A speaker equipped with an annular, expandable membrane.

Abstract

The speaker comprises a magnet, a movable coil, a support, and a membrane coupled to the movable coil, which converts the movement of the movable coil into sound. The membrane is expandable. The membrane is a single, annular, and replaceable component, protruding from the support. The annular shape of the membrane generates a wideband sound, enabling the reproduction of mid-to-high frequency sounds, along with low-frequency sounds containing harmonics, in virtually all directions in space.

Description

Technical Field

[0001] The present invention relates to an apparatus for playing sound and listening to music, which is a speaker described in the preamble part of the independent claim.

Background Art

[0002] As is well known, a general speaker includes various components such as a permanent magnet or a solenoid through which an electric current flows (hereinafter collectively referred to as a "magnet"), a basket-shaped frame constituting a structure for supporting the speaker, an elastic suspension means, i.e., a movable coil combined with a spider, a member configured to convert the movement of the movable coil into sound, and a support for the movable coil. The member that converts the movement of the movable coil into sound is generally called a cone, diaphragm, or membrane.

[0003] As is well known, a conventional speaker converts an electrical signal (which reaches a movable coil placed in a magnetic field created by a magnet and movable) into sound waves generated by the displacement of a membrane (which may be a cone or diaphragm). In particular, speakers capable of reproducing the following audible bands are also well known. 1. Subwoofer (for ultra-low frequency) 2. Woofer (for low frequency) 3. Midrange (for midrange frequency) 4. Tweeter (for high frequency)

[0004] Typically, a speaker requires an acoustic speaker box (also called a sealed speaker box or ducted speaker box) to house the above components. The speaker is the core of the acoustic speaker box, the component that actually produces sound waves, while the acoustic speaker box is the component (enclosure structure) that surrounds the speaker. The acoustic speaker box traps the sound waves generated at the rear of the speaker, preventing them from interfering with the sound waves generated outward from the front of the speaker. In fact, since the speaker generates two sound waves in opposite phases, they cancel each other out, preventing the sound waves from propagating well into the surrounding environment. However, as mentioned above, the sound waves generated at the rear remain unused (i.e., their effectiveness is not utilized). In the absence of an acoustic speaker box, a system using an opening in a ducted speaker box (bass reflex type) or a passive cone or trumpet-shaped opening in a ducted speaker box results in a very partial underutilization of these sound waves. Therefore, the acoustic speaker boxes inevitably have to be large.

[0005] Another perspective concerns woofers currently in use and available on the market. Woofers (speakers designed to reproduce low frequencies) are considerably larger in both size and weight compared to other speakers. Generally, speaker systems feature a cone or membrane with a fairly large diameter, and furthermore, the cone or membrane is fitted with a basket-shaped metal frame of a corresponding size, as well as a heavy and cumbersome coil and magnet. The reason for the large size of woofers is that low frequencies radiate sound properly; therefore, to radiate sound properly, sufficiently, and in a balanced manner, a large membrane with a large ducted speaker box that can vibrate the membrane with the appropriate output is required.

[0006] International Publication No. 2017089875 (published June 1, 2017, “Inflatable Acoustic System”, International Application No. PCT / IB2016 / 001464) discloses a speaker system that aims to slightly amplify the low frequencies of a speaker used as a sound source, comprising a combination speaker housed in a unique housing and consisting of an extendable or expandable resonant chamber. However, the speaker itself cannot radiate low or very low frequencies because its membrane is small and not directly coupled to the resonant chamber. Therefore, even with the use of the resonant chamber, it is not possible to adequately and significantly amplify the sound radiated by the speaker. The resonant chamber functions as a resonant chamber that is not directly coupled to the vibrating coil and performs modest resonance for some of the frequencies radiated by the speaker of the system. This resonant chamber itself is not a vibrating membrane that generates sound like a normal speaker.

