JP2008187213A - Audio signal processing device, speaker box, speaker system, and video/audio output device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problem points arising when a discrete OSD technique is applied to an actual product. <P>SOLUTION: An audio signal processing device generates an audio signal subjected to a discrete OSD (discrete Optimal Sound Distribution) process for supply to a pair of first speakers to which a relatively high range sound is assigned, a pair of second speakers to which a relatively intermediate range sound is assigned, and a pair of third speakers to which a relatively low range sound is assigned. These speakers constitute a three-way discrete OSD system. The pair of first speakers and the pair of second speakers are arranged in such a manner that their sound emitting surfaces are on substantially the same plane within a common enclosure. The device generates an audio signal with correction of a distance difference between an ideal position of the first speakers based on the discrete OSD principle around a listening position and the actual position of the first speakers contained in the enclosure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technology for high-quality consumer sound reproduction.

  Conventionally, various multi-channel surround technologies have been developed for three-dimensional sound reproduction, and one of them is a virtual surround system. In the virtual surround technology, by using a head related transfer function (HRTF), a virtual three-dimensional sound is generated by making the listener feel that sound comes from a virtual position different from the actual speaker position. Build the environment.

  As a sound reproduction method using such a virtual surround technology, a binaural discrete optimal sound distribution (OSD) method has recently been considered (see Non-Patent Document 1 and Patent Document 1 below). In this discrete OSD system, a virtual surround environment is constructed using binaural signals obtained from sound sources of two or more channels. In a discrete OSD system, crosstalk between signals is canceled by an inverse filter, and a plurality of acoustic radiations arranged at predetermined discrete intervals by a binaural signal divided into different frequency bands by a crossover filter (frequency divider). Vibrate each pair of speakers (speakers). According to such a discrete OSD system, low dynamic range loss, high control effect (low error), and sound reproduction with a low distortion and a wide sweet spot in almost the entire band are realized.

Takashi Takeuchi, Philip A. Nelson, "Stereoscopic sound synthesis by binaural sound field control using speakers" (December 20, 2002 Applied (Electrical) Acoustics Study Group program, tutorial lecture material), IEICE Tech. The Institute of Electronics, Information and Communication Engineers, EA2002-101 (2002-12), pp. 29-34 JP-T-2004-511118

  However, the discrete OSD technology described above is theoretical only, and has never been applied to an actual consumer (home) sound reproduction system. An object of the present invention is to solve the problems that occur when applying discrete OSD technology to actual consumer products.

In order to achieve the above object, an audio signal processing device according to an aspect of the present invention includes:
A pair of first speakers to which a relatively high-frequency sound is assigned and a pair of second speakers to which a relatively mid-range sound is assigned, constituting a 3-way discrete OSD system, An audio signal processing device for generating an audio signal subjected to discrete OSD processing, which is supplied to an arbitrary pair of third speakers to which low-frequency sounds are assigned.
The pair of first speakers and the pair of second speakers are disposed in a common enclosure so that their sound emitting surfaces are substantially on the same plane,
An audio signal is generated in which a deviation in distance between the ideal position of the first speaker based on the discrete OSD principle centered on the listening position and the actual position of the first speaker accommodated in the enclosure is corrected. .

  The audio signal processing apparatus having the above configuration delays the impulse response for the first speaker by, for example, dividing the distance deviation by the wavelength of the sampling frequency of the audio signal to be processed, so that the second and third A filter coefficient storage unit that stores a filter coefficient obtained by combining with an impulse response for a speaker of the speaker, and a discrete OSD that performs a discrete OSD process on the audio signal using the filter coefficient stored in the filter coefficient storage unit And a filter.

  The audio signal processing apparatus having the above configuration may further include a frequency determining unit that determines the sampling frequency of the audio signal to be processed, and an amount corresponding to the sampling frequency is determined based on the sampling frequency determined by the frequency determining unit. A corrected audio signal may be generated.

