JP5112358B2 - Speaker system and television - Google Patents

Description

  The present invention relates to a speaker system particularly suitable for a flat-screen television and the like and a television equipped with a speaker.

  There has been known a device in which an opening is provided in an enclosure of a speaker for a thin television and a space shape for transmitting sound to the opening is devised (see, for example, Patent Document 1 and Patent Document 2). In these, a part of the enclosure has a duct structure, and the bass reproduction performance is improved by Helmholtz resonance. However, these techniques are not intended to increase sound power for the midrange.

JP 2008-131541 A JP 2006-237899 A Japanese Patent No. 3842578

  The acoustic characteristics of a single speaker unit are known to be that the low frequency range with a long wavelength is likely to interfere because the radiated sound on the front and back sides are opposite in phase, resulting in a significant reduction in radiation efficiency. Yes. In view of this, the speaker unit generally has a structure in which an enclosure is provided on the back thereof to suppress the back-radiated sound and maintain the low-pitched sound reproduction performance.

  If the volume of the enclosure is sufficiently large, the volume velocity necessary for reproducing the low frequency range can be easily moved and reproduced. However, if the enclosure is too small, the trapped air acts as a spring and prevents the movement of speaker vibration. Try to. For this reason, even if the backside radiated sound can be blocked, the low-frequency radiating performance from the front is deteriorated.

  Therefore, the speaker built in the TV case is originally intended to have an enclosure, but in order to make the case thinner, the enclosure with sufficient volume for low-pitched sound playback cannot be installed. It is currently built in.

  Accordingly, the television housing panel itself behind the speaker unit only needs to replace the enclosure, but the panel is provided with a waste heat opening, and therefore does not replace the enclosure. Therefore, although the speaker unit alone has the ability to reproduce bass sounds, the result is a structure in which bass sounds cannot be reproduced.

  In addition, when the television is thinned, the tendency to be placed close to the wall becomes stronger. At this time, the sound radiated from the waste heat opening on the back of the panel is reflected by the wall, and the mid-high range with a short wavelength tends to interfere with the wall reflected sound and the frequency characteristics deteriorate. Therefore, the opening provided in the back panel is suitable for waste heat, but is not necessarily effective from the viewpoint of sound reproduction.

  The present invention solves the above-described problems, and an object of the present invention is to improve acoustic characteristics in a speaker system including a speaker that spreads in a plane and an enclosure that accommodates the speaker.

  In order to achieve the above object, a speaker system according to the present invention is a speaker system including a speaker that spreads in a plane and an enclosure containing the speaker, wherein the enclosure includes a front plate that covers the front of the speaker. A back plate that is parallel to the front plate and covers the back of the speaker, a side plate that connects the peripheries of the front plate and the back plate to each other, and has at least one opening formed therein; and at least two of the openings. A plurality of cylindrical bodies which are partitioned into a plurality of small openings arranged in a row and whose axes are parallel to each other and adjacent to each other.

  Further, the television according to the present invention is a television including a speaker that spreads in a plane and an enclosure containing the speaker. The enclosure covers the front of the speaker, and at least a part of the enclosure forms a display panel. A front plate, a back plate that is parallel to the front plate and covers the back of the speaker, a side plate that connects the peripheries of the front plate and the back plate to each other, and at least one opening is formed; and the opening Is divided into a plurality of small openings arranged in at least two rows, and has a plurality of cylindrical bodies whose axes are parallel to each other and adjacent to each other.

  ADVANTAGE OF THE INVENTION According to this invention, an acoustic characteristic can be improved in the speaker system provided with the speaker which spreads planarly, and the enclosure which accommodates it.

