JP2008285016A - Sound field control device and sound field control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically stop a sound field control function without physically breaking a circuit when a speaker is removed. <P>SOLUTION: In an active noise control device for a vehicle, a value of resistance of wiring with the speaker SP1 is monitored by the removal detection part 11. When the value of resistance becomes not less than a predetermined value, a switch SW1 provided between the noise control circuit 12 and the speaker SP2 is turned off. Thus, the noise control is automatically stopped when the speaker is removed by a user for exchanging the speaker. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sound field control device and a sound field control method for controlling a sound field in a specific space, and in particular, a sound field control for detecting noise generated when a vehicle travels and performing ANC (active noise control) to reduce the noise. The present invention relates to an apparatus and a sound field control method.

  In recent years, a noise control technique has been devised that cancels noise by giving an antiphase control sound to the noise. For example, Patent Document 1 discloses a technique for detecting an ambient noise and automatically adjusting the volume and quality of a sound source signal according to the amount and quality of the noise to provide an optimal listening environment.

  Patent Document 2 discloses a technique for controlling the frequency characteristics and volume of a sound source signal according to the noise signal when unnecessary noise is present in addition to the sound source signal to be reproduced in the sound field.

  Further, Patent Document 3 discloses a technique for automatically determining a control target value from the radiated sound and noise from a speaker and performing natural correction while following the amount of noise with respect to masking at a listening point.

  These noise control techniques can be used for reducing engine noise, motor noise, and road noise of an automobile in a vehicle interior when applied to a vehicle.

  In such vehicle noise control, noise to be controlled (engine sound, motor sound, road noise, etc.) is acquired by a reference microphone, etc., and control sound is generated from the acquired result and output from a speaker at a target position. Control sound interferes with noise, reducing and eliminating noise. In addition, an error microphone is installed at a target position, and the control sound is adaptively changed by feeding back the sound collection result of the error microphone to the control sound.

  Here, the speaker of the vehicle may be removed or replaced by the user. As a technique for detecting the connection state of a speaker in a device capable of outputting sound, Patent Document 4 discloses a technique for detecting a non-connection of a speaker to a mobile terminal device and stopping a reproduction operation.

JP-A-10-224171 JP 2000-1114899 A JP 2003-9276 A JP 2006-352520 A

  It is desirable to share a speaker used for vehicle interior noise control with other in-vehicle devices such as an audio device and a navigation device. When the user removes and replaces the speaker, the purpose is mainly to match the sound field in the audio output with the user's preference, and the operation of the noise control is often not considered.

  In vehicle noise control, technologies for rewriting transfer characteristic data and adaptive control have been devised in order to cope with changes in the transfer characteristics of the space caused by aging of the vehicle, opening and closing of windows, and the number and position of passengers. .

  However, the change in the path characteristic due to the exchange of the speaker is so large that it cannot be compared with the secular change and the like, and it is difficult to absorb it by the technique for dealing with the change in the transfer characteristic. Therefore, unpleasant noise may be superimposed on the music signal after the speaker is replaced.

  Therefore, if the user does not have sufficient knowledge about noise control, there has been a problem that the originally intended audio environment cannot be improved.

  Further, even when measures against noise control are taken, the user has stopped noise control by physically disconnecting the signal line of the noise control device built in the amplifier unit when replacing the speaker. However, if the signal line for noise control is cut, noise control is possible even if the characteristics of the noise control can be changed according to the speaker after replacement, for example, when bringing a dealer at the time of vehicle inspection. The problem arises that the physical wiring must be reconnected before returning to the correct state.

  The present invention has been made to solve the above-described problems in the prior art and to solve the problems. When the speaker is removed, the sound is automatically and without physically destroying the circuit. An object of the present invention is to provide a sound field control device and a sound field control method capable of stopping the field control function.

  In order to solve the above-described problems and achieve the object, a sound field control device and a sound field control method according to the present invention perform noise reduction control based on transfer characteristics of a specific space with respect to sound output in the specific space. At the time of application, the connection state of the transmission path for transmitting the control result of the output control step to the speaker is monitored, and if it is detected that the speaker has been removed, the transmission path is disconnected or the output control is stopped.

  Further, when the present invention is used for vehicle noise control, the noise reduction sound for detecting the noise generated in the vehicle and reducing the noise is reproduced from the speaker, and the sound collection result by the error microphone provided at a predetermined position in the vehicle interior Is fed back to the noise reduction sound, the connection state of the transmission path for transmitting the noise reduction sound to the speaker is monitored, and the transmission path is disconnected when the speaker is removed.

  According to the present invention, the sound field control device and the sound field control method monitor the connection state of the transmission path to the speaker, and disconnect the transmission path and stop the output control when it is detected that the speaker has been removed. Therefore, when the user removes the speaker, the sound field control device and the sound field control method that can stop the sound field control function automatically and without physically destroying the circuit can be obtained. .

  When the present invention is used for vehicle noise control, the noise control function can be selectively stopped automatically and without physically destroying the circuit when the user removes the speaker. .

