WO2014125581A1 - 音声再生装置、音声再生方法及び音声再生プログラム - Google Patents
音声再生装置、音声再生方法及び音声再生プログラム Download PDFInfo
- Publication number
- WO2014125581A1 WO2014125581A1 PCT/JP2013/053408 JP2013053408W WO2014125581A1 WO 2014125581 A1 WO2014125581 A1 WO 2014125581A1 JP 2013053408 W JP2013053408 W JP 2013053408W WO 2014125581 A1 WO2014125581 A1 WO 2014125581A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- speakers
- pair
- audio signal
- phase
- speaker
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
- H04R1/40—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers
- H04R1/403—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers loud-speakers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/12—Circuits for transducers, loudspeakers or microphones for distributing signals to two or more loudspeakers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2499/00—Aspects covered by H04R or H04S not otherwise provided for in their subgroups
- H04R2499/10—General applications
- H04R2499/13—Acoustic transducers and sound field adaptation in vehicles
Definitions
- the present invention relates to a technique for adjusting the level of sound heard by a listener in an acoustic space.
- Patent Document 1 proposes a method of adjusting the sound pressure level according to the acoustic space and listening position by correcting the level of reproduced sound for each frequency band using an equalizer.
- Patent Document 2 proposes a method of forming a high sound pressure region in a specific place by arranging a speaker array including a plurality of speakers and controlling the phase and volume of an audio signal output from each speaker. ing.
- the sound of the rear speaker is smaller than the sound of the front speaker and tends to be difficult to hear. This is probably because the sound output from the rear speaker is blocked by the seat or reflected by the window.
- Patent Document 2 a method of increasing the sound pressure near the driver's seat using a speaker array as in Patent Document 2 is also conceivable.
- the method of Patent Document 2 requires a large-scale system to perform control using a plurality of speakers, and is not suitable for application to a vehicle.
- An object of the present invention is to provide an audio reproduction device capable of increasing the reproduction sound level at a specific listening position without causing adverse effects on the surroundings and without requiring a large-scale system. To do.
- the invention according to claim 1 is an audio reproduction device, which is a pair of speakers arranged before and after a plurality of listening positions having two evaluation points in an acoustic space, and an input unit that receives an audio signal.
- a phase control unit that controls the phase of the audio signal and supplies the phase to the pair of speakers, wherein the phase control unit is a sum of reproduced sound levels at two evaluation points at each of the plurality of listening positions.
- the control band and the phase difference are determined to be larger than when the audio signal is reproduced by only one speaker of the pair of speakers, and the audio signal supplied to the pair of speakers is controlled.
- the invention according to claim 7 is an audio reproducing method executed by an audio reproducing apparatus including a pair of speakers arranged in front and rear with respect to a plurality of listening positions having two evaluation points in an acoustic space, An input step for receiving an audio signal; and a phase control step for controlling the phase of the audio signal and supplying the phase to the pair of speakers.
- the phase control step includes two steps at each of the plurality of listening positions. A control band and a phase difference are determined so that the sum of the reproduced sound levels at the evaluation point is larger than when the audio signal is reproduced by only one speaker of the pair of speakers, and is supplied to the pair of speakers. And controlling an audio signal to be transmitted.
- the invention according to claim 8 is an audio reproduction program that is executed by an audio reproduction apparatus including a pair of speakers arranged at the front and rear with respect to a plurality of listening positions having two evaluation points in an acoustic space,
- the audio reproduction device functions as input means for receiving an audio signal, phase control means for controlling the phase of the audio signal and supplying the audio signal to the pair of speakers, and the phase control means is provided at each of the plurality of listening positions.
- the control band and the phase difference are determined such that the sum of the reproduced sound levels at the two evaluation points is larger than when the audio signal is reproduced only by one of the pair of speakers. It is characterized by controlling an audio signal supplied to a speaker.
- FIG. 1 shows a schematic configuration of a first embodiment of an audio reproducing apparatus according to the present invention.
- An example of a control band and phase difference calculation method will be described.
- the amplitude level of a synthesized wave obtained by synthesizing two sine waves with different phase differences is shown.
- the structure of the phase control part in 1st Example is shown.
- the process sequence in 1st Example is shown.
- voice reproduction apparatus based on this invention is shown. It is a figure which shows the characteristic of the binaural level sum in 2nd Example. It is a figure which shows the characteristic of the binaural level sum in 2nd Example.
- the process sequence in 2nd Example is shown.
- the effect of the level increase by a prior art is shown.
- the effect of the level increase by 2nd Example is shown. It is a figure for considering the positional relationship of a speaker and a listening position. The relationship between the axis
- an audio reproduction device includes a pair of speakers arranged at the front and rear of a plurality of listening positions having two evaluation points in an acoustic space, an input unit that receives an audio signal, A phase control unit that controls the phase of an audio signal and supplies the phase signal to the pair of speakers, and the phase control unit includes a sum of reproduced sound levels at two evaluation points at each of the plurality of listening positions.
- a control band and a phase difference are determined so as to be larger than when the audio signal is reproduced by only one speaker of the pair of speakers, and the audio signal supplied to the pair of speakers is controlled.
