JP4508008B2 - Vehicle interior sound field control device - Google Patents

Description

  The present invention relates to a vehicle interior sound field control device that generates sound having characteristics of engine sound in a vehicle.

The engine sound of the vehicle has a timbre unique to each vehicle, particularly resulting from the explosion sound of the internal combustion engine. Such engine noise is highly likely to be noise, but it is also true that it contributes to a refreshing feeling for the driver. In recent years, there has been a demand for vehicles that emit less engine sound to the outside from the viewpoint of noise prevention. On the other hand, there is also a demand for enjoying powerful engine sounds in the vehicle. In order to meet such a demand, for example, Patent Literature 1 discloses a vehicle interior acoustic control that reproduces a sine wave from a memory at a speed synchronized with an engine ignition pulse, generates a pseudo engine sound, and emits the sound into the vehicle. A device is proposed.
Japanese Patent Laid-Open No. 5-80790

  By the way, the engine sound changes dynamically according to the driving state. In many cases, the driver feels refreshed by driving in response to such changes in engine sound. However, since the conventional vehicle interior acoustic control device described above generates engine sound simply by reproducing a sine wave at a speed synchronized with the rotation of the engine, the generated engine sound lacks force, The driver's requirements cannot be fully met.

  The present invention has been made in view of the circumstances described above, and it is an object of the present invention to provide a vehicle interior sound field control device capable of generating a fresh engine sound reflecting the driving state in the vehicle interior.

The present invention is a means for generating a plurality of speakers provided in a vehicle and a plurality of channels of engine sound signals representing engine sounds or pseudo engine sounds generated in the vehicle and supplying them to the plurality of speakers. Engine sound signal generation means including sound field control means for performing signal processing for giving sound field effects to sounds reproduced from the plurality of speakers in the generation process of the engine sound signals of the plurality of channels; There is provided a vehicle interior sound field control device comprising control means for monitoring and controlling signal processing of the sound field control means in accordance with the driving state.
According to this invention, engine sound is reproduced from a plurality of speakers, and the sound field of the engine sound is controlled according to the driving state. Therefore, a fresh engine sound reflecting the driving state can be generated in the passenger compartment.
In a preferred aspect, the sound field control means includes a sound image localization control unit that executes signal processing for sound image localization control of sound reproduced from the plurality of speakers.
According to this aspect, the sound image localization of the engine sound reproduced from the speaker can be controlled according to the driving state.
In another preferred aspect, the engine sound signal generation means includes sound collection means for collecting engine sounds generated at a plurality of locations of the vehicle to generate a plurality of sound signals, and each of the plurality of sound signals is provided. The engine sound signals of the plurality of channels are generated, and the same channels are synthesized with each other. The sound field control means is reproduced from a plurality of speakers for each type of sound signal in the process of generating the engine sound signal of the plurality of channels from each of the plurality of sound signals according to the driving state. A plurality of sound image localization control units that perform signal processing for controlling the sound image localization of the sound are provided.
According to this aspect, it is possible to control the sound image localization of sound reproduced from a plurality of speakers for each type of audio signal.
In this aspect, means for controlling the gain for each type of audio signal may be provided in the sound field control means.
In a preferred aspect, the sound field control means includes a filter that executes a filter process for controlling a correlation coefficient of sounds reproduced from the plurality of speakers.
According to this aspect, the filter processing can give a sense of spread to the engine sound reproduced from the plurality of speakers according to the driving state.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a vehicle interior acoustic control apparatus according to an embodiment of the present invention. This vehicle interior acoustic control device is a device that applies a sound field effect to engine sound collected in a vehicle and outputs the sound from speakers 60L and 60R. In the example shown in FIG. 1, the intake sound, the sound in the engine room, the exhaust sound, and the outside sound are selected as components of the engine sound, and the microphones 11 to 14 are placed at positions where the sounds can be collected. Is arranged. The filters 21 to 24 are components having characteristics as intake sounds, components having characteristics as sounds in the engine room, components having characteristics as exhaust sounds, and sounds outside the vehicle from the electric signals obtained from the microphones 11 to 14. This is a filter that selects and outputs each component having the above characteristics.

