Patent ID: 12225342

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described, with reference toFIG.1toFIG.4.

As shown inFIG.1andFIG.2, a coaxial speaker1includes a woofer2, a tweeter3, and a horn4(coaxial speaker horn). The woofer2vibrates to thereby output mainly low-mid range sounds. The tweeter3vibrates to thereby output mainly high range sounds. The woofer2and tweeter3are coaxially arranged having therebetween a clearance in the vibration direction thereof.

InFIG.1toFIG.3, the vibration direction of the woofer2and the tweeter3is indicated by the X-axis direction. InFIG.1toFIG.3, the direction indicated by the arrow is the X-axis positive direction, and the opposite direction is the X-axis negative direction. The woofer2and the tweeter3being coaxially arranged means that the woofer2and the tweeter3are arranged so that the center axes of the woofer2and the tweeter3extending in the X-axis direction (the axis denoted by reference symbol O1inFIG.1toFIG.3) completely or substantially align with each other.

The woofer2is configured such that the sound output from the woofer2mainly propagates toward one side in the vibration direction of the woofer2(toward the side that is indicated by the X-axis positive direction inFIG.1toFIG.3). The sound output from the woofer2also propagates toward the other side in the vibration direction (toward the side that is indicated by the X-axis negative direction inFIG.1toFIG.3).

In the following description, the side mainly toward which sounds are output from the woofer2(one side in the vibration direction) may be referred to as front side in some cases. Moreover, the side opposite to the front side may be referred to as rear side in some cases. InFIG.1andFIG.2, the upper side (or up-side) corresponds to the “front side” and is indicated by the X-axis positive direction. Also, inFIG.1andFIG.2, the lower side (or down-side) corresponds to the “rear side” and is indicated by the X-axis negative direction.

As shown inFIG.3, the woofer2is formed in a circular shape when viewed from the front side.

As shown inFIG.1andFIG.2, the tweeter3is arranged coaxially with the woofer2with a clearance on the front side of the woofer2.

As shown inFIG.3, the tweeter3is formed in a circular shape similar to that of the woofer2when viewed from the front side. The size (diameter dimension) of the tweeter3as viewed from the front side is sufficiently smaller than the size (diameter dimension) of the woofer2.

As shown inFIG.1andFIG.2, the horn4is attached to the tweeter3. The horn4increases the sound pressure output from the tweeter3and controls the directivity of the sound output from the tweeter3. Specifically, the horn4actively directs the sound output from the tweeter3to the front side of the horn4.

The horn4is formed in a cylindrical shape, the diameter of which increases gradually with approach to the one side (X-axis positive direction) in the axial direction. The horn4is arranged so that the axial direction thereof (X-axis direction) aligns with the vibration direction of the tweeter3(vertical direction inFIG.1andFIG.2), and that the larger diameter side is oriented forward in the axial direction. The tweeter3is attached to a first end part (rear end) of the horn4having a smaller diameter, that is, a central portion of the horn4. As shown inFIG.3, the horn4is formed in a circular shape similar to that of the woofer2and the tweeter3when viewed from the front side. The size (diameter dimension) of the horn4as viewed from the front side is greater than the size (diameter dimension) of the woofer2.

The woofer2, the tweeter3, and the horn4, which are of circular shape as viewed from the front side, are arranged so that their center axes (the axis denoted by reference symbol O1) are completely or substantially aligned.

As shown inFIG.1andFIG.2, the horn (horn body)4has a plurality of through holes41. Each through hole41penetrates through the horn4in the axial direction thereof. Each through hole41penetrating through the horn4in the axial direction is not limited to the direction of the through hole41being completely aligned with the axial direction of the horn4, but also includes, for example, the direction of the through hole41being slightly pitched from the axial direction of the horn4. The through holes41of the horn4have the role of allowing the sound output from the woofer2arranged on the rear side of the tweeter3and the horn4to pass therethrough and propagate to the front side of the horn4.