  Hereinafter, a vehicle noise control apparatus which is a preferred embodiment of a sound field control apparatus and a sound field control method according to the present invention will be described in detail with reference to the accompanying drawings.

  First, the concept of the present invention will be described with reference to FIG. As shown in the figure, the vehicle noise control device 1 shares the same speaker SP1 as other in-vehicle devices such as the audio unit 2 and the navigation unit 3.

  The audio unit 2 is a unit that reproduces and outputs content data such as music and video acquired by reading from a recording medium such as an HDD, CD, or DVD, or receiving a television or radio broadcast, and uses the speaker SP1 for audio output. .

  The navigation unit 3 is a unit that specifies the current position of the host vehicle and provides information such as guidance on the travel route, notification of surrounding facilities and road conditions, and the speaker SP1 when providing information by voice output. Is used.

  The vehicle noise control device 1 records noise such as vehicle engine sound, motor sound, road noise, and the like, and a noise control circuit 12 creates a control sound that cancels the noise. And noise control is performed by outputting the produced control sound from speaker SP1.

  Here, the speaker SP1 may be replaced by the user. In such a case, the user mainly aims to match the sound field in the audio output with the user's preference, and the operation of the noise control is often not considered.

  The noise control circuit 12 is set on the premise of a path characteristic when using a speaker that is initially installed, that is, a transmission characteristic from when the control sound is output from the speaker to the control target position. If this is done, the path characteristics will change greatly, and unpleasant noise may be superimposed on the music signal due to the implementation of noise control.

  Therefore, in the present invention, when the switch SW1 is provided on the transmission path from the noise control circuit 12 to the speaker SP1, the connection state of the speaker SP1 is monitored by the removal detection unit 11, and the removal detection unit 11 detects the removal of the speaker SP1. Then, the switch SW1 is disconnected to electrically stop the noise control function.

  As described above, the vehicle noise control device 1 can automatically stop noise control when the user removes the speaker in order to replace the speaker. It can be prevented from being reproduced.

  At this time, since the connection between the other on-vehicle device such as the audio unit 2 and the speaker SP1 is maintained, the user can obtain a desired sound field using an arbitrary speaker.

  Furthermore, when the noise control characteristic can be changed by a dealer or the like, the noise control function can be easily returned to the usable state by switching the switch SW1 to the ON state.

  FIG. 2 is a schematic configuration diagram showing a schematic configuration of the vehicle noise control apparatus 1 according to the embodiment of the present invention. The vehicle noise control device 1 includes a removal detection unit 11, a noise control circuit 12, a reference microphone M1, a switch SW1, a speaker SP1, and an error microphone M2.

  The noise control circuit 12 includes an adaptive filter F11, an LMS calculation unit F12, and an Fx (Filtered-X) filter F13.

  In the vehicle noise control device 1, the reference microphone M1 acquires sound generated from a noise source (for example, an engine) and inputs the sound to the adaptive filter F11 and the Fx filter F13.

  The adaptive filter F11 convolves the filter coefficient with the input from the reference microphone M1, generates a control sound, and reproduces it in the vehicle interior via the switch SW1 and the speaker SP1. Here, the speaker SP1 and the error microphone M2 are installed in the vehicle interior as shown in FIG.

  In particular, as shown in the figure, the error microphone M2 is installed in the vicinity of the headrest of the seat St1, that is, in the vicinity of the occupant's ear, and the sound collection result is input to the LMS calculation unit F12.

  The Fx filter F13 stores a filter coefficient for noise control that compensates for an error path. The Fx filter F13 performs processing based on the stored filter coefficient on the input from the reference microphone M1, and inputs the processed coefficient to the LMS calculation unit F12. The filter coefficient of the Fx filter F13 is a value corresponding to the spatial transfer characteristic from the speaker SP1 to the error microphone M2, and this value is set in advance.

  The LMS calculation unit F12 receives the inputs of the Fx filter F13 and the error microphone M2, and updates the filter coefficient of the adaptive filter F11 so that the input from the error microphone M2 is minimized using the least square method.

  The removal detection unit 11 monitors the connection state of the speaker SP1, and performs a process of disconnecting the switch SW1 when the removal of the speaker SP1 is detected. Specifically, as shown in FIG. 4, the removal detection unit 11 monitors the resistance value between a plurality of wires included in the transmission path, and the speaker SP1 is removed when the resistance value exceeds a predetermined value. It is determined that In the state where the speaker SP1 is removed, the wiring is opened and the resistance value becomes infinite. Therefore, it is desirable that the threshold used by the removal detection unit 11 for determination is a sufficiently large value.

  The operation of the removal detection unit 11 will be further described with reference to FIG. As shown in the figure, when the removal detection unit 11 detects that the resistance value between the connection wires of the speaker SP1 has become infinite, it controls the switch SW1 to be turned off.

  With this off control, a new speaker is connected thereafter, and the switch SW1 remains off even if the resistance value between the wirings is less than a predetermined value, and a control sound for noise control is output from the speaker SP1. There is nothing.

  When the filter coefficient of the noise control circuit 12 (for example, the coefficient of the Fx filter F13 shown in FIG. 2) is reset according to the speaker at that time by a dealer or the like, the removal detection unit 11 receives the notification. Then, the switch SW1 is turned on to return to a state where the noise control function can be used.