  The audio signal processing apparatus having the above configuration may further include an amplifier that amplifies the generated audio signal. That is, the present invention is applicable to amplifier products.

  The audio signal processing apparatus having the above-described configuration may further include a reproducing unit that reproduces an audio signal to be processed from a recording medium. That is, the present invention can be applied to products such as a DVD player.

  In another aspect of the present invention, a pair of the first speakers and a pair of the second speakers, to which an audio signal generated by the audio signal processing apparatus having the above-described configuration is supplied, are emitted in a common enclosure. You may comprise as a speaker box arrange | positioned so that a surface may exist on the substantially same plane.

In another aspect of the present invention, the audio signal processing apparatus having the above-described configuration is provided, and the pair of the first speakers and the pair of the second speakers are in a common enclosure, and each sound emitting surface is substantially the same plane. You may comprise as a speaker box arrange | positioned so that it may be on.
In another aspect of the present invention, it may be configured as a video / audio output device including such a speaker box and a display unit that displays a video based on a video signal input together with an audio signal. In particular, a large-screen television for home theater and such a speaker box can be integrated.

  In another aspect of the present invention, a speaker system including the speaker box having the above-described configuration and the third speaker may be configured.

  ADVANTAGE OF THE INVENTION According to this invention, the consumer audio signal processing apparatus which enables high quality stereophonic sound reproduction using discrete OSD technology is provided.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, an example in which the present invention is applied to an amplifier will be described. However, the embodiment described below is an example, and the present invention is not limited to this.

  FIG. 1 shows the configuration of an audio signal processing apparatus according to an embodiment of the present invention. The audio signal processing apparatus 10 illustrated in FIG. 1 includes a processor 12, an input interface 14, a decoder 16, an OSD filter 18, an amplification unit 20, and an output interface 22.

  The processor 12 controls the overall operation of the audio signal processing apparatus 10 of the present embodiment described below.

A multi-channel digital audio signal such as a stereo 2 channel or 5.1 channel is input to the input interface 14. For example, a playback device that plays back digital audio data recorded on a recording medium is connected to the input interface 14. Recording media include DAT (Digital Audio Tape), MD (Mini Disc), CD (Compact Disc), SACD (Super Audio CD), DVD (Digital Versatile Disc), DVD-Audio, Blu-ray Disc (Blu-Ray Disc) HD (Hard Disk), flash memory, buffer memory, and the like. When a playback device having a buffer memory is connected to the input interface 14, a digital audio signal broadcast by BS (satellite broadcasting), CS (communication satellite), CATV (cable TV) or streamed is input. May be.
Of course, an analog audio signal may be input to the input interface 14, and in this case, the input analog signal can be processed in the same manner as a digital audio signal by digitally converting the analog signal with an ADC (Analog to Digital Converter). .
As the input interface 14, a general interface that can accept a wired connection such as a coaxial cable or an optical cable, or a wireless connection based on a broadcast signal, packet transmission, or the like can be used according to an input signal.

The decoder 16 decodes the digital audio signal compressed in the MPEG (Moving Picture Experts Group) format or the like, and outputs it in, for example, an I ² S (Inter-IC Sound) format. A signal obtained by digitally converting an analog signal is not decoded but simply converted into a predetermined format.

  The OSD filter 18 includes a FIR (Finite Impulse Response) filter or an IIR (Infinite-duration Impulse Response) filter. The coefficients of the OSD filter 18 are stored in the filter coefficient memory 24 and are determined in advance by analysis of actually measured data. The OSD filter 18 reads necessary coefficients from the addresses of the filter coefficient memory 24 under the control of the processor.

The amplifying unit 20 amplifies the signal from the OSD filter 18 and sends it to the output interface 22.
The output interface 22 is connected to the speaker system 26 and sends the amplified signal to the speaker system 26. As described in detail below, the speaker system 26 includes one speaker box and any two woofers (and / or one or two subwoofers). When an analog amplifier is used, the signal may be converted using a DAC (Digital to Analog Converter).

