Extended duct with damping for improved speaker performance

An electronic audio device including an enclosure having an acoustic output opening and a speaker positioned within the enclosure. The speaker and the acoustic output opening are acoustically coupled by an acoustic output pathway. The acoustic output pathway includes a damping chamber to dampen a resonance frequency of the acoustic output pathway. The speaker is between the damping chamber and the acoustic output opening.

BACKGROUND

In modern consumer electronics, audio capability is playing an increasingly larger role as improvements in digital audio signal processing and audio content delivery continue to happen. There is a range of consumer electronics devices that are not dedicated or specialized audio playback devices, yet can benefit from improved audio performance. For instance, smart phones, portable personal computers such as laptop, notebook, and tablet computers, and desktop personal computers with built-in speakers. Integrating speakers into such devices in a manner that promotes optimal sound output is challenging. For example, in cases where the speakers are built into the device and hidden from view, sound waves output from the speaker must travel a distance within the enclosure before they exit the device. The pathway through which the sound waves travel may have resonances associated with it that cause the output from the device to vary with frequency. In particular, at some frequencies, the device may have a lot of output sound power for a given input power (resonance of the pathway) and at other frequencies the system has very little sound power output for a given input power (anti-resonances of the duct). These variations result in a reduction in audio quality.

SUMMARY

An embodiment of the invention is an electronic audio device including an enclosure having an acoustic output opening and a speaker positioned within the enclosure. The speaker may be acoustically coupled to the acoustic output opening by an acoustic output pathway. The acoustic output pathway may have any size or shape, and in some embodiments, may be a duct. One or more damping chambers may be connected to the acoustic output pathway or duct at a position upstream from the speaker. The one or more damping chambers may include an acoustic damping material that dampens a resonance frequency of the pathway and/or absorbs sound waves generated by the speaker. Since the damping chamber is positioned upstream from the speaker, it does not interfere with sound waves traveling downstream from the speaker, toward the acoustic output opening. Instead, the damping chamber absorbs sound waves reflected by the acoustic output opening in an upstream direction toward the speaker. In some embodiments, the damping chamber may have a neck portion that is dimensioned to dampen a specific resonance frequency of the acoustic output pathway. In embodiments where additional damping chambers are provided, each of the damping chambers may be tuned to dampen different resonance frequencies of the acoustic output pathway.

The above summary does not include an exhaustive list of all aspects of the embodiments disclosed herein. It is contemplated that the embodiments may include all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary.

DETAILED DESCRIPTION

In this section we shall explain several preferred embodiments with reference to the appended drawings. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not clearly defined, the scope of the embodiments is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments may be practiced without these details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this description.

FIG. 1is a side cross-sectional view of an embodiment of an electronic audio device having an acoustic output pathway and damping chamber. In some embodiments, electronic audio device100may be a desktop computer. In still further embodiments, electronic audio device100may be any type of electronic device having built-in speakers, for example, a smart phone, portable personal computer such as laptop, notebook, or tablet computer; a portable radio, cassette or compact disk (CD) player. Still further, electronic audio device100may be a telecommunications device such as a television or a DVD player or interactive video gaming machine. Electronic audio device100may include enclosure102which houses the various electronic device components, for example, a display128such as a flat panel liquid crystal display (LCD) viewed by user130and speaker104. Speaker104is built into frame106which may be of a typical material used for speaker enclosures, such as plastic. Frame106may be integrally formed as part of enclosure102or may be a separate component mounted within enclosure102. Enclosure102may include an acoustic output port108through which a sound emitted from a sound emitting surface or face110of speaker104may exit electronic audio device100to the environment outside of enclosure102.

An acoustic output pathway112may be formed between speaker104and acoustic output port108to direct sound waves114emitted from face110of speaker104toward acoustic output port108. In some embodiments, acoustic output pathway112is a duct that forms an acoustic channel between speaker104and acoustic output port108. In this aspect, acoustic output pathway112may be an elongated channel having a length greater than its width. For example, as illustrated inFIG. 2, acoustic output pathway112may have a width (w) that is substantially equivalent to a diameter of speaker104and a length (l) that is at least two times the diameter of speaker104, in other words the length is at least twice as long as the width. In other embodiments, acoustic output pathway112has any structure suitable for transmitting sound waves between speaker104and acoustic output port108, for example, a square, circular, elliptical or triangular shape.