- the above-described audio reproduction device is applied to an acoustic space such as a passenger compartment, for example, and controls the level of reproduced sound at two evaluation points at two listening positions set on a seat in the passenger compartment.
- the audio reproduction device controls the phase of an audio signal input from the outside and supplies it to a pair of speakers.
- the phase control the sum of the reproduced sound levels at the two evaluation points at each of the plurality of listening positions is more than when the audio signal is reproduced by only one speaker of the pair of speakers.
- the control band and the phase difference are determined so as to increase. Therefore, the reproduction of the audio signal can be controlled so that the reproduced sound can be heard clearly at a plurality of listening positions in the acoustic space.
- the phase control unit calculates a control band and a phase difference based on a distance between the pair of speakers and the listening position. In another preferred example, the phase control unit determines a control band and a phase difference based on measurement data obtained by collecting sound reproduced from the speaker at the listening position.
- one speaker of the pair of speakers is opposite to the other speaker of the pair of speakers with respect to a line segment connecting the plurality of listening positions. Is arranged. As a result, it is possible to synchronize the reproduced sound output from the two speakers and effectively increase the level.
- the two evaluation points correspond to the positions of two ears of a listener located at the listening position.
- the acoustic space is a vehicle compartment
- the pair of speakers are a front speaker and a rear speaker arranged on the right or left side of the vehicle compartment
- the plurality of listening positions are The two evaluation points correspond to the positions of the left and right ears of the listener located in the driver seat and the passenger seat.
- an audio reproduction method executed by an audio reproduction apparatus including a pair of speakers arranged at the front and rear with respect to a plurality of listening positions having two evaluation points in an acoustic space,
- An input step for receiving an audio signal; and a phase control step for controlling the phase of the audio signal and supplying the phase to the pair of speakers.
- the phase control step includes two steps at each of the plurality of listening positions. A control band and a phase difference are determined so that the sum of the reproduced sound levels at the evaluation point is larger than when the audio signal is reproduced by only one speaker of the pair of speakers, and is supplied to the pair of speakers. To control the audio signal.
- an audio reproduction program executed by an audio reproduction device including a pair of speakers arranged in front and rear with respect to a plurality of listening positions having two evaluation points in an acoustic space
- the audio reproduction device functions as an input unit that receives an audio signal, a phase control unit that controls the phase of the audio signal and supplies the audio signal to the one speaker, and the phase control unit is provided for each of the plurality of listening positions.
- the control band and the phase difference are determined such that the sum of the reproduced sound levels at the two evaluation points is larger than when the audio signal is reproduced only by one of the pair of speakers.
- the audio signal supplied to the speaker is controlled.
- the present embodiment aims to increase the sound pressure level in a specific place in an acoustic space such as a passenger compartment, for example, a driver seat and a passenger seat. Therefore, in this embodiment, a special environment in the vehicle is used.
- FIG. 1 is a plan view schematically showing an in-vehicle environment according to the present embodiment.
- a listener L1 sits in the passenger seat corresponding to one listening position
- a listener L2 (driver) corresponds to the driver seat corresponding to the other listening position.
- a front speaker SP1 and a rear speaker SP2 are provided on the right side of the driver's seat.
- a front speaker and a rear speaker are similarly provided on the left side of the vehicle, but illustration thereof is omitted here.
- the fact that two speakers SP1 and SP2 are arranged in front and back so as to sandwich the driver's seat and the passenger seat is used.
- the sound pressure levels of the left and right ears of the listeners L1 and L2 are simultaneously controlled so that the listener L1 in the passenger seat and the listener L2 in the driver's seat can easily hear the reproduced sound.
- the subscripts are omitted and simply referred to as “listener L”.
- the volume of sound that humans feel is determined based on the sum of the sound intensity of both ears. That is, humans feel the same loudness when listening to sound with a sound pressure of 6 dB in both ears and listening to sound with a sound pressure of 12 dB with only one ear. This is also pointed out in the following literature.
- the listener L when the listener L is located on the center line CL equidistant from the pair of speakers SP1 and SP2, and the left and right ears of the listener L are on the center line CL, the listener L can listen to the sound output from the speakers SP1 and SP2 in synchronization. That is, the sum of the sound pressure levels in the left and right ears of the listener L (hereinafter also referred to as “the binaural level sum”) is maximized.
- the speakers SP1 and SP2 can be arranged in the positional relationship as shown in FIG. 2 with respect to the driver seat and the passenger seat, the voice signal is output from the two speakers SP1 and SP2 as they are and the passenger seat is in the passenger seat.
- the binaural level sum of the listener L1 is maximized, and at the same time, the binaural level sum of the listener L2 in the driver's seat is also maximized. In this case, it is not necessary to perform any processing or adjustment on the audio signal supplied to the speakers SP1 and SP2.
- the binaural level sum in the driver seat and the binaural level sum in the passenger seat are both increased by giving an appropriate phase difference to the audio signals supplied to the two speakers SP1 and SP2.
- FIG. 3 schematically shows a method for giving a phase difference to the audio signals supplied to the two speakers SP1 and SP2.
