JP2007135098A - Back load horn speaker system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate horns even in the case that adjacent horns are different in length. <P>SOLUTION: On the assumption that a fixed inner width is set to a cabinet, a back load horn speaker system satisfies S<SB>1</SB>≈ä(S<SB>2</SB>-S<SB>0</SB>)×L<SB>1</SB>/(L<SB>1</SB>+L<SB>2</SB>)}+S<SB>0</SB>wherein;S<SB>1</SB>is an output-side aperture area of one straight tube-shaped horn out of a plurality of straight tube-shaped horns; S<SB>0</SB>is an output-side aperture area of a straight tube-shaped horn connecting to a preceding stage of the one straight tube-shaped horn; S<SB>2</SB>is an output-side aperture area of a straight tube-shaped horn connecting to a succeeding stage of the one straight tube-shaped horn; L<SB>1</SB>is length of the one straight tube-shaped horn; and L<SB>2</SB>is length of the straight tube-shaped horn connecting to the succeeding stage of the one straight tube-shaped horn. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, a speaker unit is attached to a baffle plate of a cabinet, and a plurality of horns are sequentially connected from an opening portion of a back cavity provided on the back side of the baffle plate in the cabinet via a throat. This is related to a backloaded horn type speaker system that is well configured for bass reproduction by partitioning the inside of a cabinet with a plurality of flat partition plates so that the opening area on each outlet side is sequentially increased. is there.

  In recent years, with the spread of high vision, wide vision, etc., the screen of a television receiver has become larger and a horizontally long one is becoming common, and this type of television receiver is required to have higher image quality. The speaker system built in the television receiver is required to have high sound quality and a thin thickness.

  Also, a speaker system applied to an AV (Audio Video) device that records and reproduces package media such as an optical disc is required to have high sound quality with the speaker unit attached to a thin cabinet.

  In this type of speaker system, in general, in order to prevent the radioactivity in the low frequency range from being significantly reduced by the interference of sound waves generated by the emission of sound waves of opposite phases from the front and back of the speaker unit, By attaching the speaker unit to the baffle plate of the cabinet, separating the sound waves on the front and back with this baffle plate, further extending back around the baffle plate to form the back cavity (air chamber) in a box shape, The sound quality in the bass is improved.

Further, a non-patent document 1 discloses a back loaded horn type speaker system that further improves the bass characteristic of the speaker system.
Tetsuo Nagaoka's original speaker design technology, pages 30-34, published by Ongaku no Tomosha

FIG. 8 is a cross-sectional view schematically showing a general back load horn type speaker system.
FIG. 9 is a diagram schematically showing a state in which a sound path is formed in a general backloaded horn type speaker system, and (a) shows a state in which a plurality of straight tubular horns are connected to form a sound path. , (B) is a diagram showing a state in which a sound path is formed by connecting a plurality of conical horns or quadrangular pyramid horns;
FIG. 10 is a diagram for explaining a calculation method of a horn when a sound path is formed by connecting a plurality of conical horns or quadrangular pyramid horns in a general backload horn type speaker system.

  The general back load horn type speaker system 100 shown in FIG. 8 is disclosed in Non-Patent Document 1 described above, and will be briefly described with reference to Non-Patent Document 1.

  As shown in FIG. 8, in a general back load horn type speaker system 100, a cabinet 102 for mounting the speaker unit 101 is formed in a box shape using a plate material or the like.

  The speaker unit 101 is attached to the baffle plate 102a of the cabinet 102, and the back cavity (air chamber) 102b is formed in a box shape by extending around the baffle plate 102a backward. A throat 103 having a constant opening area is connected to the opening 102b1 that is opened, and a horn 104 with a gradually increasing opening area is connected to the throat 103 to form a sound path by the horn 104. Is opened in a trumpet shape.

  At this time, sound waves are emitted from the front surface of the speaker unit 101, and sound waves from the back surface of the speaker unit 101 are emitted to the outside through the back cavity 102b, the throat 103, and the horn 104 in the cabinet 102 in this order.

  The characteristics of the general back load horn type speaker system 100 configured as described above can increase the radioactivity in a low sound, and the acoustic impedance characteristic can be flat over a wide band to increase the radioactivity.

