JP2017122781A - Device and method for measuring delay time, and device and method for correcting delay time - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a delay time measurement device and method, which enable accurate measurement of delay time from speakers to a listening position.SOLUTION: An audio system includes: speakers 30-36 disposed in an interior space of a car, or an acoustic space; a microphone 38 disposed at a listening position in the car; a tone burst generator 40 configured to generate a tone burst signal of a predetermined frequency and feed the same to each of the speakers; a tone burst detector 42 configured to detect a tone burst signal output from the microphone 38; and a delay time computation unit 44 configured to compute delay time of a sound wave from each speaker to the microphone 38 on the basis of the tone burst signal fed to each speaker and the tone burst signal detected by the tone burst detector 42.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a delay time measuring apparatus and method for measuring a delay time until an audio sound output from a speaker reaches a listening position, and an audio sound output from each of a plurality of speakers reaches the listening position. The present invention relates to a delay time correction apparatus and method for correcting a difference in delay time until.

  2. Description of the Related Art Conventionally, there is known an acoustic reproduction apparatus that generates a test noise including a mixed signal of white noise and a pulse signal and measures a distance from a listening position to a speaker (see, for example, Patent Document 1). The test noise output from the test noise generator drives the speaker through the D / A conversion circuit and the amplifier. Test noise generated from the speaker is collected by a microphone and input to the acoustic processing unit via the A / D conversion circuit, the digital input switching unit, and the multi-channel decoder unit. The distance measurement unit in the sound processing unit measures the delay time from the time when test noise (for example, a pulse signal included in the test noise) is output to the speaker to the time when the test noise collected by the microphone is detected. The distance from the speaker to the microphone can be measured.

JP 2006-279247 A

  By the way, in the sound reproduction apparatus of Patent Document 1 described above, the delay time from the speaker to the microphone is measured using the pulse signal included in the test noise, but the response component (impulse response) included in the output of the microphone is Since a peak with a small amplitude level (first peak) appears before the component with the peak amplitude level, measuring the delay time when the peak position where the amplitude level is maximum is measured, the accurate delay time is measured There was a problem that could not be done.

  Although it is conceivable to measure the delay time by detecting the leading peak, since the test noise of Patent Document 1 includes white noise in addition to the pulse signal, the leading peak may be hidden behind the white noise. There is. In addition, it is conceivable to use test noise that includes only a pulse signal, but in reality, the frequency characteristics vary depending on the speaker mounting position, mounting peripheral structure, microphone position, etc. The shape of the waveform including the peak is different for each speaker, and an accurate delay time cannot be measured even when the first peak is used.

  The present invention was created in view of the above points, and an object of the present invention is to provide a delay time measuring apparatus and method capable of accurately measuring a delay time from a speaker to a listening position. . Another object of the present invention is to provide a delay time correction apparatus and method capable of accurately correcting a difference in delay time from a plurality of speakers to a listening position.

  In order to solve the above-described problem, a delay time measuring apparatus according to the present invention includes a speaker installed in an acoustic space, sound collection means installed at a listening position in the acoustic space, and a sine wave signal having a predetermined frequency. A sine wave generating means for generating and inputting to the speaker; a response sine wave signal detecting means for detecting a response sine wave signal output from the sound collecting means in response to an input sine wave signal input to the speaker; Based on the input sine wave signal input and the response sine wave signal detected by the response sine wave signal detection means, a delay for calculating a delay time until the sine wave signal is output from the speaker and reaches the sound collecting means Time calculating means.

  The delay time measuring method of the present invention includes a step of generating a sine wave signal having a predetermined frequency and inputting the sine wave signal to a speaker installed in the acoustic space by a sine wave generating means, and an input sine wave signal input to the speaker. Corresponding to the step of detecting the response sine wave signal output from the sound collection means installed at the listening position in the acoustic space by the response sine wave signal detection means, and the input sine wave signal input to the speaker and the response And a step of calculating a delay time until the sine wave signal is output from the speaker and reaches the sound collecting means based on the response sine wave signal detected by the sine wave signal detecting means. ing.

