JP7489724B2 - Sound amplification structures and building wall structures - Google Patents

Description

The present invention relates to a sound amplification structure and a building wall structure.

There has traditionally been a demand for creating a realistic sound field. However, to provide a high-quality acoustic space, the speakers placed inside the building must be large, and installing such an acoustic space inside a building imposes constraints in terms of both space and floor load-bearing capacity.

As an attempt to resolve the constraints in terms of both space and floor load-bearing capacity when providing a high-quality acoustic space, for example, it has been proposed to use the foundation under the first floor of a building as a back-loaded horn for a speaker (see Patent Document 1). The invention described in Patent Document 1 has the effect of realizing a realistic sound field inside a building without increasing the size of the speakers placed inside the building.

Patent No. 7017826

However, the invention described in Patent Document 1 uses the foundation under the floor of the first floor of a building as a back-loaded horn for the speaker, so there is room for further improvement in terms of providing a back-loaded horn on floors other than the first floor of a building.

In addition, the invention described in Patent Document 1 requires work to renovate the underfloor foundation if a back-loaded horn or the like is to be installed at a time other than when a building is newly constructed. There are concerns that such work will be a burden for the building manager and/or users, etc.

The present invention was made to solve the problems of the conventional technology as described above, and aims to make it possible to realize a realistic sound field on any floor in a building without increasing the size of the speakers placed in the building, and without having to renovate the foundations under the floor, even when installing speakers after the building is newly constructed.

As a result of intensive research into solving the above problems, the inventors discovered that the above problems could be solved by providing a structure equivalent to the tubular structure that amplifies sound in a back-loaded horn speaker within the building's wall, rather than in the building's underfloor foundation, and thus completed the present invention. Specifically, the present invention provides the following:

The invention according to the first aspect provides a sound amplification structure in which a space that can communicate with a speaker unit is formed within a wall of a building, a sound path that can communicate with this space at one end is further formed within this wall, the width of this sound path increases from one end to the other end of the sound path, and the other end of the sound path can output sound that is emitted from the speaker unit and amplified through this sound path to the outside of the wall, and the length of this sound path is 4m or more.

Speaker types include sealed, bass reflex, front-loaded, and back-loaded horn.

Back-loaded horn speakers are known to produce sound more efficiently than sealed, bass-reflex, and front-loaded speakers. This makes it possible to reproduce a realistic sound field with a sharp attack not only in the low-frequency range but across the entire effective range.

Thus, in terms of reproducing a realistic sound field, the back-loaded horn type is superior, but with the back-loaded horn type, a tubular structure several meters in length must be installed behind the speaker unit to amplify the sound, which creates the problem that the enclosure (also called a "case" or "cabinet") is larger than with other types. For this reason, back-loaded horn type speakers are not currently mass-produced in Japan.

According to the first aspect of the invention, a sound path equivalent to a tubular structure is provided inside the wall of a building, so there is no need to provide a long tubular structure on the housing of a speaker to be placed inside the building.

As a result, even though it is a large back-loaded horn type speaker system that uses a long sound path of over 4m in length, the size of the housing that houses the speaker unit is about the same as other types of sealed, bass reflex, and front-loaded types, making it possible to place it in a room.

In addition, according to the first aspect of the invention, a sound path equivalent to a tubular structure is provided inside the wall of a building, so that a back-loaded horn type large speaker system can be realized without repairing the foundation under the floor even when installing it after new construction, and without limiting the installation location to the first floor of the building.

Therefore, according to the first aspect of the invention, a realistic sound field can be realized on any floor in a building without increasing the size of the speakers placed in the building, and without having to renovate the foundations under the floors even when installing them after new construction.

The second aspect of the invention is the first aspect of the invention, which provides a sound amplifying structure in which the wall material includes concrete, and the space and sound path are defined by the concrete and the wall.

Whether they are sealed, bass reflex, front-loaded or back-loaded horn type, the enclosure is generally made of wood. However, wood is vulnerable to low-frequency vibrations, and distortion occurs in the low-frequency range of 20 Hz to 600 Hz. This means that there are limitations to how well it can reproduce the atmosphere of a live performance. It is particularly difficult to output low-frequency sound waves below 30 Hz and fully experience the atmosphere of a live performance, affecting not only one's senses and hearing, but also the vibrations caused by sound waves to the entire body.