Each through hole41of the horn4is formed in a point shape when viewed from the front side (in the axial direction) as shown inFIG.3. In the present embodiment, each point-like through hole41is of a circular shape when viewed from the front side. The shape of each point-like through hole41may be, for example, a regular polygonal shape such as a square shape, a circular shape, an elliptical shape similar to a regular polygonal shape, or a slightly flattened polygonal shape (a shape with an aspect ratio close to 1).

The plurality of through holes41are arranged around the entire circumference of the horn4. The plurality of through holes41being arranged around the entire circumference of the horn4means that the point-like through holes41are lined up in a ring shape at equal intervals over the entire range around the circumferential direction of the horn4(the direction denoted by reference symbol C inFIG.2andFIG.3). The shape of a ring unit40, in which the point-like through holes41are arranged in a ring shape, may correspond to the shape of the woofer2as viewed from the front side, and is a circular shape in the present embodiment. The interval between the point-like through holes41around the circumferential direction is preferably small enough so that the horn4does not function as a low-pass filter or as a compression chamber for the woofer2, for example.

The plurality of through holes41are also arranged in the radial direction of the horn4(as denoted by reference symbol R inFIG.3, the direction from the position of the axis denoted by reference symbol O1at the center of the horn4toward the outer side of the horn4) when the horn4is viewed from the front side (in the axial direction of the horn4). Specifically, a plurality of the ring units40, in each of which the point-like through holes41are arranged in the ring shape, are arranged concentrically (in the radial direction of the horn4) centered on the axis of the horn4(the axis denoted by reference symbol O1inFIG.1toFIG.3). The arrangement of the plurality of through holes41being lined up in the radial direction of the horn4is not limited to arranging the plurality of through holes41strictly on a straight line extending in the radial direction of the horn4from the axis of the horn4, but also includes arranging them in positions slightly offset around the circumferential direction from the straight line. That is to say, the through holes41adjacent to each other in the radial direction of the horn4may be offset from each other around the circumferential direction of the horn4. The interval between the point-like through holes40in the radial direction (interval between the ring units40) is preferably small enough so that the horn4does not function as a low-pass filter or as a compression chamber for the woofer2, for example.

In present embodiment, the plurality of through holes41are arranged in a Fibonacci sequence spiral pattern. The plurality of through holes41may be arranged radially around the axis of the horn4, for example.

In the present embodiment, the opening area of the through holes41that are located on the radially inner side of the horn4is smaller than the opening area of the through holes41that are located on the radially outer side of the horn4. That is to say, the opening area of the through holes41increases with approach from the inner side to the outer side of the horn4in the radial direction. The opening area of the through holes41is an area when viewed from the front side (in the axial direction of the horn4) as shown inFIG.3.

The upper limit value of the opening area of each of the through holes41is set so that the horn4maintains the function thereof to increase the sound pressure of the sound at a predetermined frequency (high range sound) output from the tweeter3. This is because if the opening area of each through hole41is excessively large, the function of the horn4(the function to increase the sound pressure of the sound at a predetermined frequency output from the tweeter3) becomes impaired.

The lower limit value of the opening area of each of the through holes41is set so that the sound at a predetermined frequency (low-mid range sound) output from the woofer2travels through the through hole41to be propagated to the front side of the horn4.

The range of the opening area of each through hole41may be set so that the diameter of the through hole41, which is of a circular shape as viewed from the front side, is 2.5 mm or more and 7.5 mm or less, for example.

The total opening area of the plurality of through holes41formed in the horn4may be 35% or more of the total area of the horn4as viewed from the front side (the total area of the horn4). Moreover, the total opening area of the through holes41may be 60% or less of the total area of the horn4.

The plurality of through holes41are formed only in a region of the horn4that overlaps the woofer2as viewed from the front side as shown inFIG.3. That is to say, the through holes41of the horn4are not formed in regions of the horn4located outside the woofer2in the radial direction.

In the present embodiment, the plurality of through holes41are formed in the entire region of the horn4that overlaps the woofer2(the region denoted by reference symbol R1inFIG.1andFIG.3). Therefore, the shape of the entire plurality of through holes41viewed from the front side is formed in a shape that corresponds to the woofer2(a circular shape in the present embodiment).

