU. (Central processing unit) 55 (an example of a processor), an A / D converter 57, and a D / A converter 58.
The first filter unit 51 has a band-pass filter designed to pass an audio signal and a direct current signal and attenuate other signals. FIG. 3 shows a configuration example of the first filter unit 51. In this example, a parallel resonant circuit is cited as the bandpass filter. The filter design is not limited to this configuration, and other known bandpass filters or high-pass filters may be used.

The second filter unit 52 is connected to the speaker line 4. The second filter unit 52 includes a band-pass filter designed to pass a communication signal including a response signal and attenuate other signals.
The switch 53 is connected to the second filter unit 52 via a transformer. The switch 53 switches between the reception unit 54 a and the transmission unit 54 b in accordance with a command from the CPU 55, and transmits and receives signals to and from the speaker line 4.

  The receiving unit 54 a receives a communication signal, for example, a response signal from the monitoring device 10 connected to the speaker line 4 via the second filter unit 52. The receiving unit 54a transmits a communication signal to the CPU 55 via the A / D converter 57. The transmission unit 54 b transmits a communication signal received from the CPU 55 via the D / A converter 58, for example, a polling signal, to the monitoring device 10 via the speaker line 4.

The A / D converter 57 converts the analog communication signal into a digital communication signal processed by the CPU 55. The D / A converter 58 converts the digital communication signal processed by the CPU 55 into an analog communication signal.
The CPU 55 controls transmission / reception of communication signals. The CPU 55 generates a polling signal and transmits it to the designated monitoring device 10 connected to the speaker line 4. The polling signal includes address data of the designated monitoring device 10. The CPU 55 also receives a response signal from the designated monitoring device 10. As a result, the CPU 55 transmits a polling signal to each designated monitoring device 10 and determines whether a response signal from each designated monitoring device 10 has been received. In this way, the CPU 55 detects the state of the loudspeaker system 1. Then, the CPU 55 outputs information related to the state of the loudspeaker system 1. For example, the CPU 55 outputs failure data and information of the loudspeaker system 1 to an external management system that monitors and manages the operation of the loudspeaker system 1 via the network. The CPU 55 may execute the above operation of the loudspeaker system 1 in accordance with a program read from a memory (not shown).

(Monitoring device 10)
FIG. 4 shows a possible configuration of the monitoring device 10. In the present embodiment, the left side of the monitoring device 10 shown in FIG. 4 is referred to as “upstream side” and is the side close to the control device 5 along the speaker line 4. Also, the right side of the monitoring device 10 shown in FIG.

  The monitoring device 10 has a unique address (for example, an IP address) or identification information for identifying the monitoring device 10. The monitoring device 10 includes an isolator unit 11 (an example of an isolator unit), a filter unit 12, a switch 13, a receiving unit 14a, a transmitting unit 14b, and a CPU (central processing unit) 15 connected to the speaker line 4. (An example of a control unit), an A / D converter 17, and a D / A converter 18. The monitoring device 10 also includes a filter unit 61, a rectifier 62, and a DC power source 63.

  The isolator unit 11 is provided on the speaker line 4. As shown in FIG. 5, the isolator unit 11 includes a switch 111, a comparator 112, and a relay control unit 113. In the normal state, the speaker line 4 continuously sends a direct current. The comparator 112 compares the voltage across the switch 111 and outputs the comparison result to the relay control unit 113. When a disconnection occurs between the monitoring devices 10 on the speaker line 4, the current stops and a voltage difference between both ends of the switch 111 is made. The relay control unit 113 monitors and detects the difference between the voltages, and determines whether the speaker line 4 is disconnected. When the relay control unit 113 determines that the speaker line 4 is disconnected, the relay control unit 113 opens the switch 111, so that the monitoring device 10 is separated from the speaker line 4. The separated monitoring device 10 cannot transmit a communication signal. As a result, the control device 5 can determine that a disconnection has occurred around the monitoring device 10 where no response signal is received.

The filter unit 12 illustrated in FIG. 4 is connected to the speaker line 4. The filter unit 12 has a band-pass filter designed to pass a communication signal and attenuate other signals.
The switch 13 is connected to the filter unit 12 through a transformer. The switch 13 switches between a receiving unit 14 a that receives a signal from the speaker line 4 and a transmitting unit 14 b that transmits a signal to the speaker line 4 in accordance with a command from the CPU 15.