  By the way, according to the above-mentioned Non-Patent Document 1, since it is difficult to form a sound path by the horn 104 in a curved shape when using a plate material or the like when producing a general backloaded horn type speaker system 100. As shown in FIG. 9A, when a plurality of straight tubular horns are sequentially connected, they are connected so that the opening area of each connection portion (each connection point) increases stepwise to form a sound path. Or when connecting a plurality of conical horns or quadrangular pyramid horns sequentially as shown in FIG. 9B, the opening area of each connection portion (each connection point) has an inclination. There has been proposed a method of connecting in an increasing manner to form a sound path.

  Further, according to Non-Patent Document 1 described above, in the calculation method of the back load horn, for example, in the case of a conical horn or a quadrangular pyramid horn, the cross-sectional area (opening area) of the horn is proportional to the height. A simplified example is presented as shown in.

In this example, as illustrated in FIG 10, separated into n horn at intervals of a predetermined length L, and the inlet area of the horn and S _0, and the area at which the advanced n × L and S _n Further, when K is a constant for determining the cut-off frequency, the following equation (1) is established.

[Equation 1]
S _n = S ₀ × K ⁿ ............ Formula (1)

  Therefore, if the horn is calculated based on the above formula (1), a conical horn or a quadrangular pyramid horn can be formed so that each opening area gradually increases in an exponential manner.

  By applying the technical idea of the general back load horn type speaker system 100 described above, a back load horn type speaker system is newly developed using a thin cabinet with a speaker unit attached and a narrow inner width dimension of a baffle plate. In this case, the horn can be formed in the structure as previously described in FIGS. 9A and 9B by dividing the inside of the thin cabinet with a plurality of flat partition plates. There may be a case where the described formula (1) cannot be applied.

  The reason for this will be explained. A thin cabinet with a speaker unit attached and a narrow inner width dimension of a baffle plate has an inner width dimension, an inner depth dimension, an inner volume, etc. in advance depending on the dimensional relationship with a television receiver or AV equipment. There are many cases where it is set, and the horn is divided into a certain length by a plurality of flat partition plates based on the above-described formula (1), and a plurality of horns are formed in the thin cabinet. Difficult to do. Thus, when the length of each horn is changed according to the shape of the thin cabinet without dividing the length of each horn by a fixed length, the formula (1) described above cannot be applied. found.

  Therefore, even when a back load horn type speaker system is newly developed using a thin cabinet having a narrow width dimension, a back load horn type speaker system capable of obtaining a good bass characteristic is desired.

This invention is made | formed in view of the said subject, The invention of Claim 1 is the speaker unit attached to the baffle board of the cabinet,
A back cavity provided on the back side of the baffle plate in the cabinet;
A throat having a certain opening area connected to an opening part of the back cavity partially opened;
A plurality of horns that are sequentially connected via the throat and formed by partitioning the cabinet with a plurality of flat partition plates so that the opening area on each outlet side sequentially increases,
In the back load horn type speaker system with
After setting the inner width dimension of the cabinet to be constant,
S ₁ : an opening area on the outlet side of one of the plurality of horns,
S ₀ : the opening area of the outlet side of the horn connected to the previous stage of the one horn,
S ₂ : an opening area on the outlet side of the horn connected to the subsequent stage of the one horn,
L ₁ : length of the one horn,
L ₂ : the length of the horn connected to the subsequent stage of the one horn,
When
S ₁ ≈ {(S ₂ −S ₀ ) × L ₁ / (L ₁ + L ₂ )} + S ₀
It is a back load horn type speaker system characterized by satisfying

The invention according to claim 2 is the back load horn type speaker system according to claim 1,
The plurality of horns are connected so that the opening area of each connection part increases stepwise to form a sound path, or connected so that the opening area of each connection part increases with an inclination. The back load horn type speaker system according to claim 1, wherein the sound path is formed.