An end of acoustic output pathway112may form exit port126, which is aligned with acoustic output opening108of enclosure102(when pathway112is formed by a structure separate from enclosure102, for example, a separate frame106), so that sound traveling through acoustic output pathway112exits enclosure102through acoustic output opening108. Alternatively, acoustic output pathway112may be formed by frame106integrally formed with enclosure102such that exit port126and acoustic output opening108are at the same location. Although in the illustrated embodiment, acoustic output port108is shown formed within a portion of the bottom wall of enclosure102aligned with the end of acoustic output pathway112, it is further contemplated that the acoustic output port may be formed through a front, back or side wall of enclosure102. For example, the acoustic output port may be formed through front wall122of enclosure102and instead of having exit port126at the end of pathway112, exit port126may be formed within a portion of front face120of pathway112aligned with the acoustic output opening so that sound from speaker104can exit device100through a front of device100. It is further contemplated that, although not illustrated, acoustic output pathway112may include a vent hole for tuning of pathway112.

Sound waves114emitted from face110of speaker104travel down acoustic output pathway112toward acoustic output port108. When sound waves114reach acoustic output port108, some of waves114exit enclosure102and some of waves114are reflected off of sound output port108and propagate back upstream, toward speaker114. Waves114traveling upstream are reflected off a portion of acoustic output pathway112upstream from speaker104and travel back downstream toward acoustic output port108. Waves114can continue to bounce between speaker104and acoustic output port108. This bouncing of waves114up and down acoustic output pathway112means that a single wave exiting speaker104actually exits acoustic output pathway112as a series of waves over a period of time. The bouncing of waves114back and forth, however, causes a reduction in audio quality of device100because they interfere with one another. In addition, resonances of acoustic output pathway112may cause sound output from device100to vary with frequency. Specifically, wave frequencies that match the resonances of acoustic output pathway112will cause sound waves output from device100to be more powerful at a given input power while at other frequencies that do not match the resonance of acoustic output pathway112, the waves may have very little sound power output for a given input power (i.e. anti-resonances of the duct).

Damping chamber118is therefore provided to minimize the effects the resonance frequency of acoustic output pathway112and the bouncing of waves114between speaker104and acoustic output port108have on the quality of sound emitted from device100. In other words, damping chamber118dampens an acoustic response of acoustic output pathway112. Damping chamber118may be a separate cavity connected to a portion of acoustic output pathway112or formed by an end of acoustic output pathway112. Damping chamber118may have a size and shape suitable to dampen a resonance frequency of acoustic output pathway and/or absorb one or more of sound waves114traveling within acoustic output pathway112upstream of speaker104.

In some embodiments, damping chamber118may include an acoustic damping material116that is placed within damping chamber118and secured with, for example, an adhesive, glue or the like. Acoustic damping material116may be any material capable of absorbing sound waves and/or dampening a resonance frequency of acoustic output pathway112. Suitable acoustic damping materials may include, but are not limited to, for example, sponge, fiberglass, foam or a perforated material. In other embodiments, one or more of the walls forming damping chamber118may be made of an acoustic damping material. Representatively, damping chamber118may include a wall, portion of a wall or other structure that is made of fiberglass or other suitable damping material.

Damping chamber118may be formed at a position along acoustic output pathway112upstream from speaker104, in other words speaker104is positioned between damping chamber118and acoustic output port108. In some embodiments, speaker104may be positioned at a point along acoustic output pathway112that is halfway between exit port126(or acoustic output port108) and the closed end of damping chamber118. In other embodiments, speaker104is positioned at any point between the halfway point and the closed end of damping chamber118such that speaker104is closer to the end of damping chamber118than exit port126.

Speaker104may be mounted within a face120of acoustic output pathway112connecting opposing ends of acoustic output pathway112and damping chamber118is formed at the end of acoustic output pathway112opposite to exit port126and acoustic output opening108. In some embodiments, face120may be formed by a side of frame106having speaker104mounted therein and the opposing face of acoustic output pathway112may be formed by enclosure102. In other embodiments, acoustic output pathway112and damping chamber118are integrally formed by enclosure102such that the entire pathway112, damping chamber118and frame106system is one integrally formed piece made of the same material (e.g. a molded piece). Since damping chamber118is upstream to speaker104, damping chamber118does not interfere with sound waves114traveling downstream from speaker104, toward acoustic output port108. Instead, damping chamber118absorbs sounds waves114that are deflected back upstream from acoustic output port108and prevents them from further interfering with sound waves114traveling within acoustic output pathway112. In addition, acoustic damping material116may dampen a resonance of acoustic output pathway112as previously discussed, which further improves sound output from device100.

