JP5194614B2 - Sound field generator - Google Patents

Description

  The present invention relates to a sound field forming apparatus that forms a sound field around a user.

  Recently, an increasing number of users enjoy contents such as movies and music in their homes by providing AV systems capable of reproducing multi-channel surround sound in living rooms and listening rooms. When a user plays a DVD such as a movie or music on this AV system, multi-channel surround sound is played from a plurality of speakers. Therefore, the user can enjoy movies and music while experiencing the sensation of being surrounded by sound. I can enjoy it.

In addition, conventional AV systems not only play multi-channel surround sound, but also create multiple sound fields by generating multiple reflected sounds from multi-channel surround sound, creating a more three-dimensional sound. There is a sound field control device that reproduces (see, for example, Patent Document 1).
Japanese Patent No. 2755208

  In the conventional sound field control device, when setting to form a plurality of sound fields, if the playback volume is reduced, the sound field is felt to be narrow, and it is as wide as the designer intended. There was a case where it was not a sound field.

  In addition, when processing is performed to automatically adjust the characteristics of the speakers connected to the sound field control device and the output stage is adjusted so as to suppress the high frequency characteristics, a setting is made to form a plurality of sound fields. In some cases, the sound is filled with high frequencies, so the sound field does not have the frequency characteristics that the designer intended.

  Therefore, according to the present invention, when a plurality of sound fields are formed, the sound field effect as intended by the designer can be obtained even if the reproduction volume is low or the high frequency characteristics of the reproduction sound are adjusted. An object is to provide a sound field forming apparatus.

  The present invention has the following configuration as means for solving the above problems.

(1) Sounds based on a plurality of channels of sound signals and reflected sounds and reverberation sounds generated from the plurality of channels of sound signals are emitted from a plurality of speakers arranged around the listening position, and around the listening position. A sound field forming apparatus for forming a plurality of sound fields, wherein an operation means for receiving a plurality of sound field generation instructions, and when the operation means receives a plurality of sound field generation instructions, the plurality of channels of audio signals Reverberation sound generating means for generating reflected sound and reverberant sound from the sound, effect level adjusting means for adjusting the effect level of the sound field by the reflected sound and reverberant sound generated by the reverberant sound, and a standard measured in the reference environment Storage means for storing the sound pressure, measuring means for measuring the sound pressure in the reproduction environment, and the effect level as the sound pressure measured by the measuring means is smaller than the reference sound pressure. A large control means for setting a, characterized by comprising a.

  In this configuration, the sound field forming device responds to the effect level adjusting unit according to the output volume if the output volume of the main volume adjusting unit is equal to or less than the threshold when the operation unit receives a plurality of sound field generation instructions. To correct the sound field effect level. Therefore, when the sound field forming device of the present invention forms a plurality of sound fields around the listening position, the sound field formed by the reflected sound and the reverberant sound becomes narrow even if the output volume is smaller than the threshold value. It is possible to make the listener feel that the width of the sound field is not changed.

  In this configuration, the sound field forming device calculates an actually measured sound pressure ratio that is a ratio of the reference sound pressure and the sound pressure of the test sound, and from this actually measured sound pressure ratio and the value of the volume acquired from the main volume adjusting means. The actual output sound pressure is calculated, and if the output sound pressure is equal to or less than the threshold value, the effect level adjusting means is made to correct the sound field effect level according to the output sound pressure. Therefore, by calculating the measured sound pressure ratio, the output sound pressure in the playback environment can be corrected to the output sound pressure in the reference environment, so that the multiple sound fields formed around the listening position are narrowed. The effect level of the sound field according to the output sound pressure can be corrected more accurately so as not to feel it.