- FIG. 3A shows a configuration for supplying an audio signal to the two speakers SP1 and SP2.
- the dummy head 3 is disposed at the listening position, and the front speaker SP1 and the rear speaker SP2 are disposed before and after the right side thereof.
- the audio signal from the sound source 2 is input as it is to the front speaker SP1, and after being delayed by a fixed delay amount “Z” in the entire band by the delay unit 6, is input to the rear speaker SP2.
- the sound pressure distribution of the reproduced sound output from the speakers becomes horizontal stripes due to interference.
- the black region including the position of the dummy head 3 has a high sound pressure level
- the white region has a low sound pressure level
- the sound pressure distribution forms horizontal stripes. Therefore, by changing the delay amount Z, the binaural level can be changed synchronously, and the binaural level sum can be controlled.
- FIG. 3B shows an example of the sound pressure distribution in the vicinity of the dummy head 3 when the delay amount Z is changed.
- the numerical values displayed as contour lines in the figure indicate the sound pressure level value.
- FIG. 4 shows a schematic configuration of the first embodiment of the audio reproducing apparatus.
- the first embodiment assumes an anechoic room as the acoustic space.
- a pair of speakers that is, a front speaker SP1 and a rear speaker SP2 are arranged in front and rear with respect to the listening positions of the listeners L1 and L2.
- the front speaker SP1 is farther from the listeners L1 and L2 than the rear speaker SP2.
- the audio signal output from the sound source 2 is supplied as it is to the front speaker SP1, and is also supplied to the rear speaker SP2 with a phase difference ⁇ (f) given by the phase control unit 4.
- the phase control unit 4 gives a phase difference ⁇ (f) for each frequency to the audio signal output from the sound source.
- phase difference ⁇ (f) The method for determining the phase difference ⁇ (f) will be described.
- the phase difference ⁇ (f) is determined so that both the binaural level sum of the listener L1 and the binaural level sum of the listener L2 are both large. Note that the positions of the left and right ears of the listeners L1 and L2 correspond to two evaluation points, respectively.
- the phase difference ⁇ (f) can be determined based on the positions of both ears of the listeners L1 and L2 and the distance between the front and rear speakers SP1 and SP2.
- FIG. 5 is a diagram for explaining a method of determining the phase difference ⁇ (f).
- the point at the center of the head is calculated as the evaluation point.
- Delay amount Z (d1-d2) / c [m / s] (1) Note that “c” is the speed of sound (about 340 [m / s]).
- the distance difference between the listener and the two speakers is corrected.
- the binaural level sum is the maximum. Therefore, based on the delay amount based on the distance difference between the listener and the two speakers and the frequency of the audio signal to be reproduced, the phase difference ⁇ () to be given to the audio signals output from the two speakers in each frequency band. f) is calculated.
- the distance from the speaker SP1 to the listener L1 is “dF1”
- the distance from the speaker SP1 to the listener L2 is “dF2”
- the distance from the speaker SP2 to the listener L1 is “dR1”.
- the distance from the speaker SP2 to the listener L2 is “dR2”.
- the phase difference ⁇ is such that the sum of the binaural levels of the audio signals output from the two speakers is larger at both listening positions than when the audio signal is output from each one speaker.
- F is given.
- this fixed band that is, a frequency band that can increase the binaural level sum at both listening positions is referred to as a “control band”. Theoretically, the smaller the distance between the two listening positions, the wider the control band.
- FIG. 6 shows the amplitude level of a synthesized wave obtained by synthesizing two sine waves with different phase differences.
- phase difference 0
- the amplitude of the synthesized wave is twice the amplitude of the original sine wave, as shown in graph 41.
- the amplitude of the two sine waves and the amplitude of the combined wave are equal as shown in the graph 42.
- phase difference 180 ° the amplitude of the synthesized wave becomes smaller than the amplitude of the original sine wave as shown in graph 43.
- the amplitude of the composite wave of the two sine waves is at least greater than the amplitude of the original sine wave.
- the phase difference exceeds 120 ° the amplitude of the combined wave of the two sine waves becomes smaller than the amplitude of the original sine wave. Therefore, in order to increase the binaural level sum at the two listening positions, it is necessary that the phase difference given to the audio signals output from the two speakers is within 120 ° for the audio signals in each band.
- the range of the phase difference of 120 ° is wide for the low frequency, but the range of the phase difference of 120 ° is narrowed as the frequency is increased.
- the control band in the present embodiment is from the lower limit of the audible band to the certain upper limit band Fmax.
- Upper limit band Fmax Frequency F satisfying F ⁇ D / c ⁇ 1/3 (7)
- “1/3” indicates 120 ° / 360 ° (phase difference).
- the distance dF1 from the speaker SP1 to the listener L1 1.46 [m]
- the distance dF2 from the speaker SP1 to the listener L2, and 1.03 [m] and the distance from the speaker SP2 to the listener L1.
- the upper limit band Fmax according to the equation (7) is 1420 Hz.
