JP2006279864A - Acoustic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acoustic system which enables forward normal positioning and attains the reduction of a crosstalk phenomenon with a light and easy load on processing. <P>SOLUTION: The acoustic system comprises: a left speaker 2 and a right speaker 3 installed near left and right ear positions of a sitting person sitting on a seat 7 while directing an acoustic output part toward the front side of the seat 7; a center speaker 4 installed in front of the seat 7 while directing the acoustic output part toward the seat; an acoustic signal output means 5 for outputting acoustic signals to the left speaker 2, the right speaker 3 and the center speaker 4: and an acoustic control means 6 which extracts acoustic the signals outputted to the left speaker 2 and the right speaker 3 from the acoustic signals outputted by the acoustic signal output means 5 and applies an IIR filter to these acoustic signals so as to reduce the influence of crosstalk. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an acoustic system including a left speaker and a right speaker installed in the vicinity of the left and right ear positions of a seated person who is seated on a seat with an acoustic output unit facing the front of the seat.

  In today's acoustic system, a system in which a speaker is installed on an upper portion of a seat backrest, a headrest, or the like has been proposed (see, for example, Patent Document 1). These speakers are installed in the vicinity of the right ear position and the left ear position of the seated person, so that the seated person can experience a high sense of realism with the left and right speakers placed close to the ear position. .

  However, when a speaker is installed on the backrest or the headrest, the speaker is located behind the ear of the seated person, so that the localization of the output sound may not be in front of the viewer. There is also known a method for obtaining a forward localization by performing a reference process on the output sound using a head-related transfer function measured in advance, but the head-related transfer function largely depends on the subject and the dummy head at the time of measurement, It is difficult to obtain a sufficient forward orientation only with these processes.

  In addition, when a seated person listens to sound from the left and right speakers, the sound of the right speaker may be heard by the left ear and the sound of the left speaker may be heard by the right ear. In this case, there is a difference (time difference) between the time when the sound emitted from the same speaker reaches the right ear and the time until it reaches the left ear, so that it is more difficult to perform forward localization. (This phenomenon is called the crosstalk phenomenon).

  As a method for avoiding such a crosstalk phenomenon, a crosstalk cancellation process using an FIR filter is generally used. Specifically, the inverse characteristic is obtained from the frequency characteristic of the sound heard by the left ear out of the sound output from the right speaker with respect to the sound signal heard by the left ear out of the sound output from the left speaker. Multiplying the output sound from the left speaker with respect to the output sound output from the right speaker, and similarly, the right ear of the sound output from the right speaker is eliminated. Multiplying the sound signal heard by the left speaker with the inverse of the frequency characteristic of the sound heard by the right ear out of the sound outputted from the left speaker, Eliminates the effects of crosstalk caused by the output sound from the speakers.

However, when the crosstalk cancellation process is performed using the FIR filter, the process for obtaining the inverse characteristic of the frequency characteristic is required as described above, which causes a problem that the processing load on the acoustic system becomes heavy.
JP-A-5-262184 (page 2-3, FIG. 1)

  The present invention has been made in view of the above problems, and in an acoustic system in which a left speaker and a right speaker are installed in the vicinity of a seated person's ear position, the front localization is realized, and crosstalk is reduced by a simple processing burden. It is an object to provide an acoustic system capable of reducing the influence.

  In order to solve the above-mentioned problems, an acoustic system according to the present invention includes a left speaker and a right speaker installed in the vicinity of the left and right ear positions of a seated person seated on the seat with a sound output portion facing the front of the seat, and the seat A center speaker installed in front of the seat with the sound output portion directed in a direction, an acoustic signal output means for outputting an acoustic signal to the left speaker, the right speaker, and the center speaker; and the acoustic signal output means Is extracted from the sound signals output by the left speaker and the right speaker, and the effect of crosstalk is reduced by applying an IIR filter to the sound signals. Means.

  In addition, the acoustic control means is configured such that the frequency characteristic obtained by the sound heard from the ear of the seated person out of the sound output from the speaker on one side is corrected to be flat by a parametric equalizer. By creating the IIR filter based on the setting information of the parametric equalizer and applying the created IIR filter to the acoustic signal output from the one side speaker, the influence of the crosstalk is reduced. You may perform the process to reduce.

  In the acoustic system according to the present invention, since the center speaker is installed in front of the seat, the front localization can be easily obtained without performing the reference processing or the like on the signal for the left and right speakers or simply performing the easy processing. It becomes possible.