[0007] U.S. Patent Publication No. 20180048949 (published on February 15, 2018, "Inflatable Speaker") discloses an expandable and inflatable ducted or acoustic speaker box applicable to a speaker, comprising a membrane, a basket-shaped frame, and a fixing structure. The solution proposed in this publication merely makes the ducted or acoustic speaker box easy to fold and transport without the ducted speaker box or acoustic speaker box becoming a vibrating membrane that generates sound, but it does not solve the problem of low frequencies as a sound source, nor does it solve the problem of the number of necessary parts. This prior art has the same problems as the prior art document mentioned above.

[0008] There are inflatable structures that have a sealed component attached around the speaker to make the speaker shock-resistant, water-resistant, able to float in space, and luminous. One example of such is U.S. Patent Publication No. 20090136076 ("Portable Inflatable Luminous Speaker," published on May 28, 2009). However, the prior art disclosed in this prior art document does not solve the above-mentioned problems, but merely modifies existing speaker systems or acoustic systems.

[0009] U.S. Patent No. 2009028369A1 discloses an annular member to be combined with a rigid cone in a conventional speaker so as to be able to support the cone in a vibratory manner.

[0010] In the solution proposed in this prior art document, similar to those disclosed in Italian Patent Application No. 101998900707532 and U.S. Patent Publication No. 20018-0316997, the inflatable member is not directly coupled to the speaker's vibrating coil, and the inflatable member itself does not act as a sound source, receiving only sound waves transmitted through the air by the speaker and vibrating almost silently. Since the inflatable member is coupled to the speaker, it does amplify the sound waves to some extent. Furthermore, this prior art document utilizes a piezoelectric transducer to prevent undesirable low-frequency radiation.

[0011] Even in the solution disclosed in U.S. Patent No. 4,638,207, a piezoelectric film balloon speaker, in which a piezoelectric film is attached to an inflatable member, cannot reproduce extremely low frequencies as a sound source (a piezoelectric speaker can emit sharp, high-pitched sounds but does not vibrate in a way that allows it to emit low-pitched sounds).

[0012] The vibrating coil disclosed in International Publication No. 1997022225 (Sound Reproducing Device or Microphone) vibrates the central part of a rocker arm structure with two spheres on its sides. However, as described in this prior art document, only a portion of the inflated membrane, and at best only the central part, i.e., only a small portion, vibrates, so it is not designed to efficiently reproduce low frequencies. In fact, this prior art document states that the reproduced sound can be used in portable radios or personal radios and can be sold as a small electronic device, but it is not designed to radiate low or deep sounds.

[0013] Federal Republic of Germany Patent Publication No. 102004007020 discloses a speaker in which the membrane is formed from an inflatable material. Furthermore, this prior art document explicitly states that speakers in which an inflatable membrane is filled with air are known. In this prior art document, anything that expands in the form of a membrane is referred to as an "inflatable cover."

[0014] German Published Patent No. '020 discloses a flat, expandable membrane, rather than an annular membrane, in embodiments comprising a double-wall structure or two flat wing-like structures. In this prior art, the expandable membrane is reinforced by walls formed of expensive carbon nanotubes embedded in a plastic material or expensive Kevlar fibers embedded in the membrane. This allows for the generation of high pressure between the walls of the membrane, which is achieved using a compressor.

[0015] This prior art document makes no mention of annular membranes. Furthermore, a speaker configured in this way would require a large basket-like frame to house it.

[0016] Federal Republic of Germany Patent Publication No. 4302593 discloses a speaker comprising multiple membranes for a speaker housed in a basket-shaped frame. The membranes can take various shapes, but are consistently disclosed as at least two parts (structures shown in Figures 1 and 2) or several parts (structures shown in Figure 3).

[0017] The problem addressed by the invention in Federal Republic of Germany Patent Publication No. 4302593 is to solve the problem of partial vibration of a speaker diaphragm. The membrane is always housed within a basket-shaped frame, and the sound produced by the speaker in this prior art document is radiated only in the forward direction (the sound production state in known speakers). To radiate low frequencies, the basket-shaped frame or speaker box with a duct must be large. Consequently, the above-mentioned problems naturally arise regarding the overall dimensions, weight, and price of the woofer, as well as the speaker box with a duct that houses the woofer. [Overview of the project] [Problems that the invention aims to solve]

[0018] A challenge that has been strongly demanded in the field of sound reproduction technology but has remained unresolved until now is the low-frequency radiation of small, lightweight, portable, and cost-effective speakers. While such systems can be created with high-power, small amplifiers and speakers, conventional speakers cannot radiate low frequencies and their harmonics, mainly because the surface of the vibrating membrane is miniaturized. Therefore, the solutions using prior art are in the following state.

