JP7368835B2 - Speaker equipment and audio equipment - Google Patents

Description

The present invention relates to a speaker device and an audio device that can produce more natural sounds.

First, audio speaker devices include the so-called single cone speaker system, in which a single speaker unit handles the entire frequency band. There is also a multi-way speaker device in which the reproduction frequency region is divided into a plurality of frequency regions and each frequency region is reproduced by a separate speaker unit.

In the multi-way speaker device, a relatively large-diameter speaker takes charge of a relatively low-frequency region, and a relatively small-diameter speaker takes charge of a relatively high-frequency region. It is something. For example, a singer's voice contains sounds with frequencies ranging from several hundred hertz to several thousand hertz. When these wide range of frequencies are reproduced using multi-way speakers, the sound comes out from different speakers for each frequency range. Only when these are synthesized does it become the singer's voice.

Here, sound can be expressed as a three-dimensional curved (approximately spherical) wavefront that propagates through the air one after another. As this wavefront crosses a microphone placed at one point one after another, the time change in sound pressure (degree of change in air density) at that microphone point is recorded as a waveform and is recorded on a source such as a CD. It is a sound waveform. This waveform is amplified using an amplifier and drives a speaker to produce sound again. The sound emitted from this speaker is, after all, a spherical wavefront that propagates through the air one after another.

Japanese Patent Application Publication No. 2014-175883

By the way, for example, the wavefront (spherical surface) of the sound coming out of the mouth of a live singer is considered to be a spherical surface centered on one point, the mouth, regardless of the frequency. In other words, a singer's voice contains sounds with frequencies ranging from several hundred hertz to thousands of hertz.

On the other hand, let us consider, in particular, the case where a CD or the like on which the waveform of the recorded sound of the singer's voice is engraved is played back using a multi-way speaker device. Therefore, in a multi-way speaker system, sounds with relatively low frequencies will come out from the speaker unit with a relatively large diameter, and sounds with relatively high frequencies will come out from the speaker unit with a small diameter. It will come.

Here, the sound emitted from the speaker unit is also a three-dimensional curved wavefront that propagates through the air one after another. In this case, it is considered that the wavefront of the sound emitted from the speaker unit can also be approximately approximated to a spherical surface. In other words, it can be approximated as a spherical surface centered on a virtual sound source point assumed to be behind the diaphragm of the speaker unit. Now, assume a wavefront of sound emitted from a speaker unit with a large diameter and a wavefront of sound emitted from a speaker unit with a small diameter. Let us consider the radius of curvature of each sound wavefront when it comes into contact with a certain surface. This means that the radius of curvature of the wavefront (spherical surface) of the sound coming out of a loudspeaker unit with a large diameter is considered to be larger than the radius of curvature of the wavefront (spherical surface) of the sound coming out of a loudspeaker unit with a small diameter.

Then, when the above-mentioned singer's voice is reproduced by a multi-way speaker device, the low-frequency sound component and the high-frequency sound component of the sound components of the singer's voice will have different wavefronts. When coming into contact with a surface, the radius of curvature of the wavefront (spherical surface) of the sound will differ from each other. In other words, the virtual sounding point of the singer's voice differs depending on the frequency component.

The phenomenon in which the point of sound of a singer's voice differs depending on the frequency component is considered to be an unnatural phenomenon that is hard to imagine in the natural world. Furthermore, according to the research of the present inventor, a singer's voice is originally detected and recorded at one point (in stereo, one point each for the left and right sides). When playing back information recorded at one point, it is thought that unless it is emitted from a sounding body with one point as a virtual sound source point, the sound will be different from the original recorded sound. It will be done. From this point of view, the phenomenon that the sound generation point differs depending on the frequency component is considered undesirable from the viewpoint of faithful reproduction.

Furthermore, in sources such as CDs, all sounds such as music are recorded as waveforms. Therefore, faithful reproduction of audio can be considered to mean producing sound that faithfully reproduces this music waveform from a speaker or the like. However, with current audio devices, when the waveform recorded on a source such as a CD is played back through a speaker, and the waveform detected by a microphone and recorded again is compared with the waveform of the original source such as a CD, the The inventors' research has revealed that the degree of waveform coincidence is approximately 0.6 to 0.7 (waveform recall rate is 60 to 70%) in terms of cross-correlation value. It is thought that this cannot be called faithful reproduction at all.
The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a speaker device and an audio device that can produce sound that is more natural and faithful to the source.