The OSD filter 18 performs discrete optimal sound distribution (OSD) processing on the input digital audio signal. Here, the discrete OSD process is a process for constructing a high-quality virtual surround environment by synthesizing binaural signals from two or more channels of sound sources.
Specifically, the OSD filter 18 that performs discrete OSD processing 1) converts input multi-channel audio signals into binaural signals, 2) cancels crosstalk between binaural signals, and 3) converts each binaural signal into a binaural signal. Output in multiple frequency bands. The OSD filter 18 processes a signal using a head related transfer function (HRTF), and the output audio signal constructs a virtual surround environment in the vicinity of a predetermined listening position.

  Here, the virtual surround environment refers to forming a plurality of channels of audio signals input to the input interface 14 at a predetermined listening position using speakers arranged in a different number and / or different from the recording of the sound source. A surround environment with multiple channels equivalent to the sound source being played. FIG. 2 shows a 5.1 channel surround system recommended by ITU (International Telecommunications Union) -R recommendation. As shown in the figure, in this recommended system, the center speaker is arranged at a position of 0 ° with the listener as the center, and the front L / R speakers L and R are arranged at a position of −30 ° or + 30 °, respectively. The Surround L / R speakers SL and SR are arranged between −100 ° and −120 ° or between + 100 ° and + 120 °, respectively. A sound source recorded by such a system is recorded as a multi-channel audio signal on a recording medium such as a DVD. According to OSD technology, the stereophonic sound environment of this sound source can be reproduced with high fidelity and high quality. It is.

  The OSD principle is described in detail in JP-T-2004-511118. According to this, an OSD-processed audio signal having a higher frequency is emitted from the front direction of the listener, and an audio signal having a lower frequency is emitted from the side. That is, in an ideal OSD system, an audio signal having a gradually lower frequency is emitted from 0 ° to ± 180 ° in front of the listener. However, since the realization of such an environment is not realistic, a discrete OSD system is considered in which a frequency band is assigned to each pair of speakers arranged at predetermined discrete intervals.

  Theoretically, in a discrete OSD system, a higher quality stereophonic environment can be constructed as the frequency band is finely divided and the number of speaker pairs is increased. However, a three-way (three pairs of speakers) system as shown in FIG. 3 can achieve a sufficiently high quality (low dynamic range loss, etc.) stereophonic environment and is practical in terms of cost. Is described in the above publications.

As shown in FIG. 3, the 3-way discrete OSD system has a first speaker pair (tweeter) TW to which a high frequency (for example, 3 kHz or more) is allocated and a first speaker to which a mid frequency (for example, 3 kHz to 150 Hz) is allocated. 2 speaker pairs (mid) M, and a third speaker pair (woofer) W to which a low frequency (for example, 150 Hz or less) is assigned.
The tweeters TW are arranged at ± 3.2 ° with an interval of 6.4 ° between each other and the front of the listening position as 0 °. The mids M are arranged at an interval of 32 ° and ± 16 ° with the front of the listening position being 0 °. The woofers W are arranged at ± 90 ° with a mutual interval of 180 ° and the front of the listening position as 0 °.

  In such a 3-way discrete OSD system, the woofer W to which the low frequency band is assigned has low directivity and may not be arranged so strictly. However, the higher the reproduction frequency, the higher the accuracy required for the speaker arrangement. Therefore, it is desirable that the arrangement of the tweeters TW and mids M to which the high frequency band is allocated is strictly accurate.

  For example, a 10 kHz sound wave handled by the tweeter TW has a speed of sound of about 340 m / s in a standard state, and thus one wavelength thereof is about 34 mm. According to the OSD principle, the speaker pairs are arranged such that the phase shift due to the distance between one ear of the listener and the left and right speaker pairs is π / 2. Therefore, the effect of canceling the crosstalk is halved if the mutual positions are shifted by only about 4.25 mm (= 34/4/2). The same applies to the mid-M speaker pair, and even if the relative position is shifted by only about 28 mm, the effect is halved. As described above, it is extremely difficult for the user himself / herself to arrange and maintain the speaker pair of the tweeter TW and the mid M with high precision so that the effect of the OSD system is sufficiently exhibited.