[0019] In small speakers, low frequencies cannot be radiated with high quality because they require a large, rigid membrane (and therefore a large, heavy basket-shaped frame) and a corresponding speaker box with a duct.

[0020] High-quality low frequencies are radiated by large speakers.

[0021] A speaker cannot mainly diffuse sound waves in the front direction unless combined with other systems.

[0022] In order to efficiently generate and radiate high-quality sound (amplify and control the output sound), prior art speakers required a speaker box with a duct that houses the entire speaker with a membrane and other components (coils, magnets, heavy basket-shaped metal frames, etc.). As a result, the acoustic device (speaker box and speaker) was difficult to handle, heavy, and generally expensive. Furthermore, the effect of miniaturization of other devices connected to the acoustic device, such as audio devices and amplifiers, was nullified.

[0023] An object of the present invention is to provide a high-quality speaker that can radiate extremely low-frequency sound without using difficult-to-handle, heavy, and expensive components, such as a large basket-shaped metal frame, a magnet, a woofer with a coil, a heavy wooden acoustic speaker box, and a large membrane made of cardboard or hard synthetic material.

[0024] Furthermore, another object of the present invention is to provide a speaker with reduced size that, when not in use, has a volume and overall dimensions of several centimeters and a weight of several grams, and becomes a pocket-sized speaker.

[0025] Another object is to provide the above-described type of speaker that has a high cost-effectiveness compared to an acoustic system with the same quality and can reduce the price, transportation, and storage costs (because the weight is reduced and the overall dimensions are reduced when folded small).

[0026] Another object is to provide a speaker that, unlike the prior art, can propagate sound in space substantially omnidirectionally.

[0027] Another object is to provide a speaker that does not need to be incorporated into a difficult-to-handle and expensive speaker box with a duct.

[0028] Another object of the present invention is to provide a speaker and a stereo system that are part of an article with excellent design (a purely industrial design article where the appearance and the essential shape are both functional), which can be freely arranged, can be used in various environments such as unstable situations and stable installation situations, have a visually pleasing appearance, and for example, when suspended from a support, the overall dimensions can be made close to zero.

[0029] Furthermore, another object of the present invention is to enable the speaker according to the present invention to be combined with other speakers or incorporated into an acoustic system with excellent portability that is weak in reproducing low frequencies.

[0030] Furthermore, an object of the present invention is to enable it to be used as a subwoofer.

[0031] Furthermore, an object of the present invention is to provide a speaker that can cover an extremely wide listening area by connecting a plurality of systems placed in various areas using a Bluetooth device or an attached cable.

[0032] Furthermore, another object of the present invention is to provide a speaker that can bring about a bass - reflex effect according to the distance from the wall or the distance from other acoustic obstacles on the back side when installed close to the wall.

[0033] Furthermore, another object of the present invention is to enable both the radiation and the amplification of low - frequency sounds and high - frequency sounds.

[0034] Another object of the present invention is to provide a speaker that can obtain various acoustic effects and tone color effects according to the requirements of the user for the tone color, either by the position of the speaker in space or by replacing the membrane with a membrane of another size.

Means for Solving the Problems

[0035] These objectives, and other objectives that would be apparent to those skilled in the art, are achieved by the speakers described in the attached claims. [Brief explanation of the drawing]