(2) storage means for storing a plurality of frequency characteristic correction pattern, either the frequency characteristic correction pattern of the plurality of frequency characteristic correction pattern read out from said storage means, on the basis of the frequency characteristic correction pattern, the plurality speech, comprising: a characteristic adjusting means for adjusting the frequency characteristics of the reflected sound and the reverberation sound, a high-frequency attenuation means for attenuating the high frequency of the reflected sound and the reverberation, the said control means, before Symbol characteristic adjustment When the means is adjusted based on a frequency characteristic correction pattern that lowers the high-frequency gain, the cutoff frequency of the high-frequency attenuating means is moved by a predetermined amount to the high frequency side.
(3) Sounds based on a plurality of channels of sound signals and reflected sounds and reverberation sounds generated from the plurality of channels of sound signals are emitted from a plurality of speakers arranged around the listening position, and the surroundings of the listening position A sound field forming apparatus for forming a plurality of sound fields, wherein an operation means for receiving a plurality of sound field generation instructions, and when the operation means receives a plurality of sound field generation instructions, the plurality of channels of audio signals Reverberation sound generating means for generating reflected sound and reverberation sound from the sound, effect level adjusting means for adjusting the effect level of the sound field by the reflected sound and reverberation sound generated by the reverberation sound generating means, and the sound, reflected sound and reverberation Main volume adjusting means for collectively adjusting the output volume of the sound, and if the output volume value of the main volume adjusting means is less than or equal to a threshold value, the effect level is set to be larger as the output volume value is smaller Control means and storage means for storing a plurality of frequency characteristic correction patterns, and reading one of the frequency characteristic correction patterns of the plurality of frequency characteristic correction patterns from the storage means. Based on the characteristic adjustment means for adjusting the frequency characteristics of the plurality of sounds, reflected sound and reverberation sound, and high frequency attenuation means for attenuating the high frequency of the reflected sound and the reverberation sound, the control means, When the characteristic adjusting means is adjusted based on a frequency characteristic correction pattern for reducing the high frequency gain, the cutoff frequency of the high frequency attenuating means is moved to the high frequency side by a predetermined amount.

  In this configuration, when the operation unit receives instructions for generating a plurality of sound fields, the control unit adjusts based on the frequency characteristic correction pattern that reduces the gain in the high frequency range. The cut-off frequency of the band cut-off means is moved a predetermined amount to the high band side. Therefore, in the sound field forming device according to the present invention, even if a plurality of sound fields are generated in a state where the high-frequency gain of voice, reflected sound, and reverberant sound is set to be low, the high-frequency field seems to be covered. The sound field can be made to feel as if the sound field is formed by a sound with a good omission.

  According to the present invention, in the sound field forming device, when the sound field program is selected and set, it is corrected so that the high frequency characteristics of each speaker are lowered, or the reproduction volume is below a certain value. Since the effect level of reflected sound and reverberant sound is corrected, or the cutoff frequency of the high-frequency cutoff means (low-pass filter) for giving a specific effect to the reflected sound and reverberant sound is changed to the high frequency side. Since the sound field effect as intended by the designer is maintained, the user can enjoy a three-dimensional effect by a plurality of sound fields regardless of the setting.

  FIG. 1 is a diagram illustrating a schematic configuration of a sound field forming device and an arrangement state of speakers in a listening room. FIG. 2 is a block diagram showing the configuration of the reverberation generator. FIG. 3 is a top view and a perspective view showing an image in a state where four sound fields are formed by the sound field forming device.

  As an example, the sound field forming device 1 outputs a surround sound of 5 channels, and as shown in FIG. 3, a presence sound field 93, a left surround (LS) sound field 95, a right surround (RS) sound field 97, And four sound fields of a back surround (BS) sound field 99 are formed. The presence sound field 93 is a sound field that gives a sense of depth and stereoscopic effect to the front of the user U at the listening position 90 and wraps the user U from the front. The left surround sound field 95 and the right surround sound field 97 are sound fields that give a sense of depth and stereoscopic effect to the left and right of the user U at the listening position 90 and wrap the user U from the side. The back surround sound field 99 is a sound field that surrounds the user U at the listening position 90 and surrounds the user U from behind.

  As shown in FIG. 1, the sound field forming apparatus 1 includes a signal input terminal 31, a DIR (Digital Audio Interface Receiver) 33, an A / D converter 35, an HDMI (High Definition Multimedia Interface) (registered trademark) receiver 37, a DSP. (Digital Signal Processor) Decoder 39, test sound generator 41, parameter memory 43, signal processor 45, delay processor 46, parametric equalizer 47, D / A converter 49, electronic volume 51, power amplifier 53, speaker terminal 55, A microphone terminal 57, a microphone amplifier 59, an A / D converter 61, a control unit 63, a memory 65, an operation unit 67, and a display unit 69 are provided. Further, the digital television tuner 5 and the CD player 7 are connected to the signal input terminal 31 of the sound field forming device 1, and the speakers 11 to 18 are connected to the speaker terminal 55. The microphone terminal 57 is connected to an optimizer microphone 3 (hereinafter simply referred to as a microphone 3).