  The mixer 30 is a device that synthesizes and outputs two-channel engine sound signals XL and XR from the sound signals that have passed through the filters 21 to 24. In the process of synthesizing the engine sound signals XL and XR, the mixer 30 is a sound image of a corresponding component of the speaker reproduction sound for each sound source such as an intake sound, an engine room sound, an exhaust sound, and an outside sound under the control of the control unit 100. Signal processing for localizing to the target position or region is performed.

  In the mixer 30, gain control amplifiers 31 to 34 are amplifiers capable of gain control, and amplify the electrical signals that have passed through the filters 21 to 24 and output them. The gain control amplifiers 31 to 34 are devices provided to independently control the intensity of the intake sound, engine room sound, exhaust sound, and vehicle exterior sound in the speaker reproduction sound. The sound image localization control units 35 to 38 synthesize an L channel audio signal and an R channel audio signal for obtaining a target sound image localization from each of the output signals of the gain control amplifiers 31 to 34, and the L channel audio signal is a signal line. The R channel audio signal is output to the signal line 39R. The L channel audio signals output from the sound image localization control units 35 to 38 are added on the signal line 39L to become the engine sound signal XL, and the R channel audio signals output from the sound image localization control units 35 to 38 are Are added on the signal line 39R to become the engine sound signal XR.

  Various configurations of the sound image localization control units 35 to 38 are conceivable. In one aspect, the sound image localization control units 35 to 38 distribute the output signals of the gain control amplifiers 31 to 34 to the left and right channel signals and adjust the phases of these signals in accordance with instructions from the control unit 100. By doing so, the L channel audio signal and the R channel audio signal are synthesized. The distribution ratio and the phase adjustment amount of the left and right two-channel signals when distributing to the left and right two channels are prepared in advance according to the target sound image position or region, and are instructed by the control unit 100 to the sound image localization control units 35 to 38. The In another aspect, an L-channel filter coefficient sequence and an R-channel filter coefficient sequence for sound image localization are prepared in advance according to a target sound image position or region, and the sound image localization control units 35 to 35 are provided from the control unit 100. 38. Each sound image localization control unit 35 to 38 convolves an L channel filter coefficient sequence with each output signal of the gain control amplifiers 31 to 34 to synthesize an L channel audio signal, and the output signal and the R channel filter coefficient sequence Are combined to synthesize an R channel audio signal. Various other configurations of the sound image localization control units 35 to 38 are conceivable, but the configuration of the sound image localization control units 35 to 38 may be selected in consideration of the required quality and cost of speaker reproduction sound. The above is the configuration of the mixer 30.

  The filter 40 is, for example, two sets of convolution calculators, each of which convolves two sets of filter coefficient sequences given from the control unit 100 with the engine sound signals XL and XR obtained from the mixer 30, and obtains the engine sound obtained as a result. Signals YL and YR are output. In the present embodiment, the filter 40 is used as a filter for changing the correlation coefficient between both ears of the sound heard by the driver and adjusting the feeling of sound spread. The control unit 100 adjusts the feeling of spread of the reproduced sound of the speaker by adjusting the correlation coefficients of the two sets of filter coefficient sequences to be given to the filter 40. That is, when the sound image of the speaker reproduction sound is dispersed over a wide range, two sets of filter coefficient sequences corresponding to flat filter characteristics and low correlation are given from the control unit 100 to the filter 40, and the speaker reproduction sound is reproduced. Are concentrated in a narrow range, two sets of filter coefficient sequences corresponding to flat filter characteristics and having a low correlation are provided from the control unit 100 to the filter 40.

  The signal processing unit 50 is a circuit that performs predetermined signal processing on the engine sound signals YL and YR, respectively, and outputs them to the left and right two-channel speakers 60L and 60R. Engine sound signals YL and YR are ATT (attenuators) 51L and 51R, HPFs (high-pass filters) 52L and 52R, and LPFs (low-pass filters) corresponding to the left and right channels in the signal processing unit 50. 53L and 53R, sound insulation characteristic filters 54L and 54R, and dynamic filters 55L and 55R are sequentially passed through and output as final engine sound signals ZL and ZR to speakers 60L and 60R, respectively.