[0036] To make the present invention easier to understand, the following drawings are attached, which merely illustrate non-limiting examples. [Figure 1] Figures 1A to 1D are a plan view, side view, bottom view, and enlarged view, respectively, of the speaker according to the present invention as seen from each of its respective surfaces. [Figure 2] This is a schematic cross-sectional view along line 2-2 in Figure 1A. [Figure 3] This is an exploded view of the speaker components shown in Figure 1, although it is a similar cross-sectional view to Figure 2. [Figure 4] Figures 4A and 4B are schematic cross-sectional and bottom views, respectively, illustrating examples of the speaker shown in Figure 1. In Figure 4A, some components are omitted to more clearly illustrate the present invention. [Figure 5] Figure 1 illustrates the way a speaker emits sound. [Figure 6] This figure schematically illustrates different embodiments of the present invention. [Figure 7] Figures 7A and 7B are plan and perspective views, respectively, of different embodiments of the present invention shown in Figure 6. [Modes for carrying out the invention]

[0037] Referring to the above drawing, the speaker according to the present invention is shown as a whole by reference numeral 100. The speaker according to the present invention comprises a vibrating coil, or movable coil 10, which is assembled to a support 8 by screw-type (or plug-in pin-type) connecting means 9. The movable coil 10 cooperates with a known magnet (not shown) that generates sound, which is combined with electrical and mechanical components. These components themselves are known and will not be described further. These components are included in the concept of the term "coil".

[0038] A hole 8A is provided in the support 8 for the sealing cap 5. A component 3 to which the movable coil 10 is directly fixed (via the support 8) is integrally connected to the support 8. This component comprises a frustoconical flat edge portion or a frustoconical spoke-shaped edge portion 4 and a plate 3A. In the illustrated embodiment, the spoke-shaped edge portion may be foldable so that it can be folded onto the rigid plate.

[0039] The expandable annular membrane 1 is fixed to the support 3 and directly combined with the movable coil 10. The membrane constitutes the diaphragm of the speaker according to the present invention and diffuses the sound generated by the movement of the vibrating coil 10 into the air. The membrane is integrally coupled to the vibrating coil via the above-mentioned structure 3, particularly via the plate 3A. In this way, the structure 3 supports the membrane 1 (while it remains fixed to the structure). For this reason, the structure 3 will henceforth be referred to as the support structure 3.

[0040] The annular membrane is a single unit and comprises a trumpet-shaped or horn-shaped cone-shaped central portion 12, extending upward and laterally from the support structure 3, and thus comprising an upper free surface or free surface 1A and a lower free surface or free surface 1B connected by a side surface 1C (a free surface or free surface located laterally to the support structure 3 or plate 3A and protruding from one side of the plate) relative to the support structure (see Figure 2).

[0041] When the membrane is integrally bonded to the plate 3A, the edge portion 4 (for example, the spoke-shaped portion) is also firmly constrained by the membrane, and the membrane vibrates integrally with the plate 3A and therefore integrally with the movable coil 10 which is integrally bonded to the plate.

[0042] Due to its shape and size, Membrane 1 functions as a woofer, eliminating the need for a separate, heavy, and expensive speaker box with a duct.

[0043] Typically, the known membranes that make up a woofer require not only a certain size but also lightness, sensitivity, and rigidity, and must be housed within a large protective basket-like frame. Consequently, woofers are not easy to transport, and the protective basket-like frame must be housed within a speaker box with a duct to improve sound quality, which increases weight and volume, ultimately making them expensive.

[0044] Figure 3 shows the configuration of the speaker 100. The support structure 3, which has a plate 3A with a central portion 3B and an edge portion 4, houses a connecting pipe 2 that is closed at one end and a sealing cap 5. The sealing cap is housed in the support 8, i.e., a screw mounting fixture for the movable coil 10, and is configured to close the other end of the connecting pipe from which air flows into the annular membrane. The connecting pipe 2 is screwed into the plate 3A, and the connecting pipe is provided with a hole 2K for inflating the annular membrane 1, and the annular membrane is fixed by a sealing strip 7 (Figure 2). The annular membrane is attached in an uninflated state to the mounting location 11 provided at one end of the connecting pipe 2 and fixed by a strip 6 (Figure 2). Next, the membrane is inflated, and then the sealing cap 5 is attached to connect the support 8 of the movable coil 10.

