Patent Grant
9485587
The present disclosure relates generally to acoustic devices, and more specifically to improved noise attenuation, including noise caused by recoil effects, for speaker device assemblies.
Widespread access to various types of multi-media data is facilitated, in part, by advances in communication technologies. Increasingly, consumer preferences, when accessing such multi-media, highlights a demand for quality, portability, and the like, and supports a marketplace for smaller, lighter, portable, as well as integrated acoustic devices. However, design choices for these acoustic devices typically balance size (e.g., form factor, portability, etc.) against sound quality, which may result in poor overall acoustic quality. For example, certain acoustic devices having reduced form factors typically include speaker drivers that move diaphragms (e.g., to produce sound, etc.), but also transfer vibration to structural elements or housings (e.g., recoil vibration), which causes unwanted noise (e.g., an undesired frequency response, rattling, knocking, etc.). Further, this vibration can interfere with other noise cancellation features (e.g., acoustic echo, etc.), and may even reduce an overall operable lifetime of the underlying acoustic device (e.g., additional vibration produces stress on various components, etc.). Moreover, conventional approaches to reduce or attenuate the unwanted vibration typically include overly complex designs (e.g., including various components such as gaskets, rubber bushings, and extensive use of bracing, etc.). Further other conventional approaches such as those incorporating dual motors, dual radiators, and the like, attenuate or reduce vibration for only a limited or specific frequency of vibration.
In order to describe the manner in which the above-recited and other advantages and features of the disclosure can be obtained, a more particular description of the principles briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings in which:
An element or functionally similar component is indicated with the same reference number.
Overview
The present disclosure provides improved noise attenuation techniques and designs for acoustic devices such as speaker device assemblies. For example, according to one or more embodiments of the disclosure, a speaker device assembly includes a first voice coil assembly moveable along an axis of a magnetic core responsive to an induced current to facilitate pressure variations in a medium (e.g., sound waves in an air medium, etc.) and cause recoil vibration on a speaker assembly structure. To attenuate the recoil vibration on the speaker assembly structure, the speaker device assembly further includes a second voice coil assembly having a counter balance mass that accounts for at least a mass of the first voice coil assembly, and moveable along the axis of the magnetic core in a direction opposite to a direction of the first voice coil assembly. In this fashion, the second voice coil assembly attenuates the recoil vibration on the speaker assembly structure (e.g., caused by a recoil force from the first voice coil assembly) when the first voice coil assembly moves along the axis of the magnetic core. Put differently, forces from the two opposed voice coil assemblies provide harmonically balanced differential vibration cancellation for the recoil force in an electrodynamic transducer, which cancels re-radiation of unwanted audio noise through and from the speaker device assembly (e.g., a loudspeaker enclosure, etc.).
Various embodiments of the disclosure are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the disclosure.
As discussed above, certain acoustic devices typically include a speaker driver that produces sound, but may also cause undesirable vibration to an acoustic device structure or housing resulting in noise. This undesirable vibration is particularly problematic for acoustic devices that have smaller (e.g., reduced dimension, reduced form factor, etc.) acoustic assemblies such as video endpoints, IP-phones, tablets, TVs, cellphones, other stand-alone portable acoustic devices, and the like. Specifically, these acoustic devices typically include multi-component assembly designs and also have less mass—the combination of which fails to attenuate structural vibration (e.g., recoil vibration, etc.).
Accordingly, as discussed herein, the present disclosure provides generally speaker devices and assemblies that including two voice coils movable in opposing directions, with one of the two voice coils having a counter balance mass that attenuates structural vibration in the speaker device assembly. Such structural vibration can be caused, for example, by recoil forces of a voice coil assembly.
For example, referring to the drawings,
As shown, speaker device assembly 100 has a structure including a top frame 105 and a bottom frame 110. Speaker device assembly 100 also includes a diaphragm 115 coupled to top frame 105 and a portion of a first voice coil assembly (not shown).
Speaker device assembly 100 further includes a magnetic core 120, including a top pole piece 121, a magnet 122, a center support 123, a magnet 124, and a bottom pole piece 125. Magnetic core 120 produces a magnetic field having one or more axes, such as axis 120a, that attracts or repels voice coils when the voice coils receive a corresponding electrical current.
As discussed in greater below, speaker device assembly 100 also includes two voice coil assemblies (not shown)—e.g., a first voice coil assembly and a second voice coil assembly. Operatively, the first voice coil assembly moves along an axis of the magnetic core 120 in response to an induced current to facilitate pressure variations in a medium to cause diaphragm 115 to vibrate at a particular frequency and produce sound waves. A suspension 130 (e.g., a spider suspension, etc.) is coupled to a portion of the first voice coil assembly, and guides the first voice coil assembly as it moves along axis 120a. A second voice coil assembly also moves along axis 120a, but in response to a reverse induced current (e.g., an opposite current relative to the induced current for first voice coil assembly), which causes the second voice coil assembly to move in a direction opposite to a direction of the first voice coil assembly. This opposing movement of the second voice coil assembly facilitates recoil vibration attenuation (e.g., producing a counter acting force) for speaker device assembly 100. That is, the second voice coil assembly provides a harmonically balanced differential vibration cancellation of recoil forces from the first voice coil assembly to thereby cancel re-radiation of the vibration (e.g., as unwanted noise) through and from the speaker device assembly 100. In addition, a suspension 135 is also coupled to the second voice coil assembly, and guides the second voice coil assembly as it moves along axis 120a.