  As shown in FIG. 1, in the listening room 91, the left channel (Lch) speaker 11, the center channel (Cch) speaker 12, and the right on the front left, front center, and front right of the listening position 90, respectively. A speaker 13 for a channel (Rch) is installed. Further, in front of the listening position 90, a subwoofer channel (LFEch) speaker 18 is installed as a low-frequency speaker. Furthermore, a presence left channel (PLch) speaker 14 and a presence right channel (PRch) speaker 15 are installed as sound field control speakers in front of the listening position 90 in the front left and right directions. In addition, a surround left channel (SLch) speaker 16 and a surround right channel (SRch) speaker 17 are installed on the left and right sides of the listening position 90. A microphone 3 is installed at the listening position 90.

  The DSP decoder 39 includes a digital TV tuner 5 connected via a signal input terminal 31 and an HDMI (registered trademark) receiver 37, a CD player 7 connected via a signal input terminal 31 and an A / D converter 35, and the like. An analog sound signal or digital bit stream output from an AV device is converted into a digital sound signal (PCM signal) of 5 channels of Lch (channel), Rch, Cch, SLch, and SRch, and output to the signal processing unit 45 To do. The DSP decoder 39 supports various data formats such as AAC (registered trademark), Dolby Digital (registered trademark), DTS (registered trademark), MPEG-1 / 2, MPEG-2 multi-channel, and MP3. The external input signal is decoded into a 5-channel digital sound signal (PCM signal) by a decoder (not shown). For example, when a 5-channel digital sound signal (PCM signal) is directly input from the digital television tuner 5, the DSP decoder 39 outputs these signals to the signal processing unit 45 as they are.

  The signal processing unit 45 includes a main signal line 71, an echo sound generation unit 73, a test sound analysis unit 75, and adders 77 and 79. The reverberation sound generation unit 73 includes a presence (P) reflection sound generation unit 80, a left surround (LS) reflection sound generation unit 81, a right surround (RS) reverberation sound generation unit 82, and a back surround (BS) reverberation sound generation unit. 83 and a reverb sound generator 84.

  The main signal line 71 is a line for sending the 5.1 channel digital sound signal output from the DSP decoder 39 to the parametric equalizer 47. The main signal line 71 is generated by the reflected sound generation unit 73 by the adders 77 and 79 provided in the middle. The EBL signal and EBR signal are added.

  The reverberation sound generation unit 73 reads parameters corresponding to the sound field program selected by the user U from the parameter memory 43, and the presence sound field 93, the left surround sound field 95, the right surround sound field 97, and the back surround sound field 99. The reflected sound and reverberation sound signals for forming the signal are generated, and the EFL signal, EFR signal, EBL signal, and EBR signal are generated from the reflected sound and reverberation sound signals. The reverberation generator 73 outputs the EFL signal to the delay processor 46 as a signal for emitting the sound from the PLch speaker 14, and outputs the EFR signal as a signal for emitting the sound from the PRch speaker 15. The EBL signal is output to the adder 77 as a signal for emitting sound from the SLch speaker 16, and the EBR signal is output to the adder 79 as a signal for emitting sound from the SRch speaker 17. Further details will be described later.

  The parameter memory 43 stores parameters for forming a sound field corresponding to a plurality of sound field programs with reflected sound and reverberant sound. The parameter memory 43 is, for example, a sound field program for music reproduction that realistically reproduces the sound fields of world-famous concert halls, live houses, churches, etc. based on data measured in concert halls, live houses, churches, etc. In addition, a plurality of sound field programs for movie reproduction capable of obtaining different sound effects for each movie genre are stored. The parameters of these sound field programs are such that reflected sound is emitted from the four sound field control speakers 14 to 17 to form four sound fields 93, 95, 97, and 99 in the listening room 91. It consists of a combination of delay time and gain.

  The adder 77 adds the EBL signal output from the reverberation generator 73 and the SLch audio signal as an input signal, and outputs the result to the delay processor 46.

  The adder 79 adds the EBR signal output from the reverberation generator 73 and the SRch audio signal as an input signal, and outputs the result to the delay processor 46.

  The delay processing unit 46 has a total of 8 (7.1) channels of LFEch, Lch, Rch, Cch, SLch, SRch, PLch, and PRch output from the signal processing unit 45 based on the setting in the viewing space automatic setting mode to be described later. Delay the audio signal.

  The parametric equalizer 47 corrects the frequency characteristics of the 8-channel audio signals output from the delay processing unit 46 by independently varying the three parameters of frequency, level, and Q factor.