The means for solving the above problems are as follows.
(1)
The reproduction frequency region is divided into a plurality of frequency regions, and the reproduction of each frequency region is handled by a speaker unit group consisting of one or more speaker units, respectively.
The speaker unit group responsible for the relatively low frequency range is composed of speaker units with a relatively large diameter,
The unit group responsible for relatively high frequency ranges is composed of speaker units with a relatively small diameter,
The speaker unit group is a multi-way speaker device in which one or more speaker units can be regarded as one unit that virtually produces sound in the frequency range assigned to the speaker,
approximating the wavefront of the sound emitted from the speaker unit group as a spherical surface centered on the virtual sound source point of each unit group,
Based on the recognition that the ideal state is when the virtual sound source points of the respective unit groups overlap and the spherical surfaces of the wave fronts of the sounds emitted from the respective speaker unit groups overlap into one spherical surface,
so that the wavefront of the sound emitted from each unit group approaches one spherical surface,
A speaker device characterized in that each of the units is arranged in a positional relationship such that virtual sound source points of each unit group are as close to each other as possible in a positional relationship that is allowed by the structure of each of the units.
(2)
The speaker device according to (1), wherein each of the unit groups is arranged so that virtual sound source points of each of the unit groups are on a common plane.
(3)
As described in (2), each unit is arranged in a positional relationship such that the virtual sound source points of each unit group are as close as possible to each other in the arrangement relationship permitted by the structure of each unit. speaker device.
(4)
The virtual sound source point of each speaker unit or speaker unit group is
The diaphragm of the speaker unit or speaker unit group is approximated to one circular shape,
Let the aperture, which is the diameter of the circle, be 2L,
Let D be the radius of the wavefront of the sound emitted from the unit,
When the virtual sound source point is located at a distance A behind the diaphragm on the central axis of the diaphragm,
The speaker device according to any one of (1) to (3), wherein the value of A is determined by the formula A=L+(L ² /2D).
(5)
The arrangement position of the relatively small diameter speaker unit group that produces the relatively high frequency sound is as follows:
With respect to the arrangement position of the speaker unit group having a relatively large diameter that produces sound with a relatively low frequency, set at a position further away from the reference plane S0 by a distance of AL-AH as seen from the listening position. The speaker device according to (4), characterized in that:
However, AL is the distance from the diaphragm to the virtual sound source point when the diaphragm of the relatively large-diameter speaker unit group that produces sound at a relatively low frequency is approximated as one circular diaphragm. be.
In addition, AH is the distance from the diaphragm to the virtual sound source point when the diaphragm of the relatively small diameter speaker unit group that produces sound at a relatively high frequency is approximated as one circular diaphragm. be.
(6)
The reproduction frequency region is divided into a plurality of frequency regions, and the reproduction of each frequency region is handled by a speaker unit group consisting of one or more speaker units, respectively.
The speaker unit group responsible for the relatively low frequency range is composed of speaker units with a relatively large diameter,
The unit group responsible for relatively high frequency ranges is composed of speaker units with a relatively small diameter,
The speaker unit group is a multi-way speaker device in which one or more speaker units can be regarded as one unit that virtually produces sound in the frequency range assigned to the speaker,
The speaker device has a radius of curvature RLn of a spherical surface of a wavefront WLn of a relatively low frequency sound emitted from the relatively large diameter speaker unit group, and a relatively low frequency sound wavefront WLn emitted from the relatively small diameter speaker unit group. The radius of curvature RHn of the spherical surface of the wavefront WHn of high-frequency sound is approximated as the radius of curvature of a sphere centered on the virtual sound source point of each speaker unit group, and these wavefronts are set in front of this speaker device. The above ΔRn is possible based on the recognition that the ideal state is when the difference ΔRn between the radii of curvature RLn and RHn of these wavefronts is zero when they touch the reference plane S0. As close to zero as possible,
The number of speaker units constituting the relatively small diameter speaker unit group that produces the relatively high frequency sound,
A speaker device characterized in that the number of the relatively large-diameter speaker unit groups that emit sound at a relatively low frequency is greater than the number of speaker unit groups constituting the speaker unit group.
(7)
The speaker unit constituting the speaker unit group that takes charge of each frequency range is capable of handling sound of the frequency range even when it is alone,
In addition, each single speaker unit is characterized in that in the frequency range for which it is responsible, the cone paper does not cause split vibration, and the sound in the frequency range for which it is responsible is generated by piston motion (1) ~ ( 6) The speaker device according to any one of item 6).
(8)
The speaker device according to any one of (1) to (7), wherein the speaker units are arranged as close to each other as possible.
(9)
The speaker device described in any one of (1) to (8) is characterized in that a sound absorbing member is provided on the main surface of the speaker box to absorb noise generated from the surface of the speaker box to which the speaker unit is attached. speaker device.
(10)
a channel divider device that divides an input sound signal into multiple frequency regions and outputs the divided sound signals;
a plurality of amplifying devices each inputting, respectively amplifying and outputting the sound signals output from the channel divider device;
An audio device comprising a multi-way speaker device that inputs and reproduces the outputs of the plurality of amplifier devices to separate speaker units in charge of reproducing respective frequency regions, the audio device comprising:
A digital correction device for correcting group delay characteristics and frequency characteristics of the audio device, and
An audio device characterized in that the speaker device is the speaker device according to any one of (1) to (9).
(11)
The correction device has a correction algorithm created based on impulse response characteristics obtained by placing a measurement microphone at a measurement position installed within a range of 10 cm to 100 cm from the speaker device, and this correction algorithm This is an algorithm that corrects the frequency characteristics and group delay characteristics so that they become almost ideal characteristics in the playback frequency range that the device is scheduled to play. Therefore, this audio device plays music recorded on a source such as a CD, and the playback When the sound is detected and recorded by a microphone installed at the measurement position, and the recorded music waveform is compared with the music waveform recorded on the original source such as a CD, the two waveforms will almost match. The audio device according to (10), characterized in that:

According to the means (1) to (8) described above, the wavefront of the sound emitted from each speaker unit group can be brought closer to one spherical surface. Moreover, according to the means (9), it is possible to significantly reduce the sound (noise) from sources other than the cone paper of the speaker. When the speaker devices in (1) to (9) are corrected by the method in (11), the speaker device produces sounds whose waveforms are reproduced and whose wavefronts also match (meaning that they come closer to each other). be able to utter. That is, the difference in distance between the speaker units from the trial listening position is also automatically corrected. In this way, the sound produced by waveform reproduction and wavefront matching is completely different from the sound emitted from conventional speakers, for which such things were not considered at all, and it is as if all the plating and veil had been removed. We have confirmed that it produces a truly vivid, lively and attractive sound.

1 is a diagram showing the overall configuration of an audio device according to an embodiment of the present invention. 1 is an external configuration diagram of a speaker device 10 according to an embodiment of the present invention. 3 is a partial sectional view taken along line A-A' of the speaker device 10 according to the embodiment of the present invention shown in FIG. 2. FIG. FIG. 2 is an image diagram of a wavefront WHn of sound reproduced by the high-pitched speaker unit group 14 of the speaker device 10 and a wavefront WMHn of the sound reproduced by the medium-high-pitched speaker unit group 13. FIG. FIG. 3 is an image diagram of a wave surface WMH1 caused by the mid-high sound speaker unit MH1 and a wave surface WH1 caused by the high sound speaker unit H1. The figure is illustrated to make it easier to understand the difference ΔRn in the radius of curvature between the wavefront WMHn and the wavefront WHn. The diagram is illustrated to make it easier to understand the difference ΔR1 in the radius of curvature between the wave surface WMH1 and the wave surface WH1. FIG. 7 is an explanatory diagram of a speaker device according to another embodiment of the present invention. FIG. 3 is an explanatory diagram of a method for finding a virtual sound source point such as a mid-high sound speaker unit MH1. FIG. 7 is an explanatory diagram of the arrangement relationship of the speaker units when a virtual sound source point OMH1 of the mid-high sound speaker unit MH1 and a virtual sound source point OH1 of the high sound speaker unit H1 are determined.

(Audio device according to embodiment)
FIG. 1 is a diagram showing the configuration of an audio device according to an embodiment of the present invention, FIG. 2 is an external view of a speaker device 10, and FIG. 3 is a partial sectional view taken along line AA' of the speaker device 10. As shown in these figures, the audio device according to the embodiment includes a speaker device 10, a bass amplifier 21 that drives a speaker unit provided in the speaker device 10, a mid-bass amplifier 22, and a mid-to-high frequency amplifier. An amplifier 23, a treble amplifier 24, a channel divider 3 that sends a bass signal, a mid-bass signal, a mid-treble signal, and a treble signal to these amplifiers, and a sound field that sends a sound signal to the channel divider 3. It is composed of a preamplifier 4 with a correction function and a sound source device 5 that sends a sound signal to the preamplifier 4.

The speaker device 10 includes a bass speaker unit group 11 in charge of a bass region, a mid-bass speaker unit group 12 in charge of a mid-bass region, a mid-treble speaker unit group 13 in charge of a mid-treble region, and a treble speaker unit group 14 in charge of a treble region. It is provided.

The bass speaker unit group 11 in charge of the bass region is composed of one large-diameter bass speaker L1. This bass speaker unit L1 has a diameter of about 40 cm and handles a frequency range of 25 Hz to 70 Hz. Further, the mid-bass speaker unit group 12 which takes charge of the mid-bass region is composed of two mid-bass speaker units ML1 and ML2. These mid-bass speaker units ML1 and ML2 have a diameter of about 13 cm and are in charge of a frequency range of 70Hz to 650Hz. These two speaker units ML1 and ML2 are connected in series or in parallel as appropriate depending on the resistance of the voice coil.