  For this reason, when this 3-way discrete OSD system is actually commercialized, the tweeter TW and the mid M can be housed in an integral enclosure in order to accurately arrange and as a result create a high-quality acoustic environment. Therefore, it is preferable. Moreover, such an integrated structure is easy to handle for both users and manufacturers as product forms. From these facts, it is realistic that the 3-way discrete OSD system is commercialized as a 3-box consisting of a speaker box in which the tweeter TW and mid M are housed in a common enclosure and two speakers constituting the woofer W. It is. Further, two woofers W with low directivity can be made into one subwoofer to make a two-box product, or if so high fidelity is not required, the woofer W can be made into a one-box product.

  However, when the tweeter TW and the mid M are housed in a common enclosure, the following problem occurs. That is, the tweeter TW and the mid M must be arranged on the circumference centered on the listener, and when they are housed in a common enclosure, it is necessary to form irregularities on the sound emitting surface. Such an uneven enclosure has low productivity and high cost compared to a normal flat enclosure, and requires a depth corresponding to the depression of the sound emitting surface, which further increases the manufacturing cost.

  Furthermore, the tweeter TW that emits high-frequency sound is generally configured with a smaller aperture than the mid M that emits mid-range sound. For this reason, there is a possibility that sound emission from the small-diameter tweeter TW, which is sandwiched between the larger-diameter mids M and arranged at a deeper position, may be hindered, or undesirable reflection and crosstalk may occur. Therefore, special devices and shapes are required for the common enclosure. This causes an increase in cost, substantially limits the shape of the enclosure to be used, reduces the degree of freedom in designing the mounted model, and makes development work difficult. Furthermore, since there are irregularities in front of the user when listening, a user who does not like such a design may be considered, and the appeal as a product may be impaired.

  As described above, when the discrete OSD technology is applied to a product as it is, the shape of the enclosure that accommodates the tweeter TW and the mid M causes problems such as high cost and design restrictions.

  In the present embodiment, the speaker pair constituting the tweeter TW and the speaker pair constituting the mid M are attached to a common flat plate (baffle plate), and these sound emitting surfaces are arranged on substantially the same plane. To solve the problem. As a means for this, the OSD filter 18 according to the present embodiment processes an audio signal by correcting a deviation between the ideal position of the tweeter TW and the position on the common plane.

Hereinafter, this correction method will be described with reference to the drawings. FIG. 4 is a diagram for explaining a distance difference Δ with respect to the listening position when the tweeter TW is arranged on the same plane (flat plate) as the mid M and when the tweeter TW is arranged on an ideal circumference. Show. For ease of understanding, the drawings are conceptual and do not correspond to actual angles or scales.
Here, an ideal tweeter TW and mid M are arranged on the circumference of a radius a (m) with the listener as the center, and the actual tweeter TW and mid M are provided on a flat plate 30 at a distance x from the listener. Suppose that Here, from the figure, since x = a · cos 16 and the distance y of the actual tweeter TW is y = x / cos 3.1, the deviation Δ between the position of the actual tweeter TW and the ideal position is Δ = a−y = a (1− (cos16 / cos3.1)) ≈0.0373a (m).

If the propagation speed of the sound wave in the standard state is v ₀ (m / s), the distance traveled by one sampling sound wave at the sampling frequency f _s (Hz) is represented by v ₀ / f _s (m). Therefore, the delay amount d _s obtained by dividing the deviation Δ by the wavelength of the sampling frequency is d _s = Δ / (v ₀ / f _s ) = Δ · f _s / v ₀ = 0.0373 a · f _s / v _0. .