  The D / A converter 49 converts the 8-channel digital sound signals output from the parametric equalizer 47 into analog sound signals.

  The electronic volume 51 adjusts the amplification amount of the power amplifier 53 according to the volume amount set by the operation unit 67. The electronic volume 51 outputs the currently set volume value.

  The power amplifier 53 amplifies the 8-channel analog sound signals output from the D / A converter 49 and outputs them to the speakers 11 to 18.

  The speakers 11 to 18 emit sound according to the analog sound signal output from the power amplifier 53. That is, the speaker 11 emits Lch, the speaker 12 Cch, the speaker 13 Rch, the speaker 14 PLch, the speaker 15 PRch, the speaker 16 SLch, the speaker 17 SRch, and the speaker 18 emits LFEch.

  The control unit 63 controls each unit according to the operation performed by the operation unit 67. For example, when a volume adjustment operation is performed at the operation unit 67, the control unit 63 outputs a control signal corresponding to this operation to the electronic volume 51 to change the volume of sound emitted from each speaker 11-18. . As the control unit 63, a CPU or MPU is suitable.

  The memory 65 stores programs executed by the control unit 63 and target curves.

  The operation unit 67 is for the user to input various operations and settings to the sound field forming device 1.

  The display unit 69 is for displaying items transmitted from the sound field forming device 1 to the user.

  In addition, the sound field forming device 1 collects the test sound generated by the test sound generation unit 41 and emitted from each of the speakers 11 to 18 with the microphone 3, and after emitting the test sound, the microphone 3 By measuring the time until the sound is collected or measuring / analyzing the sound pressure, frequency characteristics, etc. of the test sound collected by the microphone 3, the arrangement, capability, and listening room 91 of each speaker 11-18 are measured. It has a function to measure the acoustic characteristics and automatically set the optimal viewing space.

  When the operation unit 67 is operated to set the viewing space automatic setting mode, the test sound generation unit 41 generates a test sound signal and outputs it to the DSP decoder 39. This test sound signal is output to each speaker 11-18 via the signal processing unit 45, parametric equalizer 47, D / A converter 49, power amplifier 53, and speaker terminal 55, and the test sound is output from each speaker 11-18. Is emitted.

  The microphone 3 collects the test sound emitted from the speakers 11 to 18 and outputs a sound collection signal to the microphone amplifier 59 via the microphone terminal 57.

  The microphone terminal 57 is a terminal for connecting the microphone 3.

  The microphone amplifier 59 amplifies the collected sound signal output from the microphone 3.

  The A / D converter 61 converts the analog sound pickup signal output from the microphone amplifier 59 into a digital sound pickup signal.

  The test sound analysis unit 75 measures the time from when the test sound is emitted from each of the speakers 11 to 18 until it is picked up by the microphone 3, or the sound pressure, frequency characteristics, etc. of the test sound picked up by the microphone 3 And the measurement result is output to the control unit 63.

  Based on the analysis result output from the test sound analysis unit 75, the control unit 63 sets parameters for the signal of each channel for the delay processing unit 46 and the parametric equalizer 47.

  Next, a detailed configuration of the reverberation sound generation unit 73 will be described. As shown in FIG. 2, the reverberation sound generation unit 71 includes a presence reflection sound generation unit 80, a left surround reflection sound generation unit 81, a right surround reverberation sound generation unit 82, a back surround reverberation sound generation unit 83, and a reverb sound generation unit 84. , Adders 85 to 88, and an effect level variable amplifier 89.

  The presence reflected sound generation unit 80 includes an Lch amplifier 101, an Rch amplifier 102, a Cch amplifier 103, an SLch amplifier 104, an SRch amplifier 105, an adder 106, a low pass filter 107, a high pass filter 108, an amplifier 109, and a convolution processing unit 110. I have.

  The Lch amplifier 101, the Rch amplifier 102, the Cch amplifier 103, the SLch amplifier 104, and the SRch amplifier 105 respectively receive the Lch, Rch, Cch, SLch, and SRch audio signals (hereinafter referred to as 5ch) input via the main signal line 71. (Referred to as an audio signal) and output to the adder 106.

  The adder 106 adds 5ch audio signals and outputs the addition signal to the low-pass filter 107.

  The low-pass filter 107 is a filter for simulating the effect of changing the frequency due to air attenuation or wall reflection, and attenuates a cut-off frequency (cutoff frequency) or more with respect to the added signal. As an example, the low-pass filter 107 has a slope characteristic of −6 dB / oct, a standard cutoff frequency of 7.1 kHz, and the cutoff frequency can be changed by 1/6 octave.

