JPS58120395A - Loudspeaker dome type movable coil driver and vibrating plate therefor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a loudspeaker, also referred to as a dynamic loudspeaker, having a town coil or permanent magnet driver. The present invention relates to the structure of a dome@C) driver and a diaphragm for such a Drino. Here, the term "driver" refers to a solid speaker, and the term "loudspeaker" The term refers to a combination of drivers configured as an integrated system.

In an effort to provide a loudspeaker system that effectively radiates sound over the entire range of the human ear, usually considered to be 20 Hz to 20 KHz, it is common practice to use two or more loudspeaker systems within a single loudspeaker system. It is common to provide drivers, each driver radiating primarily only sound within a portion of the range. Electronic crossover networks are provided, each of which is designed to obtain a composite response tube that is as close to uniform as possible over the entire sensitivity range, measured in decibels of acoustic output per unit of electrical energy. operates to distribute electrical audio output to the drivers of the In the construction of such speaker systems, attention must be paid to the distribution of the acoustic energy, and it is generally preferred that it be widely distributed throughout the above range. In addition, attention must be paid to the physical durability of the loudspeaker, especially of the diaphragm, which typically has a large surface area and is made of thin sheet material. .

What is superimposed in the configuration of such a single driver type system is that there is a radiator that mainly emits low frequencies, i.e.
It is in the selection of "Wu 77". The ones usually selected are;-
It is a 7 position driver. The low frequency response of such a driver is generally scaled by the diameter of a cone, and the high frequency response has an inverse relationship to the diameter.

Generally, in the case of a cone type speaker, the dispersion of the radiated sound is limited by the following.

(1) λ=πd Here, d is the diameter of the cone, and λ is the wavelength below which the directivity of dispersion increases.

Thus, the choice of 11 factors determines both the low frequency characteristics and the degree of dispersion of the system. In any case, the use of a "tweeter" increases the response at frequencies above the woofer's radiating capacity, with or without the use of intermediate or mid-range speakers. is often desired.

Dome-shaped drivers are well known. As an example, 19
U.S. Pat.
No. 4,190,74 <5, issued by Harwood et al. The diaphragm of these drivers is convexly curved in the direction in which the sound is radiated, so they have excellent dispersion at high frequencies. Thus, my second son combined a cone-shaped woofer with a dome-shaped tweeter of appropriate dimensions for higher frequency response.

Cone-shaped woofer and corn salt tweeter f: Km< to maintain a sound dispersion closer to that of the woofer than the combination. However, as shown in the above-mentioned patent, for example, a dome-shaped driver with a conventional structure is effective when the woofer is configured to provide the appropriate response intended for the speaker system. It is not possible to provide sufficient response at intermediate frequencies. In nine cases where such drawbacks exist, it may be necessary to provide a third or intermediate range driver. Suggestion nine opposite K,
Configuring a dome driver to provide an adequate response to compensate for the woofer cutoff at the frequency of the intermediate lens 2 often severely limits the high frequency response and requires the use of an amplifier to extend the high frequency response. driver or tweeter will have to be used.

For the above reasons, the present invention has an overlapping object.

Has substantially mid-range and high frequency response,
and may provide a driver with substantially wider dispersion characteristics than cone-placed drivers.

Another object of the invention is to provide a driver tube of the type described above which has a durable construction and is capable of handling high acoustic power with minimal fatigue and failure.

Another object of the invention is to provide a driver of the above type with low distortion in the intermediate frequency range.

Yet another object of the present invention is to provide a driver made of a material with uniform properties that is less susceptible to the effects of humidity, temperature fluctuations or extremes, and fatigue.

Ninthly, the present invention has a diaphragm with a dome part and a folded annular surrounding part, and when the dome part is simulated by a conventional surrounding part, is characterized by a nine-dome driver configuration configured to radiate significant acoustic power at frequencies below the range that cannot be effectively radiated.