1 is a rear view of a first embodiment of a speaker system according to the present invention. It is a sectional side view of the speaker system of FIG. FIG. 3 is an enlarged plan view of one opening in the speaker system of FIG. 1 as viewed in the direction of the arrow III in FIG. 2. It is an enlarged plan view of the direction corresponding to FIG. 3 of one opening part in the modification of 1st Embodiment of the speaker system which concerns on this invention. It is a figure which shows the result of having measured the frequency characteristic and impulse response at the time of installing the conventional capacitor type speaker away from the wall surface. It is a figure which shows the result of having measured the frequency characteristic and impulse response at the time of installing the conventional capacitor | condenser type speaker close to a wall surface. When each small opening of an enclosure is circular, it is a graph which compares and shows the acoustic power increase amount at the time of arranging 7 pieces in a horizontal line and arrange | positioning equally, Comprising: One opening part diameter d = 0.05m Show the case. It is a graph which compares and shows the acoustic power increase amount similar to FIG. 7, Comprising: The case where one opening part diameter d = 0.01m is shown. Schematic explaining the model of Helmholtz resonance. It is a rear view of 2nd Embodiment of the speaker system which concerns on this invention. It is a front view of the speaker system of FIG. FIG. 11 is a partially cutaway side view of the speaker system of FIG. 10. It is a sectional side view of 3rd Embodiment of the speaker system based on this invention.

  In order to realize excellent acoustic characteristics in a speaker system including a thin enclosure, it is a priority to improve the bass reproduction performance of the speaker unit alone. As a countermeasure, it is necessary to increase the volume velocity obtained by multiplying the speaker vibration velocity by the speaker radiation area. In general, a cone type dynamic speaker mounted on an AV device has to increase the vibration speed because the radiation area is small. However, there is a stroke limit because the center of the diaphragm, which is a circular surface, is moved by a piston with a circular voice coil and the vibration is transmitted to a large diaphragm and air is emitted to radiate sound. If the vibration exceeds the allowable range, distortion will occur and not only low frequencies can be reproduced, but also the middle and high range deterioration.

  Therefore, it is considered to use a flat speaker that realizes a large radiation area by arranging thin and light acoustic vibration elements in a plane. A large-area diaphragm can obtain a sufficient sound pressure with a minimum amplitude operation, and realizes a small amplitude and low distortion when the maximum sound pressure level is the same as that of a conventional cone type speaker. For example, it is also known that the amplitude at the maximum sound pressure level of 124 dB is only 1.27 mm (50 Hz) by employing a large area diaphragm corresponding to a woofer having a diameter of 152 cm. Accordingly, the volume velocity of the speaker unit can be increased as much as the vibration amplitude of the speaker can be allowed, and the performance of the speaker unit alone is improved. In addition, the speaker unit itself can be made thinner by the amount that does not have a voice coil than the cone type dynamic speaker, and as a result, the enclosure can be made smaller.

  However, as described above, since the enclosure acts as an air spring to prevent the movement of the speaker vibration, it cannot be reduced unnecessarily.

  Therefore, it is considered to maintain the bass reproduction capability by using the waste heat opening to reduce the movement of air. Here, it should be noted that when the shape of the opening is made long and narrow, the radiation distribution is also deteriorated in the mid-high range. Furthermore, the radiated acoustic power is also deteriorated.

  Therefore, by combining the openings, it is possible to increase the radiated acoustic power in the mid-high range. As a result, by combining a plurality of openings in one place, even in the low sound range, this opening can be regarded as a Helmholtz resonance nozzle (or a port portion of a bass reflex type speaker), and the speaker unit alone has It can also be expected to increase the sound beyond the lower limit.

  Specific embodiments of the speaker system according to the present invention will be described below with reference to the drawings.

[First Embodiment]
The first embodiment will be described with reference to FIGS.

  FIG. 1 is a rear view of a first embodiment of the speaker system according to the present invention, FIG. 2 is a side sectional view of the speaker system of FIG. 1, and FIG. 3 is a view of one opening portion of the speaker system of FIG. It is a direction arrow enlarged plan view.

  A rectangular planar speaker 1 is accommodated in an enclosure 2. The enclosure 2 includes a rectangular front plate 20 that covers the front surface of the speaker 1 in parallel with the front surface of the speaker 1, a rectangular back plate 21 that covers the back surface of the speaker 1 in parallel with the front plate 20, and each of the front plate 20 and the rear plate 21. And four side plates 22 connecting the four sides. The front plate 20 is larger than the back plate 21, and each side plate 22 is inclined with respect to the front plate 20 and the back plate 21.

