JP2020178336A - Diffuser, speaker including the same, and electronic musical instrument - Google Patents

Abstract

To provide a diffuser, a speaker including the same, and an electronic musical instrument that prevent large peaks from appearing on the sound pressure frequency characteristics due to resonance that tends to occur in a space between a diaphragm of the speaker and the diffuser, reduce the non-uniformity of the directional characteristics due to the frequency, and support a full range speaker having a wide frequency band of the emitted sound waves.SOLUTION: A diffuser includes a first reflective member having an opening whose outer diameter is larger than the outer diameter of a diaphragm and which defines the inner diameter through which the central axis that defines a direction in which the diaphragm vibrates passes, and having a substantially truncated conical shape having an annular pyramid surface facing the diaphragm and an annular concave surface formed on the opposite side of the annular pyramid surface, and a substantially conical second reflective member that is placed in close proximity to the first reflective member and has a conical surface with a central axis passing through its apex.SELECTED DRAWING: Figure 1

Description

The present invention relates to a diffuser that is arranged so as to face the diaphragm of a speaker that emits sound waves and that radiates sound waves in the outer radial direction to realize omnidirectional characteristics, and a speaker and an electronic musical instrument provided with the diffuser.

In an electrokinetic speaker having a diaphragm that vibrates and emits sound waves, the sound pressure level is almost one in the outer radial direction in the low frequency band where the wavelength of the sound waves radiated relative to the diaphragm diameter is relatively long. It tends to be omnidirectional. On the other hand, the higher the frequency band in which the wavelength of the sound wave radiated with respect to the diameter of the diaphragm becomes shorter, the higher the sound pressure of the sound wave radiated in the front direction where the diaphragm vibrates, and the sound pressure radiated in the side direction increases. It tends to have a directional characteristic that lowers the sound pressure.

In a normal speaker system in which a speaker is mounted in a cabinet, the radiation characteristic tends to have a directivity characteristic, so that there is a problem that the reproduced sound quality changes depending on the orientation of the speaker with respect to the listener. Therefore, there has been a conventional method in which a diffuser attached so as to face the diaphragm of a speaker is provided to change the directivity characteristic of sound wave radiation. For example, some diffusers that change to omnidirectional characteristics include a substantially conical reflector that reflects sound waves radiated from a diaphragm (Patent Document 1). The diffuser, which is a reflector, is sometimes called a reflector.

There are various types of speakers equipped with a diffuser that seeks to achieve omnidirectional characteristics. In the case of a full-range speaker, one having one substantially conical reflector arranged so as to face the diaphragm is typical. In addition, in a multi-way speaker system in which the reproduction frequency band is divided into bands and composed of multiple speakers, a diffuser is provided in the full-range speaker, squawker, or tweeter that reproduces the mid-high range, and the omnidirectional characteristics are provided in all bands. It may be realized. Some woofers that reproduce low frequencies that are close to omnidirectional characteristics are only mounted on the cabinet and do not have a diffuser.

The shape of the diaphragm of the speaker, the shape of the corresponding diffuser, and their arrangement affect the quality of the reproduced sound and the sound pressure frequency characteristics. In particular, there is a problem that a large peak is likely to appear on the sound pressure frequency characteristic due to resonance that tends to occur in the space between the diaphragm of the speaker and the diffuser. Further, particularly in the case of a full-range speaker, since the frequency band of the radiated sound wave is wide, there is a problem that it is difficult for one reflector to correspond from a low frequency having a long wavelength to a high frequency having a short wavelength.

Conventionally, the speaker is housed in the uppermost portion of the bell-shaped enclosure, and a horizontal annular opening is formed in the peripheral wall portion of the enclosure, and the sound from the speaker is transmitted to the inside of the enclosure. There is a carillon type speaker system characterized by forming an acoustic guide for guiding to an annular opening (Patent Document 2). Further, conventionally, the sources of acoustic waves having a frequency higher than the upper limit of wooha are arranged on the same surface, and the transcript signal is reflected / diffracted in the direction perpendicular to this surface. There is an omnidirectional radiation device for acoustic waves that radiates along with the system (Patent Document 3).

Further, conventionally, an acoustic reflector having a truncated cone shape including a generally conical outer surface, an upper surface, and a conical shaft, and having an opening in the upper surface centered on the conical shaft. There is an omnidirectional acoustic deflector characterized by including a reflector and a sound absorbing material arranged in the opening on the upper surface (Patent Document 4). Further, in an electronic musical instrument, for example, there is a speaker box in which a musical sound is sounded downward from a speaker, and the pronounced music sound is diffused by a diffuser to be sounded to the side of the electronic musical instrument (). Patent Document 5).

Jikkensho 56-41431 (Fig. 1) Jitsukaisho 64-47189 Japanese Unexamined Patent Publication No. 55-13592 Special Table 2018-504056 Japanese Patent No. 4646765 (Fig. 9)

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to have a large peak on the sound pressure frequency characteristic due to resonance that tends to occur in the space between the diaphragm of the speaker and the diffuser. To provide a diffuser that prevents the appearance of sound waves, reduces the non-uniformity of the directional characteristics due to frequency, and supports a full-range speaker with a wide frequency band of emitted sound waves, and a speaker and an electronic instrument equipped with the diffuser. It is in.

The diffuser of the present invention is a diffuser arranged so as to face the diaphragm of a speaker that emits sound waves, and its outer diameter dimension is larger than the outer diameter dimension of the diaphragm, and defines the direction in which the diaphragm vibrates. A first reflective member having a substantially truncated conical shape, having an opening through which the central axis is passed and defining the inner diameter dimension, and having an annular pyramid surface facing the diaphragm and an annular concave surface formed on the opposite side of the annular pyramid surface. A second reflecting member having a substantially conical shape, which is arranged in close proximity to the first reflecting member and has a conical surface whose central axis passes through the apex thereof, and a diaphragm and an annular pyramid surface of the first reflecting member. A first acoustic path is formed in which sound waves propagate and radiate sound waves in the outer radial direction, and an opening of the first reflective member is formed between the annular concave surface of the first reflective member and the conical surface of the second reflective member. The passed sound wave propagates to form a second acoustic path that radiates the sound wave in the outer radial direction.

