Patent Application
20160295337
This disclosure relates to a method for manufacturing a loudspeaker.
Loudspeakers generally include a diaphragm and a linear motor. When driven by an electrical input signal, the linear motor moves the diaphragm to cause vibrations in air, thereby generating sound. Various techniques have been used to control the directivity and radiation pattern of a loudspeaker, including acoustic horns, pipes, slots, waveguides, and other structures that redirect or guide the generated sound waves. In some of these structures, an opening in the horn, pipe, slot or waveguide is covered with an acoustically resistive material to improve the performance of the loudspeaker over a wider range of frequencies.
In general, in some aspects a method for manufacturing a loudspeaker includes creating a dual-layered fabric having an acoustic resistance by attaching a first fabric having a first acoustic resistance to a second fabric having a second acoustic resistance lower than the first acoustic resistance. The method further includes applying a coating material to a first portion of the dual-layered fabric. The coating material forms a pattern on the first portion of the dual-layered fabric that changes the acoustic resistance of the dual-layered fabric along at least one of: a length and radius of the dual-layered fabric.
Implementations may include any, all or none of the following features. The first acoustic resistance may be approximately 1,000 Rayls. The first fabric may be a monofilament fabric. The second fabric may be a monofilament fabric. The first fabric may be attached to the second fabric using at least one of: a solvent and an adhesive.
Applying a coating material to a first portion of the dual-layered fabric may include masking a second portion of the dual-layered fabric, the second portion being adjacent to the first portion. Applying a coating material to a first portion of the dual-layered fabric may further include applying the coating material to an unmasked portion of the dual-layered fabric. Applying a coating material to a first portion of the dual-layered fabric may include selectively depositing the coating material to form the pattern on the first portion of the dual-layered fabric. Applying a coating material to a first portion of the dual-layered fabric may include attaching a pre-cut sheet of material to the first portion of the dual-layered fabric. The coating material may include at least one of: paint, an adhesive, and a polymer.
The method may further include thermoforming the dual-layered fabric into at least one of: a spherical shape, a semi-spherical shape, a conical shape, a toroidal shape, and a shape comprising a section of a sphere, cone or toroid.
The method may further include attaching the dual-layered fabric to an acoustic waveguide.
The method may further include attaching an electro-acoustic driver to the acoustic waveguide.
In general, in some aspects a method of manufacturing a loudspeaker includes providing a fabric having an acoustic resistance and applying a coating material to a first portion of the fabric. The coating material forms a pattern on the first portion of the fabric that changes the acoustic resistance of the fabric along at least one of: a length and radius of the fabric.
Implementations may include any, all or none of the following features. The acoustic resistance may be approximately 1,000 Rayls. The fabric may include a monofilament fabric.
Applying a coating material to a first portion of the fabric may include masking a second portion of the fabric, the second portion being adjacent to the first portion. Applying a coating material to a first portion of the fabric may further include applying the coating material to an unmasked portion of the fabric. Applying a coating material to a first portion of the fabric may include selectively depositing the coating material to form the pattern on the first portion of the fabric. Applying a coating material to a first portion of the fabric may include attaching a pre-cut sheet of material to the first portion of the fabric. The coating material may include at least one of: paint, an adhesive, and a polymer.
The method may further include thermoforming the fabric into at least one of: a spherical shape, a semi-spherical shape, a conical shape, a toroidal shape, and a shape comprising a section of a sphere, cone or toroid.
The method may further include attaching the fabric to an acoustic waveguide.
The method may further include attaching an electro-acoustic driver to the acoustic waveguide.
In general, in some aspects a method of manufacturing a loudspeaker includes creating a dual-layered fabric having an acoustic resistance by attaching a first fabric having a first acoustic resistance to a second fabric having a second acoustic resistance lower than the first resistance. The method further includes altering the acoustic resistance of the dual-layered fabric along at least one of: a length and radius of the dual-layered fabric by fusing a first portion of the dual-layered fabric to form a substantially opaque pattern on the first portion of the dual-layered fabric.