The envelope H according to the invention has an annular attachment means in fixed relation to the permanent magnet structure, the location of which is K where the dome and enclosure are joined. There is a considerable amount of noise coming from the voice coil. That is, the diameter of the diaphragm measured at its annular attachment to the fixed magnet structure is significantly larger than the diameter of the dome and the voice coil. Preferably, the ratio of the former diameter to the latter diameter is greater than 2.25.

The dome itself may have a partially spherical shape or a parabolic shape, the latter having an expanded high frequency response compared to the former. .

By selecting an appropriate material for the diaphragm structure, 41. selecting a material with appropriate internal damping;
It is thus possible to provide a mid-range loudspeaker with smooth frequency response characteristics and large dynamic range, as well as extended frequency response characteristics.

FIG. 1 is a diagram illustrating a preferred embodiment tube of a dome-shaped driver according to the present invention, the driver being designated generally at 12. The driver includes a conventional permanent magnet structure having a pole piece 14 with an integral bottom plate 16, 191 or more magnets 18, and a top plate 20, which parts are bonded in a conventional manner. etc. are combined as appropriate. The magnet creates a permanent magnetic flux within the mass gap 22. Mounting plate 24
are mounted on the top plate 20, and a fastening plate 26 for fastening the diaphragm is appropriately fixed to the plate 24.

The diaphragm 28 is attached to the boiling coil 30, which
The acoustic energy produced by the flow of current in the coil causes the tube to radiate vibrations.

The diaphragm 28 has two parts, a dome part 62 and a surrounding part 64. In the illustrated embodiment, which is presently preferred, these two parts are vacuum formed or otherwise formed from a single sheet of material, thus forming one unitary body. Alternatively, the two parts may be made of separate sheets of material and connected to the outer periphery of the dome part and the inner periphery of the surrounding part by suitable means such as adhesive. In this specification, the dome part, the capsular reservoir part, and t
- [Join] includes both the above-mentioned preferred integrally molded embodiment and the above-mentioned f-shaped embodiment; As shown in Figure 1, it means something that has a curved shape when viewed in cross section. The curvature in this shape is preferably substantially circular.

A cylindrical coil mold 66 is mounted at the junction of the dome portion and the envelope portion, and this coil mold 36 supports the voice coil 30 within the gap 22. The diaphragm 28 also has seven langes 371, which are mounted between the plates 24.26. Preferably, the dome portion and the surrounding portion are imperforate and have the configuration shown in all cross-sections on a plane passing through the axis of the driver, as shown in FIG. A hole 58 is provided in the plate 26 at the round end which is attached to the plate 24 by the plate 26t screw.

A wire 40 is attached to the plate 26 and the lead wires 22.24
It is connected to both sides of the voice coil 30 by.

A capsule 46 comprising an object such as fiberglass, foam plastic, or a mass of fibers is attached below the dome 32 (by adhesive to the surface of a piece 140) to absorb acoustic energy radiating from the bottom surface of the dome. This minimizes reflections from the pole piece 14 that would otherwise interfere with acoustic energy radiating directly from the surface of the dome if such a capsule were used.

Here KEI! The gap 22 between the coil mold 66 and the pole piece 14 and the space between the voice coil 60 and the top plate 20
including both the space between.

This gap is essentially “ferrofluid” (f@rr
offluid) f-filled. 1 Ferrofluid is a liquid containing suspended magnetic particles and serves as a heat conduction path (heat conduit) from the voice coil to the plate 20.
It is conventionally used in loudspeakers to act as a

In the structure of FIGS. 1 and 2, the relative dimensions of the dome and the enclosure are selected to cause the surface of the enclosure to act as a radiator of substantially greater acoustic power. To clarify the importance of this dimension, the letters ji+b are shown in Figure 1.
+e! +d+e+f+g' was added. a and d are the edges of the outer periphery of the enclosure 64, b and C are the connecting point tubes between the dome and the enclosure, and f are the plates 26 and 24.
2g is the point on the dome that is farthest from the plane of the annular attachment of the enclosure at the intersection of t. Also, h, i
and JFi, respectively, are the points where a line to the above plane passing through the above points g, e and ft falls on the above plane.