FIG. 2is a back side view of the acoustic output pathway and damping chamber ofFIG. 1. From this view, it can be seen that speaker104is mounted within an opening formed along face120of acoustic output pathway112. In addition, side wall202extends perpendicular to face120to form an elongated channel having exit port126at the end of acoustic output pathway112. Alternatively, the exit port may be formed through face120of acoustic output pathway112as illustrated by phantom lines. Side wall202may be sealed to a portion of back wall124of enclosure102to form acoustic output pathway112and damping chamber118. In other embodiments, as previously discussed, acoustic output pathway112and damping chamber118are integrally formed by frame106, which is formed by enclosure102, such that side wall202and the back face sealing pathway112and damping chamber118are formed by frame106. In some embodiments, damping chamber118is formed off-axis to that of acoustic output pathway112. In other embodiments, damping chamber118may be on-axis or aligned with an axis of acoustic output pathway112.

FIG. 3is a side cross-sectional view of an embodiment of an acoustic output pathway and damping chamber. Electronic audio device300includes enclosure302having speaker304mounted to frame306positioned therein. Sound waves314emitted from face310of speaker304travel to acoustic output port308of enclosure302through exit port326of acoustic output pathway312. Damping chamber318is formed at an end of acoustic output pathway312upstream from speaker304. In some embodiments, acoustic output pathway312and damping chamber318are formed separately from frame306and mounted to frame306while in other embodiments, acoustic output pathway312, damping chamber318and frame306are integrally formed together as a single piece, such as by molding. In this embodiment, damping chamber318is configured to dampen a particular resonance frequency of acoustic output pathway312. In this aspect, damping chamber318includes chamber portion322connected to the end of acoustic output pathway312by neck portion324. Neck portion324may be configured to dampen a first resonance frequency of acoustic output pathway312. For example, neck portion324may have a narrow cross-sectional size relative to chamber portion322that is suitable for dampening the first resonance frequency. It is contemplated, however, that a size and shape of neck portion324may vary depending upon the resonance frequency neck portion324is designed to dampen. In some embodiments, acoustic damping material316may be positioned within neck portion324.

FIG. 4is a side cross-sectional view of an embodiment of an acoustic output pathway and damping chamber. Electronic audio device400is substantially similar to electronic audio device300described in reference toFIG. 3except that in this embodiment, acoustic output pathway412includes more than one damping chamber. In particular, electronic audio device400includes enclosure402having speaker404mounted to frame406. Sound waves414emitted from face410of speaker404travel to acoustic output port408of enclosure402through exit port426of acoustic output pathway412. Acoustic output pathway412may include damping chambers418aand418bformed along a portion of acoustic output pathway412upstream from speaker404. In some embodiments, acoustic output pathway412and damping chambers418a,418bare formed separately from frame406and mounted to frame406while in other embodiments, acoustic output pathway412, damping chambers418a,418band frame406are integrally formed together as a single piece, such as by molding. Although damping chambers418aand418bare shown formed along face420of acoustic output pathway412, which is opposite to face420, it is contemplated that damping chambers418a,418bmay be formed along any portion of acoustic output pathway that is upstream to speaker404. For example, damping chamber418amay be formed at an end of acoustic output pathway412and damping chamber418bmay be formed along face420of acoustic output pathway412. Damping chamber418amay include chamber portion422aconnected to acoustic output pathway412by neck portion424a. Similarly, damping chamber418bmay include chamber portion422bconnected to acoustic output pathway412by neck portion424b. In other embodiments, damping chambers418aand418bmay have different shapes. Still further, although two damping chambers418a,418bare illustrated, it is contemplated that more than two or less than two damping chambers may be used.

Neck portions424aand424bmay be configured to dampen particular resonance frequencies of acoustic output pathway412. For example, in one embodiment, neck portion424amay be configured to dampen a first resonance frequency of acoustic output pathway412and neck portion424bmay be configured to dampen a second resonance frequency of acoustic output pathway412. In this aspect, each of neck portions424aand424bmay have different cross-sectional sizes than each other and chamber portions422aand422b, respectively. For example, where the first resonance frequency is lower than the second resonance frequency, neck portion424amay be longer and narrower and chamber portion422amay have a larger cross-sectional size (i.e. larger volume) than neck portion424band chamber portion422b, respectively. It is contemplated, however, that a size and shape of neck portions424aand424bmay vary depending upon the resonance frequency neck portion424is designed to dampen. Acoustic damping material416aand416bmay be positioned within neck portions424aand424b, respectively.