  The high pass filter 108 cuts unnecessary low frequency components from the addition signal output from the low pass filter 107.

  The amplifier 109 amplifies the addition signal output from the high pass filter 108.

  The convolution processing unit 110 includes an FIR filter, performs convolution calculation processing to generate an initial reflected sound signal for forming a presence sound field, and converts the signal into four signals, an EFL signal, an EFR signal, an EBL signal, and an EBR signal. Output separately.

  With such a configuration, the presence reflected sound generation unit 80 generates and outputs an initial reflected sound signal for forming a presence sound field.

  Similarly, the left surround reflected sound generator 81 generates and outputs an initial reflected sound signal for forming a left surround sound field, and the right surround reverberant generator 82 generates a right surround sound field. An initial reflected sound signal is generated and output, and the back surround reverberation generating unit 83 generates and outputs an initial reflected sound signal for forming a back surround sound field.

  Note that the left surround reflected sound generation unit 81, the right surround reverberation sound generation unit 82, and the back surround reverberation sound generation unit 83 have the same configuration as the presence reflection sound generation unit 80, and thus have a detailed configuration in FIG. The illustration is omitted.

  The reverb sound generation unit 84 includes an Lch amplifier 121, an Rch amplifier 122, a Cch amplifier 123, an SLch amplifier 124, an SRch amplifier 125, an adder 126, a low pass filter 127, a high pass filter 128, an amplifier 129, a reverb delay 130, and a reverb processing unit 131. , An EFL amplifier 132, an EFR amplifier 133, an EBL amplifier 134, and an EBR amplifier 135.

  The Lch amplifier 121, the Rch amplifier 122, the Cch amplifier 123, the SLch amplifier 124, and the SRch amplifier 125 each amplify the 5ch audio signal input via the main signal line 71 and output the amplified signal to the adder 126.

  The adder 126 adds the audio signals of 5ch and outputs the addition signal to the low pass filter 127.

  The low-pass filter 127 is a filter for simulating the effect of changing the frequency due to air attenuation or wall reflection, and attenuates the cut-off frequency (cutoff frequency) or more with respect to the added signal. For example, the low-pass filter 127 has a slope characteristic of −6 dB / oct, a standard value of the cutoff frequency is 7.10 kHz, and the cutoff frequency can be changed by 1/6 octave.

  The high pass filter 128 cuts an unnecessary low frequency component from the addition signal output from the low pass filter 127.

  The amplifier 129 amplifies the addition signal output from the high pass filter 128.

  The reverb delay 130 delays the addition signal so that the reverb sound (reverberation sound) is emitted later than the reflected sound.

  The reverberation processing unit 112 includes a plurality of filters, which are reverberation components to be added to the presence sound field, the left surround sound field, the right surround sound field, and the back surround sound field (also referred to as four sound fields). A signal is generated and divided into four signals, that is, an EFL signal, an EFR signal, an EBL signal, and an EBR signal.

  With such a configuration, the reverb sound generation unit 84 generates and outputs signals of reverberation components (reverberation sound) added to the four sound fields.

  The adders 85 to 88 respectively output EFL signals output from the presence reflected sound generation unit 80, the left surround reflected sound generation unit 81, the right surround reverberation sound generation unit 82, the rear surround reverberation sound generation unit 83, and the reverb sound generation unit 84. The EFR signal, the EBL signal, and the EBR signal are added and output to the effect level variable amplifier 89.

  The effect level variable amplifier 89 is for adjusting the effect level of the reflected sound and the reverberation sound. As an example, the effect level can be changed in the range of 3 dB to -6 dB. Note that the change range of the effect level is not limited to this value, and may be another value.

  When the user U sets the sound field forming device 1 and the speakers 11 to 18 as shown in FIG. 1, the user U connects the microphone 3 to the microphone terminal 57, and the height of the ear of the user U at the listening position 90 is set. The microphone 3 is installed in Then, the user U operates the operation unit 67 to select the viewing space automatic setting mode, thereby measuring the arrangement and ability of the speakers 11 to 18 and the acoustic characteristics of the listening room 91 to automatically select the optimum viewing space. Can be set automatically.

  Further, when the user U selects the viewing space automatic setting mode, the user U can select a favorite frequency characteristic correction curve (target curve) and correct the frequency characteristics of each speaker so as to be the target curve. . Here, the target curve is a curve of a frequency characteristic targeted when the parametric equalizer 47 is adjusted.