  By measuring the delay time from the speaker to the sound collection means using a single frequency sine wave signal, it is possible to reduce the distortion of the response sine wave signal output from the sound collection means and to measure the delay time accurately. become.

  The delay time calculation means described above preferably calculates the time difference between the rising position or the falling position of the waveforms of the input sine wave signal and the response sine wave signal as the delay time. By calculating the delay time using the rising position or falling position of the waveform of the sine wave signal, it is possible to always measure the delay time accurately without the influence of fluctuations in amplitude or the like.

  The delay time calculation means described above preferably calculates the time difference between the rising position or falling position of the waveform after the second period of the input sine wave signal and the response sine wave signal as the delay time. By measuring the delay time after the amplitude has stabilized, it is possible to avoid measuring the delay time in an unstable state when the speaker starts to vibrate, and to obtain a more accurate delay time. It becomes.

  Further, the delay time calculation means described above uses the average value of the time differences of the rising positions of the plurality of waveforms or the falling positions of the plurality of waveforms corresponding to the plurality of periods of the input sine wave signal and the response sine wave signal as the delay time. It is desirable to calculate. As a result, it is possible to eliminate the influence of temporary noise and obtain a more accurate delay time.

  Moreover, it is desirable that the frequency of the sine wave signal generated by the sine wave generating means described above is a frequency included in the human audible band. This makes it possible to measure the delay time using a signal having a frequency actually used in an audio device or the like.

  The delay time correction apparatus of the present invention generates a plurality of speakers installed in an acoustic space, sound collection means installed at a listening position in the acoustic space, and a sine wave signal having a predetermined frequency. A sine wave generating means for selectively inputting to each of the speakers, and a response sine wave signal for detecting a response sine wave signal output from the sound collecting means in response to an input sine wave signal input to each of the plurality of speakers Based on the detection means, the input sine wave signal input to the speaker and the response sine wave signal detected by the response sine wave signal detection means, the sine wave signal is output from the speaker and reaches the sound collection means. Based on a plurality of delay times corresponding to each of the plurality of speakers calculated by the delay time calculating means and a delay time calculating means for calculating the delay time for each of the plurality of speakers. As acoustic waves output from each of the plurality of speakers simultaneously reach sound collecting means, and a delay means for adjusting the input timing of the signal at each of a plurality of speakers.

  The delay time correction method of the present invention includes a step of generating a sine wave signal having a predetermined frequency and selectively inputting the sine wave generation means to each of a plurality of speakers installed in the acoustic space; Detecting a response sine wave signal output from the sound collecting means installed at the listening position in the acoustic space in response to the input sine wave signal input to each of the speakers by the response sine wave signal detecting means; Based on the input sine wave signal input to the speaker and the response sine wave signal detected by the response sine wave signal detection means, the delay time until the sine wave signal is output from the speaker and reaches the sound collection means, A step for calculating each of the plurality of speakers by the delay time calculating means, and a step corresponding to each of the plurality of speakers calculated by the delay time calculating means. Adjusting the signal input timing of each of the plurality of speakers by the delay means so that the sound waves output from each of the plurality of speakers simultaneously reach the sound collection means based on the number of delay times. ing.

  By measuring the delay time from each speaker to the sound collecting means using a single frequency sine wave signal, the distortion of the response sine wave signal output from the sound collecting means can be reduced and the delay time can be accurately measured. It becomes possible. For this reason, it is possible to accurately correct the difference in delay time from each speaker to the listening position so that sound waves output from each speaker simultaneously reach the sound collecting means based on the measurement result of such delay time. it can.

It is a figure which shows the structure of the audio system of one Embodiment. It is a flowchart which shows the operation | movement procedure of delay time measurement and correction | amendment. It is explanatory drawing of delay time calculation. It is explanatory drawing of the modification of delay time calculation.