Preferably, in the diffuser of the present invention, the outer diameter dimension of the second reflecting member is larger than the inner diameter dimension of the opening of the first reflecting member.

Preferably, in the diffuser of the present invention, the first reflecting member and the second reflecting member are arranged so that at least a part of the second reflecting member fits in the concave space defined by the annular concave surface of the first reflecting member. ..

Further, preferably, in the diffuser of the present invention, the cross-sectional curve defining the conical surface of the second reflecting member has a cross-sectional curve defining the annular concave surface of the first reflecting member and the separation distance defined in the direction along the central axis. It is set so that it is not equidistant.

Further, preferably, the diffuser of the present invention further includes a connecting member that connects the first reflecting member and the second reflecting member so as to form a second acoustic passage.

Further, preferably, the diffuser of the present invention includes a speaker mounting member and a first reflecting member, which are mounted by arranging and mounting the diaphragm of the speaker so as to face the annular conical surface of the first reflecting member and form the first acoustic passage. Further includes a connecting member for connecting the speaker mounting member and the speaker mounting member so as to form a first acoustic passage.

Further, preferably, the diffuser of the present invention is further provided with a grill member formed of a breathable member and provided in the first acoustic passage and / or the second acoustic passage.

Further, preferably, in the diffuser of the present invention, the inner diameter dimension of the first reflecting member and the outer diameter dimension of the second reflecting member are defined by a circle, and the outer diameter dimension of the first reflecting member is defined by an oval shape.

Further, the speaker of the present invention includes at least the above-mentioned diffuser and a diaphragm arranged so as to face the diffuser.

Further, preferably, the speaker of the present invention has a cone shape in which the diaphragm forms a concave surface corresponding to the annular cone surface of the first reflecting member, and convex dust is formed at a position facing the opening of the first reflecting member. Has a cap.

Further, the electronic musical instrument of the present invention includes at least the above-mentioned diffuser, a speaker having at least a diaphragm arranged so as to face the diffuser, and a housing to which the diffuser and the speaker are attached.

Further, preferably, in the electronic musical instrument of the present invention, the sound absorbing member is further attached to at least one of the annular conical surface of the first reflective member and the attachment surface to which the speaker of the housing is attached.

Hereinafter, the operation of the present invention will be described.

The diffuser of the present invention is arranged so as to face the diaphragm of the speaker that radiates sound waves, and radiates sound waves in the outer diameter direction to realize omnidirectional characteristics. The diffuser has an outer diameter dimension similar to that of a diaphragm, has an opening through which a central axis defining the direction in which the diaphragm vibrates passes and defines an inner diameter dimension, and an annular conical surface and an annular cone facing the diaphragm. A substantially conical first reflective member having an annular concave surface formed on the opposite side of the surface, and a substantially conical surface having a conical surface arranged close to the first reflective member and having a central axis passing through its apex. The second reflective member of the above is provided.

Therefore, the diffuser forms a first acoustic path in which sound waves propagate between the vibrating plate and the annular pyramidal surface of the first reflecting member to radiate the sound waves in the outer radial direction, and the annular concave surface of the first reflecting member and the first 2 A second acoustic path is formed in which sound waves that have passed through the opening of the first reflective member propagate between the conical surface of the reflective member and emit sound waves in the outer radial direction. Since the first reflective member close to the diaphragm is provided with an opening, resonance that tends to occur in the space between the diaphragm and the diaphragm does not occur, and a large peak does not appear on the sound pressure frequency characteristics. The omnidirectional characteristic of the bass range can be realized. On the other hand, a high frequency sound wave having a short wavelength passing through the opening of the first reflecting member is reflected by the second reflecting member having a substantially conical shape having no opening, so that omnidirectional characteristics in a high frequency range can also be realized. Preferably, the outer diameter dimension of the second reflecting member may be larger than the inner diameter dimension of the opening of the first reflecting member. Further, by reflecting the sound waves by the first reflecting member and the second reflecting member and propagating the sound waves, it is possible to reduce the non-uniformity of the directivity characteristics that differ depending on the frequency. As a result, it is possible to make a diffuser compatible with a full range speaker.

Here, in the diffuser, at least a part of the second reflecting member is defined as an annular concave surface of the first reflecting member so that the first reflecting member having a substantially conical shape and the second reflecting member having a substantially conical shape are close to each other. It is preferable that the first reflective member and the second reflective member are arranged so as to fit in the concave space. Further, the diffuser is provided so that the cross-sectional curve defining the conical surface of the second reflecting member is not equidistant from the cross-sectional curve defining the annular concave surface of the first reflecting member in the direction along the central axis. It is preferable that it is set. It is possible to suppress the occurrence of resonance in the first acoustic passage or the second acoustic passage and prevent the peak from appearing on the sound pressure frequency characteristic.

The diffuser includes a speaker mounting member in which the diaphragm of the speaker is arranged and mounted so as to face the annular conical surface of the first reflecting member to form a first acoustic passage, and the first reflecting member and the second reflecting member. (2) A connecting member that is connected so as to form an acoustic passage may be further provided. Further, the speaker of the present invention may include at least this diffuser and a diaphragm arranged so as to face the diffuser. The diaphragm has a cone shape that forms a concave surface corresponding to the annular pyramidal surface of the first reflective member, and preferably has a convex dust cap at a position facing the opening of the first reflective member.