  The sound field forming device 1 has a curve named “flat” that uniformizes the characteristics of each speaker, a curve named “natural” that aligns the high-frequency characteristics, and the characteristics of the L / R speakers on the front side. A plurality of target curves such as a curve named front approximation that matches the characteristics are stored in the memory 65, and when any one of the target curves is selected by the operation of the operation unit 67, the frequency characteristics of the speakers 11 to 18 are selected. The parametric equalizer 47 is adjusted so that the characteristic along the target curve becomes. Thus, by selecting the target curve, it is possible to prevent some frequencies from being extremely corrected depending on the conditions of the room and the apparatus, or to adjust the frequency characteristics to the desired one.

  In addition, the user performs actual sound pressure ratio measurement that can correct the sound pressure based on the reference sound pressure level measured in advance in the reference room and the measured sound pressure level when performing the viewing space automatic setting mode. Can be set as follows. The sound field forming device 1 stores the reference sound pressure level data measured in advance in the reference room in the memory 65, and the user selects to perform the actual sound pressure ratio measurement when performing the viewing space automatic setting mode. When this is detected, for example, the sound pressure in the reproduction environment is measured in steps of 0.5 dB from -20 dB to 20 dB. By executing the actual measurement sound pressure ratio measurement, it is possible to more accurately correct the effect level of the reflected sound and reverberation sound described later.

  Further, the user U can set the desired parameters by operating the operation unit 67 instead of automatically setting the optimum viewing space by the viewing space automatic setting mode as described above.

  Thus, when the user U listens to music or watches a movie, the user U operates the operation unit 67 to select and set a preferred sound field program, as shown in FIG. The field forming device 1 forms the presence sound field 93, the left surround sound field 95, the right surround sound field 97, and the back surround sound field 99 around the user U, so that the user U is three-dimensionally surrounded by the sound field. You can enjoy music and movies while enjoying this feeling.

  Next, a characteristic operation in the sound field forming device 1 will be described. FIG. 4A is a diagram illustrating an example of a correction curve for the effect level of reflected sound and reverberation sound, and FIG. 4B is a diagram illustrating an example of a target curve. In the sound field forming device 1, when the sound field program is selected and set, if the sound volume is equal to or lower than the reference level (a constant value), the effect level variable amplifier 89 of the reflected sound generating unit 73 corresponds to the volume value. The amplification level is changed to correct the effect level of reflected sound and reverberant sound. For example, the reference level is set to −18 dB. Here, the reference level is the optimum level at which the user can listen to the sound comfortably, and the designer can set the optimum level at which the sound of the music or movie can be heard without a sense of incongruity when the sound field program is selected and set. Defined.

  As shown in FIG. 4A, when the sound pressure is -18 dB (reference level) or less, the effect levels of the reflected sound and the reverberant sound are corrected. Also, from -18 dB to -48 dB, the effect level is increased as the volume is decreased, and is set to 3 dB which is the maximum value of the effect level at -48 dB. Further, when the sound pressure is less than −48 dB, the effect level is set to 3 dB which is the maximum value.

  In this way, when the sound field program is selected and set, the effect level of the reflected sound and reverberation sound is corrected according to the volume, so that the difference between the sound fields can be understood, and the designer of the sound field program intends to Effect.

  The correction curve for the effect level of the reflected sound and the reverberation sound is not limited to that shown in FIG. 4A, and may be set through experiments. The correction curve, inclination, and reference level may be set according to the sound field program.

  Next, the target curve shown in FIG. 4B has a name of natural, and has a frequency characteristic that gradually lowers the gain in the high frequency range. In the sound field forming device 1, when “natural” is selected as the target curve when the viewing space automatic setting mode is performed, it is possible to prevent some frequencies from being extremely corrected depending on the conditions of the room and the device. it can. However, in the sound field forming apparatus 1, in the viewing space automatic setting mode, a target curve that reduces the high frequency characteristics as shown in FIG. 4B is selected, and the frequency characteristics of the speakers 11 to 18 are corrected. If it is, it may sound like a high-frequency sound. Therefore, in order to prevent the high-frequency sound from being heard, the present invention prevents the low-pass filter 107 of the presence reflection sound generation unit 80 and the left surround reflection sound generation regardless of which sound field program is selected. The cut-off frequency of the low-pass filter (not shown) of the unit 81, the right surround reverberation generation unit 82, the back surround reverberation generation unit 83, and the low-pass filter 127 of the reverb sound generation unit 84 is moved to the high frequency side by 1 to 2 steps. . That is, it is moved from 1/6 octave to 2/6 octave. For example, when the standard value of the cutoff frequency of each low-pass filter is 7.10 kHz, the cutoff frequency is changed to 8.08 kHz or 9.07 kHz. As a result, it is possible to output the high frequencies of the reflected sound and reverberation sound to form multiple sound fields. Can be prevented.