  Moreover, in the acoustic system according to the present invention, the influence of crosstalk is reduced using an IIR filter, so that it is easy to reduce the processing load of the entire acoustic system.

  The acoustic system according to the present invention will be described in detail with reference to the drawings.

  1 and 2 are schematic views showing a minimum configuration of an acoustic system 1 according to the present invention.

  The acoustic system 1 includes a left speaker 2, a right speaker 3, a center speaker 4, an acoustic signal output unit 5, and an acoustic control unit 6.

  The left speaker 2 and the right speaker 3 are respectively installed above the backrest portion 7a of the seat 7 and in the vicinity of the left and right ear positions of the seated occupant A. Further, the sound output portions (speaker front surfaces) of the left and right speakers are directed in the forward direction of the backrest portion.

  The center speaker 4 is provided in front of the seat 7, and the sound output portion is directed toward the seat 7.

  The acoustic signal output unit 5 outputs an acoustic signal to each speaker 2, 3, 4.

  The sound control unit 6 receives a sound signal output from the sound signal output unit 5 and extracts a center speaker signal, a right speaker signal, and a left speaker signal from the received sound signal, , Acoustic processing units 9, 10, 11 for performing acoustic processing on the extracted signals, and delay processing units 12, 13 for performing delay processing on the left speaker signal and the right speaker signal ing.

  The signal extraction unit 8 first extracts an Lch (left channel) acoustic signal as a left speaker signal and an Rch (right channel) acoustic signal as a right speaker signal. Further, the signal extraction unit 8 extracts an acoustic signal having the same output volume of the left speaker signal and the right speaker signal as the center speaker signal, and uses the acoustic signal as the center speaker signal. If the output volume of the left speaker signal and the output volume of the right speaker signal are approximately the same, it can be determined that the localization is in the middle position of the left and right speakers, that is, the center position. Therefore, by extracting an acoustic signal having the same output volume from the Lch (left channel) acoustic signal and the Rch (right channel) acoustic signal as the center speaker signal, the sound whose localization is centered is centered. It is possible to positively output from the speaker 4.

  As another method, the logical product of the Lch (left channel) acoustic signal and the Rch (right channel) acoustic signal may be obtained, and only the common acoustic signal may be used as the center speaker signal.

  The acoustic processing unit 9 performs the crosstalk phenomenon reduction processing and level adjustment using the IIR filter, which will be described below, on the left speaker signal. Similarly, the acoustic processing unit 10 uses the IIR filter to perform crosstalk. Talk phenomenon reduction processing and level adjustment are performed on the right speaker signal.

  FIG. 3 is a diagram used for explaining the crosstalk phenomenon reduction processing in the acoustic processing unit 9. FIG. 3A shows the frequency characteristics when the sound (pulse wave) output from the right speaker 3 is heard with the right ear. When the crosstalk phenomenon is reduced using the IIR filter, the center frequency / bandwidth is adjusted using a parametric equalizer with respect to the frequency characteristics shown in FIG. Filter processing is performed so that the frequency characteristics are flat. For example, in order to adjust the three frequency ranges shown in FIG. 3 (b), three general-purpose equalizers (symbols a to c in FIG. 3 (b)) are applied and shown in FIG. 3 (a). By adding to the frequency characteristic, the frequency characteristic of FIG. 3A is made flat as shown in FIG. The method of flattening the frequency characteristics using the parametric equalizer as described above is different from the crosstalk cancellation processing method using the FIR filter in that the filter processing considering the phase is not performed, but the frequency characteristics can be flattened. Can produce a common effect. In general, it is difficult for humans to recognize the phase, and the left and right speakers 2 and 3 are installed on the backrest portion of the seat 7, and the head of the seated person A exists between the two speakers 2 and 3. Since the sound output from one speaker does not easily reach the other ear, the crosstalk phenomenon is less likely to appear as compared with a general acoustic system. For this reason, the parametric equalizer is adjusted and set so that the frequency characteristic obtained by the sound heard by the right ear among the sounds output from the right speaker 3 described above becomes flat, and the adjustment and setting of the parametric equalizer is performed. An IIR filter created on the basis of information (setting information) is added to the right speaker signal. Considering that the influence of crosstalk from the left speaker 2 to the right ear is smaller than that of a general acoustic system, as described above, by correcting only the acoustic signal from the right speaker 3 to the right ear, The influence of crosstalk can be made relatively small.