  Hereinafter, an audio system according to an embodiment to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an audio system according to an embodiment. This audio system is mounted on a vehicle, for example, and includes an audio device 100, four delay devices 10, 12, 14, 16, four switches 20, 22, 24, 26, and four speakers 30, 32, 34, 36. , A microphone 38, a tone burst generation unit 40, a tone burst detection unit 42, a delay time calculation unit 44, and a delay time setting unit 46.

  The audio device 100 includes a tuner, a DVD player, and the like, and outputs an audio signal to each of the four speakers 30, 32, 34, and 36. The delay units 10, 12, 14, and 16 are provided in one-to-one correspondence with the speakers 30, 32, 34, and 36, respectively, and an audio signal output from the audio device 100 is set to a set delay time. Output with delay.

  The switches 20, 22, 24, and 26 are inserted between the delay units 10, 12, 14, and 16 and the speakers 30, 32, 34, and 36, and select either the audio signal or the tone burst signal. Input to the corresponding speaker. Specifically, the switch 20 is inserted between the delay device 10 and the speaker 30. A switch 22 is inserted between the delay device 12 and the speaker 32. A switch 24 is inserted between the delay device 14 and the speaker 34. A switch 26 is inserted between the delay device 16 and the speaker 36.

  The speakers 30, 32, 34, and 36 are installed in a vehicle interior as an acoustic space, and output sound waves corresponding to an input audio signal or tone burst signal to the vehicle interior. For example, the speaker 30 is installed on the front right side of the vehicle interior, the speaker 32 is installed on the front left side of the vehicle interior, the speaker 34 is installed on the rear right side of the vehicle interior, and the speaker 36 is installed on the rear left side of the vehicle interior. The microphone 38 is installed at a listening position in the passenger compartment, and collects sound waves corresponding to audio signals and ton burst signals output from the speakers.

  The tone burst generator 40 generates a tone burst signal as a sine wave signal having a predetermined frequency that is selectively input to the speakers 30, 32, 34, and 36. For example, the frequency of the sine wave signal is a frequency included in the human audible band, and a frequency of 50 Hz, for example, is used.

  The tone burst detector 42 detects a tone burst signal (response sine wave signal) output from the microphone 38 corresponding to a tone burst signal (input sine wave signal) input to each speaker.

  The delay time calculation unit 44 converts the tone burst signal (input sine wave signal) input to each speaker and the tone burst signal (response sine wave signal) detected by the tone burst detection unit 42 corresponding to this signal. Based on this, a delay time until the sound wave corresponding to the tone burst signal is output from each speaker and reaches the microphone 38 is calculated for each speaker.

  Based on the four delay times corresponding to each of the four speakers 30, 32, 34, and 36 calculated by the delay time calculation unit 44, the delay time setting unit 46 transmits sound waves output from the speakers to the microphone 38. The input timing of signals in each of the four speakers 30, 32, 34, 36 is adjusted so as to reach simultaneously. For example, assuming that four delay times calculated corresponding to each of the four speakers 30, 32, 34, and 36 are T1, T2, T3, and T4, and T3 is the longest of them, the delay time setting is performed. The unit 46 sets the delay times t1, t2, t3, and t4 of the four delay devices 10, 12, 14, and 16 as follows.

t1 = T3-T1
t2 = T3-T2
t3 = 0
t4 = T3-T4
That is, in accordance with the longest delay time T3 corresponding to the speaker 34, the timing of the audio signal or the like input to each of the other three speakers 30, 32, 36 is delayed using the three delay devices 10, 12, 16. By doing so, the output timing of the sound wave is varied so that the sound wave output from each of the four speakers 30, 32, 34, 36 reaches the microphone 38 simultaneously.

  The microphone 38 described above is the sound collecting means, the tone burst generating section 40 is the sine wave generating means, the tone burst detecting section 42 is the response sine wave signal detecting means, the delay time calculating section 44 is the delay time calculating means, and the delay time. The setting unit 46 and the delay units 10, 12, 14, and 16 correspond to delay means, respectively.