  In the sound field forming device 1, the number of steps for moving the cutoff frequency of each low-pass filter can be changed according to the selected sound field program. For example, when “Natural” is selected as the target curve when the viewing space automatic setting mode is set and the sound field program simulating the church is selected, the cutoff frequency is set to the high frequency range. If a sound field program simulating a large hall is selected, the cut-off frequency is moved 2 steps to the high frequency side, and the sound field program for the drama movie is selected. In such a case, it is preferable to move the cutoff frequency by one step to the high frequency side. When the feeling of high-frequency volume varies depending on the sound field program, the high frequency range of the reproduced sound can be corrected appropriately by changing the amount of change in the cut-off frequency according to the sound field program. .

  The cut-off frequency of the low-pass filter is not limited to a configuration that changes in 1/6 octave steps, and may be configured to be changed to an arbitrary value.

  Next, the processing for correcting the effect level of the reflected sound and reverberant sound according to the volume when the sound field program is selected and set will be described based on a flowchart. FIG. 5 is a flowchart for explaining an effect level correction process for reflected sound and reverberant sound.

  The control unit 63 of the sound field forming device 1 stands by until a sound field program is selected (s1: N). When it is detected that the sound field program is selected by operating the operation unit 67, the memory 65 is selected. To confirm whether natural is selected as a target curve when the viewing space automatic setting mode is performed (s2). When natural is selected as the target curve, the control unit 63 includes a presence reflection sound generation unit 80, a left surround reflection sound generation unit 81, a right surround reverberation sound generation unit 82, a back surround reverberation sound generation unit 83, and a reverb. The cutoff frequency of each low-pass filter of the sound generator 84 is moved by 2 steps (2/6 octave) (s3). Then, the control unit 63 acquires the current volume value from the electronic volume 51 (s4).

  On the other hand, if natural is not selected as the target curve when the viewing space automatic setting mode is performed in step s2, or if the viewing space automatic setting mode is not performed, the processing of step s4 is immediately performed.

  Subsequently, the control unit 63 confirms whether or not the measured sound pressure ratio is measured in the viewing space automatic setting mode and the data is stored in the memory 65 (s5). When the memory 65 does not store the measured sound pressure ratio data, the control unit 63 calculates the reproduction sound pressure of the speakers 11 to 18 from the current volume value acquired in step s2 (s6).

  On the other hand, when the memory 65 stores the actually measured sound pressure ratio data, the control unit 63 uses the actually measured sound pressure ratio data and the current volume value acquired in step s4 to actually measure the speakers 11-18. A reproduction sound pressure is calculated (s7).

  The control unit 63 calculates a difference (reference level−reproduction sound pressure) between the reference level (−18 dB) and the calculated actual reproduction sound pressure (s8).

  When the difference is 30 dB or more (s9: Y), the control unit 63 corrects the difference so that the maximum effect level is 3 dB (s10). Then, the process ends.

  When the difference is 0 dB or less (s9: N, s11: Y), the control unit 63 ends the process without correcting the effect level (s12).

  Further, when the difference is 0 dB to 30 dB (s9: N, s11: N), the control unit 63 calculates a correction value from the correction curve shown in FIG. 4 (s13), and the effect of the reflected sound and the reverberant sound is calculated. The level is corrected to the correction value (s14). Then, the process ends.

  As described above, in the sound field forming device 1, when the sound field program is selected and set, correction is made so that the high frequency gain of each speaker 11 to 18 is reduced, or the reproduction volume is below a certain value. If so, the effect level of the reflected sound and the reverberant sound is corrected, or the cutoff frequency of the low pass filter for giving the specific effect to the reflected sound and the reverberant sound is changed to the high frequency side. The user can enjoy a three-dimensional effect by a plurality of sound fields regardless of the setting.

