KR950008543B1 - Moving coil direct radiate speaker - Google Patents

Abstract

The moving coil direct radiate speaker is constructed that the sound is directly radiated from the moving coil which compensates for the defect of ribbon speaker and Blatthaller speaker. It improves the horizontal and vertical oriented feature that regenerates the sound pressure like the output sound pressure of dynamic woofer in middle and high sound band of more than 1KHz. The speaker enlarges the size of diaphragm to a ring shape without using a horn.

Description

Drive Coil Direct Radial Speaker

1 is an assembled cross-sectional perspective view of the present invention.

2 is a plan view of the present invention.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a partially enlarged plan view of FIG.

5 is a cross-sectional view taken along the line B-B in FIG.

6 (a) is an equivalent circuit diagram, and (b) is an explanatory diagram of a direction of a current and a magnetic circuit configuration.

Fig. 7 (a) shows a conventional ribbon microphone, and (b) shows a conventional ribbon speaker.

8 is a vertical direction characteristic diagram, (b) a horizontal direction characteristic diagram (k: wave number 2π / λ, λ: wavelength, a :) when ka is changed when the width of the vibration surface is 3 mm. Extrapolation diameter of vibrating surface).

9 is a vertical orientation characteristic diagram and (b) a horizontal orientation characteristic diagram when ka is changed when the width of the vibration surface is 4 mm.

10 is a horizontal direction characteristic diagram and (b) a vertical direction characteristic diagram when ka value is changed when the width of the vibration surface is 8 mm.

11 is a frequency versus output sound pressure characteristic when a is 4.3cm and the width of the vibration surface is 4mm.

* Explanation of symbols for main parts of the drawings

1: Internal driving coil and diaphragm 1 ': External driving coil and diaphragm

2: Alnico V permanent magnet 3: Central stimulus

4: External stimulus 4 ': External stimulus

5: Mounting bolt hole 6: Drive coil relay terminal

7: input lead wire 8: capacitor

9: input terminal 10: cover plate

11 drive coil lead wire 12 drive coil

12 ': External drive coil 13: Three-point metal edge

14 aluminum driving coil 15 epoxy or enamel insulation

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving coil direct radiate speaker in which sound is directly radiated from a driving coil that compensates for the disadvantages of the conventional ribbon speaker and the Brett holler type speaker. In particular, the area of the diaphragm is increased in an annular shape. It is possible to reproduce the sound pressure such as the output sound pressure of the dynamic woofer in the mid-high range of 1KHz or more without using a horn, and to improve the horizontal and vertical directivity and distortion.

In order to create an ideal speaker that can effectively express superior stereo effect and sense of presence, inertial vibration not only can transmit sound evenly in all directions with even output sound pressure characteristics in audible frequency band from low to high sound. Minimize the reverberation of. To meet these requirements, the weight of the vibrometer should be about 50mg or less in the treble speaker, the length or diameter of the vibrating surface should be less than or equal to the wavelength of the maximum treble to be reproduced, and the vibrometer will not be separated into the cone and drive coil. Most of them should be made of conductors, so all parts of the magnetic circuit should be evenly applied to suppress the split vibration of the diaphragm.

Conventional loudspeaker of the high-end sound system adopts a variety of methods, but in general, a condenser or dome type dynamic speaker (Cone or Dome Dynamic Speaker) is separated from the diaphragm and the driving coil and the electrostatic speaker that is integrated with the diaphragm and the vibrator, It can be roughly classified into ribbon speakers and Bretthaller type speakers.

Dynamic speakers have excellent bass reproduction characteristics, but there is a limit to reducing the weight and size of the vibrometer in order to reproduce the high range, so a dome type with a diameter of about 400mg and a diameter of 19mm-25mm is most commonly used. It is heavy and has strong tendency to worsen transient characteristics, and the cone and driving coil are separated, which causes distortion due to split vibration, which deteriorates the negative characteristics.To improve this, the diaphragm is made from composite pulp and polymer material (Polypropylene, Kevlar, CC Composite, etc.) and metal materials (Alumimum, Titanium) are used, but these disadvantages are not eliminated.