According to the second aspect of the invention, the building walls are made of a material that includes concrete, the space and the sound path are defined by the concrete and the walls, and the length of the sound path is 4 m or more.

To improve the accuracy of bass reproduction, a longer sound path is preferable, but in a wooden enclosure, if the length of the sound path exceeds 3m, bass sounds will reach the ears later than mid- and high-pitched sounds, causing stress to the listener. On the other hand, concrete has physical properties that are stronger than wood. Therefore, in a sound path defined by concrete, there is no distortion caused by sound waves in the bass range.

In the invention relating to the second feature, the space and sound path are defined by concrete and walls, so even if the length of the sound path is 4m or more, there is no delay in the arrival of low-frequency sounds, and the listener can listen to the sound without stress.

In addition, in the invention relating to the second feature, since the material of the building walls contains concrete, the above-mentioned effect can be obtained by utilizing not only the concrete parts of the sound amplifying structure but also the concrete parts of the walls.

Therefore, according to the second aspect of the invention, a realistic sound field can be realized on any floor in a building without increasing the size of the speakers placed in the building, and without having to renovate the foundations under the floor, even when installing the speakers after the building is newly constructed.

The third aspect of the invention is the first or second aspect of the invention, which provides a sound amplification structure in which the sound path is U-shaped, Z-shaped, or zigzag-shaped.

The invention relating to the third feature makes it possible to arrange a sound path in a limited space within a wall, and attenuates mid- and high-range sounds in the sound path, minimizing the level difference between mid- and high-range sounds and low-range sounds.

Therefore, according to the third aspect of the invention, a realistic sound field can be realized on any floor in a building without increasing the size of the speakers placed in the building, and without having to renovate the floor foundations even when installing them after new construction.

The invention according to the fourth feature is an invention according to any one of the first to third features, which provides a sound amplifying structure in which at least a portion of the wall between the sound passage and the outside of the wall is capable of passing a portion of the sound emitted from the speaker unit to the outside of the wall.

According to the fourth aspect of the invention, a realistic sound field that envelops the listener can be realized inside the building by sound passing through part of the wall.

Therefore, according to the fourth aspect of the invention, a realistic sound field can be realized on any floor in a building without increasing the size of the speakers placed in the building, and without having to renovate the floor foundations even when installing them after new construction.

The present invention makes it possible to realize a realistic sound field on any floor in a building without increasing the size of the speakers placed in the building, and without having to renovate the floor foundations even when installing speakers after a new building is constructed.

FIG. 1 is a partial perspective view showing an outline of a speaker system S of the present embodiment as viewed from the front. FIG. 2 is a partial perspective view showing an outline of the speaker system S of this embodiment as viewed from the right side. FIG. 3 is a schematic diagram of the sound amplifying structure 1 seen from the front. FIG. 4 is an enlarged schematic view of the periphery of the space 11 in FIG. FIG. 5 is a schematic diagram of the speaker system S of this embodiment as viewed from the front.

The following describes in detail an example of an embodiment of the present invention with reference to the drawings.

<<Speaker System S>>
1 is a partial perspective view showing an outline of a speaker system S of this embodiment as seen from the front. The speaker system S is configured to include at least a speaker unit U and a building wall structure BW having a sound amplifying structure 1.

<Speaker unit U>
The speaker unit U is not particularly limited as long as it can convert an electric signal into sound and can output the sound from the front and rear sides. The speaker unit U can be arranged so that the rear side of the speaker unit U communicates with a space 11 of the sound amplifying structure 1 described later.

The speaker unit U is installed in the building wall structure BW so as to communicate with the space 11 of the sound amplifying structure 1 described below. It is preferable that the speaker unit U is installed in the building wall structure BW in a manner that is not easily visible from the indoor side of the building wall structure BW.

This allows users of the speaker system S to enjoy a richly realistic sound without being aware of the presence of the speaker unit U. There are no particular limitations on the means for installing the speaker unit U in the building wall structure BW in a manner that makes it difficult to see from the interior side of the building wall structure BW.