As discussed above, speaker device assembly 100 includes two voice coil assemblies—namely, a voice coil assembly 205 and a voice coil assembly 210, with each voice coil assembly movable along axis 120a. In addition, voice coil assembly 210 also includes a counter balance 211 (e.g., a weight, etc.), and a suspension 212 (e.g., a rubber suspension member, etc.) coupled to bottom frame 110 of the speaker device assembly 100. Notably, voice coil assembly 205 and voice coil assembly 210 are illustrated for purposes of simplicity, not limitation. For example, each voice coil assembly can include or exclude various components such as insulated wire (e.g., a voice coil), various substrates (e.g., paper, aluminum, fiberglass, plastic, etc.) bonded to the wire, wire leads to induce a current, other electrical circuitry, and the like, as is understood by those skilled in the art.
However, voice coil assembly 205 may additionally cause recoil vibration to speaker device assembly 100 as it moves along axis 120a. Accordingly, a second voice coil assembly—e.g., voice coil assembly 210—is provided to attenuate such recoil vibration caused by voice coil assembly 205. In particular, voice coil assembly 210 operatively moves in a direction opposite to that of voice coil assembly 205 in response to a reverse induced current and attenuates the recoil vibration on speaker device assembly 100. For example, when voice coil assembly 210 moves along axis 120a, it transfers a counter vibration (e.g., a harmonically balanced differential vibration) to the speaker device assembly 100 using suspension 212.
For example,
As shown in
Further, although counter balance 211 is shown as a separate or independent component coupled to voice coil assembly 210, such view is for purposes of discussion, not limitation. In some embodiments, voice assembly 210 incorporates or otherwise integrates the mass of counter balance 211 in other voice coil assembly components using, for example, various manufacturing techniques (e.g., materials used, dimensions for voice assembly 210, and the like), as is appreciated by those skilled in the art.
According to the techniques discussed above, two voice coils assemblies are provided for a speaker device assembly—one voice coil assembly produces sound (but also causing unwanted vibration on the speaker device assembly), and the other voice coil assembly, moving in an opposing direction, attenuates the unwanted vibration. As is appreciated by those skilled in the art, these techniques as well as underlying design principles can be employed by various other embodiments.
For example,
Speaker device assembly 600, similar to speaker device assembly 100, also includes a magnetic core 620. Magnetic core 620 includes a top pole piece 621, a magnet 622, and a bottom pole piece 625. Magnetic core 620 produces a magnetic field having one or more axes such as an axis 620a, and operatively attracts or repels a voice coil when the voice coil receives an electrical current.
As shown, voice coil assembly 710 includes a counter balance 711 disposed in a suspension assembly, and a suspension assembly having two suspensions 735a, 735b (e.g., spider suspensions). Suspension 735a is coupled to one side of center pole piece 726, and suspension 735b is coupled to an opposing side of center pole piece 726, with counter balance 711 disposed there-between. As discussed above, the views shown herein are for purposes of illustration, not limitation, and the voice coil assemblies can include or exclude any number of additional elements, as is appreciated by those skilled in the art.
However, voice coil assembly 705 may additionally cause vibration to speaker device assembly 600 when it moves along axis 620a. Accordingly, a second voice coil assembly—namely, voice coil assembly 710—is provided to attenuate the vibration caused by voice coil assembly 705. In particular, voice coil assembly 710 operatively moves in a direction opposite to that of voice coil assembly 705 in response to a reverse induced current in order to attenuate the vibration on speaker device assembly 600. For example, when voice coil assembly 710 moves along axis 620a, it transfers a counter acting force (e.g., a counter vibration) to the speaker device assembly 600 using suspension 712. Put differently, movement of voice coil assembly 710 provides a canceling force (e.g., a harmonically balanced differential vibration) for the speaker device assembly 600, which cancels unwanted vibration (e.g., recoil force) in the structure of speaker device assembly 600.
For example,
As shown in
Further, although counter balance 711 is shown as a separate or independent component (e.g., a center bar) disposed between the suspension assembly (which includes suspensions 735a, 735b), such view is for purposes of discussion, not limitation. For example, counter balance 711 (similar to counter balance 211) can be incorporated and/or integrated into various other components of voice coil assembly 710 using various manufacturing techniques, as is appreciated by those skilled in the art.
The techniques and devices described herein, therefore, provide improvements for noise attenuation, particularly adapted for acoustic devices, including speaker device assemblies. Such techniques and devices cancel unwanted mechanical vibration from speaker drivers (e.g., noise), and provide a simple, low cost solution—e.g., using a second voice coil assembly having an appropriate counter balance mass provides a simple mechanical solution that does not require any acoustical radiation. The techniques and devices can be implemented, for example, for any speaker assembly, and further obviate the need for gaskets, rubber bushings, and extensive use of bracing. Further, such techniques and devices provide noise attenuation throughout a responsive frequency range.
While there have been shown and described illustrative embodiments that attenuate unwanted vibration for speaker device assemblies, it is to be understood that various other adaptations and modifications may be made within the spirit and scope of the embodiments herein. For example, the embodiments have been shown and described herein with relation to two exemplary embodiments, with the voice coil assemblies shown in a particular arrangement. However, the embodiments in their broader sense are not as limited, and may, in fact, be used with various other types of designs and implementations. Accordingly, it will be apparent, however, that other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. For instance, it is expressly contemplated that the components and/or elements described herein can be implemented.
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