The Brettler-type speaker, which is currently developed and used for mid-range loudspeakers in foreign countries, is made by attaching a thin conductor in a zig-zag shape to one side of a polymer film such as polystyrene, which is about 10 × 10 cm in size, and a magnet on the front and back. It is difficult to suppress the split vibration of the diaphragm during resonance because it is lighter than the polymer diaphragm, and expensive rare earth magnets should be used to increase efficiency. In the lateral direction above °, output decreases drastically. In addition, as the acoustic resistance of the air trapped between the magnets increases, an inertial resonance occurs, resulting in an increase in power between 3-14 KHz.

Ribbon speakers and microphones are typical direct radiating electroacoustic transducers, as shown in FIG. 7, in which rectangular conductors are attached in a magnetic circuit in the longitudinal direction. The characteristic of the ribbon speaker is that the direct sound is radiated from the vibrator and the entire area of the vibrator is a conductor, so that all the surfaces are evenly applied in the magnetic circuit, so there is little influence from the split vibration and the weight of the vibrometer is very light. mg-dozens of mg) It has the most excellent transient characteristics in the high frequency range and has excellent phase characteristics due to its impedance by pure resistance.

However, the shape of the corrugation formed in the longitudinal direction in order to improve the front and rear vibration has a very sensitive effect on the sound quality, and the weight of the aluminum sheet is thin (5μm-decades μm) instead of light weight, so that it is easily torn and the electrical resistance is about 0.1-1Ω. Very low output amp and impedance combination is difficult, and the directivity in the vertical direction is very high, so that viewing is possible only in a limited area, and the area where the stereo effect can be obtained is extremely limited. The vertical and horizontal directivity characteristics of the ribbon-shaped speaker can be expressed as follows by the width W of the ribbon and the length L of the ribbon. [Acoustica I Engineering, H.F. Olson P.36]

(1)

(One)

R _α : Sound pressure ratio at any angle α with respect to the sound pressure in the vertical position with respect to the vibration plane of the speaker.

α: angle between vertical line and measuring position

λ: represents the wavelength of the sound wave to be measured, respectively.

Since all ribbon speakers are very narrow compared to their lengths, the horizontal directivity is good in the audible region, while the vertical directivity is very narrow in the high range, as can be seen in (1).

When using a ribbon speaker with a length of 6 cm (8.5 cm) with a length of 8.5 cm (W), if the speaker position is high or low with respect to the height of the ear, sound above 10 kHz will drop rapidly or become extremely inaudible (speakers and If the angle α formed by the ear is 10 °, R _α is 0.017. Therefore, in order to have excellent vertical directivity without attaching a horn, the length L should be less than 1.7 cm, which is a 20 KHz wavelength, but the radiation area is reduced, so that the sound pressure is sharply lowered.

Therefore, to construct a dynamic speaker and a multi-speaker system in practical use, it is used only as a high-frequency high-pitched speaker or a horn attached to a high-pitched speaker of 2-3KHz or higher, and to be used as a direct radiant speaker. The extra long length (more than 0.5-1M) compensates for the directivity in the vertical direction and increases the area, increasing the output sound pressure in the bass range to 150Hz, but these large ribbon speakers are very expensive and dynamic speakers. In addition, there are many problems in the configuration of multi-speaker systems, such as difficulty in positioning, limitation of attachment space, and improper impedance.

The present invention is to reconfigure the shape of the diaphragm and the magnetic circuit in order to compensate for these disadvantages of the conventional ribbon and Brettler-type speaker in which the diaphragm and the driving coil are integrated to have excellent horizontal and vertical directivity characteristics even in the high frequency range and the vibrometer It is made of light aluminum conductor, which is about 90% of the weight, so that it is applied evenly across the front of the diaphragm in the magnetic circuit to suppress the split vibration of the diaphragm, reduce the distortion and have excellent transient characteristics. In addition, by eliminating wrinkles used in general ribbon speakers and forming edges around them, they eliminate not only longitudinal and lateral torsional resonance but also increase the vibration area to annular rather than longitudinal direction. It is easy to combine, and it can reproduce faithful sound with small time phase difference to mid-range (near 1KHz) without using horn, and has an electric resistance value of 4-8Ω, which provides an economically advantageous speaker with easy output amp and impedance combination. There is a purpose.

The configuration and effect of the present invention will be described in detail with reference to the embodiments and drawings as follows.