One example of such a means is to attach a planar member to the speaker unit U, which has a design on the interior side that is substantially the same as the interior side of the building wall structure BW when attached to the speaker unit U and is capable of transmitting sound. An example of such a planar member is a speaker component such as a saran net.

It is preferable that the speaker unit U includes a full-range speaker that does not use filter circuits (also called "filters," "wave filters," or "networks") such as a high-pass filter (also called "high-pass filter") and a low-pass filter (also called "low-pass filter").

The network can delay the phase of the electrical signal. The speaker unit U including a full-range speaker can output sound without using a network. This allows the speaker unit U including a full-range speaker to output sound that responds quickly to minute signals with high efficiency. Therefore, the speaker unit U including a full-range speaker can output sound that is more faithful to the original sound contained in the electrical signal and allows for the identification of minute sounds.

Full-range speakers generally have difficulty outputting low and high frequency sounds compared to mid-frequency sounds. The speaker system S of this embodiment can output rich sounds including low frequencies, even with speaker units U that include full-range speakers, by amplifying the sounds via the sound amplification structure 1 described below.

When the speaker unit U includes a full-range speaker, it is preferable that the speaker unit U is configured to combine a powerful magnetic circuit with a light diaphragm. This allows the speaker unit U to output sound with even faster response to minute signals and with even higher efficiency.

The speaker system S is preferably configured to include a left speaker unit group UL corresponding to the left audio channel, and a right speaker unit group UR corresponding to the right audio channel. The left speaker unit group UL includes one or more speaker units U corresponding to the left audio channel. The right speaker unit group UR includes one or more speaker units U corresponding to the right audio channel. This allows the speaker system S to play music, etc. in stereo.

The number of speaker units U included in each of the left speaker unit group UL and the right speaker unit group UR is not particularly limited, as long as it is 1 or more.

It is preferable that the number of speaker units U included in each of the left speaker unit group UL and the right speaker unit group UR is two or less. This makes the left speaker unit group UL and the right speaker unit group UR closer to a point sound source than when they include three or more speaker units U, and allows the output of sound in which the sound position, that is, the position of the sound, is more faithfully reproduced.

The number of speaker units U included in each of the left speaker unit group UL and the right speaker unit group UR is preferably two. This allows each of the left speaker unit group UL and the right speaker unit group UR to output a more powerful sound than if it included one speaker unit U, while maintaining a configuration close to that of a point sound source.

<Tweeter T>
When the speaker unit U includes a full-range speaker, the speaker system S may include a tweeter T capable of outputting high-frequency sounds with less distortion. This allows the speaker system S to output high-frequency sounds with less distortion even when the speaker unit U includes a full-range speaker.

When the speaker system S is configured to include a left speaker unit group UL and a right speaker unit group UR, it is preferable that the tweeter T is configured to include a left tweeter group TL corresponding to the left audio channel, and a right tweeter group TR corresponding to the right audio channel. The left tweeter group TL includes one or more tweeters T corresponding to the left audio channel. The right tweeter group TR includes one or more tweeters T corresponding to the right audio channel. This allows the tweeter T to reproduce high-frequency sounds in stereo.

<Building wall structure BW>
2 is a partial perspective view showing an outline of the speaker system S of this embodiment as seen from the right side. The building wall structure BW is formed inside a building side wall BS, which is a side wall of a building B. Hereinafter, the inside of the building side wall BS will also be simply referred to as "inside the wall". In addition to the building side wall BS, the building B includes one or more building structures exemplified by a building ceiling BC and a building floor BF, etc.

The material of the building side wall BS is not particularly limited, but preferably includes concrete. This can reduce the delay in the arrival of low-frequency sounds in the sound path 12 described below. This can also provide soundproofing so that the sound output by the speaker system S does not leak to the outside. It is more preferable that the main material of the part of the building side wall BS that defines the space 11 and the sound path 12 is concrete. The building wall structure BW at least includes a sound amplifying structure 1 formed within the wall.

The building side wall BS may be constructed to include materials other than concrete. Examples of such materials include heat insulating materials, plywood, and gypsum board. These materials are arranged, for example, on the indoor side of a concrete wall constructed as a soundproof wall. By constructing the building side wall BS to include materials other than concrete, the functionality of the building side wall BS as a wall can be improved.