  According to the back load horn type speaker system according to claim 1, the speaker unit is attached to the baffle plate of the cabinet, and a plurality of through the throat from the opening portion of the back cavity provided on the back side of the baffle plate in the cabinet. When connecting the horns in sequence and partitioning the inside of the cabinet with a plurality of flat partition plates so that the opening area on each outlet side is sequentially increased, the lengths of adjacent horns differed. Even at times, the calculation of one horn can be easily performed without impairing the acoustic characteristics.

  Further, according to the backloaded horn type speaker system according to claim 2, a plurality of horns are connected so that the opening area of each connection portion increases stepwise to form a sound path, or each connection Since the opening area of each part is connected so as to increase with an inclination to form a sound path, a plurality of horns are formed by a plurality of flat partition plates without forming a plurality of horns in a curved shape. The inside of the cabinet can be partitioned so that the opening area on each outlet side increases sequentially.

  Hereinafter, an embodiment of a backloaded horn type speaker system according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a diagram showing a backloaded horn type speaker system according to an embodiment of the present invention.
FIG. 2 is a diagram showing a modified example in which the backloaded horn type speaker system according to the embodiment of the present invention is partially modified,
FIG. 3 is a diagram for explaining a calculation method of a straight tubular horn in the backloaded horn type speaker system of the embodiment shown in FIG.
FIG. 4 is a diagram for explaining a calculation method of a quadrangular pyramid horn in the backloaded horn type speaker system of the modification shown in FIG.
FIG. 5 is a diagram showing a backloaded horn type speaker system of a comparative example for the present invention,
FIG. 6 is a diagram showing acoustic characteristics of a backloaded horn type speaker system of a comparative example according to the present invention,
FIG. 7 is a diagram showing acoustic characteristics of the backloaded horn type speaker system according to the embodiment and the modification of the present invention.

  First, as shown in FIG. 1, in the backloaded horn type speaker system 10A according to the embodiment of the present invention, the cabinet 12 for mounting the speaker unit 11 is composed of a front plate 12a serving as a baffle plate using a plate material, etc. The side plates 12b and 12c, the bottom plate 12d having a short depth, the top plate 12e having a long depth, and the back plate 12f facing the front plate 12a at a distance from each other are formed in a box shape.

  The cabinet 12 has an inner width dimension (hereinafter referred to as inner width dimension) W between the left and right side plates 12b and 12c of 3 to 5 cm, and an inner depth dimension between the front plate 12a and the rear plate 12f (hereinafter referred to as the inner width dimension). D is 10-30 cm and the internal volume surrounded by the plates 12a-12f (hereinafter referred to as the internal volume) is set to 6 liters or less. A height H (hereinafter referred to as height dimension) H from the back surface of the plate 12e to the bottom plate 12d is determined.

  Two rectangular speaker units 11, 11 having a width dimension w slightly smaller than the inner width dimension W of the cabinet 12 are attached to the front plate (baffle plate) 12 a of the cabinet 12. The number of speaker units 11 is not limited to two, and at least one speaker unit 11 may be attached to the front plate (baffle plate) 12a of the cabinet 12.

  Further, the cabinet 12 has a back cavity (air chamber) 12g above the bottom plate 12d on the back side of the front plate 12a while the inner width W between the left and right side plates 12b, 12c is kept constant. It is formed in a substantially trapezoid shape by a plurality of flat partition plates 13 to 16 connected to the top plate 12e.

  One end of the upper portion of the back cavity 12g is narrowly opened toward the top plate 12e, and the throat 12h is connected to the opening portion 12g1 of the upper portion of the back cavity 12g to the front plate 12a and the front plate 12a. In order to form a substantially trapezoidal back cavity 12g, the plate-like partition plate 17 is formed with a certain opening area Sh between the plate-like partition plate 17 provided in parallel and spaced apart from each other. It is connected to the flat partition plate 16 inclined in the direction.

  Furthermore, the inside of the cabinet 12 is partitioned by a plurality of flat partition plates 18 to 21 in which a plurality of straight tubular horns 12i to 12l are linearly arranged from an opening portion 12g1 above the back cavity 12g via a throat 12h. Each cross section is formed in a square shape.

  The plurality of straight tubular horns 12i to 12l are connected stepwise in the front and back at the connection site between the outlet side of the preceding straight tubular horn and the inlet side of the subsequent straight tubular horn connected thereto, and The sound paths are formed by setting the opening areas Si to S1 on the outlet sides so as to increase sequentially.