The mid-to-high sound speaker unit group 13, which is in charge of the mid-to-high sound region, is composed of four mid-to-high sound speaker units MH1 to MH4. These medium and high frequency speaker units MH1 to MH4 have a diameter of about 5 cm and are in charge of a frequency range of 650Hz to 1700Hz. These four speaker units MH1 to MH4 are two connected in series and connected in parallel.

Furthermore, the treble speaker unit group 14, which takes charge of the treble region, is composed of 12 treble speaker units H1 to H12. The treble speaker units H1 to H12 have a diameter of about 1 cm and handle a frequency range of 1700Hz to 20000Hz. These 12 speaker units H1 to H12 are 3 connected in series and 4 sets connected in parallel.

A bass speaker unit L1 that constitutes the bass speaker unit group 14, two mid-bass speaker units ML1 and ML2 that constitute the mid-bass speaker unit group 13, and four mid-high speaker units MH1 that constitute the mid-high speaker unit group 12. ~MH4 and each of the 12 treble speaker units that make up the treble speaker unit group is capable of reproducing the frequency range for which it is responsible. It is desirable to use a device that can reproduce almost the entire frequency range for which it is responsible through piston motion without causing so-called split vibration. Furthermore, the speaker units forming these speaker unit groups are installed as close as possible to each other. This makes it possible for the plurality of speaker units to be considered as one unit, so that sound is virtually emitted from one speaker unit. In addition, all speaker unit groups are also installed as close as possible to each other. This allows the plurality of speaker unit groups to be considered as one, virtually emitting sound from one speaker unit. This makes it possible to ideally perform the correction described later, and enables waveform reproduction as described later.

As shown in FIG. 2, the speaker device 10 includes a box main body 101 in the form of a rectangular parallelepiped box, a damping sheet 102 attached to the inner surface of the box main body 101, and a damping sheet 102 packed inside the box main body 101. The box body 101 is made up of a sound absorbing member 103 and a sound absorbing panel 104 attached to cover the outer surface of the box body 101. The box body 101 is made of a material that does not easily vibrate, such as a metal aluminum plate or hard wood. The damping sheet 102 is made of a lead plate or other damping member. The sound absorbing member 103 is made of cotton, rock wool, foamed urethane, or other material with high sound absorbing performance. The sound-absorbing panel 104 is formed of a sound-absorbing panel made of sound-absorbing material such as urethane or rock wool. As a result, the sound (noise) emitted from the surface of the box body 101 due to the vibration of the cone paper of each speaker unit, and the sound (noise) emitted from the sound reflected inside the box body 101 penetrating the cone paper (noise). etc. can be prevented from being released to the outside.

The bass amplifier 21, the mid-bass amplifier 22, the mid-high frequency amplifier 23, and the treble amplifier 24 are amplifiers for power amplification, and amplify the power of the sound signal from the channel divider 3, respectively. 11, drives a mid-bass speaker unit group 12, a mid-high sound speaker unit group 13, and a treble speaker unit group.

The channel divider 3 divides the sound signal sent from the preamplifier 4 into sound signals in the frequency ranges of bass, mid-bass, mid-high and treble, and divides the sound signals into bass amplifier 21, mid-bass amplifier 22, and mid-high frequency amplifier 23, respectively. and is sent to the treble amplifier 24. The channel divider 3 is configured using a large number of digital filters such as FIR filters or IIR filters. This is because an analog channel divider using resistors, capacitors, etc. is undesirable because it causes group delay that is harmful to waveform reproduction. A channel divider using a large number of digital filters such as FIR filters or IIR filters can be constructed using a computer device programmed to operate a large number of digital filters such as FIR filters or IIR filters to operate as a channel divider. Note that, if possible, it is desirable to use an FIR filter with good phase characteristics. The number of filter taps should be several thousand or more, and if possible, the number should be around 100,000.

The preamplifier 4 with a sound field correction function includes an amplifier that amplifies the sound signal sent from the sound source 5, and a computer device that executes sound field correction processing. Here, the sound field correction is at least correction of group delay characteristics and frequency characteristics. Group delay correction and frequency correction are performed using a digital filter such as a well-known FIR filter. According to this, correction can be performed relatively easily without causing phase disturbance.

Again, the number of filter taps should be several thousand or more, and if possible, the number of taps should be around 100,000. These corrections are performed by playing an impulse response measurement signal for measuring group delay characteristics and frequency characteristics with an audio device, and receiving it with a microphone, as is commonly used in well-known AV amplifiers. An acoustic transfer function that performs the inverse correction is created from the group delay characteristics and wave number characteristics obtained, and the correction is performed using a computer device programmed to perform these processes. This can be achieved by incorporating it into the preamplifier 4.