Since the sound velocity v ₀ in the standard state is about 340 m / s, if the sampling frequency f _s is 44.1 kHz and the listening distance a is 1.5 m (a normal listening distance in the home), the delay amount d _s is About 7.26. Therefore, in this case, when the impulse response of the tweeter TW is combined with the impulse response of the mid M and woofer W, the filter coefficient obtained by synthesizing the impulse response of the tweeter TW by delaying by about 7 samplings is obtained. If the audio signal is processed by using it, it is possible to construct a high-quality stereophonic environment equivalent to an ideal speaker arrangement while sufficiently realizing a crosstalk cancellation effect.

  The filter coefficient memory 24 stores the filter coefficient obtained by delaying the impulse response of the tweeter TW actually measured as described above and delaying the impulse response of the tweeter TW with the impulse responses of the mid M and woofer W. For example, when inputting the actual measurement value to the dedicated program for generating the filter coefficient based on the discrete OSD principle from the actual impulse response data, only the impulse response of the tweeter TW is input with data that is delayed by a predetermined sampling amount. The coefficient can be easily obtained.

  As described above, when the sampling frequency fs is 44.1 kHz and the listening distance is 1.5 m, the impulse response of the tweeter TW is delayed by about 7 samplings. In this case, for example, as shown in Table 1 below, the impulse response is synthesized to obtain the filter coefficient. In Table 1, the synthesized impulse response (SUM) indicates a coefficient stored in the filter coefficient memory 24, and when the OSD filter 18 is composed of an FIR filter having 512 taps, 512 coefficients are used. Based on the table shown in Table 1, a synthesized value SUM is derived from each impulse response in the dedicated program. At this time, as shown in the table, the impulse response of the tweeter delayed by 7 samplings is combined with other impulse responses. In this way, a filter coefficient in which the impulse response of the tweeter is delayed by a predetermined sampling is obtained.

  As described above, in this embodiment, the deviation from the ideal position of the tweeter TW is converted by the sampling frequency of the audio signal to be processed, and the filter coefficient is derived in consideration of the deviation (sampling amount). Thus, an audio signal in which the deviation is corrected is generated. This is equivalent to an ideal tweeter TW arrangement based on the discrete OSD principle, using a consumer speaker box in which a mid M and a tweeter TW that require high-precision alignment are fixed to a common flat plate 30. Thus, it is possible to realize a high-quality three-dimensional acoustic environment that can sufficiently obtain a crosstalk canceling effect.

  As described above, the tweeter TW and the mid M can be fixed to the common flat plate 30, so that the enclosure that accommodates them can be less uneven, that is, high in productivity and low in cost. In addition, the depth of the speaker box can be reduced, the product can be downsized, and the cost can be reduced and easy to handle. Furthermore, since the shape of the enclosure is not limited by the positional relationship between the tweeter TW and the mid M, the degree of freedom in design increases and the appeal to the user can be further improved.

(Other embodiments)
With the recent development of digital technology, consumer audio products are required to be able to accept audio signals with a plurality of sampling frequencies. For example, the sampling frequency is 32 kHz for DAT and digital BS, 44.1 kHz for CD, and 48 kHz for DVD. For this reason, even if a filter coefficient suitable for an audio signal having a sampling frequency of 44.1 kHz is prepared, when an audio signal of another frequency is processed, a desired effect cannot be obtained, and It may not be possible to provide sufficient service.

  In order to cope with such market demand, different filter coefficients may be read into the OSD filter 18 according to the sampling frequency of the input audio signal. FIG. 5 illustrates a block diagram of such an audio signal processing apparatus 10. In addition, in order to make an understanding easy, the same code | symbol is attached | subjected to the part similar to FIG. 1, and description is abbreviate | omitted.

  The audio signal processing apparatus 10 shown in FIG. 5 includes a frequency determination unit 40 that receives the audio signal output from the decoder 16 and determines the sampling frequency of the digital audio signal. The frequency discriminating unit 40 sends the discrimination result to the processor. The processor 12 causes the OSD filter 18 to read coefficients appropriate for the sampling frequency of the audio signal processed by the OSD filter 18.