The diffuser may be made of a breathable member and may further include a grille member provided in the first acoustic passage and / or the second acoustic passage. The diaphragm of the speaker can be protected. The diffuser has an inner diameter dimension of the first reflecting member and an outer diameter dimension of the second reflecting member so as to correspond to an oval (including an elliptical shape and a track shape) speaker having a major axis direction and a minor axis direction. It may be defined by a circular shape, and the outer diameter dimension of the first reflective member may be defined by an oval shape.

Further, the electronic musical instrument may include at least the above-mentioned diffuser, a speaker having at least a diaphragm arranged so as to face the diffuser, and a housing to which the diffuser and the speaker are attached. An electronic musical instrument equipped with this diffuser and a speaker can obtain excellent reproduced sound quality with a sense of spaciousness due to its omnidirectional characteristics. The sound absorbing member may be further attached to at least one of the annular conical surface of the first reflective member or the attachment surface to which the speaker of the housing is attached.

The diffuser of the present invention prevents a large peak from appearing on the sound pressure frequency characteristics due to resonance that tends to occur in the space between the diaphragm of the speaker and the diffuser, reduces the non-uniformity of the directional characteristics due to the frequency, and radiates. It is possible to provide a diffuser that supports a full-range speaker having a wide frequency band of sound waves, a speaker equipped with the diffuser, and an electronic musical instrument.

It is sectional drawing explaining the diffuser which concerns on one Embodiment of this invention, and the speaker which comprises this. It is a perspective view explaining the diffuser which concerns on one Embodiment of this invention. It is a front view explaining the electronic musical instrument which concerns on one Embodiment of this invention. It is a top view explaining another diffuser which concerns on one Embodiment of this invention, and the speaker which comprises this. It is sectional drawing explaining another diffuser which concerns on one Embodiment of this invention, and the speaker which comprises this. It is a graph explaining the directivity characteristic of the speaker provided with another diffuser which concerns on one Embodiment of this invention. It is a graph explaining the directivity characteristic of the speaker provided with the diffuser of the comparative example. It is a graph explaining the directivity characteristic of the speaker provided with another diffuser which concerns on one Embodiment of this invention. It is a graph explaining the directivity characteristic of the speaker provided with another diffuser which concerns on one Embodiment of this invention. It is sectional drawing explaining another diffuser which concerns on one Embodiment of this invention, and the speaker which comprises this.

Hereinafter, a diffuser according to a preferred embodiment of the present invention, a speaker provided with the diffuser, and an electronic musical instrument will be described, but the present invention is not limited to these embodiments.

1 and 2 are diagrams illustrating a diffuser according to a preferred embodiment of the present invention and a speaker including the diffuser. Specifically, FIG. 1 is a cross-sectional view of a speaker 1 including a diffuser 10, and FIG. 2 is a perspective view of the diffuser 10 as viewed from the upper front side. The form of the diffuser 10 and the speaker 1 is not limited to the case of this embodiment. Further, illustration and description of the configurations of the diffuser 10 and the speaker 1 which are not necessary for the description of the present invention will be omitted.

The speaker 1 of this embodiment is an omnidirectional speaker system in which a diffuser 10 is attached so as to face the diaphragm 3 of the speaker unit 2 to realize omnidirectional characteristics. The speaker unit 2 is a full-range type electrodynamic speaker provided with a cone-shaped diaphragm 3 and reproduces the entire band from a low frequency to a high frequency.

Only the direct radiation type speaker unit 2 has a directional characteristic that the sound pressure of the sound wave radiated in the direction in which the diaphragm 3 vibrates increases in the mid-high range and the sound pressure of the sound wave radiated in the side surface direction decreases. Prone. Therefore, in the speaker 1 of the present embodiment, the diaphragm 3 of the speaker unit 2 is arranged toward the upper side (in the Z-axis direction shown in the drawing), and the diffuser 10 is provided so as to face the diaphragm 3 to provide the Z-axis. It is designed to have omnidirectional characteristics in the horizontal direction orthogonal to.

The speaker unit 2 is an electrokinetic speaker including a cone-shaped diaphragm 3 having a concave cross section. Since the bobbin of the voice coil 6 is connected to the inner diameter portion of the diaphragm 3, a dust cap 4 having a convex cross section is attached so as to cover the inner diameter portion. The inner diameter side of the flexible edge 5 is attached to the outer diameter portion of the diaphragm 3, and the diaphragm 3 that radiates sound waves and the diaphragm portion including the dust cap 4 are vibrably supported together with the damper. The coil wound around the bobbin of the voice coil 6 is arranged in the magnetic gap of the magnetic circuit 7. The frame 8 is connected to the outer diameter side of the edge 5 and the magnetic circuit 7.

Therefore, in the speaker unit 2, when the voice signal current is supplied to the coil of the voice coil 6 arranged in the magnetic gap of the magnetic circuit 7 in which a strong DC magnetic field is generated, a driving force is generated in the Z-axis direction shown in the drawing. , The speaker vibration system including the voice coil 6, the diaphragm 3 and the dust cap 4 vibrates in the Z-axis direction. As a result, a pressure change is generated in the air existing before and after the diaphragm 33 and the dust cap 4, and the voice signal current is converted into sound waves (voice).

The frame 8 of the speaker unit 2 is attached to the opening of the attachment surface 9a provided on the upper surface side of the cabinet 9. The cabinet 9 of this embodiment is a closed cabinet that functions as a baffle that acoustically separates one side and the other side of the diaphragm 3. However, the cabinet 9 may be a phase inversion type (bass reflex type) cabinet or the like in which the acoustic capacity defined inside the cabinet 9 and the acoustic mass in the duct resonate.

A diffuser 10 is further provided on the mounting surface 9a on the upper surface side of the cabinet 9 so as to face the diaphragm 3 of the speaker unit 2 that radiates sound waves. As shown in FIGS. 1 and 2, the diffuser 10 is configured by combining two reflecting members. Specifically, the diffuser 10 includes a first reflective member 11 including a substantially truncated cone-shaped portion, and a second reflective member 12 having a substantially conical shape.

