Patent Application
20050232456
The invention relates generally to the field of loudspeakers. In particular, the invention concerns improved loudspeakers, systems and components thereof
A large percentage of loudspeakers used in audio systems are electrodynamic speakers. Such speakers employ a magnetic driver to produce movement of a diaphragm (typically cone or dome-shaped), which in turn causes sound.
A typical loudspeaker includes a frame upon which components are mounted. The frame provides a means for fastening the speaker to an enclosure or a receptacle. The frame, which is sometimes called the basket, has cut-outs in its side walls so air can freely circulate around a cone-shaped diaphragm. The loudspeaker driver includes a fixed magnet and voice coil. The magnet may be mounted to the rear of the frame behind the diaphragm. The voice coil is disposed adjacent the magnet and includes a bobbin. The bobbin is attached to the diaphragm.
In operation, electrical audio signals from an amplifier are applied to the voice coil producing a varying electromagnetic field around the coil. The electromagnetic field interacts with the magnetic field produced by the magnet. The magnet is securely fixed to the frame and the voice coil is movable, so the voice coil moves as the two fields interact. Because the voice coil is coupled to the diaphragm via the bobbin, its movement causes the diaphragm to vibrate. The vibration of the diaphragm causes air around the speaker to pressurize and depressurize, producing sound waves in the air.
Sound waves are emitted from both the front and rear of the speaker diaphragm. The waves emanating from the rear of an unmounted speaker can cause total or partial cancellation of the generated sound waves. To make speakers more efficient and improve sound quality, speakers are usually mounted within an enclosure.
A basic type of speaker enclosure is a sealed box structure. The structure is typically formed of wood or particle board and provides a sealed volume with air trapped inside. The speaker is positioned in an opening in the structure. The speaker frame has a flange with mounting holes formed therein. The speaker is positioned so that the flange is flush with one of the walls. Mounting screws can be inserted through the flange holes into the structure wall to secure the speaker within the sealed structure. The structure confines the rear pressure waves, thereby preventing interaction with the front waves resulting in better sound quality.
Speakers can be divided into three categories: woofer, midrange and tweeter. The woofer speaker reproduces low frequency (bass) sound ranging from about 20 to 3000 Hz. The midrange speaker reproduces a broad spectrum of sound, typically from about 1000 Hz to 10 kHz. The tweeter speaker reproduces high frequency (treble) sound ranging from about 4 to 20 kHz.
The present invention features improved loudspeakers, systems and components adapted to interconnect with various forms of communication media including television and video, radio and high-fidelity, computer and telephone and local intercoms and networks.
In one embodiment, the invention features a loudspeaker mountable within a receptacle or enclosure. The speaker includes an acoustic diaphragm, which may be cone or dome shaped, and a magnetic driver. The diaphragm and driver are mounted to a frame. The frame may be basket-shaped and includes a ring-shaped flange defining a flange plane. The frame also includes a mounting member extending from the frame behind the flange plane. The receptacle has a notch or groove disposed along an inner surface. The mounting member, which may be a V-shaped paw or the like, is engagable in the notch for securing the speaker within the receptacle.
In another embodiment, the invention features a method of mounting a loudspeaker. The method includes providing a loudspeaker and a receptacle as described above. The method also includes inserting the loudspeaker into the receptacle such that the mounting member is coplanar with the notch disposed along the inner surface of the receptacle. The method further includes rotating the loudspeaker until the mounting member engages the notch, thereby securing the loudspeaker within the receptacle.
The aforementioned embodiments provide several advantages over the state of the art. For example, the invention permits installation of a (nominal) X inch speaker in a (nominal) X-1 inch opening. This objective is achieved by relocating the mounting member. In contrast to typical flange or bayonet mounting schemes in which the mounting member is coplanar with the flange, the mounting member lies well behind the mounting flange in the present invention. The frame is tapered behind the flange, so the mounting member is located at diameter smaller than the speaker opening itself. Thus, the diaphragm is the largest visible component, and large flanges with mounting screws are not needed.