[About sound transmission through building side wall BS]
It is preferable that at least a portion of the building side wall BS between the sound path 12 described later and the outside of the building side wall BS is capable of allowing a portion of the sound emitted from the speaker unit U to pass to the outside of the building side wall BS.

As a result, the speaker system S can create a realistic sound field within building B that envelops the listener by using sound that passes through part of the building's side wall BS.

[About stereo playback]
When the speaker system S is configured to include a left speaker unit group UL and a right speaker unit group UR, it is preferable that the building wall structure BW comprises a left building wall structure BWL corresponding to the left speaker unit group UL, and a right building wall structure BWR corresponding to the right speaker unit group UR.

This allows the left building wall structure BWL and the right building wall structure BWR to independently amplify the sound output by the left speaker unit group UL and the sound output by the right speaker unit group UR. This allows the building wall structure BW to amplify the stereo reproduced sound while still reproducing it in stereo.

In the following description, there may be cases where the various components of the speaker system S of this embodiment, exemplified by the speaker unit U, building wall structure BW, tweeter T, etc., are not indicated as being in a left-right pair or not, and/or as being left-right. Even in such cases, a person skilled in the art will understand that it is possible to configure a speaker system S suitable for stereo reproduction by arranging the various components of this embodiment in a left-right pair, approximately symmetrically, based on the description and drawings of this embodiment.

[Sound Amplification Structure 1]
3 is a schematic diagram of the sound amplifying structure 1 as viewed from the front. The sound amplifying structure 1 has a space 11 that can communicate with the speaker unit U, a sound path 12 that can communicate with the space 11, and a wall portion 13 that defines the space 11 and the sound path 12 together with a building side wall BS. Both the space 11 and the sound path 12 are formed within the wall.

[Space 11]
The space 11 includes a speaker unit communication portion 11A capable of communicating with the speaker unit U, and a sound path communication portion 11B capable of communicating with the sound path 12.

Figure 4 is a schematic diagram showing an enlarged view of the space 11 and its periphery in Figure 2. The space 11 formed inside the building side wall BS is connected to the rear surface of the speaker unit U at the speaker unit connection part 11A. Sound output from the rear surface of the speaker unit U passes from the speaker unit connection part 11A through the sound path connection part 11B and enters the sound path 12 from the first end part 12A of the sound path 12.

In FIG. 4, the speaker unit U is embedded inside the building side wall BS. This makes it possible to build a speaker system S using the speaker unit U without installing an enclosure for the speaker unit U on the indoor side of the building side wall BS.

Figure 5 is a schematic diagram of the speaker system S of this embodiment seen from the front. The speaker unit U in Figure 5 is embedded in the wall, and the enclosure does not protrude into the room. This allows the user of the speaker system S to more effectively utilize the space in the room in which the speaker system S is installed.

[Sound Path 12]
Returning to Fig. 3, the sound path 12 is formed inside the wall. The sound path 12 can communicate with the space 11 at a first end 12A which is one end of the sound path 12. The sound path 12 can output the sound that is output from the speaker unit U at a second end 12C which is the other end of the sound path 12 and amplified through the sound path 12 to the outside of the building side wall BS.

The width of the sound path 12 increases from the first end 12A toward the second end 12C. The upper limit of the ratio of the width of the sound path 12 at the second end 12C divided by the width of the sound path 12 at the first end 12A is preferably 4 or less, more preferably 3 or less, and even more preferably 2.5 or less. This can prevent sound from traveling straight away from the wall 13 and/or building side wall BS that define the sound path in the sound path 12, which widens suddenly.

The lower limit of the above ratio is preferably 1.3 or more, more preferably 1.5 or more, and even more preferably 2 or more. This further reduces the pressure of the sound output by the speaker unit U in the sound path 12. This further increases the displacement of the sound wave, and the sound is further amplified. This allows an amplified sound with even greater displacement to be output.

The lower limit of the length of the sound path 12 is preferably 4 m or more. This can further improve the accuracy of reproducing low-frequency sounds. The upper limit of the length of the sound path 12 is preferably 15 m or less, more preferably 8 m or less, and even more preferably 5 m or less. This can further prevent the occurrence of delays in the arrival of sounds amplified in the sound path 12.