The first reflective member 11 and the second reflective member 12 are connected by the connecting member 13. Further, the first reflective member 11 and the cabinet 9 are connected by the connecting member 14. The connecting member 14 has the first reflective member 11 and the cabinet 9 so that the diaphragm 3 and the dust cap 4 of the speaker unit 2 which vibrates and is displaced so as to protrude to the maximum do not come into contact with the diffuser 10. Separate and connect.

The first reflective member 11 has a substrate having an annular conical surface 15 facing the diaphragm 3 and an annular concave surface 16 formed on the opposite side of the annular conical surface 15. The first reflective member 11 further has an opening 17 through which the Z axis, which is the central axis defining the direction in which the diaphragm 3 vibrates, passes and defines the inner diameter dimension. Further, in the present embodiment, the first reflective member 11 has a substantially square outer shape, the outer diameter dimension is larger than the outer diameter dimension of the diaphragm 3, and the radial dimension R1 defining the opening 17 vibrates. It is smaller than the outer diameter of the plate 3. The outer shape of the first reflective member 11 is not limited to a square, and may be circular or polygonal.

The first reflective member 11 has a substrate formed by processing a member having a predetermined thickness. Therefore, the concave annular concave surface 16 can be formed on the back surface side of the convex annular conical surface 15. In this embodiment, the cross-sectional curves defining the annular conical surface 15 and the annular concave surface 16 are substantially straight lines. Further, the first reflective member 11 having the annular pyramid surface 15 has a substantially truncated conical shape as if the top of the cone was cut off when viewed from the speaker unit 2, and the cut-off top is located. The shape is such that an opening 17 for ventilating is provided toward the annular concave surface 16 on the back side thereof.

On the other hand, the second reflective member 12 has a substantially conical substrate having a conical surface 18 on which the Z axis, which is the central axis, passes through the apex thereof. The second reflecting member 12 has a conical apex arranged on the lower side near the diaphragm 3 of the speaker unit 2 and the opening 17 of the first reflecting member 11, and the flat surface 19 defined by the outer diameter dimension R2 thereof is the diaphragm 3. It is located on the upper side far from. In this embodiment, the cross-sectional curve defining the conical surface 18 is a substantially straight line, which is not parallel to the straight line defining the cross section of the annular conical surface 15 and the annular concave surface 16. The outer diameter dimension R2 that defines the plane 19 is set to be at least larger than the radial dimension R1 that defines the opening 17 of the first reflective member 11. No opening is provided in the conical conical surface 18.

In the diffuser 10 of this embodiment, as shown in FIGS. 1 and 2, a first part of the second reflective member 12 fits in the concave space defined by the annular concave surface 16 of the first reflective member 11. The reflective member 11 and the second reflective member 12 are connected and arranged by the connecting member 13. Specifically, the first reflective member 11 and the second reflective member 12 are close to each other so that the apex of the conical surface 18 of the second reflective member 12 faces the opening 17 of the first reflective member 11. However, the second reflective member 12 does not block the opening 17 of the first reflective member 11.

The diffuser 10 is connected to the upper surface side of the cabinet 9 to which the speaker unit 2 is attached by a connecting member 14. Therefore, the diffuser 10 forms a first acoustic passage 21 in which sound waves propagate and radiate sound waves in the outer diameter direction between the diaphragm 3 of the speaker unit 2 and the annular conical surface 15 of the first reflecting member 11. .. The first acoustic passage 21 is also formed by the upper surface side of the cabinet 9 and the annular conical surface 15 of the first reflection member 11. The first acoustic passage 21 changes so that its cross-sectional area increases as the radius from the central axis Z increases.

Further, in the diffuser 10, sound waves that have passed through the opening 17 of the first reflective member 11 propagate between the annular concave surface 16 of the first reflective member 11 and the conical surface 18 of the second reflective member 12 arranged close to each other. A second acoustic passage 22 that radiates sound waves in the outer radial direction is formed. The second acoustic passage 22 changes so that its cross-sectional area increases as the radius from the central axis Z increases.

That is, as shown in FIG. 2, assuming that the separation distance between the annular concave surface 16 of the first reflection member 11 and the conical surface 18 of the second reflection member 12 in the direction along the central axis is Z0, the separation distance Z0 is the central axis. It changes depending on the radius from Z. Since the cross-sectional curve defining the conical surface 18 of the second reflecting member 12 is a straight line and the cross-sectional curve defining the annular concave surface 16 of the first reflecting member 11 is a straight line having different angles, it is defined in the direction along the central axis. The separation distance is set so that they are not equal. As a result, in the second acoustic passage 22, the separation distance Z0 does not become equidistant, but changes so as to increase as the radius from the central axis Z increases.

The speaker 1 of this embodiment synthesizes a sound wave radiated through the first acoustic passage 21 of the diffuser 10 and a sound wave radiated through the second acoustic passage 22 to reproduce sound.

In the full-range type electrodynamic speaker unit 2 that reproduces the entire band, both low-frequency sound waves having a long wavelength and high-frequency sound waves having a short wavelength are radiated from the vibrating diaphragm 3 and the dust cap 4. However, in the actual electrokinetic speaker unit 2, the diaphragm 3 and the dust cap 4 can vibrate substantially in the piston in the mid-low range, but the diaphragm 3 vibrates separately in the mid-high range, so vibration occurs. The central portion of the plate 3 and the dust cap 4 mainly contribute to the radiation of sound waves in the mid-high range.