- the range of the phase difference that can increase the binaural level sum at the two listening positions is defined as “ ⁇ A ” where the phase difference that maximizes the binaural level sum at the position of the listener L1 is as follows.
- ⁇ A ⁇ 120 ° + D ⁇ F / c ⁇ 360 ° ⁇ ⁇ A + 120 ° (8)
- the portion “D ⁇ F / c ⁇ 360 °” corresponds to a limit for increasing the binaural level sum even in the listener L2. That is, only for the listener L1, with ⁇ 120 ° phase difference theta A, it is possible to increase the binaural level sum than when outputting an audio signal from one speaker.
- the range of the phase difference that can increase the binaural level sum for the listener L2 is also narrowed by “D ⁇ F / c ⁇ 360 °”.
- FIG. 7 shows the characteristics when the phase difference ⁇ (f) calculated as described above is given.
- FIG. 7A shows the frequency characteristic of the binaural level sum at the position of the listener L1 (passenger seat), and
- FIG. 7B shows the frequency characteristic of the binaural level sum at the position of the listener L2 (driver's seat). Show.
- the horizontal axis indicates the frequency, and the vertical axis indicates the binaural level sum. This characteristic is obtained with a vehicle having the dimensions exemplified above.
- the binaural level sum when the phase difference is given as described above in this embodiment up to the vicinity of the upper limit band Fmax (1420 Hz) is the front speaker.
- the sum is higher than the binaural level sum when the audio signal is reproduced only by SP1 or the rear speaker SP2.
- the binaural level sum when the phase difference is given as described above in this embodiment is only the front speaker SP1 or It is larger than the binaural level sum when the audio signal is reproduced only by the rear speaker SP2. Therefore, the binaural level sum is large at the two listening positions within the control band up to the upper limit band Fmax.
- FIG. 8 shows the calculation result of the phase difference.
- FIG. 8A shows the change in the binaural level sum at the position of the listener L1 (passenger seat), and
- FIG. 8B shows the change of the binaural level sum at the position of the listener L2 (driver's seat).
- the horizontal axis indicates the phase difference ⁇ (f), and the vertical axis indicates the frequency.
- the binaural level sum passes through a high value region of about 4.7 dB.
- the binaural level sum passes through a region having a high value of about 4.3 dB. That is, by giving the phase difference ⁇ (f) calculated as described above to the audio signals reproduced by the two speakers, the binaural level sum is increased for both the listeners L1 and L2. can do.
- FIG. 9 shows a configuration for giving a phase difference ⁇ (f) to a reproduction signal from two speakers.
- the audio signal output from the sound source 2 is supplied to the speaker SP1 as it is, and is also supplied to the speaker SP2 via the phase control unit 4.
- the phase control unit 4 includes a plurality of bandpass filters 4a, a phase adjuster 4b, and an adder 4c.
- the band-pass filter 4a is provided for each divided band of the audio signal, and divides the input audio signal into a plurality of frequency bands.
- the band pass filter 4a supplies the audio signal of each band to the phase adjuster 4b.
- the phase adjuster 4b gives the phase difference ⁇ (f) calculated as described above to the audio signal and outputs it to the adder 4c.
- the adder 4c adds the output signals from the phase adjusters 4b of the respective bands and supplies them to the speaker SP2.
- FIG. 10 shows a processing procedure according to the first embodiment. This process is executed by a computing device such as a computer.
- the user measures the position of the vehicle speaker and each seat, and inputs the speaker position and listening position to the computing device.
- the computing device receives those numerical values (step S11). Specifically, the distances dF1, dF2, dR1, and dR2 shown in FIG. 5 are input to the calculation device.
- the calculation device calculates the control band and the phase difference ⁇ (f) based on the above-described formula.
- phase difference ⁇ (f) thus determined is given to the phase control unit 4 shown in FIG. Specifically, a coefficient corresponding to the phase difference ⁇ (f) is set for the phase adjuster 4b of each band of the phase control unit 4. Thus, an appropriate phase difference ⁇ (f) is given to the audio signal reproduced by the speaker SP2 in the configuration of FIG.
- FIG. 11 shows a schematic configuration of the second embodiment of the audio reproducing apparatus.
- the second embodiment assumes a passenger compartment as an acoustic space.
- a front speaker SP1 and a rear speaker SP2 are arranged on the right side of the driver's seat.
- the audio signal from the sound source 2 is supplied to the front speaker SP1 and, after the phase is corrected by the phase controller 4, is supplied to the rear speaker SP2.
- the phase control unit 4 gives a different phase difference (phase correction value) ⁇ (f) for each band of the audio signal.
- the phase difference ⁇ (f) is calculated based on the transfer function between the two speakers and the positions of the two listeners. Specifically, based on the positional relationship between the two speakers SP1 and SP2 and both ears (evaluation points) of the listeners L1 and L2, the transfer function between each speaker and both ears of the listeners L1 and L2 is expressed as follows. A binaural level sum distribution with respect to phase and frequency is generated by simulation and the like based on the transfer function.
- FIG. 12A shows the change in the binaural level sum at the position of the listener L1 (passenger seat), and FIG. 12B shows the change of the binaural level sum at the position of the listener L2 (driver's seat).