  In this case, the “straight tube horn” is a normal one having a square opening area of the same size from the inlet side to the outlet side of one straight tube horn.

  Further, a plurality of straight tubular horns 12m to 12o having a non-regular shape are sequentially connected to the subsequent stage of the plurality of straight tubular horns 12i to 12l.

  Here, the structure of the plurality of straight tubular horns 12i to 12o will be described more specifically. Each of the plurality of straight tubular horns 12i to 12o has a length in the sound path direction according to the internal shape of the cabinet 12. Yes.

  Further, among the plurality of straight tubular horns 12i to 12o, the first straight tubular horn 12i connected to the throat 12h is linear with the top plate 12e so that the first opening area Si is obtained on the outlet side. The flat partition plate 18 provided in a region surrounded by the flat partition plate 18 is connected to the flat partition plate 17 forming the throat 12h at a right angle toward the back plate 12f. The top plate 12e is provided in parallel with a gap.

  In addition, the second straight tubular horn 12j connected to the first straight tubular horn 12i has a back plate 12f that has a second opening area Sj larger than the first opening area Si described above on the outlet side. It is provided in a region surrounded by the upper portion and the linear flat plate-like partition plate 19, and here, the flat plate-like partition plate 19 connected at a right angle to the flat plate-like partition plate 18 is on the bottom plate 12d side. The rear plate 12f is provided in parallel with a distance therebetween.

  Further, the third straight tubular horn 12k connected to the second straight tubular horn 12j has a back plate 12f that has a larger third opening area Sk than the second opening area Sj described above on the outlet side. It is provided in a region surrounded by the upper part, the linear flat partition plate 20 and the linear flat partition plate 21, and here, the flat partition plate 20 is below the flat partition plate 19. And is connected to the middle portion of the back plate 12f at a right angle and provided toward the front plate 12a, and the flat partition plate 21 is located upward at the end of the flat plate partition plate 20 on the front plate 12a side. They are connected at right angles to the flat partition plate 18 and spaced from each other.

  Further, the fourth straight tubular horn 12l connected to the third straight tubular horn 12k has a flat partition plate so that the fourth opening area S1 larger than the third opening area Sk described above can be obtained on the outlet side. 17 is provided in a region surrounded by the upper portion 17, the flat partition plate 18, and the flat partition plate 19.

  Further, the fifth straight tubular horn 12m connected to the fourth straight tubular horn 12l has a flat partition plate so that a fifth opening area Sm larger than the above-described fourth opening area S1 is obtained on the outlet side. 17 is provided in a region surrounded by the lower portion 17, the inclined flat partition plate 16, and the flat partition plate 21.

  The sixth straight tubular horn 12n connected to the fifth straight tubular horn 12m has a flat partition plate so that the sixth opening area Sn larger than the fifth opening area Sm described above can be obtained on the outlet side. 15, a flat partition plate 20, and a region surrounded by an intermediate portion of the back plate 12 f.

  Further, the seventh straight tubular horn 12o connected to the sixth straight tubular horn 12n is a flat plate inclined so as to obtain a seventh opening area So larger than the sixth opening area Sn described above on the outlet side. It is provided in a region surrounded by the partition plate 14, the flat partition plate 13 and the lower part of the back plate 12f, and the outlet side of the seventh straight tubular horn 12o is largely on the bottom plate 12d side of the cabinet 12. The opening 22 is opened.

  In the above description, among the plurality of straight tubular horns 12i to 12o, the first to fourth straight tubular horns 12i to 12l are formed as regular tubular horns, but the fifth to seventh. The straight tubular horns 12m to 12o are partly distorted because the flat partition plates 16 and 14 are inclined. However, the straight tubular horns 12m to 12o can be properly formed by appropriately providing a flat partition plate (not shown). In this case, it is inevitable that a useless space is generated inside, that is, the internal volume is reduced, and the effect of exceeding the low-frequency output reduction due to the reduction of the internal volume is achieved. Since it cannot be obtained, a partially distorted shape is allowed for the fifth to seventh straight tubular horns 12m to 12o.