Therefore, in the diffuser 10 of the present embodiment, the first reflecting member 11 having an outer diameter larger than that of the diaphragm 3 reflects sound waves having a relatively long wavelength and a low frequency to realize omnidirectional characteristics. To do. On the other hand, since the first reflective member 11 close to the diaphragm 3 is provided with an opening 17 having a radius dimension R1 smaller than the outer diameter dimension of the diaphragm 3, the central portion of the diaphragm 3 and the dust cap 4 are provided. The sound waves in the relatively mid-high range radiated from the above pass through the opening 17 of the first reflecting member 11 and are reflected by the second reflecting member 12 to realize the omnidirectional characteristic.

In a conventional (not shown) speaker equipped with a single diffuser (not shown) that attempts to realize omnidirectional characteristics, the resonance that tends to occur in the space between the diaphragm of the speaker and the diffuser causes a large sound pressure frequency characteristic. Peaks are likely to appear.

However, in the speaker 1 provided with the diffuser 10 of the present embodiment, since the opening 17 of the first reflecting member 11 faces the space 20 between the diaphragm 3 of the speaker unit 2 and the diffuser 10, resonance is unlikely to occur. can do. As a result, the omnidirectional characteristic in the mid-low range can be realized by preventing a large peak from appearing on the sound pressure frequency characteristic, and the omnidirectional characteristic in the mid-high range can also be realized.

Further, in the diffuser 10 of the present embodiment, the sound wave radiated through the second acoustic passage 22 is radiated upward from the horizontal direction. Therefore, not only the horizontal direction but also the vertical direction can be widened.

Preferably, in the diffuser 10, the radius dimension R1 of the opening 17 of the first reflecting member 11 is smaller than the outer diameter dimension of the diaphragm 3, and the outer diameter dimension R2 defining the plane 19 of the second reflecting member 12 is the radius. It may be larger than the dimension R1. Further, the diffuser 10 may be arranged so that at least a part of the second reflective member 12 fits in the concave space defined by the annular concave surface 16 of the first reflective member 11.

In the diffuser 10 of the present embodiment, the cross-sectional curves defining the annular conical surface 15 and the annular concave surface 16 of the first reflecting member 11 and the conical surface 18 of the second reflecting member 12 are substantially straight lines, respectively. However, the cross section of these reflecting surfaces may be configured to be defined by a plurality of continuous straight lines or curves that change non-linearly. The separation distance Z0 defined in the direction along the central axis is set so as not to be equidistant, and the cross-sectional area of the first acoustic passage 21 and the second acoustic passage 22 increases as the radius from the central axis Z increases. It may be another cross-sectional curve as long as it changes as follows.

Further, since the first acoustic passage 21 is also formed by the mounting surface 9a on the upper surface side of the cabinet 9 and the annular conical surface 15 of the first reflection member 11, the reflection of sound waves in the first acoustic passage 21 is appropriately controlled. However, even if the sound absorbing member 23 is attached to the annular conical surface 15 of the first reflective member 11 or the attachment surface 9a on the upper surface side of the cabinet 9, for example, as shown in the first acoustic passage 21 on the right side of FIG. Good. The sound absorbing member 23 may be attached to at least one of the annular conical surface 15 of the first reflective member 11 and the mounting surface 9a on the upper surface side of the cabinet 9.

Further, in the speaker 1 of the present embodiment, the diffuser 10 is connected to the speaker unit 2 via the cabinet 9. However, the diffuser 10 and the speaker unit 2 provided with the diaphragm 3 may be directly connected so as to face each other. Further, if the diaphragm 3 included in the electrokinetic speaker unit 2 has a cone shape forming a concave surface, the shape of the dust cap 4 is suitable to be convex as in the present embodiment, but for example, the dust cap 4 is provided with a concave surface. Of course, it may be in the shape of, or another shape such as a double cone.

Further, in the speaker 1 of the present embodiment, the diffuser 10 is provided in the full-range speaker unit 2. However, the diffuser 10 may be provided in the speaker unit 2 of a woofer, squawker, tweeter or the like suitable for reproduction in a specific frequency band. Of course, the speaker 1 may be configured as a multi-way speaker system in which a plurality of speaker units are combined, and the diffuser 10 may be attached so as to face the diaphragm of any of the speaker units.

FIG. 3 is a diagram illustrating an electronic musical instrument according to a preferred embodiment of the present invention. Specifically, FIG. 3 is a front view (partial cross-sectional view) of an electronic piano 100 including speakers 1 including the diffuser 10 of the above embodiment as left and right speakers 1L and 1R. The form of the electronic piano 100 is not limited to the case of this embodiment. Further, illustration and description of the configuration of the electronic piano 100, which is not necessary for the description of the present invention, will be omitted.

The electronic piano 100 of the present embodiment outputs an audio signal corresponding to the keyboard from a sound source circuit (not shown) when the performer operates the keyboard 102, which is an operator provided in the housing 101. It is an electronic musical instrument that is amplified by an amplifier (not shown) and output to a speaker to reproduce the playing sound. The electronic piano 100 includes speakers 1L and 1R attached to the left and right sides of the upper surface side of the keyboard 102 of the housing 101, and speakers 30 attached to the lower surface side of the keyboard 102 of the housing 101, respectively. ..

The speakers 1L and 1R include the diffuser 10 of the above embodiment, and the diffuser 10 includes the first reflecting member 11 and the second reflecting member 12 as described above. Therefore, in the speaker unit 2 included in the speakers 1L and 1R, the diaphragm 3 vibrates in the vertical direction. The speaker 1L radiates the performance sound so as to have omnidirectional characteristics in the horizontal direction in response to the left audio signal of stereo reproduction. Further, the speaker 1R radiates the performance sound so as to have an omnidirectional characteristic in the horizontal direction in response to the right audio signal of stereo reproduction.