The following dimensions are suitable for the presently preferred embodiment.

be 55-08cI (2 inches) e
i=fJ 1-19m1 (0.4 inches) gh 11-60a (0.63 inches) where the ratio of ad and be is 2.6. In practice, the magnitudes and relative values of the above-mentioned dimensions may vary according to the frequency range of useful responses sought and the manageable power capabilities of the materials used. With currently available methods and materials of diaphragm construction, one area of the periphery of the dome and an enclosure can be used to obtain a sufficiently low intermediate frequency output with a structure that is stable enough to handle adequate output. N [diameter of the inner edge of the body is at least t'! 's 3.83 (1-5 inches)
Must.

In any case, the ad/be ratio is at least 2.
It is 3. Also, the ratio e i / a b is preferably at least 0.33.

the ability to handle the desired output without causing destruction, am,
In order to obtain the ability to withstand various conditions of high and low temperatures and resistance to fatigue failure, I! The material that makes up the R moving plate is extremely important. The currently preferred diaphragm material for both the dome section and the radius section is Merck (tale).
t'' filled polypropylene sheet material. Other diaphragm materials that can be used are vinyl film with a layer of aluminum deposited on top of it, and polycarbonate film.

FIG. 6 shows a second embodiment of the diaphragm according to the invention.

This embodiment, except for the shape of the cross-section of the dome,
It is the same as that shown in FIG. A dome 48 having a parabolic cross-section is formed integrally with a folded enclosure 50 of substantially the same shape as the enclosure 48, and is attached to this or the same shaped annular enclosure, the diaphragm having a permanent magnet attached thereto. A ninth flange 52 of the annular mount is provided in fixed relation to the component. , a coil holder 54 is attached to the dome-envelope joint and supports a helical voice coil 56. The parabolic shape of the dome extends the high frequency end of the V-Spons curve, which will be discussed in detail below with respect to FIG.

FIG. 4 shows, by way of example, a typical frequency Vspong Iwt for six drivers. Solid line 58ti partially spherical dome t-s') shows the response of the embodiment shown in FIGS. 1 and 2. Dashed line 60 indicates a portion of the 7 sponce curve of a prior art domed driver having the same dimensions as shown in FIG. 1, but having a typical Hiko enclosure used in the prior art. In the prior art, enclosures are used solely for dome construction or support. The color display enclosure may be made of the same material as the dome, or may be made of a different material.
It has a relatively small tube dimension radially with respect to the loudspeaker axis. In the song l1160, the ab dimension is 0.
65CrB (1/4 inch) or smaller with almost no acoustic radiation ability. If! 11
158.60 agree at frequencies slightly above 1000 Hz, and at even higher frequencies the curves substantially agree at the ninth point where the dome characteristics are common.

Next, Fig. 4 shows a driver 62, which is a driver similar to the one shown in Fig. 1, but has a diaphragm shown in Fig. 6, but has a vibration frequency and a sponse tune. This song IIA shows an expanded high frequency response, which is 10.0
It coincides with the solid line 58 at 00Hz. At lower frequencies, the embodiment with a parabolic dome t has the same characteristics as the dome embodiment shown in FIGS. 1 and 2.

Considering the FIG. 4 tube, both the FIG. 1 and FIG. 3 embodiments provide a substantially improved tube over the prior art dome shape due to the expanded low frequency response. I understand. If we consider that the response area of 72 points is essentially 0 decibels, then we can assume that the effective frequency range of the driver includes frequencies 1 within 6 decibels below the zero value. Based on the basics, conventional dome drivers are approximately 650-10,00 GHz
The partially spherical dome lid driver made by #4 of this invention has a useful range of approximately 300-10,0OOH! The parabolic dome loudspeaker according to the present invention has four V7 dimensions of approximately 300-15,000 Hz.

In embodiments comprising parabolic loudspeakers, the high frequency response can be further improved, with the upper limit of useful response approaching the 20.000Hz limit and requiring the inclusion of a separate tweeter.