  Similarly, the acoustic processing unit 10 adjusts and sets the parametric equalizer so that the frequency characteristic obtained by the sound heard by the left ear among the sounds output from the left speaker 2 is flat. Then, an IIR filter is created based on the adjusted and set parametric equalizer setting information and added to the left speaker signal. In this way, by correcting only the acoustic signal from the left speaker 2 to the left ear, the influence of crosstalk can be relatively reduced as described above.

  The sound processing unit 11 mainly performs level adjustment for the center speaker signal.

  The delay processing units 12 and 13 perform delay processing on the right speaker signal and the left speaker signal. Since the distance from the left speaker 2 and the right speaker 3 to the ear of the seated person A is shorter than the distance from the center speaker 4 to the ear of the seated person A, the timing at which sound is output from the left and right speakers 2, 3 and the center If the timing at which the sound is output from the speaker 4 is the same, the sound from the left and right speakers 2, 3 that the seated person A listens to and the sound from the center speaker 4 are shifted, and the front localization is determined. It becomes difficult to obtain. For this reason, the delay processing unit 12 delays the output timing of the left speaker signal with respect to the center speaker signal, and the delay processing unit 13 delays the output timing of the right speaker signal with respect to the center speaker signal. In this way, the forward localization is achieved.

  In the acoustic system 1 described above, since the center speaker 4 is installed in front of the seat, the front localization can be easily obtained without performing reference processing or the like on the left and right speaker signals, or simply by performing simple processing. It becomes possible.

  In the acoustic system 1 described above, the influence of crosstalk can be reduced by using the IIR filter without using the FIR filter, so that it becomes easy to reduce the processing load of the entire acoustic system. In particular, in an in-vehicle acoustic system that tends to have a large number of speakers, the output processing of multiple speakers is limited despite the limited installation space and processing capacity of the audio signal output unit and acoustic control unit. Therefore, it is possible to significantly reduce the processing load by applying the acoustic system according to the present invention.

  The acoustic system according to the present invention has been described above with reference to the drawings. However, the acoustic system according to the present invention is not limited to the above-described one. For example, in the acoustic system 1 described above, the system is configured by three speakers, that is, the center speaker 4 and the left and right speakers 2, 3, but the speakers applied to the acoustic system are not limited to these three. A configuration in which a plurality of other speakers such as a woofer unit and a tweeter are added may be used.

  Furthermore, a control switch may be provided for the acoustic control unit 6 so that the seated person controls the ON / OFF control of the operation in the acoustic processing unit / delay processing unit.

1 is a layout diagram illustrating a schematic configuration of an acoustic system according to the present invention. 1 is a block diagram showing a schematic configuration of an acoustic system according to the present invention. It is a figure for demonstrating the reduction process of the crosstalk phenomenon in an acoustic adjustment part. (A) is the frequency characteristic which showed the input pattern at the time of listening to the sound output from the right speaker with the left ear, (b) is the figure which showed the characteristic of the equalizer which adjusts a frequency range. (C) is the figure which showed the frequency characteristic of (a) adjusted to flat with the equalizer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Acoustic system 2 ... Left speaker 3 ... Right speaker 4 ... Center speaker 5 ... Acoustic signal output part 6 ... Acoustic control part 7 ... Sheet 8 ... Signal extraction part 9, 10, 11 ... Acoustic processing part 12, 13 ... Delay processing Part

Claims (2)

A left speaker and a right speaker installed in the vicinity of the left and right ear positions of a seated person seated on the seat with the acoustic output portion facing the front of the seat;
A center speaker installed in front of the seat with the sound output section facing the seat,
An acoustic signal output means for outputting an acoustic signal to the left speaker, the right speaker and the center speaker;
Out of the acoustic signals output by the acoustic signal output means, the acoustic signals output to the left speaker and the right speaker are extracted, and an IIR filter is applied to the acoustic signal to influence the crosstalk. And an acoustic control means for reducing noise.   The acoustic control means includes the parametric when the frequency characteristic obtained by the sound heard from the ear of the seated person out of the sound output from the speaker on one side is corrected flat by a parametric equalizer. The IIR filter is created based on equalizer setting information, and the created IIR filter is applied to the acoustic signal output from the one side speaker, thereby reducing the influence of the crosstalk. The acoustic system according to claim 1.

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