  Here, a plurality of straight tubular horns are connected in a staircase form before and after each connection part (each connection point) from the opening part of the back cavity provided in the cabinet via the throat, and the opening area on each outlet side is sequentially A method of calculating a straight tubular horn when the length of adjacent straight tubular horns is different will be described when the case where the sound path is formed so as to be large is shown in FIG.

In FIG. 3, after setting the inner width dimension of the cabinet to be constant,
S ₁ : The opening area of the outlet side of one straight tubular horn among the plurality of straight tubular horns,
S ₀ : the opening area of the outlet side of the straight tubular horn connected to the front stage of one straight tubular horn,
S ₂ : the opening area of the outlet side of the straight tubular horn connected to the subsequent stage of one straight tubular horn,
L ₁ : length of one straight tubular horn,
L ₂ : the length of the straight tubular horn connected to the subsequent stage of one straight tubular horn,
The following expression (2) is satisfied.

[Equation 2]
S ₁ ≈ {(S ₂ −S ₀ ) × L ₁ / (L ₁ + L ₂ )} + S ₀ ... Equation (2)

  According to the above equation (2), even when the lengths of adjacent straight tube horns are different, calculation of one straight tube horn can be easily performed without impairing acoustic characteristics.

On the other hand, since the calculation method of the straight tubular horn when the lengths of the adjacent straight tubular horns are the same is L ₁ = L ₂ in the above, when substituting this condition into the above equation (2), The following expression (3) is satisfied.

[Equation 3]
S ₁ ≒ (S ₂ + S ₀ ) / 2 ......... Formula (3)

  According to the above equation (3), even when the lengths of adjacent straight tube horns are the same, calculation of one straight tube horn can be easily performed without impairing acoustic characteristics.

  At this time, the plurality of straight tubular horns may be connected in combination with a case where the lengths of the adjacent straight tubular horns are different and the case where they are the same depending on the internal shape in the cabinet 12.

  The operation of the backloaded horn type speaker system 10A according to the embodiment configured as described above is such that sound waves are generated from the front surfaces of the two speaker units 11 and 11 attached to the baffle plate 12a of the cabinet 12 having a narrow inner width W. The sound waves emitted from the back surfaces of the two speaker units 11, 11 pass through the back cavity 12g, the throat 12h, and the plurality of straight tubular horns 12i-12o in the cabinet 12 in this order, and are provided on the bottom plate 12d side. 22 is discharged to the outside.

  Next, a modified backloaded horn type speaker system 10B obtained by partially modifying the backloaded horn type speaker system 10A (FIG. 1) according to the embodiment of the present invention is different from FIG. 1 using FIG. A brief description will be given centering on the points.

  As shown in FIG. 2, even in the backloaded horn type speaker system 10B according to the modification of the present invention, the inner width dimension W is set to 3 to 5 cm, the depth inner dimension D is set to 10 to 30 cm, and the inner volume is set to 6 liters or less. Two speaker units 11, 11 are attached to a front plate (baffle plate) 12a of a box-shaped cabinet 12, and a plurality of back cavities (air chambers) 12g are provided on the back side of the front plate (baffle plate) 12a. The point which is formed in the substantially trapezoid shape by these flat partition plates 13-16 is the same as FIG.

  Here, a different point from FIG. 1 will be described. In the state where the inner width dimension W between the left and right side plates 12b, 12c of the cabinet 12 is kept constant, the throat starts from the opening portion 12g1 above the back cavity 12g. The inside of the cabinet 12 is partitioned by a plurality of flat partition plates 18 ′ to 21 ′ in which a plurality of quadrangular pyramid horns 12i ′ to 12m ′ are respectively arranged with inclination through 12h, and each cross section has a rectangular shape. Is formed.

  The plurality of quadrangular pyramid horns 12i ′ to 12m ′ are connected to each other so that the connecting portion between the outlet side of the front quadrangular pyramid horn and the rear quadrangular pyramid horn connected thereto is inclined at the front and rear. In addition, a sound path is formed by setting the opening areas Si ′ to Sm ′ on the outlet side so as to increase sequentially.

