JPH0593199U - Speaker device - Google Patents

Abstract

(57) [Abstract] [Purpose] Regarding the cone speaker used in audio equipment, etc., the acoustic output distortion due to edge resonance is reduced as much as possible by applying a force in the same direction to the center and the periphery of the cone. It is intended to provide a cone speaker. A cone 1 composed of a conical diaphragm, a first electro-acoustic conversion means 2 for driving a central portion of the cone 1 by converting an electric signal from an acoustic signal source 5 into an acoustic vibration, and the sound. Second electro-acoustic conversion means 3 for converting the electric signal from the signal source 5 into acoustic vibration and driving the peripheral portion of the cone 1 in a phase opposite to that of the driving by the first electro-acoustic conversion means 2, and The cone 1, the first electricity-
It is composed of a sound converting means 2 and a speaker frame 4 supporting the second electro-acoustic converting means 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cone speaker used in an audio device and the like, and more particularly to a cone speaker in which distortion of acoustic output with respect to an input signal is reduced as much as possible.

[0002]

[Prior Art]

 The cone speaker is also called a direct radiating speaker because it transmits the vibration of the diaphragm directly to the air and hears it as sound. FIG. 3 schematically shows a general structure example of a conventional cone speaker. A voice coil 17 is wound around the center of a conical diaphragm 12 called a cone, and an audio electric signal from an acoustic signal line 22 is passed through the voice coil 17 via a terminal plate 18 attached to the speaker frame 11. Given. The permanent magnet 20 and the center pole 21 and the yoke 19 that are formed of a magnetically permeable member that surrounds the permanent magnet 20 form a closed magnetic circuit, and form a so-called external magnetic circuit in the figure.

A damper 16 is used to properly hold the voice coil 17 in the magnetic field between the center pole 21 and the yoke 19, and an edge 13 is used to support the peripheral portion of the cone. There is. The center cap 15 at the center of the cone is intended to protect the magnetic circuit from dust. Now, when an audio electric signal from the acoustic signal line 22 is applied to the voice coil 17, the relationship between the magnetic field between the center pole 21 and the yoke 19 and the current of the voice coil 17 causes Fleming's left hand rule. The cone moves up and down according to the signal, and its vibration produces an acoustic output.

[0004]

[Problems to be solved by the device]

 However, the above-mentioned conventional cone speaker driving method is based on one-point driving by the voice coil 17 at the center of the cone 12 and two-point support by the damper 16 at the central portion of the cone 12 and the edge 13 at the peripheral portion. Conventionally, in order to vibrate the cone 12 linearly with respect to an input signal, improvement of materials such as the cone 12, the damper 16, the edge 13 and the like, and further the corrugation of a waveform formed concentrically on the cone 12 and the like are continued. However, as described above, the method in which the voice coil 17 is driven at one point and the damper 16 and the edge 13 are supported at two points is structurally limited.

FIG. 4 shows an example of distortion rate frequency characteristics of a conventional cone speaker. In the figure, the characteristic curve 23 shows a so-called sound pressure frequency characteristic, which is a standard value at a constant distance on the axis of the speaker when a constant voltage audible frequency is applied to the voice coil of the speaker placed in the anechoic chamber. A microphone is arranged, the audible frequency is continuously changed, and the output voltage is measured and converted into a sound pressure level. The sound pressure frequency characteristic 23 becomes maximum at the lowest resonance frequency determined by the masses of the cone and the voice coil, the inertial mass during vibration of the cone and the voice coil, and the elastic force of the edge and the damper in the low sound range, and becomes the maximum thereafter. As shown in the figure, the sound pressure characteristics in the range approach a certain level, and in the high range, they are attenuated in proportion to the square of the frequency above the reproduction limit frequency determined by the cone shape, opening angle, material, and mass of the voice coil. It becomes a characteristic curve.

The characteristic curve 24 shows the distortion rate. This is the ratio of the total acoustic output from the speaker to the total harmonic components that differ from the input frequency in the speaker acoustic output, expressed as a percentage. The cause of distortion is the decrease in magnetomotive force that occurs when the voice coil goes out of the uniform magnetic flux distribution, and the cone amplitude is proportional to the square of the frequency, such as the distortion in the low range of the figure. Then, there is a large increase in non-linear distortion. In addition, non-linear changes due to displacement of edges and dampers also cause distortion when the amplitude is large. Distortion in the middle and high frequencies is often caused by higher-order resonance in which the entire edge of the cone resonates and vibrates in an opposite phase to the cone, or local excessive vibration due to divided vibration. Further, the distortion increases near the reproduction limit frequency due to the non-linear distortion in which the amplitude of the cone is attenuated in proportion to the square of the frequency.