As shown inFIG.1andFIG.2, the coaxial speaker1of the present embodiment further includes a woofer cover5that partitions the space between the woofer2and the horn4arranged in the axial direction of the horn4, from the external space. The woofer cover5is formed in a cylindrical shape that extends forward from the woofer2to the horn4. Although not shown in the drawings, the shape of the woofer cover5as viewed from the front side (in the axial direction of the horn4) is formed in a shape that corresponds to the woofer2. The shape of the woofer cover5corresponding to the woofer2as viewed from the front side is a shape corresponding to the outer circumference of the woofer2(a shape that substantially matches the outer circumference of the woofer2), and corresponds to the outer circumference circle of the woofer2in the present embodiment. In the present embodiment, the woofer cover5is integrally formed with the horn4. The plurality of through holes41formed in the horn4are located on the inner side of the woofer cover5in the radial direction of the horn4.

The space between the woofer2and the horn4is surrounded by the woofer cover5, so that the sound output from the woofer2to the front side can be efficiently propagated to the front side of the horn4through the through holes41of the horn4.

The coaxial speaker1of the present embodiment further has a casing constituent part6that constitutes a part of a casing covering the space on the rear side of the woofer2, the tweeter3, and the horn4. The casing constituent part6surrounds a second end part of the horn4(the front end of the horn4inFIG.1andFIG.2) having a larger diameter, and is formed in a cylindrical shape extending from the second end part of the horn4to the rear side of the horn4.

The casing constituent part6has a bass reflex port61. The bass reflex port61is a hole for propagating the sound that is output from the woofer2to the rear side, to the outside of the casing.

In the coaxial speaker1of the present embodiment, the sound (particularly low-mid range sound) output from the woofer2to the front side propagates efficiently to the front side of the horn4through the through holes41of the horn4. Moreover, the horn4increases the sound pressure of the sound output from the tweeter3and controls the directivity of this sound. As a result, sounds (low-mid range sounds and high range sounds) output from the coaxial speaker1can reach farther. Such a coaxial speaker1can be effectively used, for example, as a ceiling-hanging type speaker that is suspended from a high ceiling and emits sound from the ceiling toward the floor.

As described above, in the horn4(coaxial speaker horn) and the coaxial speaker1of the present embodiment, the horn4has the plurality of point-like through holes41arranged around an entire circumference of the horn4. With this shape, the horn4is unlikely to function as a low-pass filter or as a compression chamber of the woofer2. Also, it is possible to suppress or prevent the frequency characteristics of the woofer2incorporated in the coaxial speaker1from changing from the frequency characteristics of the woofer2alone. As a result, it is easy to adjust the characteristics of the coaxial speaker1by means of a passive crossover network.

Moreover, the horn4has the plurality of point-like through holes41arranged around the entire circumference of the horn4, so that the horn4functions as a horn that increases the sound pressure of the sound of a predetermined frequency output from the tweeter3. In other words, it is possible to suppress the function of the horn4from getting impaired by the formation of the through holes41. That is to say, the sound pressure of the tweeter3can be increased also in the region of the horn4where the through holes41are formed.

Moreover, in the horn4and the coaxial speaker1of the present embodiment, the total opening area of the plurality of through holes41when viewed in the axial direction of the horn4is 35% or more of the entire area of the horn4. As a result, it is possible to further suppress or prevent the frequency characteristics of the woofer2incorporated in the coaxial speaker1from changing from the frequency characteristics of the woofer2alone. As a result, it becomes even easier to adjust the characteristics of the coaxial speaker1by means of a passive crossover network.

Moreover, in the horn4and the coaxial speaker1of the present embodiment, the total opening area of the plurality of through holes41when viewed in the axial direction of the horn4is 60% or less of the entire area of the horn4. As a result, it is possible to even more effectively suppress the function of the horn4(the function of increasing the sound pressure of the sound of a predetermined frequency output from the tweeter3) from becoming impaired. In other words, the sound pressure of the tweeter3can be increased also in the region of the horn4where the through holes41are formed.