[0045] The annular membrane 1 is integrally connected to the movable coil 10 at its central portion by fixing the annular membrane to the plate 3A of the support structure 3, which is coupled to the support 8 of the movable coil. This connection is made by the aforementioned screw or push-pin type connecting means, which are made of various hard materials, such as plastic. The structure of the annular membrane and plate may be provided with one or more self-aligning members and / or counterweights 14 to prevent the movement of the movable coil from changing and the axis from shifting due to weight (even if the weight is only a few grams), so as to maintain axis alignment between the support structure 3 (or the plate 3A of the support) and the annular membrane 1 with the vibrating coil, i.e., the movable coil.

[0046] The speaker according to the present invention may be combined with a hook for suspending the speaker (Figure 4), or with a fixed support means (for example, a base or frame that supports the speaker). In this case, the annular membrane 1 may be provided with fixed points 13, 13a configured to combine with wires that support the speaker by attaching the annular membrane to the support points 200 of the fixed support 300. This embodiment is one example of a hook.

[0047] The annular membrane may be combined with indoor or outdoor lighting means.

[0048] The single inflatable annular membrane 1 is inherently robust because its annular shape contains air (the air can be at low pressure and can be introduced without the use of a compressor). Therefore, there is no need to use reinforcing means such as those disclosed in German Patent Publication No. 102004007020.

[0049] Regarding sound radiation, Federal Republic of Germany Patent Publication No. 4302593 proposes the use of a diaphragm comprising at least two components, one formed in a dome shape and the other in a cone shape, which constitute an airtight space filled with compressed air.

[0050] Furthermore, contrary to the disclosures in Federal Republic of Germany Patent Publication No. 4302593, the speaker according to the present invention has an expandable annular membrane that protrudes laterally from the plate 3A, and radiates sound not only in the forward direction but also in both directions of the plate, substantially in all directions in space (in the 4π steradian direction over the entire solid angle of the plate 3A), thereby solving the low-frequency problems in small speakers as described above.

[0051] In the modified embodiment of the present invention shown in Figures 6 and 7A and 7B, the annular membrane is integrally coupled with the mounting structure 20 of the movable coil 10, and the mounting structure is a cylindrical or frustoconical portion 22, and is equipped with screw-type (or plug-in pin type) connecting means at both open ends that are fixed to corresponding portions (e.g., screw-forming portions) 21 directly provided on the exposed portion of the movable coil (basically becoming a tweeter), thereby allowing the high frequencies generated by the movable coil to pass through the holes 12 of the annular membrane 1, and the high frequencies are further amplified because the holes 12 of the annular membrane 1 have a trumpet-like cone shape.

[0052] In this modified embodiment, the speaker radiates high frequencies passing through the cylindrical portion 22 and the hole 12 of the annular membrane, while the annular membrane radiates low frequencies through the free surfaces 1A and 1B, as the annular membrane 1 is moved by the vibration of the movable coil to which it is directly coupled by the mounting structures 20 and 21. The annular membrane is expanded through the expansion means 24.

[0053] Therefore, a characteristic feature of the present invention is that the annular membrane is firmly coupled to the vibrating coil, and the annular membrane vibrates together with the vibrating coil by being directly and integrally coupled to the vibrating coil (for example, at a known exposed portion of the vibrating coil). As a result, sound is generated as in conventional speaker membranes. In addition to being robust even at ultra-low pressure (it expands when air is blown into it), the annular membrane, due to its unique shape and structure, amplifies the radiated frequencies without the need for any other parts or devices to operate. Due to its unique shape and structure, the annular membrane can generate ultra-low frequencies, and in particular, because the annular shape protrudes from the plate 3A, it can radiate sound waves over substantially the entire solid angle. Furthermore, because the annular shape of the annular membrane is suitable for two purposes, the annular membrane enables the simultaneous generation and amplification of low frequencies and high frequencies by a cone-shaped portion (high-frequency trumpet-shaped cone portion) formed at the center of the annular shape.

[0054] Thus, the ratio of the number of parts, weight, and overall dimensions, as well as the efficiency (amplitude of the audio spectrum), are significantly improved compared to known speakers.