Implementations may include any, all or none of the following features. The first acoustic resistance may be approximately 1,000 Rayls. The first fabric and the second fabric may each include a monofilament fabric. The first fabric may be attached to the second fabric using at least one of: a solvent and an adhesive. Fusing a first portion of the dual-layered fabric may include heating the dual-layered fabric.
The method may further include thermoforming the dual-layered fabric into at least one of: a spherical shape, a semi-spherical shape, a conical shape, a toroidal shape, and a shape comprising a section of a sphere, cone or toroid.
The method may further include attaching the dual-layered fabric to an acoustic waveguide.
The method may further include attaching an electro-acoustic driver to the acoustic waveguide.
Implementations may include one of the above and/or below features, or any combination thereof. Other features and advantages will be apparent from the description and the claims.
For purposes of illustration some elements are omitted and some dimensions are exaggerated. For ease of reference, like reference numbers indicate like features throughout the referenced drawings.
A loudspeaker 10, shown in
The electro-acoustic driver 12 typically includes a motor structure mechanically coupled to a radiating component, such as a diaphragm, cone, dome, or other surface. Attached to the inner edge of the cone may be a dust cover or dust cap, which also may be dome-shaped. In operation, the motor structure operates as a linear motor, causing the radiating surface to vibrate along an axis of motion. This movement causes changes in air pressure, which results in the production of sound. The electro-acoustic driver 12 may be a mid-high or high frequency driver, typically having an operating range of 200 Hz to 16 kHz. The electro-acoustic driver 12 may be of numerous types, including but not limited to a compression driver, cone driver, mid-range driver, full-range driver, and tweeter. Although one electro-acoustic driver is shown in
The electro-acoustic driver 12 is coupled to an acoustic waveguide 14 which, in the example of
Before the generated sound waves reach the external environment, they pass through a resistive screen 16 coupled to an opening in the acoustic waveguide 14. The resistive screen 16 may include one or more layers of a mesh material or fabric. In some examples, the one or more layers of material or fabric may each be made of monofilament fabric (i.e., a fabric made of a fiber that has only one filament, so that the filament and fiber coincide). The fabric may be made of polyester, though other materials could be used, including but not limited to metal, cotton, nylon, acrylic, rayon, polymers, aramids, fiber composites, and/or natural and synthetic materials having the same, similar, or related properties, or a combination thereof. In other examples, a multifilament fabric may be used for one or more of the layers of fabric.
In one example, the resistive screen 16 is made of two layers of fabric, one layer being made of a fabric having a relatively high acoustic resistance compared to the second layer. For example, the first fabric may have an acoustic resistance ranging from 200 to 2,000 Rayls, while the second fabric may have an acoustic resistance ranging from 1 to 90 Rayls. The second layer may be a fabric made of a coarse mesh to provide structural integrity to the resistive screen 16, and to prevent movement of the screen at high sound pressure levels. In one example, the first fabric is a polyester-based fabric having an acoustic resistance of approximately 1,000 Rayls (e.g., Saatifil® Polyester PES 10/3 supplied by Saati of Milan, Italy) and the second fabric is a polyester-based fabric made of a coarse mesh (e.g., Saatifil® Polyester PES 42/10 also supplied by Saati of Milan, Italy). In other examples, however, other materials may be used. In addition, the resistive screen 16 may be made of a single layer of fabric or material, such as a metal-based mesh or a polyester-based fabric. And in still other examples, the resistive screen 16 may be made of more than two layers of material or fabric. The resistive screen 16 may also include a hydrophobic coating to make the screen water-resistant.