  The audio system of the present embodiment has such a configuration. Next, the delay time until the sound wave output from each speaker reaches the microphone 38 is measured, and the delay unit is based on the measurement result. The delay time correction operation until each delay time 10, 12, 14, 16 is set will be described.

  FIG. 2 is a flowchart showing an operation procedure of delay time measurement and correction. First, the tone burst generator 40 selects one of the four speakers 30, 32, 34, and 36 (step 100). For example, the speaker 30 is selected, and the switch 20 provided at the front stage of the speaker 30 is switched to the tone burst generating unit 40 side. Next, the tone burst generator 40 inputs a tone burst signal to the speaker 30 via the switch 20 (step 102). A sound wave corresponding to the input tone burst signal is output from the speaker 30 into the passenger compartment. The tone burst detector 42 detects the output (tone burst signal) of the microphone 38 corresponding to the tone burst signal input to the speaker 30 (step 104).

  Next, the delay time calculation unit 44 and the tone burst signal (input sine wave signal) input to the speaker 30 and the tone burst signal (response sine wave signal) output from the microphone 38 corresponding to the tone burst signal. Based on the above, the delay time T1, which is the arrival time of the sound wave from the speaker 30 to the microphone 38, is calculated (step 106).

  FIG. 3 is an explanatory diagram of delay time calculation. 3A shows the waveform of the tone burst signal input to the speaker 30, and FIG. 3B shows the waveform of the tone burst signal output from the microphone 38 corresponding to the tone burst signal. ing.

  The delay time calculation unit 44 calculates the delay time using the waveform of the nth period (n is 2 or more) in which the amplitude of the tone burst signal output from the microphone 38 is stable. In the tone burst signal shown in FIG. 3B, since the amplitudes of the first and second periods are smaller than the amplitude of the third period, for example, the delay time is calculated using the waveform of the third period. Note that depending on the structure of the speaker 30 (for example, the weight of the diaphragm of the speaker 30), the amplitude after the third cycle may be smaller than the amplitude in a stable state thereafter, so The delay time may be calculated using a waveform.

  The delay time calculation unit 44 calculates the tone burst signal shown in FIG. 3B from the rising position (position where the waveform changes from negative to positive) p10 in the third cycle of the tone bust signal shown in FIG. Is calculated as a delay time T1 (= p11−p10) corresponding to the speaker 30. Instead of using the rising position, a falling position (a position where the waveform changes from positive to negative) may be used. This also applies to the modified examples shown below.

  FIG. 4 is an explanatory diagram of a modified example of delay time calculation. The waveforms shown in FIGS. 4A and 4B are the same as the waveforms shown in FIGS. 3A and 3B, respectively.

  In this modification, the delay time calculation unit 44 calculates a delay time for each waveform of each period using a waveform of a plurality of periods after the third period of the tone burst signal, and further averages these delay times. Calculate the delay time.

  For example, the delay time calculation unit 44 extends from the rising position p10 of the waveform of the third period of the tone bust signal shown in FIG. 4A to the rising position p11 of the third period of the tone burst signal shown in FIG. From time s1 (= p11-p10) and the rising position p20 of the waveform of the fourth period of the tone bust signal shown in FIG. 4A to the rising position p21 of the fourth period of the tone burst signal shown in FIG. Time s2 (= p21-p20) and the rising position p30 of the tone burst signal shown in FIG. 4B from the rising position p30 of the waveform of the tone bust signal shown in FIG. Is calculated as a delay time T1 (= ((p11−p10) + (p21−p20) + (p31−p30)) / 3) corresponding to the speaker 30. .

  When the calculation of the delay time T1 is completed for one speaker 30 in this way, the tone burst generation unit 40 then determines whether there is another speaker whose delay time has not been calculated ( Step 108). If there is a speaker whose delay time has not been calculated, an affirmative determination is made, and the process returns to step 100 to repeat the delay time calculation operation for the next speaker. Thereafter, when calculation of the delay times (T1 to T4) is completed for all the speakers, a negative determination is made in the determination of step 108.