[0055] As shown in Figure 5, the radiating surface (perpendicular or nearly perpendicular to the air compression direction) is much larger than that of conventional solutions. This not only minimizes the region where sound waves tend to cancel each other out due to phase inversion, but also creates a linear region that effectively divides the two surfaces 1A and 1B. By appropriately positioning the speaker, the sound waves from one of these two surfaces are at least partially phase-inverted (bass reflex effect), and the low frequencies from the back surface 1B are reflected by the nearby wall and added to the sound waves generated from the front surface.

[0056] The speaker according to the present invention can reproduce high-quality sound and, despite its small size, can radiate high-frequency, mid-frequency, and low-frequency sounds using a single annular membrane without the need for a conventional speaker box. The speaker according to the present invention is lightweight and cost-effective. Furthermore, the speaker according to the present invention generates sound that spreads into space both in front and behind (substantially 360°) via two surfaces 1A and 1B. Due to these unique effects, the speaker according to the present invention is characterized in relation to the structure and design of speakers currently on the market.

[0057] The speaker according to the present invention is a single-piece speaker that can emit a wide range of frequencies without requiring a speaker box with a duct or a sealed speaker box.

[0058] Thus, Speaker 100 can provide an audio system based on a completely new concept in terms of the synergistic effect of the resulting physical principles, as well as the characteristics of its components, sound generation, and maintenance. [Effects of the invention]

[0059] The market offers integrated power amplifiers equipped with various input devices such as Bluetooth receivers and USB players. These cost tens of euros or more, and although they are only a few centimeters in size, for example, 4x4 or 5x5, and weigh only a few grams, they are heavy, expensive, and difficult to handle. They need to be combined with a suitable acoustic speaker box or ducted speaker box that is at least the size of a small piece of furniture.

[0060] Speaker 100 possesses all the necessary characteristics to produce high-quality sound across a wide spectrum without using a speaker with various components such as a large, rigid membrane, a basket-shaped metal frame, or a wooden speaker box. The annular membrane 1 (which may be separate from the vibrating coil 10) is not only extremely lightweight but also rigid and capable of radiating sound containing a variety of frequencies.

[0061] The speaker 1 according to the present invention is used without a speaker box, as described above.

[0062] Therefore, the annular membrane according to the present invention generates ultra-low frequencies through vibration based on its surface, shape, and size characteristics. As a result, the speaker 100 does not need to use commonly used components such as a speaker box, except for the vibrating coil (including minimal support structures), and thanks to the amplification power of the membrane, its size and output can be significantly reduced without sacrificing sound power or sound quality.

[0063] In addition to radiating balanced low frequencies without using a speaker box, the annular membrane according to the present invention can amplify sharp high frequencies through a cone formed in the center of the annular membrane (the "trumpet fundamental frequency range" of the tweeter), thereby reproducing a powerful and balanced sound.

[0064] The speaker 100 is equipped with a membrane 1 that expands and contracts easily, and when contracted, the dimensions, weight, and volume of the speaker according to the present invention become extremely small. Furthermore, the speaker according to the present invention is easily portable. Therefore, transportation becomes extremely easy in terms of the necessary parts. The speaker according to the present invention is also significantly more cost-effective than speaker systems of the same quality.

[0065] The combination of shape, lightness, and rigidity makes speaker 100 extremely sensitive. Therefore, regardless of the size of the environment, the speaker according to the present invention can radiate numerous harmonics, low frequencies, and a well-balanced sound despite its small volume. Even when listening casually, the warmth and perfection of the sound are not lost. Thus, speaker 100 can radiate low-frequency and high-frequency sounds simultaneously, and these sounds are also amplified by the shape (essentially cone-shaped) of the central part 12 of the annular membrane 1.

[0066] The speaker according to the present invention diffuses sound more evenly into the surrounding environment as the frequency decreases, making it possible to generate directivity at low frequencies, which are typically non-directivity in conventional systems. This is because, in speaker 100, both sides 1A and 1B of the expanded membrane 1 function with phase inversion, so the sound and bass sound are partially weakened laterally (in all directions) relative to the annular membrane of the present invention, while becoming more pronounced in the frontal direction relative to both sides of the expanded membrane 1.