It is a figure which shows the schematic structure of a sound field formation apparatus, and the arrangement | positioning state of the speaker in a listening room. It is a block diagram which shows the detailed structure of a reflected sound production | generation part. FIG. 5 is a top view and a perspective view showing an image in a state where four sound fields are formed by the sound field forming device. (A) is a figure which shows the correction curve of the effect level of a reflected sound and a reverberation sound, (B) is a figure which shows an example of a target curve. It is a flowchart for demonstrating the correction process of the effect level of a reflected sound and a reverberation sound.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sound field formation apparatus 3 ... Optimizer microphone (microphone) 9 ... Operation part 11-18 ... Speaker 31 ... Signal input terminal 39 ... DSP decoder 41 ... Test sound generation part 43 ... Parameter memory 45 ... Signal processing part 46 ... Delay processing Unit 47 ... Parametric equalizer 49 ... D / A converter 51 ... Electronic volume 53 ... Power amplifier 55 ... Speaker terminal 57 ... Microphone terminal 59 ... Microphone amplifier 61 ... A / D converter 63 ... Control unit 65 ... Memory 67 ... Operation unit 69 ... Display unit 71 ... Main signal line 73 ... Echo sound generation unit 75 ... Test sound analysis unit 80 ... Presence reflection sound generation unit 81 ... Left surround reflection sound generation unit 82 ... Right surround reverberation sound generation unit 83 ... Rear surround reverberation sound generation unit 84 ... River Sound generating unit

Claims (3)

Sounds based on the sound signals of a plurality of channels, and reflected sounds and reverberation sounds generated from the sound signals of the plurality of channels are emitted from a plurality of speakers arranged around the listening position, and a plurality of sounds around the listening position are emitted. A sound field forming device for forming a sound field,
Operation means for receiving instructions for generating a plurality of sound fields;
Reverberation sound generating means for generating reflected sound and reverberation sound from the sound signals of the plurality of channels when the operation means receives a plurality of sound field generation instructions;
Effect level adjusting means for adjusting the effect level of the sound field due to the reflected sound and reverberant sound generated by the reverberant sound generating means;
Storage means for storing a reference sound pressure measured in a reference environment;
Measuring means for measuring the sound pressure in the reproduction environment;
A sound field forming apparatus comprising: control means for setting the effect level to be larger as the sound pressure measured by the measuring means is smaller than the reference sound pressure . Storage means for storing a plurality of frequency characteristic correction patterns ;
Any of the frequency characteristic correction pattern of the plurality of frequency characteristic correction pattern read out from said storage means, on the basis of the frequency characteristic correction pattern, the plurality of audio characteristics adjustment to adjust the frequency characteristics of the reflected sound and the reverberation sound Means ,
High-frequency attenuation means for attenuating the high frequency of the reflected sound and the reverberant sound;
With
Wherein, when the pre-Symbol characteristic adjustment means is adjusted based on the frequency characteristic correction pattern to reduce the gain of the high band, according to claim 1 for moving the cutoff frequency of the high-frequency attenuation means to a predetermined amount the high-frequency side sound field forming apparatus according to.   Sounds based on the sound signals of a plurality of channels, and reflected sounds and reverberation sounds generated from the sound signals of the plurality of channels are emitted from a plurality of speakers arranged around the listening position, and a plurality of sounds around the listening position are emitted. A sound field forming device for forming a sound field,
  Operation means for receiving instructions for generating a plurality of sound fields;
  Reverberation sound generating means for generating reflected sound and reverberation sound from the sound signals of the plurality of channels when the operation means receives a plurality of sound field generation instructions;
  Effect level adjusting means for adjusting the effect level of the sound field due to the reflected sound and reverberant sound generated by the reverberant sound generating means;
  Main volume adjusting means for collectively adjusting the output volume of the sound, reflected sound and reverberant sound;
  If the value of the output volume of the main volume adjusting means is less than or equal to a threshold value, the control means for setting the effect level larger as the value of the output volume is smaller;
  Storage means for storing a plurality of frequency characteristic correction patterns,
  Characteristic adjustment that reads out one of the plurality of frequency characteristic correction patterns from the storage unit and adjusts the frequency characteristics of the plurality of sounds, reflected sound, and reverberation sound based on the frequency characteristic correction pattern Means,
  High-frequency attenuation means for attenuating the high frequency of the reflected sound and the reverberant sound;
  With
  The control means is a sound field forming device that moves the cutoff frequency of the high-frequency attenuation means to the high-frequency side by a predetermined amount when the characteristic adjustment means is adjusted based on a frequency characteristic correction pattern that reduces the high-frequency gain. .

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