- the phase difference indicated by the broken line connecting the regions with the highest binaural level sum indicates the phase difference ⁇ (f) given to the audio signals input to the two speakers in each band.
- FIG. 13 shows characteristics when the phase difference ⁇ (f) obtained as described above is given.
- 13A shows the frequency characteristics of the binaural level sum at the position of the listener L1 (passenger seat), and
- FIG. 13B shows the frequency characteristics of the binaural level sum at the position of the listener L2 (driver's seat). Show.
- the horizontal axis indicates the frequency, and the vertical axis indicates the binaural level sum.
- the binaural level sum when the above phase difference is given up to around 400 Hz corresponding to the upper limit band Fmax is only the front speaker SP1 or the rear speaker. It is equal to or larger than the binaural level sum when the audio signal is reproduced only with SP2.
- the binaural level sum according to this embodiment is close to the binaural level sum when the audio signal is reproduced only by the rear speaker SP2, and around 198 Hz, the binaural level sum according to this embodiment is the front speaker SP1. It is close to the binaural level sum when the audio signal is reproduced with This is considered to be peculiar to the structure of the interior of the vehicle used in this embodiment.
- the binaural level sum when the phase difference is given as described above in this embodiment is only the front speaker SP1 or It is larger than the binaural level sum when the audio signal is reproduced only by the rear speaker SP2. Therefore, also in the present embodiment, the binaural level sum is large at the two listening positions in the control band up to the upper limit band Fmax.
- the configuration for giving the phase difference ⁇ (f) to the audio signals supplied to the two speakers is the same as that of the first embodiment shown in FIG.
- FIG. 14 shows a processing procedure according to the second embodiment. This process is executed by a computing device such as a computer.
- the user outputs test signals from two speakers and collects them with microphones arranged at the positions of the listeners L1 and L2, thereby measuring the characteristics between the speakers and the listening position, and the measurement. Enter the value into the calculator.
- the computing device receives those numerical values (step S21).
- the calculation device generates a binaural level sum distribution as illustrated in FIGS. 12A and 12B based on the input measurement value, and based on the distribution, the control band and the phase difference are generated.
- ⁇ (f) is determined.
- the calculation device determines the phase difference in the binaural level sum distribution so that the binaural level sum is as close to the maximum value as possible at any position of the listeners L1 and L2 for each frequency band.
- the calculation apparatus sets, as an upper limit band, a frequency at which the binaural level sum does not become larger than the binaural level sum when sound is output from only one speaker at any of the positions of the listeners L1 and L2.
- a control band whose upper limit is the band is determined.
- phase difference ⁇ (f) thus determined is given to the phase control unit 4 shown in FIG. 9, and a coefficient corresponding to the phase difference ⁇ (f) is given to the phase adjuster 4 b of each band of the phase control unit 4. Is set.
- an appropriate phase difference ⁇ (f) is given to the audio signal reproduced by the speaker SP2 in the configuration of FIG.
- FIG. 15 and 16 show the effects of the conventional method and the second embodiment.
- FIG. 15 shows the binaural sum of the driver's seat, front passenger seat, and rear seat according to the conventional method
- FIG. 16 shows the sum of the binaural levels of the driver's seat, front passenger seat, and rear seat according to the second embodiment.
- the prior art method refers to a method of increasing the binaural level sum at the driver's seat by increasing the reproduced sound of the rear speaker in a certain band by using an equalizer.
- the binaural level sum in the driver seat and the passenger seat increases as shown in FIGS. 15 (A) and 15 (B).
- the binaural level sum is further increased in the rear seat as compared with the driver seat, and there is a problem in that the reproduced sound in the rear seat becomes too large.
- the binaural level sums in the driver seat and the passenger seat are obtained as shown in FIGS. 16 (A) and 16 (B) by phase correction that gives the phase difference ⁇ (f).
- FIG. 16 (C) since the binaural level sum does not change much in the rear seat, there is no problem that the reproduced sound in the rear seat becomes too loud.
- the reproduced sound level of the driver's seat can be increased without affecting the reproduced sound level in other seats.
- two speakers are arranged so that the driver's seat and the passenger seat are sandwiched between the front and rear.
- the two listening positions are located between the two speakers in the longitudinal direction of the vehicle.
- the distance differences D1 and D2 between each listening position and the two speakers are small.
- this distance difference corresponds to the correction amount of the audio signal supplied to the two speakers, that is, the phase difference ⁇ (f)
- the smaller the distance difference D1, D2 the smaller the correction amount. This makes it easier to synchronize the reproduced sound at the two listening positions. Therefore, assuming an environment such as the inside of a vehicle, even if there are two listening positions, the binaural level sum can be increased at both of the two listening positions.
- the pair of speakers arranged in the front-rear direction with respect to the two listening positions is a premise for increasing the binaural level sum at both of the two listening positions.
- the influence on the rear seat can be reduced by arranging two speakers in the front-rear direction with respect to the two listening positions.
- sound is reproduced from the two speakers SP1 and SP2, but the influence on the person in the rear seat is small. That is, the person in the rear seat does not feel that the reproduced sound is noisy.