Furthermore, in the horn4and the coaxial speaker1of the present embodiment, the upper limit value of the opening area of each of the through holes41is set so that the horn4maintains the function thereof to increase the sound pressure of the sound at a predetermined frequency output from the tweeter3. By setting the upper limit value of the opening area of each through hole41in this manner, it is possible to more effectively suppress the above “function of the horn4” from becoming impaired.

As described above, with the horn4and the coaxial speaker1of the present embodiment, it is possible to easily adjust the characteristics of the coaxial speaker1, and to suppress the “function of the horn4” from becoming impaired.

Moreover, in the horn4and the coaxial speaker1of the present embodiment, the opening area of the through holes41that are located on the radially inner side of the horn4is smaller than the opening area of the through holes41that are located on the radially outer side of the horn4. For this reason, even if the number of through holes41to be arranged around the circumferential direction of the horn4is equal in both a first ring-shaped region located on the radially inner side of the horn4and a second ring-shaped region located on the radially outer side of the horn4, it is still possible to suppress or prevent the ratio of the opening area of the through holes41to the area of the horn4from being different between the first ring-shaped region and the second ring-shaped region. That is to say, the ratio of the opening area of the through holes41to the area of the horn4can be made uniform.

Moreover, in the horn4and the coaxial speaker1of the present embodiment, the plurality of through holes41are formed only in the region of the horn4that overlaps the woofer2as viewed from the axial direction of the horn4. As a result, the sound output from the woofer2to the front side can be highly efficiently propagated to the front side of the horn4through the through holes41of the horn4.

Hereinafter, with reference toFIG.4, it will be described that the frequency characteristics of the woofer2incorporated in the coaxial speaker1can be approximated to the frequency characteristics of the woofer2alone, in the coaxial speaker1of the present embodiment.

FIG.4is a graph showing a result of comparing the frequency characteristics of the woofer2in the state of being incorporated in the coaxial speaker1of the present embodiment as a working example, with the frequency characteristics of the woofer2alone (in the state where the tweeter3and the horn4are removed from the coaxial speaker1of the present embodiment).

The same woofer2was used in both the “working example” and in the “woofer alone” example. In the “working example”, the total opening area of the plurality of through holes41as viewed in the axial direction of the horn4is 37% of the entire area of the horn4. Each through hole41is formed in a circular shape as viewed in the axial direction of the horn4. The opening area of the through holes41located on the radially inner side is smaller than the opening area of the through holes41located on the radially outer side. The diameter dimension of each through hole41is set in a range of 2.5 mm to 7.5 mm in increments of 0.5 mm.

As shown in the graph ofFIG.4, it was confirmed that the frequency characteristics of the “working example” approximate to those of the “woofer alone” example. That is to say, it has been confirmed that, in the horn4(coaxial speaker horn) and the coaxial speaker1of the present embodiment, the frequency characteristics of the woofer2incorporated in the coaxial speaker1can be effectively suppressed from changing from the frequency characteristics of the woofer2alone.

The present disclosure has been described in detail above; however, the present disclosure is not limited to the above embodiments, and various modifications may be made without departing from the scope of the present disclosure.

In the present disclosure, the upper limit value of the opening area of each through hole41may be, for example, (λ/4)2or less, where λ is the wavelength of the sound corresponding to an upper limit frequency among the sound that is output from the tweeter3and the sound pressure of which is increased by the horn4. The upper limit frequency may be, for example, an upper limit of the sound frequency that is set according to the specifications required of the coaxial speaker1. By also setting the upper limit value of the opening area of each through hole41in this manner, it is possible to effectively suppress the above “function of the horn4” from becoming impaired.

In the present disclosure, the individual opening areas of all the through holes41formed in the horn4may be equal to each other, for example.

In the present disclosure, the shapes of the woofer2, the tweeter3, and the horn4as viewed from the front side (in the axial direction) are not limited to circular shapes, and may be elliptical shapes, for example.