The receiving unit 14a receives a communication signal, for example, a polling signal, from the control device 5. The receiving unit 14 a transmits a communication signal to the CPU 15 via the A / D converter 17. The transmission unit 14 b transmits a communication signal received from the CPU 15 via the D / A converter 18, for example, a response signal to the control device 5.
The A / D converter 17 converts the analog communication signal into a digital communication signal processed by the CPU 15. The D / A converter 18 converts the digital communication signal processed by the CPU 15 into an analog communication signal. The A / D converter 17 and the D / A converter 18 are switched according to a command from the CPU 15.

  The CPU 15 is connected to the reception unit 14a and the transmission unit 14b via the A / D converter 17 and the D / A converter 18. The CPU 15 controls the switching of the switch 13 by generating a command signal and transmitting it to the switch 13. The CPU 15 determines whether the received communication signal is for the monitoring device 10, that is, whether the address data of the monitoring device 10 included in the received communication signal is its own. If the address data is its own, the CPU 15 generates a response signal and transmits it to the control device 5.

The CPU 15 also controls the corresponding speaker 3. The CPU 15 may execute these operations in accordance with a program read from a memory (not shown).
The filter unit 61 passes the direct current signal from the speaker line 4. The rectifier 62 rectifies the direct current signal. The DC power supply receives the rectified DC current signal and supplies power to the monitoring device 10.

(Operation of the control device 5)
FIG. 6 is a flowchart of processing executed by the control device 5.
Step S101: A communication signal is generated by the control device 5 for polling. The communication signal includes the address data of the designated monitoring device 10.
Step S102: The communication signal is transmitted to the speaker line 4 and is superimposed on the audio signal transmitted from the amplifier 2.

Step S103: The communication signal superimposed on the audio signal is transmitted in the first direction and the second direction of the speaker line 4. In the case of the first direction, the process proceeds to step S104, and in the case of the second direction, the process proceeds to step S105.
Step S104: The communication signal superimposed on the audio signal transmitted in the first direction of the speaker line 4 is filtered by the first filter unit 51, whereby the communication signal is attenuated and the audio signal is transmitted through the speaker line 4. The

Step S105: The communication signal superimposed on the audio signal is transmitted in the second direction of the speaker line 4.
Step S106: The CPU 55 of the control device determines whether or not the response signal from the designated monitoring device 10 has been received within a predetermined time.
Step S107: When the response signal is not received within the predetermined time, the control device 5 determines that the speaker line 4 around the designated monitoring device 10 has a failure.

  Step S108: The CPU 55 of the control device 5 determines whether or not the polling has ended. If not completed, the process returns to step S101, and the control device 5 generates a communication signal for another designated monitoring device 10. The control apparatus 5 transmits a communication signal to each monitoring apparatus 10 in order to receive a response signal from each monitoring apparatus 10 by repeating steps S101 to S108.

  Step S109: The CPU 55 of the control device 5 generates and outputs the state of the speaker line 4 based on the results up to step S108. The state of the speaker line 4 may include whether or not there is a failure in the loudspeaker system 1 due to a short circuit and / or disconnection generated in the speaker line 4. Further, the state of the speaker line 4 may include a location where the disconnection occurs. For example, when the control device 5 receives a response signal from one monitoring device 10 but does not receive a response signal from the next monitoring device 10 on the downstream side, the control device 5 It may be determined that a disconnection has occurred.

(Effect of Embodiment 1)
According to the loudspeaker system 1 of the above embodiment, the first filter unit 51 does not transmit a communication signal in the first direction of the speaker line 4 but transmits a communication signal and an audio signal in the second direction of the speaker line 4. As shown, it is connected to the speaker line 4. As a result, since the audio signal is always transmitted bidirectionally through the speaker line 4, the loudspeaker system 1 can maintain the broadcasting function effectively even if a disconnection occurs at any point of the speaker line 4.

  Further, the filter processing is performed so that the communication signal does not pass in the first direction of the speaker line 4. When the communication signal is transmitted in both directions of the speaker line 4 in the same manner as the audio signal, the communication signal is transmitted to the designated monitoring device 10 even when the designated monitoring device 10 is disconnected upstream or downstream. Is done. In this case, since the response signal from the designated monitoring device 10 is transmitted in either the first or second direction of the speaker line, there is a possibility that the failure cannot be detected appropriately. However, in the first embodiment, the communication signal is transmitted only in one direction of the speaker line 4. Therefore, the loudspeaker system 1 can reliably detect the failure of the speaker line 4 while performing safe broadcasting.