In another embodiment, the invention features a low-profile woofer loudspeaker having a front-mounted magnetic driver disposed within a cone-shaped acoustic diaphragm. The magnetic driver includes a first rare earth magnet (e.g., neodymium boron) centrally disposed within an electromagnetic shielding material (e.g., low carbon steel). The driver and diaphragm are mounted to the speaker frame. More specifically, the driver is front-mounted to an inner surface of the frame such that the driver is disposed within the cone-shaped diaphragm. The driver may further include a second rare earth magnet disposed within an electromagnetic shielding material, spaced from the first magnet and aligned 180 degrees out of phase relative to the first magnet.
The above described embodiment utilizes a state-of-the-art shielded magnetic driver, resulting in a powerful, shallow, lightweight woofer loudspeaker. The speaker has a broad range of applications including video, multimedia, auto stereo and in-wall systems.
In another embodiment, a low-profile two-way loudspeaker includes a cone-shaped acoustic diaphragm and a second acoustic diaphragm. The speaker also includes a front-mounted magnetic driver comprising first and second rare earth magnets (e.g., neodymium boron) each centrally disposed within electromagnetic shielding material (e.g., low carbon steel). The driver and cone-shaped diaphragm are mounted to a speaker frame. More specifically, the driver is front-mounted to an inner surface of the frame and disposed within the cone-shaped diaphragm. The second diaphragm is mounted onto the driver coaxially and S substantially coplanar with a forward edge of the cone-shaped diaphragm. The driver may also include a third magnet spaced from the first magnet and aligned 180 degrees out of phase relative to the first magnet. The third magnet serves as a “turbocharger” for the first magnet to wit, it cancels the stray magnetic field and enhances the flux density in the gap of the magnetic circuit. Preferably, the cone-shaped diaphragm transmits woofer frequencies to and the second diaphragm transmits tweeter frequencies.
The previously described embodiment provide several advantages over the art. For example, the speaker includes a front-mounted shielded magnetic driver, resulting in a powerful, shallow, lightweight two-way loudspeaker having a broad range of applications including video, multimedia, auto stereo and in-wall systems. Another advantage is that since the second (tweeter) diaphragm is substantially coplanar relative to cone-shaped (woofer) diaphragm, the speaker provides almost perfect acoustic time alignment. Yet another advantage is that the second (tweeter) diaphragm is positioned in an obstruction free location resulting in a wide accurate listening area. Still another advantage is that the front-mounted magnetic driver is resource efficient as the physical size of the speaker is reduced by at least a factor of two and its weight by at least a factor of four over conventional speakers.
In another embodiment, the invention features a loudspeaker enclosure which provides an increased interior volume over enclosures known in the art having identical external dimensions. The enclosure includes a perforated layer shaped to define an inner volume of the enclosure. Preferably, perforations cover at least eighty percent of the surface area of the perforated layer. A honeycomb layer surrounds the perforated layer, and a semi-rigid layer surrounds the honeycomb layer. The foregoing material combination results in an enclosure having 33% more interior volume over conventional enclosures having the same external dimensions.
The foregoing and other objects, features and advantages of the invention will become apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. The drawings are not necessarily to scale, emphasis instead being placed on illustrating the principles of the present invention.
The invention features improved loudspeakers, systems and components capable of interconnection with various forms of communication media including television and video, radio and high-fidelity, computer and telephone and local intercoms and networks.
Referring to
Referring to
The invention further includes a push-and-rotate method for securing the speaker 10 within the receptacle 12. The method includes inserting the speaker 10 into the receptacle 12 such that each mounting member 24 is coplanar with a respective notch 28 located along the inner surface of the receptacle 30. The method further includes rotating the speaker 10 until each mounting member 24 engages each notch, thereby locking the speaker 10 in the receptacle 12. For example, the speaker 10 may need be rotated about 15 degrees to secure each member 24 in a respective notch 28. Also, a foam gasket (not shown) located at the frame-receptacle interface serves as a seal and tensioning means.