As shown in FIG. 2, the central stimulus (3) made of 2V Permendur (Supermender) is not a single cylindrical or ribbon bar used in general dynamic speakers, but three bars instead of left and right. It is separated into water droplets, and the horizontal cross-sectional shape of the central stimulus is composed of a 240 ° arc and two tangent lines contacting the ends of the arc, and the lower three central stimuli have the same polarity. The center of the arc of each central stimulus 3 is composed of three vertices of an equilateral triangle, the outer stimulus 4 is similar to the central stimulus 3 and is configured to surround the central stimulus 3 at regular intervals. This external stimulus 4 is composed of another outer stimulus 4 'which is again wrapped in an annulus at regular intervals, within which the drive coil and diaphragm 1, 1' made of aluminum foil are three points. It is supported as the knowledge metal edge 13.

At the bottom of the centrally located external magnetic pole (4), an annular magnet (2) is attached with Alnico V (Alnico V), and through the central magnetic pole (3) and two external magnetic poles (4, 4 ') N, S , N or S, N, S in order to configure the magnetic circuit.

The drive coil and diaphragm (1, 1 ', 12, 12') has a shape consisting of three central magnetic poles (3) and an external magnetic pole surrounding the inner pole (4). Etching by the interval (flat) so that the flat wire is wound in a spiral form, and the corroded interval (0.05mm) was insulated with epoxy or enamel (15) to maintain the entire plane. The shape and size of the diaphragm are the main factors that determine the directivity of the speaker. As shown in (a) of FIG. 3 and FIG. 6, electric currents generated by the electric signals input through the input terminal 9 are driven by the lead coil 11-the drive coil 12-the input lead wire 7-of the internal diaphragm 1-. The terminal 6-the drive coil 12 '-the input terminal 9 of the external diaphragm 1' flows in the order of 9 to generate sound by vibrating the internal diaphragm and the external diaphragm located in the magnetic circuit. In addition, the capacitor 8 is connected in parallel at both ends of the external driving coil 12 ', and the high-frequency electric signal of a certain frequency flows through the internal driving coil and the capacitor, and the external driving coil is -6dB / Oct as the frequency increases. Only the attenuated signal flows. Therefore, when electric signals of low frequency are inputted, internal and external diaphragms vibrate simultaneously with a wide vibration area, and only internal vibration plates vibrate for electric signals of high frequency, so that the directivity and transient characteristics can be improved. It is.

As shown in (b) of FIG. 6, the driving coil of the internal diaphragm causes an electric current to flow in the same direction as the input electric signal (A). Since the N pole is located on the left side of the flowing direction, all the surfaces of the diaphragm receive the same force in the same direction, and when the direction of the current is changed, the force is received in the opposite direction, and the front vibrates back and forth to generate sound. The horizontal and vertical sound directivity, which enables the stereoscopic effect of the picker to be effectively expressed, is determined by the reproduction frequency and the size and shape of the diaphragm. The directing characteristics of disk and annular diaphragms are well known and are represented by the following equation [Acoustical Engineering, H.F.Olson].

R _{α in the} formulas (2) and (3): Sound pressure ratio measured at any angle α with respect to the axis of sound pressure measured at any point located on the axis perpendicular to the vibration plane of the speaker.

λ: Wavelength of the sound wave to be measured (cm)

R: Radius of the vibrating ring or disc (cm)

J ₀ , J ₁ : stepless, 1st Bessel function

Respectively.

(2) and (3) at high volume of 20KHz α = R _α have 25˚ the -3dB (0.5) the diameter of the disk below the 1.7cm (= λ), ring diameter in order to be in place from the formula is 2.2cm (= 1.3λ) or less. However, the weight of the vibration system of most 1.9cm dome type dynamic treble speakers is about 400mg or more, which is relatively too heavy, resulting in poor transient characteristics and increased distortion due to split vibration. In addition to the speaker, there is a problem in using it as a high-pitched speaker in practical use, so the weight of the vibrometer is about 50 mg, and it is understood that a speaker having a new shape and size is required. The shape of the diaphragm of the present invention is a new shape that can satisfy these requirements at the same time, essentially one of the shape as shown in FIG. 2 with three annular and one disc shaped at the vertex and center of the equilateral triangle. The inner diaphragm (1) formed of the diaphragm and the annular outer diaphragm (1 ') surrounding it is separated and configured to reproduce a unique sound range, respectively.

It is known that the directivity of sound emitted from this new shape of diaphragm can be calculated based on the well-known sound pressure control equation (4) and agrees well with the experimental values. (Fundamentals of Acoustics L.E.Kinsler)

(4)

(4)

o : 공기의 밀도Where C is the speed of sound

o: density of air

U: Speed Amplitude

r ': distance from the oscillating surface ds

w: 2πf angular velocity

파수k:

wave number

The directivity characteristic of the annular outer diaphragm 1 'can be known from equation (2).