The correction is set, for example, at a short distance of about 25 cm from the front of the speaker device 10, at a position that is rather close to the speaker unit group that reproduces the treble region, that is, on the virtual axis of the speaker device 10. A correction algorithm is created based on the impulse response characteristics obtained by placing a measurement microphone at the measurement position. This correction algorithm is an algorithm that corrects the frequency characteristics and group delay characteristics of this audio device so that they become almost ideal characteristics in the intended playback frequency range. When music is played, the played sound is detected and recorded by the microphone installed at the measurement position, and the recorded music waveform is compared with the music waveform recorded on the original source such as a CD, both waveforms are This means that they almost match. In other words, it enables "waveform reproduction" in which the music waveform engraved on the source is reproduced on the speaker.

In the audio device according to this embodiment, a music waveform recorded on a source such as a CD is played back by a speaker, and the waveform detected by a microphone and recorded again is compared with the waveform of the original source such as a CD. The degree of coincidence of the waveforms is an astonishing value of 0.99 or more (waveform reproduction rate of 99% or more) in terms of cross-correlation value. Note that the music waveform used here is preferably an orchestra piece or opera piece that includes sounds in a wide range of frequencies and records many types of instruments such as string instruments and percussion instruments, and voices. Here, we are comparing all the waveforms of the song Mambo Italiano (a song of just over 2 minutes) in which Rosemary Clooney is in charge of vocals. Further, the measurement position may be within a range of 10 cm to 100 cm from the front of the speaker device 10. This is because at such a distance, even in a normal room, there is little influence from reflected sound, and it is possible to measure approximately accurate impulse response characteristics. However, if this measurement is performed in an anechoic chamber, the measurement position may be further away from the speaker device.

In this way, the above-mentioned correction is definitely different from the concept of conventional sound field correction. That is, conventional sound field correction attempts to optimize the acoustic transfer function at the listening position by placing a microphone at the listening position. In contrast, the correction of the present invention is performed at a position as close to the speaker as possible within the range where multiple speaker units can be virtually regarded as one speaker, and on the virtual axis of this speaker, to adjust the frequency characteristics. This makes the group delay characteristics ideal.

Furthermore, the speaker device of this embodiment is definitely different from conventional speaker devices. That is, the conventional speaker device obtains a desired sound by making the sound of the speaker unit resonate through a box, tube, horn, or the like. In contrast, the speaker device of this embodiment is decisively different in that it does not produce any sound through a box, tube, horn, or the like. This allows the sound to be emitted only from the paper cone that vibrates depending on the signal, and all other sounds are removed as noise. Then, the correction was applied close to the speaker. As a result, the impulse response measurement that is the basis of the correction can be made accurate and free of noise, which makes it possible to perform ideal corrections and reproduce the waveforms described above. be.

On the other hand, with conventional speaker devices, it is impossible to measure the correct impulse response characteristics even if you measure close to the speaker due to noise from the speaker device box, etc.; Therefore, measurements were even more inaccurate due to the effects of reflected sound from the room. As a result of performing corrections based on such inaccurate impulse response measurements, results were obtained that were far from ideal characteristics. As a result, music recorded on a source such as a CD is played back using a conventional audio device, the played sound is detected and recorded by a microphone installed at the measurement position, and the recorded music waveform is compared to the original CD or other source. When comparing the music waveforms recorded in the source, there was a considerable difference between the two waveforms (waveform reproduction rate was 60-70%).

The sound source device 5 that sends the sound signal is a device that reads out the sound signal from a recording medium on which digital or analog sound signals are recorded, such as a well-known CD player or record player, converts it into a predetermined signal, and sends it to the preamplifier 4. be.

FIG. 4 is an image diagram of the wavefront WHn of the sound reproduced by the high-pitched speaker unit group 14 of the speaker device 10 and the wavefront WMHn of the sound reproduced by the medium-high-pitched speaker unit group 13. In FIG. 4, the treble speaker unit group 14 is shown as four treble speaker units, but the illustration is omitted as it actually consists of 12 treble speakers H1 to H12. Further, although the mid-high sound speaker unit group 13 is shown as one mid-high sound speaker unit, it is omitted to show that it actually consists of four mid-high sound speakers MH1 to MH4. It is assumed that both the wave surface WHn and the wave surface WMHn can be approximated to a spherical surface.

As shown in FIG. 4, the speaker unit mounting surface of the speaker device 10 is defined as S1, and a plane parallel to S1 set at a position 25 cm away from this surface S1 in the front direction of this speaker device is defined as a reference plane S0. . At that time, the radii of curvature when both the wave surface WMHn and the wave surface WHn touch the reference surface S0 are RMHn and RHn, respectively. It is assumed that the difference between the radii of curvature RMHn and RHn of those wavefronts is ΔRn.