(Curved portion 12B)
The sound path 12 preferably has a curved portion 12B. This allows the second end 12C to be arranged around the first end 12A. That is, the second end 12C that outputs amplified sound can be arranged around the speaker unit U arranged around the first end. This can reduce the difference in sound level between the sound output from the front of the speaker unit U and the amplified sound output from the second end 12C.

In FIG. 5, the speaker unit U is disposed around the second end 12C. This can reduce the difference in sound level between the sound output from the front of the speaker unit U and the amplified sound output from the second end 12C.

Returning to FIG. 3, the number of curved portions 12B is not particularly limited. It is preferable that the curved portions 12B are provided so that the shape of the sound path 12 is a combination of one or more of an approximately U-shape, an approximately Z-shape, and a zigzag shape. This makes it possible to arrange the sound path 12 in a limited space within the wall, and attenuates mid-range and high-range sounds, thereby minimizing the level difference between mid-range and high-range sounds and low-range sounds.

In particular, it is preferable that the curved portions 12B are provided so that the shape of the sound path 12 is a combination of approximately U-shapes. This minimizes the number of curved portions 12B, and further prevents low-frequency sounds from attenuating in the curved portions 12B of the sound path 12.

[Wall portion 13]
The wall portion 13 is disposed within the wall, and together with the building side wall BS, defines the space 11 and the sound path 12. The wall portion 13 is not particularly limited. The wall portion 13 may include a pillar of the building B.

The material of the wall portion 13 is not particularly limited, but preferably includes concrete. If the material of the wall portion 13 includes concrete, it is more preferable that the main material of the wall portion 13 is concrete.

To improve the accuracy of bass reproduction, a longer sound path is preferable, but in a wooden enclosure, if the length of the sound path exceeds 3 m, bass sounds will reach the ears later than mid- and high-pitched sounds, causing stress to the listener. On the other hand, concrete has physical properties that are stronger than wood. Therefore, in a sound path 12 defined by concrete, there is no distortion caused by sound waves in the bass range.

By using concrete as the material for the wall 13, the space 11 and the sound path 12 can be defined by the concrete and the building side wall BS. As a result, even if the length of the sound path 12 is 4m or more, there is no delay in the arrival of low-frequency sounds, and the listener can hear the sounds without stress.

In particular, when the material of the building side wall BS and the material of the wall portion 13 both contain concrete, the space 11 and the sound path 12 can be defined by concrete. This means that even if the length of the sound path is 4 m or more, there is no delay in the arrival of low-frequency sounds, and listeners can hear the sounds without stress.

[Effect of sound amplification structure 1]
There are three types of speakers: sealed, bass reflex, front-loaded, and back-loaded horn. Back-loaded horn speakers are known to produce sound more efficiently than sealed, bass reflex, and front-loaded speakers. Therefore, they can reproduce a realistic sound field with a sharp attack not only in the low frequency range but also in the entire effective frequency range.

Thus, in terms of reproducing a realistic sound field, the back-loaded horn type is superior, but with the back-loaded horn type, a tubular structure several meters in length must be placed behind the speaker unit, which means the enclosure (also called a "case" or "cabinet") is larger than with other types, which is an issue. For this reason, back-loaded horn type speakers are not currently mass-produced in Japan.

In this embodiment, the sound path 12 corresponding to the tubular structure is provided inside the wall of building B, so there is no need to provide a long tubular structure on the housing of the speaker placed inside building B.

As a result, even though it is a large back-loaded horn type speaker system that uses a long sound path 12 of 4 m or more in length, it is possible to position the speaker unit U so that the speaker enclosure does not protrude into the room.

As a way to provide a tubular structure inside a building, there is a technique for providing a sound channel in the subfloor foundation (Patent Document 1). However, when adding a sound channel to the subfloor foundation of an existing house, the subfloor foundation needs to be renovated. Furthermore, with the technique for providing a sound channel in the subfloor foundation, the applicable floors may be limited to floors directly above the building foundation, such as the first floor of a building.