  In this case, the “square pyramid horn” is a regular one that is formed with an inclination so that the square opening area gradually increases from the inlet side to the outlet side of one square pyramid horn. It shall be Of the plurality of quadrangular pyramid horns 12i 'to 12m', the quadrangular pyramid horn 12m 'is partially irregular with respect to the regular shape.

  Further, a plurality of straight tubular horns 12n 'and 12o' having the same shape as in FIG. 1 are sequentially connected to the subsequent stage of the plurality of quadrangular pyramid horns 12i 'to 12m'.

Here, the structure of the plurality of quadrangular pyramid horns 12i ′ to 12m ′ will be described more specifically.
The plurality of quadrangular pyramid-shaped horns 12 i ′ to 12 m ′ have lengths in the sound path direction according to the internal shape of the cabinet 12.

  Further, among the plurality of quadrangular pyramid horns 12i ′ to 12m ′, the first quadrangular pyramid horn 12i ′ connected to the throat 12h has a top plate so that the first opening area Si ′ can be obtained on the outlet side. 12e and the linear partition plate 18 inclined linearly. Here, the flat partition plate 18 connected to the flat partition plate 17 forming the throat 12h is the back plate 12f. Toward the top plate 12e with a predetermined inclination at a distance.

  Further, the second quadrangular pyramid horn 12j ′ connected to the first quadrangular pyramid horn 12i ′ provides a second opening area Sj ′ larger than the first opening area Si ′ described above on the outlet side. As described above, the flat plate partition plate 19 connected to the flat plate partition plate 18 is provided as a bottom plate in a region surrounded by the upper part of the back plate 12f and the flat plate partition plate 19 inclined linearly. It is provided with a predetermined inclination so that the opening area is larger on the outlet side than on the inlet side with a distance from the back plate 12f toward the 12d side.

  Further, the third quadrangular pyramid horn 12k ′ connected to the second quadrangular pyramid horn 12j ′ provides a third opening area Sk ′ larger than the second opening area Sj ′ described above on the outlet side. Thus, it is provided in a region surrounded by the upper part of the back plate 12f, the linearly inclined flat partition plate 20 and the linearly inclined flat partition plate 21, and here, the flat partition A plate 20 is provided below the flat partition plate 19 and is provided toward the front plate 12a with a predetermined inclination from an intermediate portion of the rear plate 12f. The flat partition plate 20 is provided on the front plate 12a side. A flat partition plate 21 is connected to an end of the flat partition plate 21 with a predetermined inclination toward the upper side, and is provided at a distance from the flat partition plate 18.

  Further, the fourth quadrangular pyramid horn 12l ′ connected to the third quadrangular pyramid horn 12k ′ provides a fourth opening area Sl ′ larger than the third opening area Sk ′ described above on the outlet side. Thus, it is provided in the region surrounded by the upper part of the flat partition plate 17, the inclined flat plate partition plate 18, and the inclined flat plate partition plate 19.

  Further, the fifth quadrangular pyramid horn 12m ′ connected to the fourth quadrangular pyramid horn 12l ′ provides a fifth opening area Sm ′ larger than the fourth opening area Sl ′ described above on the outlet side. Thus, it is provided in a region surrounded by the lower part of the flat partition plate 17, the inclined flat partition plate 16, and the inclined flat partition plate 21.

  Further, the straight tubular horn 12n ′ connected to the fifth quadrangular pyramid horn 12m ′ is a flat plate as in FIG. 1 so that an opening area Sn ′ larger than the above-described fifth opening area Sm ′ can be obtained on the outlet side. It is provided in a region surrounded by the partition plate 15, the flat partition plate 20, and the intermediate portion of the back plate 12 f.

  Further, the straight tubular horn 12o ′ connected to the straight tubular horn 12n ′ has a flat partition plate 14 that is inclined in the same manner as in FIG. 1 so as to obtain an opening area So ′ larger than the opening area Sn ′ described above on the outlet side. The outlet side of the straight tubular horn 12o ′ is provided in an opening 22 that is largely open to the bottom plate 12d side of the cabinet 12 and is provided in a region surrounded by the flat partition plate 13 and the lower portion of the back plate 12f. Has reached.