(Embodiment 2)
FIG. 7 schematically illustrates the configuration of the monitoring apparatus 210 according to the second embodiment. Members having the same functions as those in the first embodiment are denoted by the same reference numerals, and further detailed description is omitted. In this example, each monitoring device 210 transmits a communication signal from one to the other by a relay.
The monitoring device 210 includes an isolator unit 211 (an example of an isolator unit) connected to the speaker line 4, a filter unit 221 connected to the speaker line 4, filter units 212a and 212b, a CPU 213, and switches 214a and 214b. , Receivers 215a and 216a, transmitters 215b and 216b, switch 217, A / D converter 218, and D / A converter 219.

  The isolator unit 211 is provided on the speaker line 4. The isolator unit 211 has the same configuration and function as the isolator unit 11 (FIG. 5) according to the first embodiment. Similarly to the first embodiment, when the relay control unit 113 determines that the speaker line 4 is not connected, the monitoring device 210 is separated from the speaker line 4 in order to control the switch 111 to open. Therefore, since the separated monitoring device 210 cannot transmit a communication signal, the control device 5 can determine that a disconnection has occurred around the monitoring device 210 that has not received a response signal.

The filter unit 221 is provided on the speaker line 4. The filter unit 221 is a band-pass filter designed to pass only the audio signal and the direct current signal and attenuate other signals.
The filter units 212a and 212b are connected to the switches 214a and 214b through transformers, respectively. The filter units 212a and 212b include band-pass filters designed to pass communication signals and attenuate other signals.

  The switch 214a is connected to the filter unit 212a through a transformer. The switch 214 a switches between a receiving unit 215 a that receives a signal from the speaker line 4 and a transmitting unit 215 b that transmits a signal to the speaker line 4 in accordance with a command from the CPU 213. Initially, the switch 214 a is switched to the receiving unit 215 a and is waiting to receive a signal from the upstream side of the speaker line 4. After receiving the signal from the upstream side, the switch 214 a switches to the transmission unit 215 b and transmits the signal to the upstream side of the speaker line 4.

  The switch 214b switches between a reception unit 216a that receives a signal from the speaker line 4 and a transmission unit 216b that transmits a signal to the speaker line 4 in accordance with a command from the CPU 213. First, the switch 214b is switched to the transmission unit 216b and waits to transmit a signal to the downstream side of the speaker line 4. After transmitting the signal to the downstream side, the switch 214b switches to the receiving unit 216a and receives the signal from the downstream side of the speaker line 4.

  The receiving unit 215a receives a communication signal from the upstream monitoring device 10 via the filter unit 212a. The receiving unit 215 a transmits a communication signal to the CPU 213 via the A / D converter 218. The transmission unit 215 b transmits the communication signal received from the CPU 213 to the upstream monitoring device 210 via the D / A converter 219. The receiving unit 216a receives a communication signal from the monitoring device 210 on the downstream side via the filter unit 212b. Then, the receiving unit 216a transmits a communication signal to the CPU 213 via the A / D converter 218. The transmission unit 216 b transmits the communication signal received from the CPU 213 to the downstream monitoring device 210 via the D / A converter 219.

  The switch 217 switches between the A / D converter 218 and the D / A converter 219 in accordance with a command from the CPU 213. The switch 217 switches to the A / D converter 218 when converting the analog communication signal received by the receiving units 215a and 216a into a digital communication signal. The switch 217 switches to a D / A converter 219 when converting a digital communication signal into an analog communication signal.

The A / D converter 218 converts the analog communication signal into a digital communication signal processed by the CPU 213. The D / A converter 219 converts the digital communication signal processed by the CPU 213 into an analog communication signal.
The CPU 213 connects to the reception units 215a and 216a and the transmission units 215b and 216b via the A / D and D / A converters 218 and 219. The CPU 213 controls switching of the switches 214a, 214b, and 217 by generating a command signal and transmitting the command signal to the switches 214a, 214b, and 217. The CPU 213 also communicates with the downstream monitoring device 210 and with the control device 5 if the next upstream monitoring device 210 or the CPU 213 is the first monitoring device connected to the speaker line 4 next to the control device 5. Relay between them.

