JP2013198026A - Speaker device using spheroid type enclosure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce an audio more faithful to an original sound by reducing generation of noise resulting from an enclosure of a speaker device by devising the position of a speaker unit incorporated in the enclosure, and to reproduce a deep bass exceeding various elements of the speaker unit even by a device of compact size which can be placed on a desk top with practical sound volume.SOLUTION: An inner surface of an enclosure 1 is formed in a spheroid shape, and a speaker unit is installed such that a diaphragm (corn paper) is at one focus thereof.

Description

    The present invention reduces the generation of noise due to the enclosure by devising the shape of the inner surface of the enclosure in which the speaker unit is incorporated, and enables reproduction faithful to the original sound over the entire frequency band of the sound, and the speaker unit. It is related with the speaker apparatus which implement | achieves the low-pitched sound reproduction which breaks through the specifications.

    Conventionally, the enclosure of a speaker device is generally a box type, but because the box type has planes parallel to each other on the inner surface, sound waves radiated into the enclosure from the back of the unit are reflected on the inner surface. Resonance (standing wave) was repeatedly generated, and the resonance of the enclosure itself was added to generate noise, resulting in a turbid reproduction sound.

    As countermeasures, measures are generally taken to reduce the parallel surfaces of the enclosure or to use a sound absorbing material or a vibration damping material inside. Some enthusiasts have also attempted to improve sound quality by incorporating speaker units into ceramic bowls that do not have a plane parallel to each other on the inner surface. Has also been made. (For example, see Patent Documents 1 and 2)

    For bass reproduction, the speaker unit has the lowest resonance frequency corresponding to the aperture of the diaphragm, and at lower frequencies, the function of the diaphragm drops sharply, so the lowest resonance frequency is practically a bass reproduction. Is the lower limit. Moreover, in order to reproduce sufficiently to the vicinity of the lowest resonance frequency, the volume of the enclosure corresponding to the diameter of the speaker unit is necessary, so that a large speaker device occupies the installation place. Therefore, by adopting a phase reversal (bass reflex) type that resonates and amplifies the internal bass with a duct attached to the enclosure and releases it to the front, a device that reduces the volume of the enclosure to some extent while ensuring low-frequency reproduction, etc. Has also been done. (For example, see Patent Document 3)

JP 2010-258800 A Japanese Patent No. 4416216 Japanese Patent No. 4870242

    However, even if a sound absorbing material or a vibration damping material is used for noise reduction, its effect is naturally limited, and if used excessively, it is difficult to make adjustments such as causing an unnatural change in the reproduced sound. In addition, the adoption of non-box type enclosures such as porcelain jars has a certain effect on noise reduction, but it is often not a rigorously examined shape, so there is still a limit, and the bass reflex method is adopted. However, it is difficult to greatly reduce the volume of the enclosure.

    In any case, if you want to get enough bass with conventional technology, you need a large-diameter speaker knit and a large enclosure, so the installation place is limited and it is not suitable for using in a small place such as a desk It is. However, although a small speaker unit with a diameter of 4 to 5 cm or less can have a small enclosure, the lowest resonance frequency is generally 100 Hz or more, so with existing methods, 40 Hz and 50 Hz, a so-called heavy bass sound that sounds like the body. Reproduction is difficult. Because of these technical limitations, it is difficult to connect a personal computer or portable music player with a small speaker device that does not get in the way when placed on a desk. Currently.

    As shown in FIG. 1, the shape of the inner surface of the enclosure 1 is a curved surface of a spheroid obtained by rotating around the major axis a of the ellipse, and one of the two focal points f on the major axis a. An opening is provided at the position, a baffle 3 is attached to the opening, and the diaphragm of the speaker unit 2 is placed at the focal point.

    As shown in FIG. 1, there are two focal points f on the major axis a of the ellipse, and due to the nature of the enclosure 1 whose inner surface is a spheroid, the speaker unit 2 placed at one focal point f. The sound wave s radiated from the diaphragm toward the inner surface is reflected by the inner wall of the enclosure 1 and focused on another focal point f, and then reflected again by the inner wall to return to the diaphragm at the original focal point. No harmful noise is generated by irregular reflection in the enclosure. In addition, since all the paths of the sound waves are equidistant, there is an advantage that there is no time shift in the sound waves returning to the diaphragm. Note that some reflected waves do not return to the diaphragm when they hit the baffle, but diffuse reflection occurs. Much less. Furthermore, by adjusting the material and thickness of the enclosure as necessary, or by using a sound absorbing material and damping material in combination, the generation of noise due to irregular reflection and resonance is extremely reduced, and clear sound close to the original sound Can be played.