The filter coefficient memory 24 stores a plurality of filter coefficients corresponding to sampling frequencies that the input audio signal can have. For example, when the listening distance is 1.5 m, about 7 samplings (d _s = 7.25) for a signal with a sampling frequency of 44.1 kHz and about 5 samplings (d _s = 5.26) for a signal with 32 kHz. ), A plurality of coefficients obtained by delaying the impulse response for each sampling frequency of the actually measured tweeter TW for about 8 samplings (d _s = 7.89) for a 48 kHz signal.

  Under the instruction of the processor 12, the OSD filter 18 reads a coefficient corresponding to the sampling frequency of the audio signal to be processed, and generates a discrete OSD processing signal in which the position shift of the tweeter TW is corrected. Therefore, it is possible to prevent a reduction in the crosstalk cancellation effect by using coefficients for audio signals having different sampling frequencies, and to construct an optimal OSD stereophonic environment for each of a plurality of types of audio signals in a general home. be able to.

  In the above embodiment, the example in which the present invention is applied to an amplifier has been described. However, the present invention is not limited to this, and the present invention can be applied to audio signal processing devices other than amplifiers. For example, the present invention may be applied to a playback device such as a CD player or a DVD player. The playback device 60 shown in FIG. 6 includes a playback unit 62 that plays back a digital audio signal from a recording medium such as a CD or a DVD. The reproduction signal reproduced by the reproduction unit 62 is subjected to discrete OSD processing and sent to a box having a tweeter TW and a mid M via an amplifier or directly. As described above, even when the present invention is applied to the reproducing apparatus, the same effect as that obtained when the present invention is applied to the amplifier described above can be obtained.

  Furthermore, the present invention can be configured only by a speaker box including a tweeter TW and a mid M. FIG. 7 shows an example of such a speaker box 70. The speaker box 70 shown in the figure performs discrete OSD processing on an audio signal input to the input interface 14 from a playback device for a DVD player, for example, and the driver 72 has a tweeter TW or mid M based on the obtained signal. Drive woofer W (or subwoofer). Even with such a configuration, the effects of the present invention described above can be obtained.

  Furthermore, the present invention can be applied to a video / audio output device such as a television provided with a speaker box having a tweeter TW and a mid M. FIG. 8 shows an example of a block diagram of such a video / audio output device 80. The video / audio output device 80 shown in the drawing receives a digital video signal and a digital audio signal via the input interface 14. Of course, when an analog signal is received, it is converted into a digital signal using an ADC. The video signal decoded by the decoder 16 is processed by the video signal processing unit 82 based on a predetermined method and output to the display unit 84. The display unit 84 includes a liquid crystal display panel, a plasma display panel, and the like. On the other hand, the audio signal is subjected to discrete OSD processing as described above, and is sent to each speaker via the driver 72.

  Such a video / audio output device 80 is configured as a product as shown in FIG. 9, for example. In the example shown in the figure, a speaker box 92 in which a tweeter TW and a mid M are fixed to a common flat plate is integrally provided at a lower portion of a panel 90 constituting the display unit 84. Of course, a woofer W (subwoofer) may be provided as an option. As described above, in a discrete OSD system for home use with a listening distance of 1.5 m, the width of the speaker box 92 can be configured to be about 1 m, and a panel having a relatively large screen, for example, 32 inches or more. Very suitable for integrating with 90. A flat speaker box 92 is preferably provided under the flat panel 90. In this respect, the present invention in which a flat speaker box can be used to construct a high-quality stereophonic environment based on the OSD principle The present invention can be particularly preferably applied to the video / audio output device 80. In addition, it can be said that such a video / audio output device capable of constructing a large-screen and high-quality stereophonic environment is extremely excellent in merchandise, particularly as a home theater device.