Further, the speaker 30 has a horizontally long cabinet, and includes a speaker 31L corresponding to the left audio signal of stereo reproduction on the left side thereof and a speaker 31R corresponding to the right audio signal of stereo reproduction on the right side thereof. The speakers 31L and 31R are provided with a plurality of speaker units arranged so that the diaphragm vibrates in the front-rear direction, and are not particularly provided with a diffuser or the like, so that they have a directional characteristic in which the sound pressure increases in the front direction. Therefore, the speakers 31L and 31R radiate the performance sound with directivity in the front direction corresponding to the left and right audio signals of the stereo reproduction, respectively. The speaker 30 may form a multi-way speaker system when the audio frequency bands reproduced by the plurality of speaker units of the speakers 31L and 31R are divided.

The speaker 30 will be arranged at the knee of the player of the electronic piano 100, and is suitable for reproducing the direct sound component of the performance sound of the electronic piano 100. On the other hand, the speakers 1L and 1R are suitable for reproducing the indirect sound component of the performance sound. The balance of the volume of the performance sound reproduced from the speaker 30 and the speakers 1L and 1R can be controlled by setting the electronic piano 100. By adopting such a configuration for the speaker of the electronic piano 100, it can be expected that the playing sound of the electronic piano 100 can be perceived by the performer and the listener as being close to the playing sound of the original acoustic piano.

Of course, the electronic piano 100 includes only the speakers 1L and 1R, and does not have to include the speaker 30. In that case, the speakers 1L and 1R may reproduce both the direct sound component and the indirect sound component of the performance sound.

The electronic piano 100 of this embodiment is an electronic musical instrument including a keyboard, but may be another electronic musical instrument.

4 and 5 are diagrams illustrating a diffuser according to a preferred embodiment of the present invention and a speaker including the diffuser. Specifically, FIG. 4 is a plan view of the speaker 1a provided with the diffuser 10a, and FIG. 5 is a cross-sectional view corresponding to the AA cross section of the speaker 1a mounted on the mounting surface 9a in FIG.

The diffuser 10a and the speaker 1a of this embodiment have the same configuration as the diffuser 10 and the speaker 1 of the previous embodiment except that some configurations are different. Therefore, in the following, common configurations will be designated by common reference numerals and description will be omitted, and different configurations will be described. The configurations of the diffuser 10a and the speaker 1a, which are not necessary for the description of the present invention, are not shown or described.

The diffuser 10a of this embodiment is formed in a rectangular shape having an outer shape having a major axis direction and a minor axis direction corresponding to the speaker unit 2a provided with the oval diaphragm 3, and is attached to the speaker unit 2a. Further, the speaker 1a includes a speaker unit 2a, which is an electrokinetic speaker including a diaphragm 3 having an oval outer diameter, and a diffuser 10a, which are connected and integrally formed. The speaker 1a is attached to the mounting surface 9a of the cabinet 9 of an electronic musical instrument (not shown) from the inside (lower side in the drawing).

In the first reflective member 11 of the diffuser 10a, although the opening 17 that defines the inner diameter dimension of the substrate is circular, it corresponds to the diaphragm 3 of the oval speaker unit 2a having the major axis direction and the minor axis direction. It differs from the diffuser 10 of the previous embodiment in that the outer diameter of the substrate is defined by an oval shape. On the other hand, the second reflective member 12 is common in that the Z-axis, which is the central axis, has a substantially conical substrate having a conical surface 18 passing through the apex thereof. However, in the diffuser 10a, the apex of the conical surface 18 of the second reflecting member 12 penetrates into the opening 17 of the first reflecting member 11. Further, in the second reflective member 12, the substantially conical base has a concave back side of the conical surface 18, and the flat surface 19 defined by the outer diameter dimension R2 like the diffuser 1 of the previous embodiment is not formed. ..

The diffuser 10a of this embodiment includes a first reflective member 11, a second reflective member 12, a connecting member 13 that connects the first reflective member 11 and the second reflective member 12, and a speaker mounting that connects the speaker unit 2a. It is a component in which the member 24, the connecting member 14 that connects the first reflective member 11 and the speaker mounting member 24 are integrally molded with resin. Therefore, in the diffuser 10a, the outer diameter dimension R2 of the second reflective member 12 is the first reflective member 11 so that the mold for molding the resin (not shown) is divided into two in the vertical direction shown in the drawing. It is slightly smaller than the radius R1 of the opening 17.

Further, the diffuser 10a is configured to include the speaker mounting member 24, and is designed so that the overall height is lower than that of the diffuser 10 in the previous embodiment and the diffuser 10a does not protrude much upward from the cabinet 9. .. Specifically, the speaker mounting member 24 includes an annular concave surface 25 that faces the annular conical surface 15 of the first reflection member 11 and forms the first acoustic passage 21, and is connected to the speaker unit 2a at its inner diameter (inner diameter portion). It has a connecting part (not shown). Further, the speaker mounting member 24 includes a rib-shaped portion 26 having a short substantially long cylindrical shape extending from the outer diameter portion of the annular concave surface 25 to the lower side shown in the drawing. Further, the speaker mounting member 24 includes flange portions 27 formed by extending from the lower end side of the rib-shaped portion 26 to the outer peripheral side at four locations.

The flange portion 27 engages with the edge of the opening provided on the mounting surface 9a on the upper surface side of the cabinet 9 from below, and attaches the speaker 1a including the diffuser 10a and the speaker unit 2a to the cabinet 9. Since the heights of the annular concave surface 25 and the rib-shaped portion 26 substantially define the total height dimension of the speaker mounting member 24, the total height is relatively low and the diffuser 10a does not protrude from the mounting surface 9a. There is an advantage that the speaker 1a including the diffuser 10a becomes inconspicuous, and the restrictions on the product design of the attached electronic musical instrument are reduced.