In this embodiment, the sound channel 12, which corresponds to a tubular structure, is provided inside the wall of the building B, so that even when the system is installed after a new building is constructed, it is possible to realize a large back-loaded horn type speaker system without having to renovate the foundation under the floor, and without limiting the installation location to the floor directly above the building foundation.

As a result, the speaker system S of this embodiment can create a realistic sound field on any floor in building B without increasing the size of the speakers placed in building B, and without having to renovate the foundations under the floors even when installing the speaker system after new construction. In other words, the speaker system S of this embodiment can be realized not only on the first floor of building B, which does not have a basement, but also on floors that are not directly above the building foundations, such as the second or higher floors above ground.

[Other components]
[Installation section 2]
The building wall structure BW is preferably a structure in which an installation section 2 in which the playback device P, the amplifier A, etc. can be installed is formed inside the wall (FIG. 5). This allows not only the speaker unit U but also the playback device P, the amplifier A, etc. to be arranged inside the wall. This allows the user of the speaker system S to more effectively utilize the space in the room in which the speaker system S is installed.

[Regarding not installing a subwoofer]
The speaker system S of this embodiment is preferably configured without a subwoofer. This allows the speaker system S to utilize a wider area inside the building wall structure BW, which has a more limited volume than the underfloor foundation, as a back-loaded horn. This also allows the speaker system S to form an installation section 2 inside the building wall structure BW. This also allows the speaker system S of this embodiment to prevent the sound image in the low-frequency range from becoming blurred due to the low-frequency sounds amplified by the sound path 12 and the low-frequency sounds from the subwoofer.

[Effects of building wall structure BW]
As described above, according to the building wall structure BW of the embodiment, the sound amplifying structure 1 formed in the wall amplifies sound. As a result, the building wall structure BW of the embodiment can realize a realistic sound field in the house without enlarging the size of the speaker.

Speaker devices that are placed on a floor or the like have size and weight limitations due to the strength of the floor or the like. The building wall structure BW of this embodiment can eliminate size and weight limitations by forming the back-loaded horn portion as the sound amplification structure 1 inside the wall. This allows for a large sound amplification structure 1 to be realized that is made of concrete, and can dramatically improve acoustic performance, especially in low-frequency reproduction, without distortion that pollutes the sound.

The building wall structure BW of this embodiment can be formed inside the wall, and can be provided to double as the building side wall BS. This allows the building wall structure BW to be constructed at the same time as residential construction work such as house construction or wall remodeling work. This provides a new option for residential construction work, which is to provide the building wall structure BW.

The building wall structure BW of this embodiment is formed inside the wall, so that a realistic sound field can be realized on any floor in building B without increasing the size of the speakers placed in building B, and without having to renovate the underfloor foundations even when installing them after new construction.

The building wall structure BW of this embodiment not only improves acoustic performance, especially in low-frequency reproduction, but also makes effective use of the space within the walls, providing homes with the ability to play music with excellent sound quality, given the housing situation in Japan, where land area is limited.

The experience of hearing air vibrations with the ears is different from the experience of feeling vibrations through the shaking of a building in addition to the vibrations of the air. For example, the sense of fear and the vividness of the experience may differ when listening to earthquake vibrations as sound through headphones and when feeling earthquake vibrations including shaking at an earthquake experience facility.

The building wall structure BW of this embodiment amplifies sound by using the space within the wall, so that not only the sound of the speaker unit U vibrating the air, but also the sound waves, vibrations, and/or vibrations caused by the building wall structure BW can be transmitted to the entire body of a person via the building side wall BS. As a result, the building wall structure BW can give people an emotional response through vivid sound, not only through the hearing of the human ears, but also through other senses possessed by the entire human body.

The building wall structure BW of this embodiment can provide a speaker system S that is larger than a speaker that uses a wooden enclosure. In addition, because the building wall structure BW is formed inside the wall, the sound amplification structure 1 can be realized with a large weight that makes it difficult to place it on the floor, and the problem of wooden enclosures being vulnerable to low-frequency vibrations can be solved.