  Each side plate 22 has an opening 23 formed therein. The opening 23 serves both as a waste heat outlet for releasing heat generated in the enclosure 2 and as a role for improving acoustic characteristics. Each opening 23 is partitioned by seven cylindrical tubular bodies 24. Each cylindrical body 24 arranged in each opening 23 has the same cross-sectional shape, all of which are parallel to the spreading surface of the front plate 20 and have axes parallel to each other in the direction away from the speaker 1. The other six cylindrical bodies 24 closely surround the cylindrical body 24. The length of each cylindrical body 24 is preferably at least 0.9 times the diameter d.

  The enclosure 2 also accommodates electrical components (not shown) such as a mechanism for supplying power to the speaker 1.

  In the first embodiment, each cylindrical body 24 is cylindrical, but as a modification, the cross-sectional shape of each cylindrical body 24 may be a regular hexagon as shown in FIG. In manufacturing the opening 23 as shown in FIG. 4, it is not always necessary to combine a plurality of individually manufactured cylindrical bodies 24. For example, a shape in which a plurality of cylindrical bodies 24 as shown in FIG. 4 are combined may be integrally formed from the beginning.

  In the first embodiment, the first goal is to improve the bass reproduction performance of the speaker unit alone. Therefore, consider increasing the volume velocity obtained by multiplying the speaker vibration velocity by the speaker radiation area. Here, cone type dynamic speakers mounted on AV devices and televisions generally need to increase the vibration speed because the radiation area is small, but there is a stroke limit, and in vibrations exceeding the allowable range, Distortion occurs, causing low-frequency reproduction as well as deterioration of the mid-high range.

  Therefore, a flat speaker that realizes a large radiation area is arranged by arranging thin and light acoustic vibration elements in a flat shape, and a radiation area enough to fit in the enclosure volume is secured and incorporated. Since there is no voice coil, the speaker itself becomes thinner, and the enclosure itself can be made thinner accordingly. However, as described above, consider the use of the waste heat opening to reduce the air movement and maintain the bass reproduction capability so that the air spring acts as the air spring and does not hinder the movement of the speaker vibration. Thereby, the bass can be reproduced.

  For bass, a plurality of openings can be regarded as one opening having the same area due to the length of the wavelength, and there is no effect of making a plurality of openings. In addition, in the case of low sound, it is not easily affected by wall reflection. Therefore, the arrangement and shape of the opening cannot be characterized only in the low sound range, but the shape and arrangement of the opening and the enclosure rectangular shape play an important role for measures against the middle and high sounds.

  Then, the effective opening part seen from the mid range is described in detail.

  The mid-range has a shorter wavelength and a larger radiation area, so that the larger the opening, the more the difference in the propagation path to the opening, and the greater the variation in amplitude and phase on the surface of the opening. Further, when there is a wall near the opening, it easily interferes with the wall reflection sound, and as a result, the frequency characteristics are also likely to deteriorate.

  5 and 6 show an actual measurement example measured at a position of about 10 cm from the front enclosure 41 when a conventional capacitor type speaker is brought close to a wall. In this case, an opening 42 is formed on the back surface of the enclosure 41 made of a steel plate having a thickness of 2 mm for housing the speaker 40.

  FIG. 5 shows a case where the speaker system is sufficiently separated from the wall, and FIG. 5 (a) shows a schematic cross section thereof. 6 shows a case where the same speaker system as in FIG. 5 is used and the back surface of the speaker system is brought close to the wall surface 43, and FIG. 6A shows a schematic cross section thereof. The material of the wall surface 43 is concrete. The distance L between the back surface of the speaker 40 and the wall surface 43 in the case of FIG. 6 is 10 cm. 5 and 6, (b) shows frequency characteristics, and (c) shows impulse response results. Comparing FIG. 5 and FIG. 6, when the back surface of the speaker system is brought close to the wall surface, it can be seen that the reflected sound is superimposed due to the reflection of the wall, and the middle sound range is degraded at the frequency.