[0067] In this way, speaker 100 can address the sound directed towards the annular membrane as needed, and even at the same distance from the speaker, it can create so-called "corridors," that is, regions where the sound is weaker and regions where the sound is higher (see Figure 5).

[0068] Surface 1B, located on the rear side facing the wall, exhibits a bass reflex effect depending on its distance from the wall (acoustic obstacles on the rear side, mounting angle).

[0069] Alternatively, two speakers 100 may be used, fixed so that the annular membranes 1 face opposite directions (the magnets face each other), and coupled so that the two speakers are in phase inverted. This would reinforce the pressing force of one coil (applied to the corresponding membrane) with the opposing pressing force of the other coil, thereby increasing the output of sound radiated by both membranes.

[0070] Alternatively, two membranes and two coils may be connected so that their front and back sides face each other, and the electrodes are connected in opposite directions (phase inversion), thereby combining and integrating the timbres emitted from each side. Other combinations of timbres may also be used for integration.

[0071] As described above, with speaker 100, the sound characteristics can be freely changed in various combinations (not limited to the above combinations which are non-limiting examples of the present invention) by changing the orientation of the speaker or by easily replacing the membrane with a different one to produce a different timbre.

[0072] In any case, the structural features of the present invention are described in the claims of the subsequent documents.

Claims

1. In a speaker comprising a magnet, a movable coil (10), a support (8) that supports the movable coil, and an expandable member that constitutes the speaker membrane and converts the movement of the movable coil (10) into sound, The membrane is firmly bonded to a support structure (3) of the membrane, which is fixed to a support (8) that supports the movable coil. The membrane is a single, annular-shaped component that protrudes from the support structure (3). The membrane has a first free surface (1A) on the opposite side of the support structure (3) and a second free surface (1B) on the side of the support structure that protrudes from the side of the support structure. A speaker characterized in that both the first free surface and the second free surface radiate sound in accordance with the movement of the movable coil (10).

2. The speaker according to claim 1, characterized in that the annular inflatable membrane (1) is coupled to the movable coil (10) via the support (8) to which the support structure (3) of the membrane is fixed.

3. The speaker according to claim 1, wherein the annular inflatable membrane is combined with a pipe (2) fixed to a support structure (3) for the membrane, the pipe (2) having a hole (2K) for inflating the annular membrane, one end being closed and the other end being open for inflating or deflating the annular membrane (1), and the open end of the pipe (2) is combined with a sealing cap (5).

4. The speaker according to claim 1, characterized in that the movable coil is provided with a threaded portion for screwing into a support (8) integrally coupled with the support structure (3) of the membrane, or for a plug-in pin type socket that is coupled to the support (8).

5. The speaker according to claim 1, characterized in that the support structure (3) includes a plate (3A) to which an annular, expandable membrane (1) made of a single piece is fixed.

6. The speaker according to claim 5, characterized in that the plate is provided with a foldable protruding arm (4).

7. The speaker according to claim 1, further comprising at least one centering member configured to maintain the annular membrane (1) so as to have the same axis as the movable coil (10).

8. The speaker according to claim 7, characterized in that the self-aligning member provides an external counterweight (14) integrally connected to the support structure (3), thereby maintaining the support structure and the annular membrane (1) so as to have the same axis as the movable coil (10).

9. The speaker according to claim 1, characterized in that the annular membrane is combined with an indoor / outdoor lighting means.

10. The speaker according to claim 1, characterized in that it includes members (13, 13a) for fixing the annular-shaped membrane (1) to a fixing member (200) and a support member (15) configured such that the speaker can be suspended and supported by a fixed support (300).

11. The speaker according to claim 1, characterized in that it emits sound having a frequency range from low frequencies to high frequencies.

12. The speaker according to claim 1, characterized in that the annular, expandable membrane (1) has a hole in its center through which high-frequency sound generated by the movable coil (10) passes.

13. The speaker according to claim 12, characterized in that the aforementioned high-frequency sound is amplified by the central part (12) of the trumpet-shaped cone membrane.

14. The speaker according to claim 1, characterized in that the annular-shaped membrane (1) is replaceable.

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