The resistive screen 16 also includes an acoustically resistive pattern 20 that is applied to or generated on the surface of the resistive screen 16. The acoustically resistive pattern 20 may be a substantially opaque and impervious layer. Thus, in the places where the acoustically resistive pattern 20 is applied, it substantially blocks the holes in the mesh material or fabric, thereby creating an acoustic resistance that varies as the generated sound waves move radially outward through the resistive screen 16 (or outward in a linear direction for non-circular and non-spherical shapes). For example, where the acoustic resistance of the resistive screen 16 without the acoustically resistive pattern 20 is approximately 1,000 Rayls over a prescribed area, the acoustic resistance of the resistive screen 16 with the acoustically resistive pattern 20 may be approximately 10,000 Rayls over an area closer to the electro-acoustic driver 12, and approximately 1,000 Rayls over an area closer to the edge of the loudspeaker 10 (e.g., in areas that do not include the acoustically resistive pattern 20). The size, shape, and thickness of the acoustically resistive pattern 20 may vary, and just one example is shown in
The material used to generate the acoustically resistive pattern 20 may vary depending on the material or fabric used for the resistive screen 16. In the example where the resistive screen 16 comprises a polyester fabric, the material used to generate the acoustically resistive pattern 20 may be paint (e.g., vinyl paint), or some other coating material that is compatible with polyester fabric. In other examples, the material used to generate the acoustically resistive pattern 20 may be an adhesive or a polymer. In still other examples, rather than add a coating material to the resistive screen 16, the acoustically resistive pattern 20 may be generated by transforming the material comprising the resistive screen 16, for example by heating the resistive screen 16 to selectively fuse the intersections of the mesh material or fabric, thereby substantially blocking the holes in the material or fabric.
In step 104, a coating material (such as paint, an adhesive or a polymer) is applied to the resistive screen 16 to form the acoustically resistive pattern 20. In one example, as shown in
Optionally, in step 106, the coating material may be cured, by, for example, baking the assembly at a predetermined temperature, applying ultraviolet (UV) light to the coating material, exposing the coating material to the air, or any combination thereof. If a coating material is selected that does not need to be cured, step 106 would be omitted. In some examples, steps 102, 104 and 106 could be combined into a single step. For example, the first and second layers of fabric could be placed on top of each other, and a UV-curable adhesive could be deposited onto one layer of the fabric in the desired acoustically resistive pattern 20. The adhesive could then be cured via the application of UV light, which would also result in adhering the two layers of fabric.
In step 108, the fabric is formed into the desired shape for the loudspeaker 10. For example, the fabric may be formed to be a semi-circle, circle, sphere, semi-sphere, rectangle, cone, toroid, or a shape comprising a section of a circle, sphere, cone, toroid and/or rectangle. The loudspeaker 10 may also be bent and/or curved along its length, as described, for example, in U.S. Pat. No. 8,351,630, the entire contents of which are incorporated herein by reference. These various shapes may be created by thermoforming the fabric (i.e., heating it to a pliable forming temperature and then forming it to a specific shape in a mold) and/or vacuum or pressure forming the fabric. Although
In step 110, the resistive screen 16 is attached to the acoustic waveguide 14 via an adhesive, double-sided tape, a fastener (e.g., a screw, bolt, clamp, clasp, clip, pin or rivet), or other known methods. And in step 112, the electro-acoustic driver 12 is attached to the acoustic waveguide 14. The electro-acoustic driver 12 could be secured to the acoustic waveguide 14 via a fastener or other known methods. Although
Optionally, in step 206, the coating material may be cured, by, for example, the methods previously described in connection with
In step 208, the fabric is formed into the desired shape for the loudspeaker 10. As with the example of
As with the example of
In step 303, the fabric is fused to form the acoustically resistive pattern 20, such that the holes in the fabric are substantially blocked, thereby creating a substantially opaque and impervious layer on the fabric. The fabric could be fused by, for example, applying heat to the portions of the fabric that should have the acoustically resistive pattern 20, or by selectively applying chemical bonding elements to the portions of the fabric that should have the acoustically resistive pattern 20.
As with the examples of
In step 403, the fabric is fused to form the acoustically resistive pattern 20, such that the holes in the fabric are substantially blocked, thereby creating a substantially opaque and impervious layer on the fabric. The fabric could be fused by, for example, applying heat to the portions of the fabric that should have the acoustically resistive pattern 20, or by selectively applying chemical bonding elements to the portions of the fabric that should have the acoustically resistive pattern 20.
As with the examples of
A number of implementations have been described. Nevertheless, it will be understood that additional modifications may be made without departing from the scope of the inventive concepts described herein, and, accordingly, other embodiments are within the scope of the following claims.