  Therefore, if an opening is provided in the back surface of the enclosure close to a general rectangular parallelepiped, it is easily affected by wall reflection. Therefore, it is conceivable to provide openings on the upper and lower sides of the enclosure without providing openings on the back surface. However, in that case, the opening becomes elongated to reduce the thickness of the enclosure, and the variation of the opening radiation distribution becomes larger.

  As described in Patent Document 3, when the elongate opening is partitioned so as to divide its length direction, the phase can be aligned inside each partition. However, in that case, the acoustic power differs depending on the distance between the radiated sounds divided, and if they are radiated in the same phase, since the distance between them is different, sufficient power-up cannot be expected.

  Therefore, in the embodiment of the present invention, as shown in FIG. 3 or FIG. 4, even if the opening has the same area, the acoustic power can be improved by devising the arrangement of a plurality of small openings.

  The reason why the sound power can be improved in this embodiment will be described below.

  The condition that the radiated sound of each divided opening (small opening) shown in FIG. 3 and FIG. 4 can be approximated by a point sound source is that plane waves propagate in the opening, as described in Patent Document 3. In other words, the phase of the opening section is the same and the mode does not stand.

  For this purpose, the length of the partition portion is 0.9 times or more of the diameter d (m).

  Here, the sound speed is c (m / s) and the frequency is f (Hz).

  In the case of a rectangular parallelepiped cylinder, if the long side is d (m), the condition is f <c / (2d).

  In a circular (substantially hexagonal) cylinder, if the diameter is d (m), the condition is f <1.2c / (2d).

  Here, assuming that the wave number is k (1 / m), k = 2πf / c (π is the pi), so when expressed as wave number × diameter, the following conditions are satisfied.

ただし、ω＝２πｆは角周波数、ｄｉｊはｉ番目からｊ番目の開口部までの距離、ρは空気の密度（ｋｇ／ｍ^３）を表す。隣同士の開口部に限らず、Ｎ×Ｎ個、すべての開口部同士からなる相互放射パワー分が寄与することがわかる。 In the case of a rectangular parallelepiped cylinder, kd <π (1)
In the case of a circular (generally hexagonal) cylinder, kd <1.2π (2)
That is, the sound source radiated from the opening under this condition is regarded as a point sound source, and the total sound representing the sound scale when N point sound sources represented by the amplitude qi (volume velocity) and the phase θi exist. The radiation power W is expressed by equation (3).

Where ω = 2πf is the angular frequency, dij is the distance from the i-th to the j-th opening, and ρ is the air density (kg / m ³ ). It turns out that not only the opening part of adjacent but the NxN piece and the mutual radiation power part which consists of all the opening parts contribute.

ここで、開口部１個だけの場合を基準に、全体の放射パワーの増加分を式（５）に示す。

ここで、各小開口内の位相は、スピーカ放射面からほぼ等距離にあるために同位相と見なすことができる。すると、複数の各小開口が直線的に一列に配置された場合は式（６）となる。

・・・（６）
また、図３および図４のように均等配置の場合は式（７）となる。

距離ｄがゼロに近いときは、ｓｉｎｃ関数は１に近づき、ほぼ両者は同じ値になる。しかし、式（１）または式（２）の点音源実現の条件下では、式（６）よりも式（７）の方が大きくなることから、本実施形態の配置方法の方がより中高音域で増音が期待できる。 Considering the case of FIG. 3 and FIG. 4, N = 7, which is expressed by Expression (4).

Here, with reference to the case of only one opening, the increase in the overall radiation power is shown in Equation (5).

Here, since the phase in each small aperture is substantially equidistant from the speaker radiation surface, it can be regarded as the same phase. Then, when a plurality of small openings are linearly arranged in a line, Expression (6) is obtained.

... (6)
Moreover, in the case of equal arrangement as shown in FIG. 3 and FIG.