  The CPU 213 determines whether the received communication signal is for the monitoring device 210, that is, whether the address data of the monitoring device 210 included in the received communication signal is its own. If the address data is not its own, the CPU 213 transmits the received communication signal to the next downstream monitoring device 210. If the address data is its own, the CPU 213 generates a response signal and transmits it to the upstream monitoring device 210 or the control device 5.

Similar to the first embodiment, the monitoring device 210 also includes a filter unit 61, a rectifier 62, and a DC power source 63. The filter unit 61 passes the direct current signal from the speaker line 4. The rectifier 62 rectifies the direct current signal. The DC power supply receives the rectified DC current signal and supplies power to the monitoring device 210.
The response signal may include address data or identification information of the monitoring device 210 that has generated and transmitted the response signal. Thereby, the control apparatus 5 which received the response signal can specify which part of the speaker line 4 has a defect based on the address data or identification information.

In this example, the superimposed signal including the communication signal including the audio signal, the polling signal, and the response signal is filtered by the filter unit 221 so that the communication signal does not pass downstream of the speaker line 4. Therefore, the communication signal always passes between one transmission source and one transmission destination. When the control device 5 polls one monitoring device 210 connected to the speaker line 4, the polling signal transmitted from the control device 5 is first a monitoring device 210 (hereinafter referred to as “first monitoring device”) closest to the control device 5. 210 ”). At the same time, the polling signal of the first monitoring device 210 is not transmitted to the monitoring device 210 (hereinafter referred to as “second monitoring device 210”) downstream of the first monitoring device 210 through the speaker line 4. Filtered by the filter unit 221.

  When the polling signal is not for the first monitoring device 210, the CPU 213 of the first monitoring device 210 transmits the polling signal to the second monitoring device 210. Then, the filter unit 221 of the second monitoring device 210 filters the polling signal, and passes through the speaker line 4 to the monitoring device 210 (hereinafter referred to as “third monitoring device 210”) downstream of the second monitoring device 210. So that it will not be sent. This relay transmission of the communication signal is performed until the polling signal reaches the designated monitoring device 210.

When the specified monitoring device 210 receives the polling signal, to send a response signal. The response signal is transmitted by relay between the monitoring devices from the downstream side to the upstream side in the same manner as the transmission of the polling signal until the control device 5 receives the response signal.
In this example, the communication signal including the response signal of the polling signal passes only between adjacent devices on the speaker line 4, and does not pass between other adjacent devices on the speaker line 4. Therefore, during polling, the communication signal always passes only between one transmission source and one transmission destination unless passage is permitted.

  According to the second embodiment, in addition to the effects described in the first embodiment, the following effects can be achieved. In the second embodiment, each monitoring device 210 requires power only when transmitting and receiving communication signals. Therefore, other monitoring devices 210 that are not in operation for processing communication signals can be set to a sleep mode with only a minimum power. As a result, the communication signal is not attenuated, the communication performance of the loudspeaker system 1 can be improved, and further stable and reliable communication can be realized with power saving. Since a large current can be prevented from flowing through the speaker line 4, even a large number of low impedance speakers 3 can be connected in parallel to the speaker line 4.

(Other embodiments)
The control device 5 can also transmit a communication signal without a designated address. For example, the control device 5 transmits a communication signal through the speaker line 4 on the loop, and determines whether the communication signal has returned to the control device 5. In this case, the control device 5 is configured such that the CPU 55 receives a return signal that is not filtered by the second filter unit 52 (FIG. 2).

The control device 5 does not include the second filter unit 52. Instead, the second filter unit 52 may be included in another device connected to the speaker line 4, or may be directly connected to the speaker line 4. .
The frequency of the signal described above is not limited to that described in the above embodiment.
An alternating current may be supplied to the speaker line 4 instead of the direct current.

A digital audio signal may be applied to the loudspeaker system 1. In this case, the audio signal is converted from digital to analog, modulated, and superimposed on the direct current on the speaker line 4. The modulated audio signal includes address data of one or more monitoring devices 10 (or 210) and is transmitted to one or more monitoring devices 10 (or 210).
(Term interpretation in general)
For the purposes of understanding the scope of the present disclosure, the term “comprising” or derivative thereof is an open-ended term identifying a feature, element, member, group, integer, and / or step described. It is not excluded that there are other features, elements, members, groups, integers, and / or steps that are intended and not described. This also applies to “including”, “having”, and derivatives thereof having similar meanings.