Referring to
Referring to
The aforementioned embodiments of the invention permit installation of a (nominal) X inch speaker in a (nominal) X-1 inch opening. This feature is achieved by relocating the mounting member to a location well behind the plane defined by the mounting flange. Since the frame is somewhat tapered behind the flange, the mounting member is located at diameter smaller than the speaker opening itself Thus, the diaphragm is the largest visible component, and large flanges with mounting screws are not employed.
Further, the mounting scheme featured in the aforementioned embodiments reduces the mounting area of a speaker to its minimal functional size reducing the diameter by about one inch or more. Consequently, larger more powerful speakers can be installed in smaller areas, and multiple components can be installed closer together for improved sound quality. No additional hardware is needed. This enhances serviceability and reduces installation time and cost, while minimizing the visual intrusion of the speaker components. Moreover, it permits sound contractors to visually complete sound systems by investing only in inexpensive receptacles and not installing the actual speakers until the end of the process.
Referring to
The magnetic driver 74 is shown in detail in
In another embodiment, a low-profile two-way loudspeaker 89 includes the woofer loudspeaker structure described above along with a tweeter assembly mounted onto the front-mounted woofer driver.
Referring to
The speakers 70, 89 each include a front-mounted shielded magnetic driver, resulting in a powerful, shallow, lightweight loudspeaker having a broad range of applications including video, multimedia, auto stereo and in-wall systems. Referring to the two-speaker 89, there are substantial advantages including:
1) Acoustic stage stability and uniform polar response which is superior to the best conventional two-way systems.
2) A very shallow depth (e.g., two inches) because the conventional heavy magnet mounted behind the woofer cone is eliminated.
3) Since the dome is nearly flush with the rubber edge of the woofer, almost perfect acoustic time alignment is achieved.
4) The tweeter magnet also drives the woofer cone, so the added height and weight of an additional magnetic return path is eliminated.
5) The location of the tweeter is obstruction free for a wide accurate listening area.
6) In autos, the speaker permits door installation without inference with internal door elements.
7) The light weight of the speaker facilitates ex-factory auto installation. The high weight associated with conventional aftermarket hi-fi systems has proven unacceptable to many car manufacturers because it reduces the fuel economy. Further, the heavy drivers have been perceived as unacceptable passenger safety risk.
8) In commercial buildings, the light weight speaker allows safe and inexpensive ceiling and ceiling-tile installations. The excellent dispersion reduces the total number of speakers required while improving intelligibility for safety (department stores, restaurants, museums, airports etc.) and fidelity of sound.
9) In the home, the shallow depth of the speaker permits installation in 2″×4″ stud walls while maintaining proper insulation behind.
10) In home video theaters which require at least six speaker systems, the speakers can be fully flush integrated into walls or ceilings including the mandatory sub woofer bass system.
Referring to an embodiment not shown, the invention also features a loudspeaker enclosure which provides an increased interior volume over existing enclosures having identical external dimensions. The enclosure includes a perforated layer shaped to define an inner volume of the enclosure. The perforated layer may be formed aluminum or any other suitable material. Preferably, the perforations cover at least eighty percent of the surface area of the perforated layer. A honeycomb layer surrounds the perforated layer, and a semi-rigid layer surrounds the honeycomb layer. The honeycomb layer may be formed of paper or any other suitable material. The semi-rigid layer may be formed of a metallic material or the like. The foregoing material combination results in an enclosure having 33% more interior volume over conventional enclosures having the same external dimensions. The additional volume is achieved because the interior layers act as a virtual wall.
Equivalents
While various embodiments of the invention have been set forth in detail, it should be understood that the above description is intended as illustrative rather than limiting and that many variations to the described embodiments will be apparent to those skilled in the art. The invention is to be described, therefore, not by the preceding description, but by the claims that follow.
This application is a divisional of U.S. patent application Ser. No. 08/369,736, filed Jan. 6, 1995 (attorney docket no. 0322282-0001), the teachings of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 08369736 | Jan 1995 | US |
| Child | 09100411 | Jun 1998 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09100411 | Jun 1998 | US |
| Child | 11058922 | Feb 2005 | US |