  Next, the delay time setting unit 46 extracts the longest delay time from the four delay times T1 to T4 corresponding to the calculated speakers, and calculates the time difference from the other three delay times (step). 110). As described above, for example, when the delay time T3 corresponding to the speaker 34 is the longest, the time difference between this delay time T3 and the other three delay times T1, T2, and T4 is calculated.

  Next, the delay time setting unit 46 sets the delay times t1, t2, t3, and t4 of the four delay devices 10, 12, 14, and 16 using the time difference calculated in this way (step 112). ). Specifically, the delay time t1 of the delay device 10 corresponding to the speaker 30 is set to T3-T1. The delay time t2 of the delay device 12 corresponding to the speaker 32 is set to T3-T2. The delay time t3 of the delay device 14 corresponding to the speaker 34 is set to 0 (= T3-T3). Delay time t4 of delay device 16 corresponding to speaker 36 is set to T3-T4. Thereafter, the audio signal output from the audio device 100 is input to each speaker through the four delay units 10, 12, 14, and 16 in which the delay time is set in this manner, thereby the audio output from each speaker. Sound will reach the microphone 38 simultaneously.

  As described above, in the audio system according to the present embodiment, the microphone 38 is measured by measuring the delay time from each speaker to the microphone 38 using a single frequency tone burst signal (input sine wave signal, response sine wave signal). This makes it possible to accurately measure the delay time by reducing the distortion of the response sine wave signal output from. Further, based on this accurate measurement result of the delay time, it is possible to accurately correct the difference in the delay time from each speaker to the listening position so that the sound wave output from each speaker reaches the microphone 38 at the same time. Become.

  In particular, by calculating the delay time using the rising position or falling position of the waveform of the sine wave signal, it is possible to always measure the delay time accurately without the influence of fluctuations in amplitude or the like. In addition, the time difference between the rising position or falling position of the waveform after the second cycle of the sine wave signal is calculated as the delay time, and each speaker starts to vibrate by measuring the delay time after the amplitude is stabilized It is possible to avoid measuring the delay time in an unstable state, and to obtain a more accurate delay time. Furthermore, by calculating the average value of the time difference between the rising positions of multiple waveforms corresponding to multiple cycles or the falling positions of multiple waveforms as the delay time, the effects of temporary noise can be eliminated, and more accurate It is possible to obtain a long delay time.

  Further, by using the frequency of the tone burst signal generated by the tone burst generator 40 as the frequency included in the human audible band, a delay using a signal (audio signal) having a frequency actually used in the audio device 100 or the like. Time can be measured.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the delay time is measured using a tone burst signal of 50 Hz. However, focusing on the sound quality of the audio sound output from each speaker, it is desired to emphasize the component of the specific frequency included in the audio sound. In this case, the delay time may be measured and each delay unit may be set using a tone burst signal having a frequency corresponding to the specific frequency. For example, when it is desired to emphasize the weight of the low frequency band, a tone burst signal of 50 Hz is used. In addition, when it is desired to emphasize the low-frequency clumping, a 80-100 Hz tone burst signal is used. Furthermore, when it is desired to emphasize the fundamental tone of the vocal, a tone burst signal of 150 to 400 Hz is used.

  Further, in the above-described embodiment, the case where the present invention is applied to an audio system mounted on a vehicle has been described. However, the present invention may be applied to an audio system used indoors or outdoors, for example, other than on-vehicle. Good. Moreover, even if it is other than an audio system, this invention is applicable to the system which makes the user in a specific listening position hear the sound output from the speaker.

  In the above-described embodiment, a configuration for measuring the delay time and setting each delay device is provided in the subsequent stage separately from the audio device 100, but these configurations may be incorporated in the audio device 100. .

  As described above, according to the present invention, the distortion of the response sine wave signal output from the sound collecting means is measured by measuring the delay time from the speaker to the sound collecting means using a single frequency sine wave signal. This makes it possible to accurately measure the delay time.