The building wall structure BW of this embodiment has a back-loaded horn type sound amplification structure 1, and therefore, in comparison with the sealed and bass reflex types, can achieve good response (also called "transient"), capable of following instantaneous signal changes and sound rise and fall with a shorter delay. By being able to achieve excellent transients, an even better speaker system S can be realized as a pure audio system that converts information recorded on media such as CDs, records, and tapes into sound as faithfully as possible and outputs it.

The sound amplification structure 1 of this embodiment is a back-loaded horn type, so the rear of the speaker unit U is not blocked. This allows the sound amplification structure 1 to output a smaller signal as sound than the sealed and bass reflex types. This allows the sound amplification structure 1 to achieve a larger dynamic range than the sealed and bass reflex types.

In particular, when the material of the building side wall BS includes concrete and the space 11 and the sound path 12 are defined by the concrete and the building side wall BS, the building wall structure BW of this embodiment utilizes the strength, large mass, and large weight of the concrete to enable low-frequency sounds to be reproduced clearly with little distortion.

<Example of using Speaker System S>
The following is a description of an example of how to use the speaker system S in this embodiment. In the following description, a user of the speaker system S is also simply referred to as a "user."

[Connection of playback device P and amplifier A]
The user connects the playback device P to the amplifier A using appropriate wiring, etc., so that the amplifier A can amplify the electrical signal output from the playback device P. Furthermore, the user connects the amplifier A to two speaker units U on each side using appropriate wiring, etc., so that these speaker units U can output sound based on the amplified electrical signal.

[Music playback]
A user loads a medium such as a compact disc into the playback device P, and causes the playback device P to output an electrical signal corresponding to the sound recorded on the medium. The electrical signal output by the playback device P is amplified by an amplifier A and converted into sound in each of the speaker units U. The converted sound is then output from the front and rear of each of the speaker units U.

[Amplification of low-frequency sounds]
The sound output from the rear surface of the speaker unit U is amplified in the sound amplifying structure 1 and output from the second end 12C of the sound path 12.

[Listening to music]
The user hears the sound output from the front of the speaker unit U and the sound output from the second end 12C of the sound path 12. That is, the user can hear the low-frequency sound amplified in the sound amplification structure 1 in addition to the sound output from the front of the speaker unit U. This allows the user to enjoy a realistic sound that does not feel any delay in the arrival of the low-frequency sound or distortion of the low-frequency sound, and that has a sharp rise, a sense of speed, and is firmly settled without muddiness.

The user can hear the sound output from the two speaker units U on each side, the left and right tweeters T, and the left and right second ends 12C. This allows the user to hear sound output from the speaker system S that has the properties of a surface sound source. The user can also hear sound output from the speaker system S that has a greater sense of thickness and scale.

One embodiment of the present invention has been described above. However, within the scope of the concept of the present invention, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, even if a person skilled in the art appropriately adds, deletes, or modifies the design of the above-described embodiment, or adds, omits, or modifies processes, these modifications are also included in the scope of the present invention as long as they maintain the essence of the present invention.

S Speaker system BW Building wall structure BWL Left building wall structure BWR Right building wall structure 1 Sound amplification structure 11 Space 11A Speaker unit connection part 11B Sound path connection part 12 Sound path 12A First end 12B Curved part 12C Second end 13 Wall part 2 Installation part B Building BS Building side wall BC Building ceiling BF Building floor P Reproducing device A Amplifier U Speaker unit UL Left speaker unit group UR Right speaker unit group T Tweeter TL Left tweeter group TR Right tweeter group

Claims (3)

A space capable of communicating with the speaker unit is formed within the wall of the building,
A sound passage capable of communicating with the space at one end is further formed in the wall,
The width of the sound path becomes wider from the one end to the other end of the sound path,
The other end of the sound path is capable of outputting the amplified sound through the sound path from the speaker unit to the outside of the wall,
The length of the sound path is 4 m or more,
A sound amplifying structure , wherein the material of the wall includes concrete, and the space and the sound passage are defined by the concrete and the wall . The sound amplification structure of claim 1, wherein the sound path is U-shaped, Z-shaped, or zigzag-shaped. 2. The method according to claim 1, wherein at least a part of a portion of the wall between the sound passage and the outside of the wall is capable of passing a part of the sound emitted from the speaker unit to the outside of the wall.
2. The sound amplifying structure according to claim 1 .

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