    The sound wave radiated from the diaphragm forms a circulation path that returns to the diaphragm again at the same time, causing a kind of resonance with almost no noise component, and the enclosure internal space itself is integrated with the unit diaphragm It will serve as a large diaphragm. As a result, the resonance effect brought about by the circulation of sound waves acts strongly on the diaphragm, so even in the band below the lowest resonance frequency of the small-diameter speaker unit, the large-diameter speaker with a wide diaphragm exceeding its limit It becomes possible to emit a bass sound like a unit to the front of the speaker. In other words, the present invention actively forms a circulation in which the original sound emitted from the diaphragm of the speaker unit returns to the diaphragm at the same time inside the enclosure, and encourages and enhances the movement of the diaphragm by the sound pressure of the circulating wave. Therefore, it is intended to reproduce a high-quality sound that breaks through the limit of the minimum resonance frequency and has less noise in the entire band.

    Thus, for example, even a compact speaker device incorporating an ultra-small speaker unit with a caliber of 1 to 2 inches in an enclosure of a softball size can reproduce heavy bass and reproduce sound faithful to the original sound over the entire band. Is possible.

    In addition, if the outer surface of the enclosure is curved like the inner surface, the sound waves emitted to the front surface will diffuse around the four sides without resistance, providing excellent sound localization, and in music, you can clearly feel the position of each instrument. Besides being able to enjoy it, you can enjoy a very natural 3D sound field as if the listener is on the podium. Because the enclosure is small, it can be placed in various positions, and the sound field changes accordingly, which also doubles the enjoyment of listening.

The path of the sound wave in the inner surface of the spheroid-type enclosure regarding the embodiment of the present invention. 1 is a schematic structure of the entire speaker device of the present invention. The external appearance photograph (horizontal placement) of the Example of the speaker apparatus of this invention. The external appearance photograph of the Example of the speaker apparatus of this invention (lay down).

    As shown in FIG. 2, this speaker device has a simple structure in which a baffle 3 is attached to an enclosure 1 having an internal curved surface of a spheroid, and a speaker unit 2 is attached to the center of the baffle 3. Although it is possible to further adjust the sound quality by providing a bass reflex duct in the baffle or enclosure, the bassless method is not shown in the figure because it is a technique that is generally used.

    The shape of the inner surface of the enclosure 1 is a spheroid obtained by rotating an elliptical long axis. The entire structure of the enclosure portion is obtained by attaching the baffle 3 so as to cover the eyelid at the position of one of the two focal points on the long axis.

    The basic structure of the speaker device is that the speaker unit 2 is installed on the baffle 3 so that the diaphragm is at the focal point.

    FIGS. 3 and 4 are photographs of an embodiment in which the full-range speaker unit 2 having a diameter of 2 inches is incorporated into a porcelain spheroid enclosure 1 having a diameter of about 12 cm, a height of about 11 cm, and an internal volume of about 650 cc. In this embodiment, the spheroid is cut perpendicularly to the long axis at the focal point, and a disk-like baffle 3 is attached to the spheroid, and the speaker unit 2 is located near the center of the diaphragm on the baffle. It is installed to do. In this example, the inner shape and the outer shape of the enclosure 1 are similar to each other, and this outer curved surface also works advantageously for forming a sound field.

    As shown in FIG. 3 and FIG. 4, it can be placed sideways or face down. In landscape orientation, the orientation of the aperture is freely changed by placing it on a ring-shaped pedestal. In the case of lying down, four legs are attached to the baffle 3 and a reproduced sound is emitted with a proper space between the floor and the floor.

    The performance of the speaker device in this example is a practical reproduction frequency of about 40 Hz to 15 kHz without a bass reflex duct. Incidentally, the minimum resonance frequency according to the specifications announced by the manufacturer of this speaker unit is 200 Hz.

1 Enclosure 2 Speaker unit 3 Baffle a Ellipse major axis b Ellipse minor axis f Ellipse focus s Sound wave

Claims (2)

The inner surface of the enclosure has a shape of a spheroid centered on an elliptical long axis a represented by an elliptical formula x ² / a ² + y ² / b ² = 1 (a>b> 0). The ellipsoid is perpendicular to the major axis at the position of one of the two focal points represented by {± √ (a ² −b ² ), 0} on the major axis a of A speaker device having a structure in which a baffle is cut and attached, and a diaphragm (cone paper) of the speaker unit is placed on the baffle at the position of the focal point f. 2. The speaker device according to claim 1, wherein an inner surface of the enclosure is a spheroid of 1.0 <a / b ≦ 10.0 in a value of a ratio of a major axis a to a minor axis b of the ellipsoid. A speaker device having a shape and a structure in which the speaker knit is installed at the position.