  Here, a plurality of quadrangular pyramid horns are connected from the opening part of the back cavity provided in the cabinet through the throat with an inclination before and after each connecting part (each connecting point), and each outlet side opening. A method for calculating a quadrangular pyramid horn when the lengths of adjacent quadrangular pyramid horns are different will be described when the case where the sound path is formed so that the areas gradually increase is shown in FIG.

In FIG. 4, after setting the inner width dimension of the cabinet to be constant,
S ₁ : The opening area of the exit side of one square pyramidal horn among the plural pyramidal horns,
S ₀ : the opening area of the exit side of the quadrangular pyramid horn connected to the front stage of one quadrangular pyramid horn,
S ₂ : the opening area of the exit side of the quadrangular pyramid horn connected to the subsequent stage of one quadrangular pyramid horn,
L ₁ : length of one quadrangular pyramid horn,
L ₂ : the length of a quadrangular pyramid horn connected to the subsequent stage of one quadrangular pyramid horn,
The following expression (4) is satisfied.

[Equation 4]
S ₁ ≈ {(S ₂ −S ₀ ) × L ₁ / (L ₁ + L ₂ )} + S ₀ ... (4)

  According to the above equation (4), even when the lengths of adjacent quadrangular pyramid horns are different, calculation of one quadrangular pyramid horn can be easily performed without impairing acoustic characteristics.

On the other hand, the calculation method of the quadrangular pyramid horns when the lengths of the adjacent quadrangular pyramid horns are the same is L ₁ = L ₂ in the above, and therefore substituting this condition into the above equation (4) The following equation (5) is satisfied.

[Equation 5]
S ₁ ≈ (S ₂ + S ₀ ) / 2 (5)

  According to the above equation (5), even when the lengths of adjacent quadrangular pyramid horns are the same, calculation of one quadrangular pyramid horn can be easily performed without impairing acoustic characteristics.

  At this time, the plurality of quadrangular pyramid horns may be connected by appropriately combining the case where the lengths of the adjacent straight tubular horns are different from the length of the adjacent straight tube horns according to the internal shape in the cabinet 12, A quadrangular pyramid horn and a plurality of straight tubular horns may be appropriately combined.

  And the operation | movement of the back load horn type | mold speaker system 10B of the modification comprised as mentioned above is a sound wave from the front surface of the two speaker units 11 and 11 attached to the baffle board 12a of the cabinet 12 with the narrow internal width dimension W. The sound waves emitted from the back surfaces of the two speaker units 11 and 11 are a back cavity 12g and a throat 12h in the cabinet 12, a plurality of quadrangular pyramid horns 12i 'to 12m', a plurality of straight tubular horns 12n ', 12o 'is discharged | emitted outside through the opening part 22 provided in the bottom plate 12d side in order.

  Next, in order to explain the acoustic characteristics of the backloaded horn type speaker system 10A according to the embodiment of the present invention and the backloaded horn type speaker system 10B according to the modified example of the present invention, a backloaded horn type speaker serving as a comparative example will be described. The system 10C will be briefly described with reference to FIG.

  As shown in FIG. 5, even in the backloaded horn type speaker system 10C of the comparative example, a box-shaped cabinet in which the inner width dimension W is set to 3 to 5 cm, the depth inner dimension D is set to 10 to 30 cm, and the inner volume is set to 6 liters or less. Although two speaker units 11 and 11 are attached to 12 front plates (baffle plates) 12a, the cabinet 12 is not provided with a throat or a plurality of horns, and the back surface of the front plate (baffle plate) 12a. Only a back cavity (air chamber) 12p is formed on the side surrounded by the top plate 12e and the back plate 12f, and sound waves from the back of the speaker units 11 and 11 are transmitted from the back cavity 12p in the cabinet 12 to the bottom surface. It is discharged to the outside through an opening 23 that is largely open to the side.

  Here, FIG. 6 shows the acoustic characteristics of the backloaded horn type speaker system 10C of the comparative example described above, and FIG. 7 shows the backloaded horn type speaker system 10A according to the example of the present invention and the backed horn type speaker system according to the modified example of the present invention. The acoustic characteristic of the load horn type speaker system 10B is shown.