- the first reason is that there is a certain distance between the front speaker SP1 and the rear seat, and there is an obstacle such as a seat between the rear seat, so basically the reproduced sound from the front speaker SP1 is not generated. It is difficult to reach the back seat.
- the second reason is that since the rear seat is located outside the two speakers, the reproduced sound from the two speakers is difficult to synchronize as described above. This will be described with reference to FIG.
- FIG. 18 shows the positional relationship between the two speakers and the listener L.
- the axis at which the reproduced sounds from the two speakers are synchronized is the center line CL of the two speakers.
- the listener L is located inside the two speakers, both ears of the listener L are on the center line CL or close to the center line CL. The sum is likely to change.
- the above embodiment uses the front speaker and the rear speaker provided on the right side of the passenger compartment to increase the binaural level sum in the driver's seat, that is, the right front seat.
- the front and rear speakers provided on the left side of the passenger compartment may be used to increase the binaural level sum in the passenger seat, that is, the left front seat.
Landscapes
- Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- General Health & Medical Sciences (AREA)
- Stereophonic System (AREA)
- Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
Description
まず、実施例の基本的な原理について説明する。本実施例は、車室などの音響空間内の特定の場所、例えば運転席及び助手席における音圧レベルを大きくすることを目的とする。そのために、本実施例では車内の特殊な環境を利用する。
よって、本実施例では、聴取者L1、L2について、左右の耳の位置をそれぞれ評価点とし、各聴取者について2つの評価点における音圧レベルの和が大きくなるように、スピーカSP1、SP2に入力される信号を制御する。これにより、聴取者L1、L2は再生音を大きいと感じる。
図4は、音声再生装置の第1実施例の概略構成を示す。第1実施例は、音響空間として無響室を想定する。
なお、「c」は音速(約340[m/s])である。
D1=dF1-dR1 (2)
であり、遅延量Z1は、
Z1=D1/c (3)
となる。よって、音声信号の各周波数帯域について、その周波数と、この遅延量Z1とに基づいて必要な位相差θ(f)が得られる。
D2=dF2-dR2 (4)
であり、遅延量Z2は、
Z2=D2/c (5)
となる。よって、音声信号の各周波数帯域について、その周波数と、この遅延量Z2とに基づいて必要な位相差θ(f)が得られる。
D=|D1-D2| (6)
となるので、上限帯域Fmaxは以下の式により決まる。
ここで、「1/3」は、120°/360°(位相差)を示す。
θA-120°+D・F/c×360°<θ<θA+120° (8)
となる。ここで、「D・F/c×360°」の部分は、聴取者L2においても両耳レベル和を大きくするための制限分に相当する。即ち、聴取者L1のみについては、位相差θAの±120°で、一方のスピーカから音声信号を出力した場合よりも両耳レベル和を大きくすることができる。この範囲内でさらに聴取者L2についても両耳レベル和を大きくすることができる位相差の範囲は「D・F/c×360°」の分だけ狭くなる。
次に、第2実施例について説明する。図11は、音声再生装置の第2実施例の概略構成を示す。第2実施例は、音響空間として車室を想定する。図11に示すように、運転席の右側にフロントスピーカSP1とリアスピーカSP2が配置される。音源2からの音声信号は、フロントスピーカSP1に供給されるともに、位相制御部4により位相が補正された後、リアスピーカSP2に供給される。
次に、実施例における2つのスピーカ位置と聴取位置との関係について説明する。
なお、上記の実施例は、車室の右側に設けられたフロントスピーカ及びリアスピーカを用いて、運転席、即ち右側の前方座席における両耳レベル和を大きくしているが、同様の手法により、車室の左側に設けられたフロントスピーカ及びリアスピーカを用いて、助手席、即ち左側の前方座席における両耳レベル和を大きくしても構わない。
3 ダミーヘッド
4 位相制御部
SP1 フロントスピーカ
SP2 リアスピーカ
L1、L2 聴取位置
Claims (8)
- 音響空間内の2つの評価点を有する複数の聴取位置に対して前後に配置された一対のスピーカと、
音声信号を受け取る入力部と、
前記音声信号の位相を制御し、前記一対のスピーカに供給する位相制御部と、を備え、
前記位相制御部は、前記複数の聴取位置の各々について、2つの評価点における再生音レベルの和が、前記一対のスピーカのうちの一方のスピーカのみで前記音声信号を再生した場合よりも大きくなるように制御帯域及び位相差を決定し、前記一対のスピーカに供給する音声信号を制御することを特徴とする音声再生装置。 - 前記位相制御部は、前記一対のスピーカと前記聴取位置との距離に基づいて、制御帯域及び位相差を算出することを特徴とする請求項1に記載の音声再生装置。
- 前記位相制御部は、前記スピーカから再生した音を前記聴取位置で集音して得られた測定データに基づいて、制御帯域及び位相差を決定することを特徴とする請求項1に記載の音声再生装置。
- 前記一対のスピーカのうちの一方のスピーカは、前記複数の聴取位置を結ぶ線分に対して、前記一対のスピーカのうちの他方のスピーカと反対側に配置されていることを特徴とする請求項1乃至3のいずれか一項に記載の音声再生装置。
- 前記2つの評価点は、前記聴取位置に位置する聴取者の2つの耳の位置に相当することを特徴とする請求項1乃至4のいずれか一項に記載の音声再生装置。