As used herein to describe parts, sections, or portions of a device, the term “configure” refers to hardware and / or software configured and / or programmed to perform a desired function. Including.
Although only some embodiments have been selected to illustrate the present invention, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope of the invention as defined in the appended claims. From the present disclosure. For example, the size, shape, position, or orientation of each member can be changed as needed and / or desired. Members shown to be directly connected or abutting each other may have intervening structures in between. Multiple functions of a single element may be performed by two or vice versa. The configuration and function of one embodiment can also be applied to other embodiments. Some of the steps in the flowchart may be executed in a different order. All of the effects need not be present simultaneously in a particular embodiment. Each feature that differs from the prior art should also be considered, either alone or in combination, to describe further inventions by the applicant that include the structural and / or functional concepts embodied by such features. . Accordingly, the above description of the embodiments of the invention is illustrative and is not intended to limit the invention defined by the appended claims and their equivalents.

  INDUSTRIAL APPLICABILITY The present invention can be used as a loudspeaker system or a speaker communication control device used in a large-scale facility or building.

DESCRIPTION OF SYMBOLS 1 Loudspeaker system 2 Amplifier 3 Speaker 4 Speaker line (an example of a transmission medium)
5 Control device (an example of a control device)
10 Monitoring device (an example of a communication control device)
11 Isolator (an example of an isolator)
12 Filter unit 13 Switch 14a Receiving unit 14b Transmitting unit 15 CPU (an example of control unit)
51 1st filter part (an example of the 1st filter part)
52 2nd filter part (an example of 2nd filter part)
53 Switch 54a Receiver 54b Transmitter 55 CPU (an example of a processor)
57 A / D converter 58 D / A converter 61 Filter unit 62 Rectifier 63 DC power supply 210 Monitoring device (an example of a communication control device)
211 Isolator (an example of an isolator)
221 Filter unit 212a, 212b Filter unit 213 CPU (an example of a control unit)
214a, 214b Switches 215a, 216a Receivers 215b, 216b Transmitter 217 Switch 218 A / D converter 219 D / A converter

Claims (5)

A transmission medium having a loop shape and transmitting a transmission signal in a first direction and a second direction opposite to the first direction, wherein the transmission signal includes a first signal having a predetermined frequency band, A transmission medium comprising a second signal having a frequency band different from the signal,
A plurality of speakers connected to the transmission medium; and a first filter unit connected to the transmission medium and configured to filter the transmission signal so as to attenuate the first signal and output the second signal;
With
The first filter unit is connected to the transmission medium so that the first signal is not transmitted in the first direction while the first signal and the second signal are transmitted in the second direction.
Loudspeaker system. And a controller connected to a first end of the loop of the transmission medium and a second end of the loop of the transmission medium,
The transmission signal includes a signal obtained by mixing the first signal and the second signal,
The control device transmits the transmission signal to the transmission medium in both directions of the first direction through the first end of the loop and the second direction through the second end of the loop;
The first filter unit attenuates the first signal before the transmission signal is transmitted in the first direction;
The loudspeaker system according to claim 1. And a plurality of communication control devices connected to the transmission medium, each connected to a corresponding speaker,
The first signal is a polling signal;
The second signal is an audio signal;
The control device transmits the polling signal to poll each of the plurality of communication control devices;
A speaker corresponding to each communication control device outputs a sound based on the sound signal.
The loudspeaker system according to claim 2. And a plurality of communication control devices connected to the transmission medium,
Each communication control device has an isolator unit connected to the transmission medium, and each isolator unit separates the corresponding communication control device from the transmission medium when detecting a failure of the transmission medium.
The loudspeaker system according to claim 1. A control device used for a loudspeaker system having a loop-shaped transmission medium and a plurality of speakers connected to the transmission medium, and connected to both ends of the transmission medium,
A transmission signal is transmitted through the transmission medium in a first direction and a second direction opposite to the first direction, and the transmission signal has a frequency band different from the first signal and the first signal having a predetermined frequency band. A second signal having
A first filter that filters the transmission signal to attenuate the first signal and output the second signal; and filters the transmission signal to attenuate the second signal and output the first signal A second filter section to process,
With
The first filter unit is connected to the transmission medium so that the first signal is not transmitted in the first direction while the first signal and the second signal are transmitted in the second direction.
Control device.

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