In Figure 2, at three vertices of the equilateral triangle, D, from the center of the equilateral triangle, three 240 ° arcs with a radius of sigma and six bands tangentially connected to the arc past the center are shaped like intersections of six distances. In the new shape of the inner diaphragm (1), the length of these six bands is 1a, the width is 1b, and the angle formed by the horizontal axis is β, and r 'in equation (4) is expressed by equation (5). Is represented by the formula (6).

ds = dxdy

R '= [(x-rcosøsinθ) ² + (rsinø-y) ² + (rcosøcosø) ² ] ^1/2 (5)

(2{x(cosøsinøcosε+sinø·sinε)-y(cosøsinøsinε-sinøcosε)}+r)]^1/2(6)In the case of an arc

(2 (x (cosøsinøcosε + sinøsinε) -y (cosøsinøsinε-sinøcosε)} + r)] ^1/2 (6)

Where ø is the angle to the horizontal plane through the center

θ is the angle to the vertical plane passing through the center

ε is the angle formed by the small area of the arc at the vertex of the equilateral triangle.

Substituting equations (5) and (6) into equation (4) and rearranging them, and substituting the actual values and performing numerical integration using a computer, the horizontal and vertical orientation characteristics according to the change of D, σ, and 1b values are obtained. Able to know. These calculation results are shown in FIG. 8, FIG. 9, and FIG.

FIG. 8 shows the directivity characteristics according to the Ka value when 1b = 3mm, σmax = 6mm, D = 8mm, and the diameter (a) = 2.8cm of the circumscribed circle of the inner diaphragm. The directivity value is 14KHz, 16KHz, 18KHz and 20KHz sound from the top, and the sound directivity is expressed by the sound pressure ratio R _α .

If the diameter is 2.8cm, it shows similar value regardless of the horizontal and vertical direction. Even in the high frequency range of 20KHz, the angle of R _α value is 0.5 (-3dB) is more than 30 degrees left and right, evenly radiating sound to a wide area. Even though the diameter of the circumscribed circle is increased to 2.8cm, the vertical and horizontal directivity is improved to the same degree as the existing 19mm diameter dome-type speaker (vertical directivity is particularly superior to the existing ribbon speaker).

9 shows, as another embodiment, directivity according to ka value when 1b = 4mm, σmax = 8mm, D = 10mm, and diameter (a) = 3.8cm of the circumferential circle of the inner vibrating plate. (b) is the horizontal directivity characteristic value, and the directivity characteristics of 14 KHz, 16 KHz, 18 KHz, and 20 KHz sound from the top are represented by the sound pressure ratio R _α .

Diameter (a) a vertical directivity characteristic, while the increases in 3.8cm horizontal directivity in 20KHz sound becomes even bigger each R _α is a value that is half (-3dB) left and right over angle of 50 degrees is the R value of 0.5 _α ( -3dB) 0.5 (-3dB) angle is 25 degrees above and below each, and the performance is better in the horizontal direction from 30 degrees to 50 degrees compared to the 19mm diameter dome type speaker, and the vertical direction is slightly from 30 degrees to 25 degrees. It shows a narrowed directivity.

FIG. 10 shows the directivity characteristic according to the ka value when 1b = 8mm, sigma maximum = 21mm, D = 29mm diameter of the circumferential circle (a) = 10cm, as another embodiment. b) shows vertical direction characteristics, and the sound directivity characteristics of 20 KHz, 18 KHz, 16 KHz, and 14 KHz are indicated by sound pressure ratio R _α from above. As can be seen in the figure above, it is almost impossible to hear the sound when it is over 15˚, and there is a valley of discontinuous sound, so it can not be used for high sound of 7KHz or higher, but if it is below 7KHz, it has the same directivity as the ninth degree. Can be used as a speaker for. Therefore, it can be seen that by adjusting the diameter of the speaker, it is possible to produce a dedicated speaker for each use range.

As described above, the new shape of the diaphragm of the present invention not only significantly improves the horizontal and vertical directivity characteristics of the existing ribbon speaker while maintaining various advantages of the existing ribbon speaker, but also increases the length in the vertical direction to increase the area of the diaphragm. By increasing the area in the annular shape without the use of the system, it is a small size that solves the difficulty of selecting the location and the limitation of the attachment space for constructing the multi-speaker system.