- 前記音響空間は車両の車室であり、前記一対のスピーカは車室の右側又は左側に配置されたフロントスピーカ及びリアスピーカであり、前記複数の聴取位置は前記車室内の運転席及び助手席に相当し、前記2つの評価点は前記運転席及び助手席に位置する聴取者の左右の耳の位置に相当することを特徴とする請求項1乃至5のいずれか一項に記載の音声再生装置。
- 音響空間内の2つの評価点を有する複数の聴取位置に対して前後に配置された一対のスピーカを備える音声再生装置により実行される音声再生方法であって、
音声信号を受け取る入力工程と、
前記音声信号の位相を制御し、前記一対のスピーカに供給する位相制御工程と、を有し、
前記位相制御工程は、前記複数の聴取位置の各々について、2つの評価点における再生音レベルの和が、前記一対のスピーカのうちの一方のスピーカのみで前記音声信号を再生した場合よりも大きくなるように制御帯域及び位相差を決定し、前記一対のスピーカに供給する音声信号を制御することを特徴とする音声再生方法。 - 音響空間内の2つの評価点を有する複数の聴取位置に対して前後に配置された一対のスピーカを備える音声再生装置により実行される音声再生プログラムであって、
音声信号を受け取る入力手段、
前記音声信号の位相を制御し、前記一対のスピーカに供給する位相制御手段、として前記音声再生装置を機能させ、
前記位相制御手段は、前記複数の聴取位置の各々について、2つの評価点における再生音レベルの和が、前記一対のスピーカのうちの一方のスピーカのみで前記音声信号を再生した場合よりも大きくなるように制御帯域及び位相差を決定し、前記一対のスピーカに供給する音声信号を制御することを特徴とする音声再生プログラム。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/767,300 US9756418B2 (en) | 2013-02-13 | 2013-02-13 | Sound reproduction device, sound reproduction method and sound reproduction program |
JP2015500029A JP5917765B2 (ja) | 2013-02-13 | 2013-02-13 | 音声再生装置、音声再生方法及び音声再生プログラム |
PCT/JP2013/053408 WO2014125581A1 (ja) | 2013-02-13 | 2013-02-13 | 音声再生装置、音声再生方法及び音声再生プログラム |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2013/053408 WO2014125581A1 (ja) | 2013-02-13 | 2013-02-13 | 音声再生装置、音声再生方法及び音声再生プログラム |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014125581A1 true WO2014125581A1 (ja) | 2014-08-21 |
Family
ID=51353614
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2013/053408 WO2014125581A1 (ja) | 2013-02-13 | 2013-02-13 | 音声再生装置、音声再生方法及び音声再生プログラム |
Country Status (3)
Country | Link |
---|---|
US (1) | US9756418B2 (ja) |
JP (1) | JP5917765B2 (ja) |
WO (1) | WO2014125581A1 (ja) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2016063412A1 (ja) * | 2014-10-24 | 2017-08-03 | パイオニア株式会社 | 音量制御装置、音量制御方法、及び、音量制御プログラム |
WO2018011923A1 (ja) * | 2016-07-13 | 2018-01-18 | パイオニア株式会社 | 音量制御装置、音量制御方法及びプログラム |
WO2018150611A1 (ja) * | 2017-02-15 | 2018-08-23 | パイオニア株式会社 | 音出力制御装置、音出力制御方法及びプログラム |
JP2018207543A (ja) * | 2018-10-04 | 2018-12-27 | パイオニア株式会社 | 音量制御装置 |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10194260B2 (en) * | 2015-02-27 | 2019-01-29 | Pioneer Corporation | Sound volume control device, sound volume control method and sound volume control program |
EP3742762B1 (en) * | 2018-01-19 | 2022-10-26 | JVCKenwood Corporation | Reproducing device, reproducing method, and in-vehicle loudspeaker system |
US11059420B2 (en) * | 2019-01-25 | 2021-07-13 | Volvo Car Corporation | Acoustic vehicle alerting system and method |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000261900A (ja) * | 1999-03-09 | 2000-09-22 | Sony Corp | 音場補正方法および音響装置。 |
JP2011097561A (ja) * | 2009-11-02 | 2011-05-12 | Harman Becker Automotive Systems Gmbh | オーディオシステム位相イコライゼーション |
JP2012257079A (ja) * | 2011-06-09 | 2012-12-27 | Clarion Co Ltd | フィルタ係数決定装置 |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3083296B2 (ja) * | 1988-03-30 | 2000-09-04 | 三菱電機株式会社 | 車両搭載型音響再生装置 |
JPH0622388A (ja) * | 1991-11-21 | 1994-01-28 | Fujitsu Ten Ltd | 音響特性調整装置 |
JP2911692B2 (ja) * | 1992-10-26 | 1999-06-23 | 三菱電機株式会社 | 音響再生装置 |
JP4077383B2 (ja) * | 2003-09-10 | 2008-04-16 | 松下電器産業株式会社 | 能動型振動騒音制御装置 |
JP4757034B2 (ja) | 2006-01-11 | 2011-08-24 | クラリオン株式会社 | 音場補正装置及びその制御方法 |
JP2008233490A (ja) * | 2007-03-20 | 2008-10-02 | Kenwood Corp | 車載用オーディオ再生装置 |
US8724827B2 (en) * | 2007-05-04 | 2014-05-13 | Bose Corporation | System and method for directionally radiating sound |