  Of course, as shown in FIG. 10, it may be configured as an audio signal processing device (circuit) 10 for discrete OSD processing that is separate from the amplifier and the playback device. Such an independent device is installed, for example, between the playback device and the speaker box, and performs a discrete OSD process on the signal output from the playback device and adds a predetermined amount of delay to the output to the tweeter TW. To the speaker box. In this way, the same effect as described above is realized.

  The present invention is useful for consumer electronic devices capable of constructing a high-quality three-dimensional acoustic environment.

It is a block diagram which shows the structure of the audio signal processing apparatus which concerns on embodiment of this invention. It is a figure explaining the 5.1 channel surround system recommended to ITU-T recommendation. It is a figure explaining an ideal discrete OSD system. It is a figure explaining the deviation | shift of the tweeter arrangement | positioning of the discrete OSD system with which the tweeter and the mid were fixed to the common flat plate, and an ideal discrete OSD system. It is a block diagram which shows the structure of the audio signal processing apparatus which concerns on other embodiment of this invention. It is a block diagram which shows the structure of the reproducing | regenerating apparatus which concerns on other embodiment of this invention. It is a block diagram which shows the structure of the speaker box which concerns on other embodiment of this invention. It is a block diagram which shows the structure of the video / audio output device which concerns on other embodiment of this invention. It is a figure which shows the mechanical structural example of the audio-video output apparatus which concerns on other embodiment of this invention. It is a block diagram which shows the structure of the audio signal processing apparatus which concerns on other embodiment of this invention.

Explanation of symbols

10: Audio signal processing device, 12: Processor, 14: Input interface, 16: Decoder, 18: OSD filter, 20: Amplifying unit, 22: Output interface, 24: Filter coefficient memory, 26: Speaker system, TW: Tweeter, M: Mid, W: Woofer

Claims (9)

A pair of first speakers to which a relatively high frequency sound is assigned and a pair of second speakers to which a relatively mid frequency sound is assigned, constituting a 3-way discrete OSD (discrete Optimal Sound Distribution) system. An audio signal processing device for generating an audio signal subjected to discrete OSD processing, which is supplied to the speaker and an arbitrary pair of third speakers to which a relatively low frequency sound is assigned,
The pair of first speakers and the pair of second speakers are disposed in a common enclosure so that their sound emitting surfaces are substantially on the same plane,
An audio signal is generated in which a deviation in distance between the ideal position of the first speaker based on the discrete OSD principle centered on the listening position and the actual position of the first speaker accommodated in the enclosure is corrected. An audio signal processing device characterized by that. By delaying the impulse response for the first speaker by the amount divided by the wavelength of the sampling frequency of the audio signal to be processed, and synthesizing with the impulse responses for the second and third speakers. A filter coefficient storage unit for storing the obtained filter coefficient;
A discrete OSD filter that performs discrete OSD processing on the audio signal using the filter coefficients stored in the filter coefficient storage unit;
The audio signal processing apparatus according to claim 1, further comprising: A frequency discriminator for discriminating the sampling frequency of the audio signal to be processed;
The audio signal processing apparatus according to claim 1, wherein an audio signal in which an amount corresponding to the sampling frequency is adjusted is generated based on the sampling frequency determined by the frequency determination unit.   The audio signal processing apparatus according to claim 1, further comprising an amplifier that amplifies the generated audio signal.   The audio signal processing apparatus according to claim 1, further comprising a reproducing unit that reproduces an audio signal to be processed from a recording medium.   A pair of the first speakers and a pair of the second speakers, to which an audio signal generated by the audio signal processing device according to claim 1 is supplied, are substantially in the same enclosure. Speaker boxes arranged to be on the same plane.   4. The audio signal processing apparatus according to claim 1, wherein the pair of first speakers and the pair of second speakers are in a common enclosure, and each sound emitting surface is substantially on the same plane. Speaker box arranged as follows.   A speaker system comprising the speaker box according to claim 6 and the third speaker. 7. A video / audio output device comprising: the speaker box according to claim 6; and a display unit that displays video based on a video signal input together with an audio signal.

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