As shown in the embodiment of FIG. 9, when the width 1b is 4 mm, the 5.2 cm diameter including the outer annular diaphragm 1 'has a vibration area equivalent to that of the ribbon speaker having a width of 4 mm and a width of 25 cm. As shown in FIG. 11, it is possible to reproduce sound pressure (88-90dB, SPL) equivalent to that of a conventional dome type dynamic speaker without the usual, and the weight of the diaphragm is 55mg of internal diaphragm and 90mg of external diaphragm. It is about 1 / 8-1 / 10 of the weight of the vibrometer (440mg-500mg), and it is a multiple of the ribbon speaker.It is almost the same value as 50mg, which is the requirement of an ideal high-pitched speaker, and the diaphragm is composed of light weight 90% or more. Since all faces are uniformly applied within the magnetic circuit, the split vibration of the diaphragm is suppressed, so that the distortion is reduced and excellent transient characteristics are achieved.

On the other hand, by removing the wrinkles, one of the disadvantages of the ribbon speaker, and forming and supporting a three-point metal edge 13 around the ribbon speaker, it is possible to eliminate the torsional resonance phenomenon in the longitudinal direction and the lateral direction, and by using the three-point metal edge coil Heat generated inside can be easily generated by external action to prevent breakage of drive coil due to heat even at high power output. Photo-etched aluminum plate of more than 10 times thickness (50㎛) compared to ribbon speaker Since the flat lead wire is wound in a spiral shape, the load resistance value increases to 4-8 Ω, which facilitates the combination of the output amp and the impedance and prevents tearing, thereby greatly improving durability.

In addition, the speaker of the present invention can arrange the diaphragm for treble, mid and bass on the same plane coaxial by changing the size and combination, as well as maximize the advantages of the coaxial speaker as well as treble, mid, bass It can also be manufactured as a dedicated speaker, which has the effect of easily configuring a multi-speaker system along with existing dynamic speakers.

Claims (6)

In constructing the shape of the diaphragm of the drive coil direct radiation speaker, a cam formed by drilling a hole having a constant width of a similar width inside and having an outer shape combined with two straight lines having an angle of 60 degrees and an arc inscribed thereto. Cam) Three flat rings are arranged on the circumference at equal intervals, with the acute angles facing the center and overlapping each other with the same width as the ring. A ring-shaped outer diaphragm 1 'is disposed, and the inner and outer diaphragms 1 and 1' are supported by being formed in magnetic pores of the inner and outer magnetic circuits 3, 4 and 4 'having magnetic force lines formed therein. Speaker made. The diaphragm 1, 1 'is corroded to a thin aluminum plate by a photo etching technique, and the rectangular short-coil 14 is wound in a continuous spiral to form an external diaphragm-shaped flat plate 12, 12'. , 14) wherein the total weight of the insulating material 15 between the coils is less than 15% of the total weight and the input resistance value is composed of a value determined by the cross-sectional area and the total length of the coil. The speaker according to claim 1, wherein the inner and outer diaphragms (1, 1 ') are configured to be supported by a shop-like metal edge (13) attached to each of the Freids (4, 4'). A capacitor 8 is connected in parallel to both ends of the coil forming the external diaphragm 1 ', and the inner and outer diaphragm coils are connected in series, and both ends of the unconnected inner and outer diaphragm coils are input. Speaker configured to be connected to the terminal. The magnetic circuit of claim 1, wherein the magnetic circuit of the speaker comprises three cam-shaped central poles 3 arranged at equal intervals circumferentially with respect to an acute portion and a plate having an internal space formed therein so as to surround them at equal intervals. 4) are combined and again composed of a ring-shaped outer plate 4 'surrounding the plate 4 at concentric intervals, with a magnetic pole of the cylindrical magnet 2 on the back of the plate 4; It is attached to the back of the central pole (3) and the outer plate (4 ') is composed of a shielding magnetic circuit of the shape of the other plate is connected to the back plate of the basket shape, characterized in that configured to form a sufficient space closed on the back of the diaphragm Speaker made. The speaker according to claim 1, wherein the size of the inner diaphragm is configured to be equal to or less than the diameter value of the circumscribed circle equal to 14 when the circumference value of the circumscribed circle is divided by the half wavelength of the maximum reproduction limit frequency.

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