  Here, ATTs 51L and 51R are circuits that adjust the levels of engine sound signals YL and YR to levels suitable for driving the speakers. The HPFs 52L and 52R and the LPFs 53L and 53R remove unnecessary high frequency components and low frequency components that are not suitable for output from the speakers 60L and 60R from the output signals of the ATTs 51L and 51R. The sound insulation characteristic filters 54L and 54R are filters that simulate the sound insulation characteristic of the vehicle body, that is, the characteristic of the sound transmission system from the engine to the driver's ear through the vehicle body. The dynamic filters 55L and 55R are filters capable of controlling frequency versus gain characteristics. In a preferred embodiment, in order to give the engine sound heard by the driver a force corresponding to the engine speed, for example, when the engine speed per unit time is around 3000 rpm, for example, in a frequency band around 400 Hz. When the gain is increased and the engine speed per unit time is, for example, around 6000 rpm, the gain in the frequency band around 1 kHz is raised, and so on, and the frequency-to-gain characteristics of the dynamic filters 55L and 55R are controlled. Done.

  The control unit 100 monitors the measurement results of various sensors such as the accelerator depression amount sensor 111, the shift position sensor 112, the speed sensor 113, and the like to identify the driving state of the vehicle, and in accordance with the driving state, the mixer 30 Setting processing of the gain control amplifiers 31 to 34, setting processing of sound image localization parameters (parameters such as the above-described distribution ratio and phase adjustment amount or filter coefficient sequence) for the sound image localization control units 35 to 38, filter coefficients for the filter 40 This is an apparatus for performing a column setting process.

  The parameter memory 120 stores a set of gain control amplifiers 31 to 34, a sound image localization control parameter, and a filter coefficient sequence in association with various predefined operation states. When a certain operation state is specified, the control unit 100 reads the gain, the sound image localization control parameter, and the filter coefficient sequence associated with the operation state from the parameter memory 120 and sets them in the corresponding units.

Hereinafter, various operation examples of the present embodiment will be described with specific examples.
In this specific example, based on the access depression amount measured by the accelerator depression amount sensor 111 and the vehicle speed measured by the speed sensor 113, the control unit 100 determines whether the driving state is a low-speed traveling state or starts acceleration. Whether the vehicle is in a state of transition, a state of transition from an acceleration state to a high-speed driving state, or a high-speed driving state, and parameters according to the specified driving state are read from the parameter memory 120 and stored in each unit. Is set. As a result, the following operation is obtained.

  First, in a low-speed traveling state, two sets of filter coefficient sequences that have a low correlation coefficient and function the filter 40 as a decorrelation filter are read out and applied to the filter 40 as corresponding parameters. For this reason, the sound image of the engine sound reproduced from the speakers 60L and 60R is localized so as to occupy a wide area in the vehicle interior, and the driver listens to the engine sound with a sense of spread.

  When the driver depresses the accelerator and enters the acceleration start state, a sound image localization control parameter for localizing the engine sound to one place is read as a corresponding parameter, and is given to the sound image localization control units 35 to 38. In addition, two sets of filter coefficient sequences that allow the engine sound signals XL and XR to pass through without being decorrelated or that have a higher correlation coefficient than those in the low-speed running state are given to the filter 40. As a result, the driver listens to the engine sound whose sound image is localized at one point in the vehicle.

  Thereafter, when the transition from the acceleration state to the high-speed traveling state starts, control is performed to reduce the correlation coefficients of the two sets of filter coefficient sequences applied to the filter 40 as the acceleration progresses. In a preferred embodiment, a filter coefficient sequence given to the filter 40 is stored in advance in the parameter memory 120 in association with various speeds of the vehicle, and is read from the parameter memory 120 in accordance with the speed that increases every moment during acceleration. The filter coefficient sequence set in the filter 40 is switched. As a result, the sound image of the engine sound that is heard by the driver gradually increases as it accelerates.

  Thereafter, when the vehicle enters a high-speed running state, a filter coefficient sequence that causes the filter 40 to function as a decorrelation filter is read and applied to the filter 40. For this reason, the driver listens to the engine sound with a sense of spread.

In addition to the above, the embodiment may have the following operation example.
That is, using the measurement results of the speed sensor 113 and the shift position sensor 112, the engine sound reproduced from the speakers 60L and 60R has a feeling of spread during steady running, and the engine sound image is 1 when downshifting on a slope. The control unit 100 performs control to localize to a point and return to a state with a sense of spread when the speed is stabilized.