  Here, the case where the removal detection unit 11 also executes the switch on control has been described as an example, but the removal detection unit 11 is in charge of only the switch off operation, and the switch on operation is a direct operation of the switch Sw1. You may make it carry out by operation.

  As described above, the vehicle noise control device 1 according to the present embodiment monitors the resistance value of the wiring with the speaker SP1, and when the resistance value exceeds a predetermined value, the switch SW1 is controlled to be off to control the speaker. Since the connection with SP1 is disconnected, the noise control can be automatically stopped when the user removes the speaker in order to replace the speaker.

  The present embodiment is merely an example, and does not limit the present invention. The present invention can be appropriately modified and implemented within the scope of the descriptive idea described in the claims.

  For example, in the present embodiment, the case where the present invention is applied to vehicle noise control has been described as an example. However, the present invention can be widely applied to a sound field control device that controls a sound field. FIG. 6 is an explanatory diagram for explaining a configuration example when the present invention is applied to a sound field control device.

  The sound field control device 4 shown in the figure is connected to the speaker SP2, and has a sound output request receiving unit 41, a sound field characteristic storing unit 42, and a removal detecting unit 43 therein.

  The audio output request receiving unit 41 receives audio data to be output from an external device. The sound field characteristic storage unit 42 stores the processing content to be performed on the sound data as sound field characteristics. If the switch SW2 is in the ON state, the sound field characteristic storage unit 42 stores the sound data received by the sound output request receiving unit 41. By superimposing the processing contents stored in the sound field characteristic storage unit 42, a predetermined sound field characteristic is added to the audio data and output from the speaker SP2.

  The removal detection unit 43 monitors the resistance value of the wiring with the speaker SP2, and controls the switch SW2 to be turned off when the resistance value exceeds a predetermined value. As a result, the audio output data received by the audio output request receiving unit 41 is output as it is from the speaker SP2 without being added with the sound field characteristics.

  As described above, the present invention is not limited to vehicle noise control, and can be widely applied to sound field control apparatuses that require setting to be changed by exchanging speakers.

  As described above, the sound field control device and the sound field control method according to the present invention are effective for automatic response to characteristic changes caused by speaker replacement, and are particularly suitable for use in in-vehicle noise control.

It is explanatory drawing explaining the concept of this invention. 1 is a schematic configuration diagram showing a schematic configuration of a vehicle noise control device according to an embodiment of the present invention. It is explanatory drawing explaining arrangement | positioning of a speaker and an error microphone. It is explanatory drawing explaining the detection of speaker removal. It is explanatory drawing explaining switch control of a transmission path. It is explanatory drawing explaining the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle noise control apparatus 2 Audio unit 3 Navigation unit 4 Sound field control apparatus 11,43 removal detection part 12 Noise control circuit 41 Audio | voice output request | requirement part 42 Sound field characteristic storage part M1 Reference microphone M2 Error microphone F11 Adaptive filter F12 LMS calculation F13 Fx filter SW1, SW2 switch SP1, SP2 Speaker

Claims (6)

Transfer characteristic holding means for holding transfer characteristics for sound in a specific space;
Output control means for performing noise reduction control based on the transfer characteristics;
A transmission path for transmitting a control result by the output control means to a speaker;
A removal detection means for monitoring the connection state of the transmission path and detecting that the speaker has been removed,
A switch that disconnects the transmission path or stops control by the output control means when removal of the speaker is detected by the removal detection means;
A sound field control device comprising:   The specific space is a vehicle cabin, noise reduction creating means for creating noise reduction sound for detecting noise generated in the vehicle and reducing the noise, and output from the speaker at a predetermined position in the vehicle cabin The sound field control device according to claim 1, further comprising feedback means for collecting sound by an error microphone provided on the sound microphone and feeding back the sound collection result to the noise reduction sound.   The speaker is shared with another audio output device mounted on the vehicle, and the switch selectively disconnects a transmission circuit from the output control means to the speaker, and the other audio output device and the speaker. The sound field control device according to claim 2, wherein the connection is maintained.   The removal detection unit monitors a resistance value between a plurality of wires included in the transmission path, and determines that the speaker has been removed when the resistance value is equal to or greater than a predetermined value. The sound field control device according to any one of 1 to 3. An output control step of performing control based on transfer characteristics of the specific space for sound output in the specific space;
A removal detection step of monitoring a connection state of a transmission path for transmitting a control result of the output control step to a speaker, and detecting that the speaker has been removed;
A transmission path cutting step of disconnecting the transmission path when the removal of the speaker is detected by the removal detection step, or stopping control by the output control step;
The sound field control method characterized by including.   The specific space is a passenger compartment of a vehicle, detects noise generated in the vehicle, and generates a noise reduction sound for reducing the noise as a sound to be output in the specific space; and from the speaker The method further includes a feedback step of collecting the output of the sound by an error microphone provided at a predetermined position in the vehicle interior and feeding back the sound collection result to the noise reduction sound. Sound field control method.

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