When the distance d is close to zero, the sinc function approaches 1, and the two values are almost the same. However, since the expression (7) is larger than the expression (6) under the condition for realizing the point sound source of the expression (1) or the expression (2), the arrangement method according to the present embodiment is more moderately high-pitched. Sound increase can be expected in the area.

  For simple comparison, FIGS. 7 and 8 show a comparison result between the case where each small opening is circular and the case where seven small openings are arranged in a horizontal row and the case where they are equally arranged as in the present embodiment.

  When the diameter d of each small opening is 0.05 m, as shown in FIG. 7, up to 4080 Hz is a range in which the radiated sound can be approximated as a point sound source without mode being established in each small opening cross-sectional direction. It can be seen that the sound power increases by about 4 dB in the mid-high range of 1000 Hz or higher when the uniform arrangement (concentrated arrangement) shown in FIG. 3 or 4 is used.

  In addition, when the diameter d of each small opening is 0.01 m, as shown in FIG. 8, it can be seen that the acoustic power is increased by about 4 dB in the middle and high frequencies similarly at 20400 Hz, that is, in the audible range of the sound. .

［第２の実施形態］
図１０ないし図１２を参照して、本発明に係るスピーカシステムの第２の実施形態について説明する。図１０は本発明に係るスピーカシステムの第２の実施形態の背面図、図１１は図１０のスピーカシステムの正面図、図１２は図１０のスピーカシステムの部分切欠き側面図である。第１の実施形態と同一または類似の部分には共通の符号を付して重複説明は省略する。 In particular, in the case of the uniform arrangement, in the low sound range, it can be regarded as a housing with a duct having an opening having a diameter of approximately 3d. Therefore, as shown in FIG. In the case of the shape with the S duct attached, sound increase at the resonance frequency of equation (8) can also be expected. ΔL is a coefficient to be changed according to the area S as opening end correction.

[Second Embodiment]
A second embodiment of the speaker system according to the present invention will be described with reference to FIGS. 10 is a rear view of the second embodiment of the speaker system according to the present invention, FIG. 11 is a front view of the speaker system of FIG. 10, and FIG. 12 is a partially cutaway side view of the speaker system of FIG. Portions that are the same as or similar to those in the first embodiment are denoted by common reference numerals, and redundant description is omitted.

  In this embodiment, two rectangular planar speakers 1 having the same shape are arranged side by side symmetrically, and these are accommodated in the enclosure 2. A rectangular front opening 30 is formed at the center of the front plate 20 of the enclosure 2, and the rectangular liquid crystal panel 12 is fitted in the front opening 30. That is, this speaker system constitutes a thin television with a built-in speaker.

  The four side plates 22 that connect the four sides of the front plate 20 and the back plate 21 are composed of a lower side plate 22a, an upper side plate 22b, and two lateral side plates 22c. A television stand 13 is attached to the lower part of the lower side plate 22a, and the speaker 1 and the enclosure 2 are supported by the television stand 13. Openings 23 are formed near the left and right ends of the upper side plate 22b and at the bottom of each side plate 22c. Each opening 23 is partitioned by a plurality of cylindrical tubular bodies 24 as in the first embodiment.

  The enclosure 2 also houses a mechanism for supplying power to the speaker 1 and various electrical components (not shown) for displaying images on the liquid crystal panel 12.

  Considering that the TV stand 13 (and a not-shown stand below it) spreads horizontally near the lower portion of the enclosure 2, avoid the reflection of sound from the lower surface when the opening 23 is not on the lower side plate 22 a. This is preferable.

  Considering the stereo acoustic characteristics, it is preferable that the speaker 1 and the opening 23 are arranged symmetrically.

  According to this embodiment, an excellent acoustic characteristic can be realized by using the ventilation port for waste heat and ventilation of a flat-screen television.