  In the present embodiment, the gain and the sound image localization can be controlled for each sound source such as the intake sound, the sound in the engine room, the exhaust sound, and the sound outside the vehicle, and there may be an operation example using the gain and sound image localization. For example, when the speed is stable, the sound image of each sound source may be localized at different positions in the passenger compartment. Alternatively, only a specific sound source, for example, an intake sound may be localized forward, and the others may be localized backward. In that case, the position of a specific sound source may be changed according to the speed or the accelerator depression amount.

  By adjusting the gain given to the gain control amplifiers 31 to 34, the sound source reproduced as the engine sound may be limited to one. In this case, there is an effect that the position of the sound image can be clearly understood as compared with the case where the sounds of a plurality of sound sources are reproduced. The process of narrowing down the sound source to one may be performed when the vehicle is in a specific driving state such as a state where the vehicle is running quietly, or a predetermined operator is operated by the driver. Sometimes it can be done.

  As described above, according to the present embodiment, when the engine sound is processed and reproduced, the sound field effect according to the driving state can be given and the presence of the engine can be emphasized. Can feel comfortable driving from the reproduced engine sound and can drive comfortably.

Although one embodiment of the present invention has been described above, other embodiments are possible for the present invention. For example:
(1) In the above-described embodiment, the filter 40 functioning as a decorrelation filter is provided separately from the sound image localization control units 35 to 38. You may make it function as a correlation filter.
(2) In the above embodiment, the state grasped from the current values of the output signals of the various sensors is used as the operation state. However, even if the mode of temporal change of the output signals of the various sensors is used as the operation state, Good. Specifically, a plurality of types of changes in the output signals of one or a plurality of sensors within a certain period are defined as movement states, and gains, sound image localization control parameters, sound sounds for each sound source are associated with these movement states. A filter coefficient sequence for adjusting the feeling of spread is stored in advance in the parameter memory 120. During driving, pattern matching is performed between the state of change of the output signal of each sensor in the past fixed time and each driving state stored in the parameter memory 120, and the parameter corresponding to the matching motion state is set in the sound field. It is used to control the effect. According to this aspect, the sound field effect according to the driving state can be imparted to the engine sound more flexibly.
(3) In the above embodiment, the engine sound is picked up, and the sound field effect is given to the picked up sound and reproduced from the speaker. However, instead of actually collecting the engine sound in this way, the engine sound waveform data is read from the memory that stores the engine sound waveform data in advance at a read speed corresponding to the engine speed, and the pseudo engine sound signal is reproduced. However, a sound field effect corresponding to the driving state may be applied to the pseudo engine sound signal and output from a speaker. According to this aspect, an effect similar to that of the above embodiment can be obtained even in a vehicle that does not have an engine and travels by a motor.
(4) In the above embodiment, the engine sound is reproduced by the 2-channel speaker. However, the engine sound may be reproduced by a multi-channel speaker such as 4-channel or 5.1-channel.

It is a block diagram which shows the structure of the vehicle interior sound field control apparatus which is one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Control part, 111 ... Accelerator depression amount sensor, 112 ... Shift position sensor, 113 ... Speed sensor, 120 ... Parameter memory, 11-14 ... Microphone, 21-24 ... Filter, 30 ... Mixer, 31 to 34... Gain control amplifier, 35 to 38... Sound image localization control unit, 40... Filter, 50... Signal processing unit, 60L, 60R.

Claims (3)

A plurality of speakers provided in the vehicle;
A means for generating engine sound signals of a plurality of channels representing engine sounds or pseudo engine sounds generated in the vehicle and supplying the sound signals to the plurality of speakers, wherein sound field effects are applied to sounds reproduced from the plurality of speakers. Engine sound signal generation means including sound field control means for performing signal processing to provide engine sound signals of the plurality of channels,
A vehicle interior sound field control device comprising: a control unit that monitors a driving state and controls signal processing of the sound field control unit according to the driving state.   2. The vehicle interior sound field according to claim 1, wherein the sound field control unit includes a sound image localization control unit that executes signal processing for sound image localization control of sound reproduced from the plurality of speakers. Control device.   The vehicle interior sound field control according to claim 1 or 2, wherein the sound field control means includes a filter that executes a filter process for controlling a correlation coefficient of sounds reproduced from the plurality of speakers. apparatus.

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