FIG. 5 shows a state in which the entire edge 13 described above resonates and vibrates in a phase opposite to that of the cone 12. In the figure, since the vibration direction of the cone 12 and the vibration direction of the edge 13 are opposite to each other at the intersection of the solid line and the dotted line, a harmonic wave is generated for the fundamental wave in which the vibration directions of the cone 12 and the edge 13 are the same. It will be. This is due to the basic structure of the cone speaker, that is, one-point driving of the voice coil 17 in the central part of the cone 12 and fixing of the edge 13 in the peripheral part of the cone 12, and the shapes of the cone 12 and the edge 13, It is affected by material, thickness, weight, and the above-mentioned corrugation.

In view of the above problems, the object of the present invention is to reduce the acoustic output distortion due to the resonance characteristic of the edge shown in FIG. 5, in addition to driving the central portion of the cone 12 by the voice coil 17, By using a driving means corresponding to the voice coil without fixing the peripheral portion of 12 as in the prior art, the vibration (driving) directions of the voice coil at the central portion of the cone 12 and the driving means at the peripheral portion are opposite in phase. Therefore, the cone 12 is always applied with a uniform force irrespective of the input signal frequency, amplitude, etc., and a cone speaker in which a so-called bending force of the cone 12 is not exerted is provided. According to this, the resonance characteristic near the edge described above does not occur, and accordingly, the acoustic output distortion due to it does not occur.

[0009]

[Means for Solving the Problems]

 According to the present invention, as shown in FIG. 1, a cone 1 composed of a conical diaphragm, and a first portion for driving a central portion of the cone 1 by converting an electric signal from an acoustic signal source 5 into an acoustic vibration. The electric-acoustic conversion means 2 converts the electric signal from the acoustic signal source 5 into acoustic vibration, and drives the peripheral portion of the cone 1 in a phase opposite to the driving by the first electric-acoustic conversion means 2. There is provided a cone speaker including a second electro-acoustic converting means 3, the cone 1, the first electro-acoustic converting means 2 and the speaker frame 4 supporting the second electro-acoustic converting means 3. To be done.

[0010]

[Action]

 The first electro-acoustic conversion means 2 converts the electric signal from the acoustic signal source 5 into acoustic vibration of the central portion of the cone 1. The second electro-acoustic conversion means 3 arranged in the peripheral portion of the cone 1 converts the electric signal from the acoustic signal source 5 into the acoustic vibration of the peripheral portion of the cone 1 to generate the first electric-acoustic signal. The sound is converted in a phase opposite to that of the sound conversion means 2. Therefore, when the cone 1 is vertically vibrated, when one of the two electro-acoustic conversion means 1 and 2 pushes the cone 1, the other pulls, and when one pulls, the other pushes the other so that the inside of the cone 1 is pushed. Is applied with a substantially uniform force even if the frequency and amplitude of the input signal are changed, and particularly the force for bending the cone 1 does not work. Therefore, in this state, the edge resonance distortion shown in FIG. 5 does not occur.

[0011]

【Example】

 FIG. 2 schematically shows an embodiment of a cone speaker according to the present invention. In FIG. 2, the same parts as those in the conventional example of FIG. 3 are designated by the same reference numerals. Further, in relation to FIG. 1, the first electro-acoustic conversion means 2 corresponds to the above-mentioned magnetic circuits 16 to 22 in FIG. 2, and the cone 1 and the speaker frame 4 in FIG. 1 correspond to the cone 12 in FIG. Each corresponds to the speaker frame 11. The second electro-acoustic converting means 3 of FIG. 1 which is the feature of the present invention is composed of the permanent magnet 31, the yoke 32, the protruding portion 33 of the cone and the second voice coil 34 wound around the permanent magnet 31, of FIG.