[Third Embodiment]
A third embodiment of the speaker system according to the present invention will be described with reference to FIG. FIG. 13 is a side sectional view of a third embodiment of the speaker system according to the present invention. This embodiment is a modification of the first embodiment. The front plate 20 is smaller than the back plate 21, and each side plate 22 is opposite to the first embodiment with respect to the front plate 20 and the back plate 21. It is inclined to. In this embodiment, each opening 23 is in a position where it can be seen from the front side of the speaker system, and the sound emitted from the opening 23 is easily transmitted to the front side.

[Other Embodiments]
The above embodiments are merely examples, and the present invention is not limited to these.

  For example, the features of the embodiments may be combined. For example, a regular hexagonal cylindrical body shown in FIG. 4 may be used for each opening 23 in the second and third embodiments. Further, the feature that the front plate 20 is smaller than the back plate 21 as in the third embodiment may be incorporated into the thin-type television of the second embodiment.

  Further, a mesh or the like may be arranged in the opening 23 in order to prevent dust from entering the enclosure 2 from the opening 23.

  Moreover, in the said embodiment, although the axis | shaft of the cylindrical body 24 arrange | positioned in the opening part 23 was parallel to the front plate 20, even if it is not necessarily parallel to the front plate 20, for example to the side plate 22 It may be vertical.

  Further, the front plate 20 may be the same size as the back plate 21, and the side plate 22 may be perpendicular to the front plate 20 and the back plate 21.

1: Speaker 2: Enclosure 12: Liquid crystal panel 13: Television stand 20: Front panel 21: Rear panel 22: Side panel 22a: Lower side panel 22b: Upper side panel 22c: Side panel 23: Opening 24: Cylindrical body 30: Front opening

Claims (10)

In a speaker system including a speaker that spreads in a plane and an enclosure that incorporates the speaker,
The enclosure is
A front plate covering the front of the speaker;
A back plate that is parallel to the front plate and covers the back of the speaker;
Connecting each periphery of the front plate and the back plate to each other, and a side plate formed with at least one opening;
A plurality of cylindrical bodies that divide the openings into a plurality of small openings arranged in at least two rows, and whose axes are parallel to each other and adjacent to each other;
A speaker system characterized by comprising:   The speaker system according to claim 1, wherein the plurality of cylindrical bodies have cylindrical shapes having openings of the same size, and are tightly joined to each other in a staggered pattern.   The speaker system according to claim 1, wherein the plurality of cylindrical bodies are regular hexagonal cylinders having openings of the same size, and are in close contact with each other.   The said some cylindrical body consists of one cylindrical body of a center, and six cylindrical bodies surrounding this central cylindrical body, The Claim 2 or Claim 3 characterized by the above-mentioned. Speaker system.   The speaker system according to any one of claims 1 to 4, wherein an axis of the cylindrical body is parallel to the front plate and the back plate.   The said front plate is larger than the said back plate, The said side plate is inclined and arrange | positioned with respect to the said front plate and a back plate, The Claim 1 thru | or 5 characterized by the above-mentioned. The speaker system described.   The said front board is smaller than the said back board, and the said side board is inclined and arrange | positioned with respect to the said front board and back board, The Claim 1 thru | or 5 characterized by the above-mentioned. The speaker system described.   The speaker system according to any one of claims 1 to 7, wherein at least a part of the front plate is a display panel. The side plate includes an upper side plate connecting upper sides of the front plate and the back plate, a lower side plate connecting lower sides of the front plate and the back plate, and right sides or left sides of the front plate and the back plate. Two lateral side plates connecting each other,
The speaker system according to any one of claims 1 to 8, wherein the opening is formed in each of the upper side plate and the lateral side plate. In a television including a speaker spreading in a plane and an enclosure containing the speaker,
The enclosure is
A front plate covering the front of the speaker, at least a part of which constitutes a display panel;
A back plate that is parallel to the front plate and covers the back of the speaker;
Connecting each periphery of the front plate and the back plate to each other, and a side plate formed with at least one opening;
A plurality of cylindrical bodies that divide the openings into a plurality of small openings arranged in at least two rows, and whose axes are parallel to each other and adjacent to each other;
A television characterized by comprising:

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