On the other hand, it is assumed that the mid-high sound speaker unit group 13 is composed of only one mid-high sound speaker unit MH1, and the high-pitched sound speaker unit 14 is composed of only one high-pitched sound speaker unit H1. FIG. 5 is an image diagram of a wavefront WMH1 caused by the mid-high sound speaker unit MH1 and a wavefront WH1 caused by the high sound speaker unit H1 in that case. In FIG. 5, as in the case of FIG. 4, the speaker unit mounting surface of the speaker device 10 is S1, and a surface parallel to S1 is set at a position 25 cm away from this surface S1 in the front direction of this speaker device. Let the reference plane be S0. At that time, the radii of curvature when both the wave surface WMH1 and the wave surface WH1 touch the reference surface S0 are RMH1 and RH1, respectively. It is assumed that the difference between the radii of curvature RMH1 and RH1 of those wavefronts is ΔR1.

Figure 6 shows the difference ΔRn in the radius of curvature between the wave surfaces WMHn and WHn to make it easier to understand, and Figure 7 shows the difference ΔR1 in the radius of curvature between the wave surfaces WMH1 and WH1 to make it easier to understand. It is something. As is clear from these figures, the radius of curvature RMHn of the wavefront WMHn due to MHn (MH1+...+MH4) using four relatively large-diameter medium- and high-frequency speaker units, and the curvature radius RMHn of a relatively small-diameter high-frequency speaker unit The difference ΔRn (FIG. 6) between the wavefront WHn and the radius of curvature RHn due to Hn (H1+...+H12) using 12 Hn (H1+...+H12) is almost equal to zero. On the other hand, the radius of curvature RMH1 of the wavefront WMH1 created by MH1 using one medium-high sound speaker unit with a relatively large diameter, and the radius of curvature RH1 of the wavefront WH1 created by H1 using one high-frequency sound speaker unit with a relatively small diameter. It can be seen that the difference ΔR1 between the two values is clearly much larger than zero.

What has been described above also applies to the relationship between the mid-high sound speaker unit group 13 and the mid-bass speaker unit group 12, as well as the relationship between the mid-bass speaker unit group 12 and the bass speaker unit group 11. In other words, in order to reduce the difference between the radius of curvature of the wavefront caused by a speaker unit with a large diameter and the radius of curvature of a wavefront caused by a speaker unit with a small diameter, the number of speaker units with a small diameter must be larger than the number of speaker units with a large diameter. You just need to increase it.

In addition, the relationship between the number of large-diameter units and the number of small-diameter units can be determined by referring to, for example, the value of the ratio of the size of the aperture, or the value of the ratio of the area of cone paper, etc. Determine the number of pieces, actually listen to the number of pieces, increase or decrease the number, listen again, and decide on the optimal number of pieces based on your hearing. For example, for a unit with a diameter of 5 cm and a unit with a diameter of 1 cm, first try listening to one unit with a diameter of 5 cm and five units with a diameter of 1 cm. Next, try listening to the music using four or six units with a diameter of 1 cm, and find the number that seems most preferable in terms of hearing sensation.

Note that the number can be more accurately determined by regarding a plurality of units as one speaker and determining its virtual sound source point. For example, a pulse signal is applied to a group of units that are considered as one unit, the sound that comes out is measured at a certain point, and the pulse sound is observed at the same time as the time observed at that measurement point. If you find the possible points one after another, you can identify the wavefront, so it is thought that you can find it using a method such as finding the center of that wavefront. Once the virtual sound source points have been determined in this way, arrange the virtual sound source points of each speaker unit group on the same plane, and arrange the unit groups so that the virtual sound source points of each speaker unit group are as close as possible to each other on that plane. Deploy. Ideally, the virtual sound source points should match. By doing so, the wavefronts of the sounds emitted from each unit group will completely match, resulting in a revolutionary sound quality improvement effect.

According to the audio device according to the embodiment described above, the radius of curvature of the wavefront of the sound emitted from the speaker device 10 differs greatly depending on the frequency, and the wavefronts of the sound emitted from the speaker device 10 may be separated from each other in the conventional audio device. In comparison, it is possible to make the radius of curvature of the wavefront almost constant regardless of the frequency, and to match each other's wavefronts as much as possible.In other words, it is possible to get closer to "ideal wavefront creation" and create a more natural wavefront. Now you can play sound. In addition, since the audio device according to this embodiment can perform ideal correction, it has become possible to "reproduce the waveform" of the music waveform engraved on the source. The audio device according to this embodiment is radically different from conventional audio devices in these two points, namely, "ideal wavefront creation" and "waveform reproduction." Therefore, the reproduced sound becomes a revolutionary reproduced sound that is different in dimension from the reproduced sound by conventional audio devices.