The parts other than the part corresponding to the second electro-acoustic conversion means 2 in FIG. 2 are the same as the already-described conventional example (FIG. 3), and therefore will not be described again here. The permanent magnet 31 and the yoke 32 composed of a magnetically permeable member shown in FIG. 2 form a so-called inner magnet type magnetic circuit. As described above, in this example, the magnetic circuit in the center of the cone 12 is an external magnetic circuit. The inner magnet type has the advantages of low magnetic leakage and the disadvantage of high magnetic resistance because a long magnet is required to obtain a large magnetic energy, while the outer magnet type has large magnetic leakage. However, since the cross-sectional area of the magnet can be made large, it is possible to use materials with high magnetic force and high magnetic resistance such as ferrite. Therefore, in the present embodiment, an external magnetic circuit is provided in the center of the cone 12 that requires a large driving force, and an auxiliary magnet is used in the magnetic circuit around the cone 12 having a large shape or a plurality of auxiliary magnetic circuits to assist the magnetic circuit. Shapes are used.

A cone protrusion 33 provided inside the edge 13 around the cone 12 of FIG. 2 is inserted into a gap between the yokes 32 of the magnetic circuit according to the present invention. A second voice coil 34 connected to the acoustic signal line 22 is wound around the cone protrusion 33. In this case, as described above, in order to cause the force acting on the conventional voice coil 17 and the force acting on the second boil coil 14 according to the present invention to act in opposite directions, the connection direction of the acoustic signal line 22 to the coil 14, The winding direction of the coil 14 and the polarity of the permanent magnet 31 are adjusted. Therefore, in the case of the cone 12 of this example, it is necessary to bend the cone 12 because the central portion and the peripheral portion of the cone 12 are always kept uniformly applied with the force in the same direction regardless of the input frequency and the input amplitude. Force does not work, and the acoustic output distortion due to the edge resonance described above does not occur.

In the case of the embodiment shown in FIG. 2, a case where a donut-shaped magnetic circuit is arranged on the outer peripheral portion of the cone 12 is shown, but for example, four-point arrangement of the magnetic circuit on the outer peripheral portion is made. As described above, the magnetic circuit according to the present invention may be locally arranged. Even in that case, it is obvious that the same effect as described above according to the present invention can be obtained.

[0015]

[Effect of the device]

 As described above, the cone speaker according to the present invention does not cause the acoustic output distortion due to the resonance characteristic of the edge in principle, and even if the acoustic output distortion occurs in the actual speaker, it does not occur in the conventional cone speaker. This is a significant reduction. Further, the second electro-acoustic conversion means according to the present invention can be provided in a donut shape on the entire outer circumference of the cone, or can be locally arranged at several points on the outer circumference. It is possible to flexibly deal with manufacturing requirements such as performance, cost, etc. Furthermore, since the second electro-acoustic conversion means according to the present invention can be incorporated into a conventional speaker without changing its shape, only the speaker inside the audio device can be easily replaced with the speaker according to the present invention. You can

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a cone speaker according to the present invention.

FIG. 2 is a schematic view of an embodiment of a cone speaker according to the present invention.

FIG. 3 is a diagram schematically showing a general structure example of a conventional cone speaker.

FIG. 4 is a diagram showing an example of distortion rate frequency characteristics of a conventional cone speaker.

FIG. 5 is a diagram schematically showing a conventional vibration state of a phase opposite to that of a cone due to resonance of the entire edge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cone 2 ... 1st electro-acoustic conversion means 3 ... 2nd electro-acoustic conversion means 4 ... Speaker frame 5 ... Acoustic signal source 12 ... Cone 13 ... Edge 16 ... Damper 17,34 ... Voice coil 19,32 ... Yoke 20,31 ... Permanent magnet 21 ... Center pole 22 ... Acoustic signal line

Claims (1)

[Scope of utility model registration request] 1. A cone (1) comprising a conical diaphragm,
A first electro-acoustic conversion means (2) for driving the central portion of the cone (1) by converting an electric signal from the acoustic signal source (5) into an acoustic vibration, from the acoustic signal source (5). The cone (1) is in a phase opposite to that of driving by the first electro-acoustic conversion means (2) by converting an electric signal into acoustic vibration.
Second electro-acoustic conversion means (3) for driving the peripheral part of
Then, the cone speaker comprises a speaker frame (4) supporting the cone (1), the first electro-acoustic conversion means (2) and the second electro-acoustic conversion means (3). .