10, 12, 14, 16 Delay device 20, 22, 24, 26 Switch 30, 32, 34, 36 Speaker 38 Microphone 40 Tone burst generation unit 42 Tone burst detection unit 44 Delay time calculation unit 46 Delay time setting unit 100 Audio device

Claims (8)

A speaker installed in the acoustic space;
Sound collecting means installed at a listening position in the acoustic space;
A sine wave generating means for generating a sine wave signal of a predetermined frequency and inputting it to the speaker;
Response sine wave signal detection means for detecting a response sine wave signal output from the sound collecting means in response to an input sine wave signal input to the speaker;
Based on the input sine wave signal input to the speaker and the response sine wave signal detected by the response sine wave signal detection means, a sine wave signal is output from the speaker and reaches the sound collecting means. Delay time calculating means for calculating the delay time until
A delay time measuring apparatus comprising: In claim 1,
The delay time measuring device is characterized in that the delay time calculating means calculates a time difference between a rising position or a falling position of each waveform of the input sine wave signal and the response sine wave signal as the delay time. In claim 1 or 2,
The delay time calculating unit calculates a time difference between a rising position or a falling position of a waveform after the second period of the input sine wave signal and the response sine wave signal as the delay time. . In claim 2 or 3,
The delay time calculating means uses, as the delay time, an average value of time differences of rising positions of a plurality of waveforms or falling positions of a plurality of waveforms corresponding to a plurality of periods of the input sine wave signal and the response sine wave signal. A delay time measuring apparatus characterized by calculating. In any one of Claims 1-4,
The delay time measuring apparatus according to claim 1, wherein the frequency of the sine wave signal generated by the sine wave generating means is a frequency included in a human audible band. Generating a sine wave signal of a predetermined frequency and inputting the sine wave generation means to a speaker installed in the acoustic space;
Corresponding to an input sine wave signal input to the speaker, detecting a response sine wave signal output from a sound collecting means installed at a listening position in the acoustic space by a response sine wave signal detecting means;
Based on the input sine wave signal input to the speaker and the response sine wave signal detected by the response sine wave signal detection means, a sine wave signal is output from the speaker and reaches the sound collecting means. Calculating a delay time until the delay time calculating means,
A delay time measuring method comprising: A plurality of speakers installed in the acoustic space;
Sound collecting means installed at a listening position in the acoustic space;
Sine wave generating means for generating a sine wave signal having a predetermined frequency and selectively inputting the sine wave signal to each of the plurality of speakers;
Response sine wave signal detection means for detecting a response sine wave signal output from the sound collection means in response to an input sine wave signal input to each of the plurality of speakers;
Based on the input sine wave signal input to the speaker and the response sine wave signal detected by the response sine wave signal detection means, a sine wave signal is output from the speaker and reaches the sound collecting means. Delay time calculating means for calculating a delay time until each of the plurality of speakers;
Based on a plurality of delay times corresponding to each of the plurality of speakers calculated by the delay time calculating means, so that sound waves output from each of the plurality of speakers simultaneously reach the sound collecting means. Delay means for adjusting the input timing of signals in each of a plurality of speakers;
A delay time correction apparatus comprising: Generating a sine wave signal of a predetermined frequency and selectively inputting the sine wave generation means to each of a plurality of speakers installed in the acoustic space;
The response sine wave signal output from the sound collecting means installed at the listening position in the acoustic space is detected by the response sine wave signal detection means in response to the input sine wave signal input to each of the plurality of speakers. And steps to
Based on the input sine wave signal input to the speaker and the response sine wave signal detected by the response sine wave signal detection means, a sine wave signal is output from the speaker and reaches the sound collecting means. Calculating a delay time until each of the plurality of speakers by a delay time calculating means;
Based on a plurality of delay times corresponding to each of the plurality of speakers calculated by the delay time calculating means, so that sound waves output from each of the plurality of speakers simultaneously reach the sound collecting means. Adjusting a signal input timing in each of the plurality of speakers by a delay means;
A delay time correction method comprising:

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