FIG. 8 is an explanatory diagram of a speaker device according to another embodiment of the present invention. As shown in FIG. 8, in the speaker device according to this embodiment, by changing the front-to-back positional relationship between a relatively large-diameter speaker unit group and a relatively small-diameter speaker unit group, both units are This reduces the difference in the radius of curvature of the wavefront depending on the group. That is, the mid-high sound speaker unit MH1 is arranged on the surface S1 which is a distance d1 from the reference surface S0, and the treble speaker unit H1 is arranged on the surface S2 which is a distance d2 which is farther from the reference surface S0 than the distance d1. This is what I did. Although a description of the speaker box and the like having such a configuration will be omitted, the configuration is substantially the same as that of the previous embodiment except for this difference in configuration.

The relationship between d1 and d2 can be determined by, for example, determining a candidate value based on the value of the difference in aperture between both speaker units, actually listening to the candidate value, increasing or decreasing that value, and then listening again. Then, determine the optimal value based on your sense of hearing. For example, for a unit with a diameter of 5 cm and a unit with a diameter of 1 cm, first try setting d1 = 25 cm and d2 = 29 cm for trial listening. Next, try listening with only d2 set to 28 cm or 30 cm, and find the value that seems most audible.

Furthermore, if the virtual sound source point of the mid-high sound speaker unit MH1 and the virtual sound source point of the high sound speaker unit H1 are known, the positional relationship between them can be determined more accurately. FIG. 9 is an explanatory diagram of a method for determining a virtual sound source point such as the mid-high sound speaker unit MH1. Now, assume that the cone paper C, which is the diaphragm of this speaker unit, has a circular shape with a diameter of 2L. Also, let the center point of this cone paper C be Co, and one end be C1. Assume that the virtual sound source point O is located at a distance A backward from Co on the center line Lc passing through the center point Co.

Then, the wavefront WMHn of the sound emitted from the paper cone C is the wavefront of the sound emitted from the virtual sound source point O. In other words, WMHn is a spherical surface with a radius R centered on the virtual sound source point O. Here, the point where the center line Lc of the cone paper C intersects with the wave surface WMHn is designated as Po, and the point where a straight line Lc1 passing through the center point Co of the cone paper C and parallel to the cone paper C intersects with the wave surface WMHn is designated as P1. Then, since the distance traveled to reach P0 and P1 on the same wavefront is the same, it follows that CoP0 and C1P1 are the same distance D.

Then, in triangle CoP1O,
(L+D) (L+D)+A×A=R×R
The relationship holds true. here,
R=D+A
It is. Therefore,
(L+D) (L+D)+A×A=(D+A)(D+A)
It is. Therefore,
A=L+L×L÷2D
becomes.

FIG. 10 is an explanatory diagram of the arrangement relationship of the speaker units when the virtual sound source point OMH1 of the mid-high sound speaker unit MH1 and the virtual sound source point OH1 of the high sound speaker unit H1 are determined. In this case, the mid-high sound speaker unit MH1 is arranged so that the virtual sound source point OMH1 of the mid-high sound speaker unit MH1 is placed on the surface S3 which is located at a distance d3 farther from the reference plane S0 than d2. Next, the speaker unit H1 is arranged so that the virtual sound source point OH1 of the speaker unit H1 also lies on the surface S0. As a result, the radius of curvature RMH1 of the wavefront WMH1 of the sound emitted from the mid-high frequency speaker unit MH1 becomes equal to the radius of curvature RH1 of the wavefront WH1 of the sound emitted from the speaker unit H1.

According to experiments conducted by the inventor, it has been confirmed that when the radius of curvature RMH1 and the radius of curvature RH1 become equal, the auditory sense of sound is dramatically improved. Then, if the virtual sound source point OMH1 of the mid-high sound speaker unit MH1 and the virtual sound source point OH1 of the speaker unit H1 are further moved on the surface S3 and brought closer to each other as shown by the dotted line in FIG. It has been confirmed that the auditory sense of sound will further improve dramatically. Here, the fact that the virtual sound source points of speaker units MH1 and H1 become closer means that the wavefronts become closer to each other. In other words, it is thought that the closer the wavefronts are to each other, the better the perceived sound will be. When the virtual sound source points of two speakers completely overlap, their wavefronts also completely overlap. Therefore, this state is considered to be an ideal state. Therefore, it is desirable to get as close to the ideal state as the speaker arrangement allows.

This embodiment also provides substantially the same effects as the previous embodiment. However, this embodiment has the advantage that the number of speaker units used can be reduced compared to the previous embodiment. On the other hand, since the distance to the measurement microphone position during correction differs for each speaker unit, certain ingenuity is required in channel divider settings and correction algorithms. Note that the previous embodiment is advantageous compared to this embodiment in this respect.

In the embodiments described above, an example has been given of whether to select the relationship between the numbers of speaker units with a large diameter and the speaker units with a small diameter, or the relationship between the installation distances. Of course, the two methods may be combined. By doing so, it becomes possible to reduce the distance between speakers and the number of speakers used.