The diffuser 10a propagates sound waves between the diaphragm 3 of the speaker unit 2a and the annular concave surface 25 of the speaker mounting member 24 and the annular conical surface 15 of the first reflection member 11 to radiate sound waves in the outer radial direction. The first acoustic passage 21 is formed. Further, sound waves that have passed through the opening 17 of the first reflective member 11 propagate between the annular concave surface 16 of the first reflective member 11 and the conical surface 18 of the second reflective member 12 arranged in close proximity to the outside. A second acoustic passage 22 that radiates sound waves in the radial direction is formed. Therefore, the omnidirectional characteristic in the mid-low range can be realized by preventing a large peak from appearing on the sound pressure frequency characteristic, and the omnidirectional characteristic in the mid-high range can also be realized.

FIG. 6 is a graph illustrating the directivity characteristics of the speaker 1a including the diffuser 10a of this embodiment. Further, FIG. 7 is a graph for explaining the directivity characteristics of the speaker 100 (not shown) including the diffuser 100a (not shown) of the comparative example.

Specifically, the diffuser 100a of the speaker 100 of the comparative example is different from the diffuser 10a only in that the first reflective member 11 is substantially removed, and includes the same speaker unit 2a. Therefore, the graphs of FIGS. 6 and 7 show the difference between the diffuser 10a of the present embodiment and the diffuser 100a of the comparative example.

In the graphs of the directivity characteristics of FIGS. 6 and 7, the Z-axis direction in FIG. 5 is the direction of the directivity angle: 0 degrees, and each directivity angle (-90 degrees) standardized by the sound pressure level in the Z-axis direction. The sound pressure level (~ 90 degrees) is displayed in polar coordinates to show the directivity. The graphs at the respective frequencies of 4 kHz, 5 kHz, 6.3 kHz, 8 kHz, and 10 kHz are overwritten. As a result, the graphs of FIGS. 6 and 7 show how the mounting surface 9a radiates with omnidirectional characteristics in the upper surface direction and the horizontal direction orthogonal to the Z axis.

As can be seen by comparing the graphs of FIGS. 6 and 7, in the case of the speaker 1a provided with the diffuser 10a of the present embodiment of FIG. 6, the non-uniformity of the directional characteristics depending on the respective frequencies is compared with FIG. It is less than the case of the speaker 100 including the diffuser 100a of the example. In the case of the diffuser 10a, the increase / decrease in the sound pressure level depending on the directivity angle can be made smaller than in the case of the diffuser 100a.

In the diffuser 10a, a mounting portion 28 for mounting a breathable punching member or a grill member (not shown) having a frame portion for stretching a breathable net is attached to the connecting member 14 and the speaker mounting member 24. I have. Since the grill member is attached so as to cover the first acoustic passage 21 and the second acoustic passage 22, the speaker unit is prevented from entering the first acoustic passage 21 or the second acoustic passage 22 by foreign matter or a user's hand. The diaphragm 3 of 2a can be protected.

Further, the diffuser 10a may have a circular or square outer shape so as to correspond to another speaker unit 2 having a circular diaphragm 3. Further, in the diffuser 10a, the speaker mounting member 24 does not necessarily have to be provided with the rib-shaped portion 26, and the flange portion 27 may extend from the outer diameter portion of the annular concave surface 25 to the outer peripheral side. In that case, the flange portion 27 engages with the edge of the opening provided on the mounting surface 9a of the cabinet 9 from above so that the speaker 1a including the diffuser 10a and the speaker unit 2a is mounted on the cabinet 9. You may.

FIG. 8 is a graph illustrating the directivity characteristics of the speaker 1b (not shown) including the diffuser 10b (not shown) of this embodiment. Further, FIG. 9 is a graph illustrating the directivity characteristics of the speaker 1c (not shown) including the diffuser 10c (not shown) of this embodiment.

The diffuser 10b and the speaker 1b, the diffuser 10c and the speaker 1c of the present embodiment have the same configuration as the diffuser 10 and the speaker 1 of the previous embodiment except that the outer diameter of the first reflective member 11 is different. Therefore, in the following, common reference numerals will be given to common configurations, and description thereof will be omitted, different configurations will be described, and illustration and description will be omitted.

In this embodiment, the speaker unit 2b (not shown) is common, and the outer diameter dimension of the diaphragm 3b (not shown) is 108.8 mm. The outer diameter of the diaphragm 3b is an external dimension that does not include the edge 5b (not shown), but may include the edge 5b in some cases.

In the diffuser 10b of the present embodiment in the graph of FIG. 8, the outer diameter dimension of the first reflecting member 11 is 114.0 mm, which is larger than the outer diameter dimension of the diaphragm 3b of 108.8 mm. On the other hand, in the diffuser 10c of the present embodiment in the graph of FIG. 9, the outer diameter dimension of the first reflecting member 11 is 104.0 mm, which is smaller than the outer diameter dimension of the diaphragm 3b of 108.8 mm. However, when comparing FIGS. 8 and 9, no significant difference is observed. That is, the diffusers 10b and 10c of this embodiment have substantially the same directivity.

Therefore, in the diffuser 10b or 10c of the present embodiment, even the first reflecting member 11 whose outer diameter dimension is not larger than the outer diameter dimension of the diaphragm 3b reflects sound waves having a relatively long wavelength and a low frequency. It is possible to realize omnidirectional characteristics. The external dimensions of the first reflective member 11 of the diffuser 10b or 10c need only be as large as the outer diameter dimension of the diaphragm 3b of the speaker unit 2b, and is not necessarily larger than the outer diameter dimension of the diaphragm 3b. May be good.

In the speaker 1b or 1c provided with the diffuser 10b or 10c of the present embodiment, the opening 17 of the first reflecting member 11 faces the space 20 between the speaker unit 2b and the diaphragm 3b, so that resonance is less likely to occur. be able to. As a result, the omnidirectional characteristic in the mid-low range can be realized by preventing a large peak from appearing on the sound pressure frequency characteristic, and the omnidirectional characteristic in the mid-high range can also be realized.