  Comparing the two, the frequency characteristic of the present invention is clearly increased with respect to the low-frequency part (80 to 200 Hz) as compared with the comparative example, and it is not a sharp peak (as it is flat). Therefore, better frequency characteristics can be obtained with the present invention than with the comparative example. Further, the second order distortion and the third order distortion are also reduced in the present invention compared to the comparative example. Furthermore, although the level of the admittance, which is the reciprocal of the impedance, is slightly different between the comparative example and the present invention, the present invention has generally better flatness than the comparative example.

  From the above, overall, the present invention can provide better acoustic characteristics than the comparative example, and in particular, can improve the low range.

It is the figure which showed the back load horn type | mold speaker system based on the Example of this invention. It is the figure which showed the modification which partially deformed the back load horn type | mold speaker system based on the Example of this invention. It is a figure for demonstrating the calculation method of the straight tube | pipe horn in the back load horn type | mold speaker system of the Example shown in FIG. It is a figure for demonstrating the calculation method of the quadrangular pyramid-shaped horn in the back load horn type speaker system of the modification shown in FIG. It is the figure which showed the back load horn type speaker system of the comparative example with respect to this invention. It is the figure which showed the acoustic characteristic of the back load horn type speaker system of the comparative example with respect to this invention. It is the figure which showed the acoustic characteristic of the back load horn type | mold speaker system which concerns on the Example and modification of this invention. It is sectional drawing which showed typically the general back load horn type | mold speaker system. It is the figure which showed typically the state which forms a sound path in a general back load horn type | mold speaker system, (a) shows the state which formed the sound path by connecting several straight tubular horns, (b ) Is a view showing a state in which a plurality of conical horns or quadrangular pyramid horns are connected to form a sound path. In a general back load horn type speaker system, it is a figure for explaining the calculation method of a horn, when a plurality of conical horns or a quadrangular pyramid horn is connected and a sound path is formed.

Explanation of symbols

10A ... Backloaded horn type speaker system according to an embodiment of the present invention,
10B ... Backloaded horn type speaker system according to a modification of the present invention,
10C ... Back load horn type speaker system of comparative example,
11 ... Speaker unit,
12 ... cabinet, 12a ... baffle plate (front plate), 12b, 12c ... left and right side plates,
12d ... bottom plate, 12e ... top plate, 12f ... back plate, 12g ... back cavity (air chamber),
12h ... Throat, 12i-12o ... Straight tubular horn,
12i 'to 12m' ... quadrangular pyramid horn, 12n ', 12o' ... straight tubular horn,
13-21 ... Flat plate partition, 18'-21 '... Flat plate partition,
22, 23 ... opening,
W: Internal width of cabinet, D: Internal dimensions of cabinet,
H: Dimensions within the height of the cabinet,
w: The width dimension of the speaker unit.

Claims (2)

A speaker unit mounted on the baffle plate of the cabinet;
A back cavity provided on the back side of the baffle plate in the cabinet;
A throat having a certain opening area connected to an opening part of the back cavity partially opened;
A plurality of horns that are sequentially connected via the throat and formed by partitioning the cabinet with a plurality of flat partition plates so that the opening area on each outlet side sequentially increases,
In the back load horn type speaker system with
After setting the inner width dimension of the cabinet to be constant,
S ₁ : an opening area on the outlet side of one of the plurality of horns,
S ₀ : the opening area of the outlet side of the horn connected to the previous stage of the one horn,
S ₂ : an opening area on the outlet side of the horn connected to the subsequent stage of the one horn,
L ₁ : length of the one horn,
L ₂ : the length of the horn connected to the subsequent stage of the one horn,
When
S ₁ ≈ {(S ₂ −S ₀ ) × L ₁ / (L ₁ + L ₂ )} + S ₀
Back load horn type speaker system characterized by satisfying The plurality of horns are connected so that the opening area of each connection part increases stepwise to form a sound path, or connected so that the opening area of each connection part increases with an inclination. The back road horn type speaker system according to claim 1, wherein the sound path is formed.

Images