As described in detail above, according to the audio device according to the present invention, "ideal wavefront creation" is possible, and more natural sound can be reproduced. Furthermore, since the audio device according to the present invention can perform ideal correction, it is possible to "reproduce the waveform" of the music waveform engraved on the source. Furthermore, since the audio device according to the present invention can simultaneously realize "ideal wavefront creation" and "waveform reproduction," it is possible to obtain revolutionary reproduced sound that is different in dimension from the reproduced sound by conventional audio devices.

3 Digital channel divider 4 Preamplifier with sound field correction function 5 Sound source 10 Speaker device 11 Bass speaker unit group 12 Mid-bass speaker unit group 13 Mid-high speaker unit group 14 Treble speaker unit group 21 Bass amplifier 22 Mid-bass amplifier 23 Mid-high sound amplifier 24 treble amplifier 101 box member 102 damping sheet 103 sound absorbing member 104 sound absorbing panel

Claims (5)

The reproduction frequency region is divided into a plurality of frequency regions, and the reproduction of each frequency region is handled by a speaker unit group consisting of one or more speaker units, respectively.
The speaker unit group responsible for the relatively low frequency range is composed of speaker units with a relatively large diameter,
The unit group responsible for relatively high frequency ranges is composed of speaker units with a relatively small diameter,
The speaker unit group is a multi-way speaker device in which one or more speaker units can be regarded as one unit that virtually produces sound in the frequency range assigned to the speaker,
approximating the wavefront of the sound emitted from the speaker unit group as a spherical surface centered on the virtual sound source point of each unit group,
Based on the recognition that the ideal state is when the virtual sound source points of the respective unit groups overlap and the spherical surfaces of the wave fronts of the sounds emitted from the respective speaker unit groups overlap into one spherical surface,
so that the wavefront of the sound emitted from each unit group approaches one spherical surface,
The arrangement position of the relatively small diameter speaker unit group that produces the relatively high frequency sound is as follows:
With respect to the arrangement position of the relatively large diameter speaker unit group that produces sound with a relatively low frequency, it is set at a position further away from the listening position by a distance of AL-AH. Features speaker equipment.
However, AL is the distance from the diaphragm to the virtual sound source point when the diaphragm of the relatively large-diameter speaker unit group that produces sound at a relatively low frequency is approximated as one circular diaphragm. be.
In addition, AH is the distance from the diaphragm to the virtual sound source point when the diaphragm of the relatively small diameter speaker unit group that produces sound at a relatively high frequency is approximated as one circular diaphragm. be. 2. The speaker device according to claim 1, wherein each of the unit groups is arranged so that virtual sound source points of each of the unit groups lie on a common plane. 3. The units are arranged in a positional relationship such that the virtual sound source points of each unit group are as close as possible to each other in the arrangement relationship permitted by the structure of the units. speaker device. The virtual sound source point of each speaker unit or speaker unit group is
The diaphragm of the speaker unit or speaker unit group is approximated to one circular shape,
Let the aperture, which is the diameter of the circle, be 2L,
The distance between the wavefront of the sound emitted from the unit and the diaphragm is D,
When the virtual sound source point is located at a distance A behind the diaphragm on the central axis of the diaphragm,
4. The speaker device according to claim 1, wherein the value of A is determined by the formula A=L+(L×L÷2D). The reproduction frequency region is divided into a plurality of frequency regions, and the reproduction of each frequency region is handled by a speaker unit group consisting of one or more speaker units, respectively.
The speaker unit group responsible for the relatively low frequency range is composed of speaker units with a relatively large diameter,
The unit group responsible for relatively high frequency ranges is composed of speaker units with a relatively small diameter,
The speaker unit group is a multi-way speaker device in which one or more speaker units can be regarded as one unit that virtually produces sound in the frequency range assigned to the speaker,
The speaker device has a radius of curvature RLn of a spherical surface of a wavefront WLn of a relatively low frequency sound emitted from the relatively large diameter speaker unit group, and a relatively low frequency sound wavefront WLn emitted from the relatively small diameter speaker unit group. The radius of curvature RHn of the spherical surface of the wavefront WHn of high-frequency sound is approximated as the radius of curvature of a sphere centered on the virtual sound source point of each speaker unit group, and these wavefronts are set in front of this speaker device. The above ΔRn is possible based on the recognition that the ideal state is when the difference ΔRn between the radii of curvature RLn and RHn of these wavefronts is zero when they touch the reference plane S0. As close to zero as possible,
The number of speaker units constituting the relatively small diameter speaker unit group that produces the relatively high frequency sound,
A speaker device characterized in that the number of the relatively large-diameter speaker unit groups that emit sound at a relatively low frequency is greater than the number of speaker unit groups constituting the speaker unit group.

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