FIG. 10 is a diagram illustrating a diffuser according to another preferred embodiment of the present invention and a speaker including the diffuser. Specifically, FIG. 10 is a cross-sectional view of a speaker 1d provided with a diffuser 10d and mounted on a mounting surface 9a on the inner surface side of the cabinet 9.

The diffuser 10d and the speaker 1d of this embodiment have the same configuration as the diffuser 10a and the speaker 1a of the previous embodiment, except that some configurations are different. Therefore, in the following, common configurations will be designated by common reference numerals and description will be omitted, and different configurations will be described. The configurations of the diffuser 10d and the speaker 1d, which are not necessary for the description of the present invention, are not shown and described.

Further, the diffuser 10d of the present embodiment is configured to include the speaker mounting member 24, similarly to the diffuser 10a of the previous embodiment. However, as compared with the diffuser 10a in the previous embodiment, the speaker mounting member 24 does not have a short substantially long cylindrical rib-shaped portion 26 extending from the outer diameter portion of the annular concave surface 25 to the lower side shown in the drawing. Is different.

That is, since the speaker mounting member 24 includes flange portions 27 formed by extending to the outer peripheral side at four locations in the radial direction, the speaker mounting member 24 is below the edge of the opening provided on the mounting surface 9a inside the cabinet 9. The speaker 1d including the diffuser 10d and the speaker unit 2d can be attached to the cabinet 9 by engaging from.

In the diffuser 10d, sound waves propagate to the outside between the diaphragm 3 of the speaker unit 2d, the annular concave surface 25 of the speaker mounting member 24, and the opening of the mounting surface 9a, and the annular conical surface 15 of the first reflecting member 11. The first acoustic passage 21 that radiates sound waves in the radial direction is formed. Further, sound waves that have passed through the opening 17 of the first reflective member 11 propagate between the annular concave surface 16 of the first reflective member 11 and the conical surface 18 of the second reflective member 12 arranged in close proximity to the outside. A second acoustic passage 22 that radiates sound waves in the radial direction is formed. Therefore, the omnidirectional characteristic in the mid-low range can be realized by preventing a large peak from appearing on the sound pressure frequency characteristic, and the omnidirectional characteristic in the mid-high range can also be realized.

The diffuser of the present invention is not limited to the electrokinetic type speaker unit as shown in the figure, and may be a speaker unit having a piezoelectric type, electrostatic type or electromagnetic type drive unit and having a diaphragm.

1, 1a, 1b, 1c, 1d Speaker 2, 2a, 2b, 2c, 2d Speaker unit 3 Diaphragm 4 Dust cap 9 Cabinet 10, 10a, 10b, 10c, 10d Diffuser 11 First reflective member 12 Second reflective member 13 , 14 Connecting member 15 Circular cone surface 16 Circular concave surface 17 Opening 18 Conical surface 21 First acoustic passage 22 Second acoustic passage 23 Sound absorbing member 24 Speaker mounting member 25 Circular concave surface

Claims (13)

A diffuser that is placed so as to face the diaphragm of a speaker that emits sound waves.
An annular conical surface facing the diaphragm and an annular concave surface formed on the opposite side of the annular conical surface, having an opening through which the central axis defining the direction of vibration of the diaphragm passes and defining the inner diameter dimension. The first reflective member, which has a substantially truncated conical shape,
A substantially conical second reflective member, which is arranged in close proximity to the first reflective member and has a conical surface whose central axis passes through its apex.
A first acoustic path is formed between the vibrating plate and the annular pyramidal surface of the first reflective member to propagate the sound wave and radiate the sound wave in the outer radial direction, and the annular concave surface of the first reflective member And the conical surface of the second reflective member, the sound wave that has passed through the opening of the first reflective member propagates to form a second acoustic passage that radiates the sound wave in the outer radial direction.
Diffuser. The outer diameter of the first reflective member is larger than the outer diameter of the diaphragm.
The diffuser according to claim 1. The outer diameter dimension of the second reflective member is larger than the inner diameter dimension of the opening of the first reflective member.
The diffuser according to claim 1 or 2. The first reflective member and the second reflective member are arranged so that at least a part of the second reflective member fits in the concave space defined by the annular concave surface of the first reflective member.
The diffuser according to any one of claims 1 to 3. The cross-sectional curve defining the conical surface of the second reflecting member is not equidistant from the cross-sectional curve defining the annular concave surface of the first reflecting member in the direction along the central axis. Set,
The diffuser according to any one of claims 1 to 4. A connecting member for connecting the first reflecting member and the second reflecting member so as to form the second acoustic passage is further provided.
The diffuser according to any one of claims 1 to 5. A speaker mounting member for mounting the diaphragm of the speaker so as to face the annular conical surface of the first reflecting member and forming the first acoustic passage.
A connecting member for connecting the first reflective member and the speaker mounting member is further provided.
The diffuser according to claim 6. Further comprising a grille member formed of a breathable member and provided in the first acoustic passage and / or the second acoustic passage.
The diffuser according to any one of claims 1 to 7. The inner diameter dimension of the first reflective member and the outer diameter dimension of the second reflective member are defined by a circle, and the outer diameter dimension of the first reflective member is defined by an oval shape.
The diffuser according to any one of claims 1 to 8. The diffuser according to any one of claims 1 to 9 and the diaphragm arranged to face the diffuser are provided at least.
speaker. The diaphragm has a cone shape that forms a concave surface corresponding to the annular cone surface of the first reflective member, and has a convex dust cap at a position facing the opening of the first reflective member.
The speaker according to claim 10. With the diffuser according to any one of claims 1 to 9.
A speaker having at least the diaphragm arranged to face the diffuser,
The housing to which the diffuser and the speaker are attached,
At least equipped with an electronic musical instrument. A sound absorbing member is further attached to at least one of the annular conical surface of the first reflective member and the attachment surface to which the speaker of the housing is attached.
The electronic musical instrument according to claim 12.