When implementing the present invention, as shown in the points and f shown in FIG.
It is preferable that a point on the enclosure that is one distance away from the surface of the annular attachment part is also closer than a point on the dome that is farthest from the surface mentioned above, such as point g. Such a standard would provide a better distribution of acoustic energy over a wider frequency range than a cone-based loudspeaker of comparable dimensions.

As previously mentioned, one of the advantages of the present invention is that it is configured to provide a frequency response range suitable for use as a mid-range driver in a multi-driver loudspeaker system. 6 in durability. That is, when selected to obtain the desired frequency response, the dome and enclosure configurations described above are configured to minimize fracture of the diaphragm through the use of preferred material tubing. Additionally, this preferred material is
Allows the driver to work as designed in varying conditions of humidity and temperature.

Here, the shape of the dome in the illustrated embodiment has been described as a t-S spherical shape and a parabolic shape, but in reality,
There may be variations in shape due to manufacturing conditions. The exact effect of such force variations on the overall performance of the driver could be determined by experimental methods. However, such modifications do not depart from the technical scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the opening portion of the first preferred embodiment of the present invention. 2 is a plan view of the embodiment of FIG. 1; FIG. FIG. 3 is a diametrical cross-sectional view of a second embodiment of a diaphragm with a parabolic dome. FIG. 4 is a diagram showing the frequency response characteristics of the driver shown for comparison. 12...driver 14... and one piece 16...
Bottom plate 18...Grinding stone set 0...Top plate
22...Annular gap 24...Mounting plate
26...Tightening plate 28...Vibration plate 60
...Voice coil 32...Dome part 64.
...Encircling portion 36...Coil type 37°°°Flange 58...Hole 40...Terminal 42.
44... Lead 11 46... Capsule 48...
Dome 50...Envelope 52...7 Lunge 54...Coil type 56...Voice coil FIG, I FIG, 2

Claims (1)

[Claims] 1. Permanent magnetic means with pole piece tubes defining an annular gap, a diaphragm, and a coil, the diaphragm having an outer circumference of at least 5.8 am (1.5 inches). a dome portion having a diameter of annular attachment means in a nine-way relationship, said coil being vibrationally mounted fjc at the junction of said dome and enclosure and extending into said gap; The diameter shall be at least 2.6 times the diameter of the coil.1-Characteristics of a moving coil driver for a loudspeaker. 2. The driver according to claim 1, wherein the dome is substantially Ks spherical. 3. The dome is substantially parabolic in the claimed OS
The driver described in Section 1. 4. The surrounding portion has a substantially circular curvature in any diametrical cross section of the diaphragm.
Drivers listed in section. 5. The driver according to claim 1, wherein the maximum distance of the surface of the dome part from the surface of the annular attachment means is greater than the maximum distance of the fitting of the surrounding part from the surface. . 6. The driver according to claim 4, wherein the maximum distance of the surrounding portion different surface from the surface of said annular attachment means is at least one-sixth of the distance of said annular attachment means from the coil. 2 At least 3.81+ (1.5 inches) at the outer circumference
The cough dome includes a dome portion having a diameter of 100 mm, and a folded annular surrounding portion, the inner edge of the surrounding portion being joined to the periphery of the cough dome portion, and the outer edge thereof serving as an annular attachment portion. The diameter of the outer edge of the scissors is at least 2.6 times the diameter of one pole of the inner edge of the movable coil driver. 8. The diaphragm according to claim S, wherein the dome portion and the surrounding portion are formed of a single integral body. 9. A diaphragm according to claim 8, wherein the dome portion has a substantially partially spherical shape. The diaphragm according to claim 8, wherein the dome portion has a substantially parabolic shape t. 11. The diaphragm according to claim 8, wherein the surrounding portion has a substantially circular curvature in any diametrical cross section of the diaphragm. 12. The diaphragm according to claim 9, wherein the maximum distance of the surface of the dome part from the surface of the outer edge is greater than the maximum distance of the surface of the surrounding part from the iron surface. The maximum distance of the surface of the enclosure from the surface of the outer edge is at least one-third of the distance from the junction of the enclosure and the dome to the outer edge. The diaphragm described.