JP2011151559A (ja) | 2010-01-20 | 2011-08-04 | National Institute Of Advanced Industrial Science & Technology | 高音圧領域形成方法 |
US20120281858A1 (en) * | 2011-05-03 | 2012-11-08 | Menachem Margaliot | METHOD AND APPARATUS FOR TRANSMISSION OF SOUND WAVES WITH HIGH LOCALIZATION of SOUND PRODUCTION |
-
2013
- 2013-02-13 WO PCT/JP2013/053408 patent/WO2014125581A1/ja active Application Filing
- 2013-02-13 US US14/767,300 patent/US9756418B2/en active Active
- 2013-02-13 JP JP2015500029A patent/JP5917765B2/ja active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000261900A (ja) * | 1999-03-09 | 2000-09-22 | Sony Corp | 音場補正方法および音響装置。 |
JP2011097561A (ja) * | 2009-11-02 | 2011-05-12 | Harman Becker Automotive Systems Gmbh | オーディオシステム位相イコライゼーション |
JP2012257079A (ja) * | 2011-06-09 | 2012-12-27 | Clarion Co Ltd | フィルタ係数決定装置 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2016063412A1 (ja) * | 2014-10-24 | 2017-08-03 | パイオニア株式会社 | 音量制御装置、音量制御方法、及び、音量制御プログラム |
US10237652B2 (en) | 2014-10-24 | 2019-03-19 | Pioneer Corporation | Volume control apparatus, volume control method and volume control program |
WO2018011923A1 (ja) * | 2016-07-13 | 2018-01-18 | パイオニア株式会社 | 音量制御装置、音量制御方法及びプログラム |
WO2018150611A1 (ja) * | 2017-02-15 | 2018-08-23 | パイオニア株式会社 | 音出力制御装置、音出力制御方法及びプログラム |
JPWO2018150611A1 (ja) * | 2017-02-15 | 2019-12-12 | パイオニア株式会社 | 音出力制御装置、音出力制御方法及びプログラム |
US10945075B2 (en) | 2017-02-15 | 2021-03-09 | Pioneer Corporation | Sound output control device, sound output control method and program |
JP2018207543A (ja) * | 2018-10-04 | 2018-12-27 | パイオニア株式会社 | 音量制御装置 |
Also Published As
Publication number | Publication date |
---|---|
JPWO2014125581A1 (ja) | 2017-02-02 |
US9756418B2 (en) | 2017-09-05 |
JP5917765B2 (ja) | 2016-05-18 |
US20160014505A1 (en) | 2016-01-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5917765B2 (ja) | 音声再生装置、音声再生方法及び音声再生プログラム | |
US9930468B2 (en) | Audio system phase equalization | |
US9554226B2 (en) | Headphone response measurement and equalization | |
US10158944B2 (en) | Noise estimation for dynamic sound adjustment | |
WO2006077953A1 (ja) | 音像定位制御装置 | |
US20140348353A1 (en) | Sound system for establishing a sound zone | |
JP5103522B2 (ja) | 音声再生装置 | |
JP2004506396A (ja) | 音声周波数応答処理システム | |
WO2013145127A1 (ja) | 音声再生装置 | |
US9462383B2 (en) | Audio signal processing device and audio signal processing method | |
JP2004023486A (ja) | ヘッドホンによる再生音聴取における音像頭外定位方法、及び、そのための装置 | |
JP2007019940A (ja) | 音場制御装置 | |
JP2011228956A (ja) | 車載用音場制御装置 | |
JP6647362B2 (ja) | 音量制御装置、音量制御方法、及び、プログラム | |
JP2018113718A (ja) | 音声再生装置、音声再生方法及び音声再生プログラム | |
JP2017017717A (ja) | 音声再生装置、音声再生方法及び音声再生プログラム | |
WO2016063412A1 (ja) | 音量制御装置、音量制御方法、及び、音量制御プログラム | |
JPWO2013145127A1 (ja) | 音声再生装置 | |
JPH0965483A (ja) | 車室内周波数特性自動補正システム | |
JP2013165387A (ja) | 車載用オーディオ装置 | |
GB2583438A (en) | Signal processing device for headphones | |
WO2010061458A1 (ja) | 音声再生装置 | |
JP2010034764A (ja) | 音響再生システム | |
JP2010154119A (ja) | 音響装置、音像定位制御回路及び音像定位方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 13875222 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2015500029 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14767300 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 13875222 Country of ref document: EP Kind code of ref document: A1 |