FIG. 5is a block diagram of some of the constituent components of an embodiment of an electronic audio device within which the previously described speaker and acoustic pathway having a dampening chamber may be implemented. Electronic audio device500may be any one of several different types of desk top electronic devices having a built-in speaker system, for example a desk top computer or a television. In this aspect, electronic audio device500includes a main processor512that interacts with camera circuitry506, storage508, memory514, display522, and user input interface524. Main processor512may also interact with communications circuitry502, optical drive504, power supply510, speaker518, and microphone520. The various components of the electronic audio device500may be digitally interconnected and used or managed by a software stack being executed by the main processor512. Many of the components shown or described here may be implemented as one or more dedicated hardware units and/or a programmed processor (software being executed by a processor, e.g., the main processor512).

The main processor512controls the overall operation of the device500by performing some or all of the operations of one or more applications or operating system programs implemented on the device500, by executing instructions for it (software code and data) that may be found in the storage508. The processor may, for example, drive the display522and receive user inputs through the user input interface524. In addition, processor612may send an audio signal to speaker618to facilitate operation of speaker618.

Storage508provides a relatively large amount of “permanent” data storage, using nonvolatile solid state memory (e.g., flash storage) and a kinetic nonvolatile storage device (e.g., rotating magnetic disk drive). Storage508may include both local storage and storage space on a remote server. Storage508may store data as well as software components that control and manage, at a higher level, the different functions of the device500.

In addition to storage508, there may be memory514, also referred to as main memory or program memory, which provides relatively fast access to stored code and data that is being executed by the main processor512. Memory514may include solid state random access memory (RAM), e.g., static RAM or dynamic RAM. There may be one or more processors, e.g., main processor512, that run or execute various software programs, modules, or sets of instructions (e.g., applications) that, while stored permanently in the storage508, have been transferred to the memory514for execution, to perform the various functions described above. It should be noted that these modules or instructions need not be implemented as separate programs, but rather may be combined or otherwise rearranged in various combinations. In addition, the enablement of certain functions could be distributed amongst two or more modules, and perhaps in combination with certain hardware.

The device500may include communications circuitry502. Communications circuitry502may include components used for wired or wireless communications, such as data transfers. For example, communications circuitry502may include Wi-Fi communications circuitry so that the user of the device500may transfer data through a wireless local area network.

The device500also includes camera circuitry506that implements the digital camera functionality of the device500. One or more solid state image sensors are built into the device500, and each may be located at a focal plane of an optical system that includes a respective lens. An optical image of a scene within the camera's field of view is formed on the image sensor, and the sensor responds by capturing the scene in the form of a digital image or picture consisting of pixels that may then be stored in storage508. The camera circuitry500may be used to capture video images of a scene.

Device500also includes an optical drive504such as a CD or DVD optical disk drive that may be used to, for example, install software onto device500.

FIG. 6is a block diagram of some of the constituent components of another embodiment of an electronic device within which the previously described speaker driver and acoustic pathway having a dampening chamber may be implemented. Device600may be any one of several different types of consumer electronic devices that can be easily held in the user's hand during normal use. In particular, the device600may be any speaker-equipped mobile device, such as a cellular phone, a smart phone, a media player, or a tablet-like portable computer, all of which may have a built-in speaker system.

In this aspect, electronic audio device600includes a processor612that interacts with camera circuitry606, motion sensor604, storage608, memory614, display622, and user input interface624. Processor612may also interact with communications circuitry602, primary power source610, speaker618, and microphone620. The various components of the electronic audio device600may be digitally interconnected and used or managed by a software stack being executed by the processor612. Many of the components shown or described here may be implemented as one or more dedicated hardware units and/or a programmed processor (software being executed by a processor, e.g., the processor612).

The processor612controls the overall operation of the device600by performing some or all of the operations of one or more applications or operating system programs implemented on the device600, by executing instructions for it (software code and data) that may be found in the storage608. The processor may, for example, drive the display622and receive user inputs through the user input interface624. (which may be integrated with the display622as part of a single, touch sensitive display panel). In addition, processor612may send an audio signal to speaker618to facilitate operation of speaker618.

Storage608provides a relatively large amount of “permanent” data storage, using nonvolatile solid state memory (e.g., flash storage) and a kinetic nonvolatile storage device (e.g., rotating magnetic disk drive). Storage608may include both local storage and storage space on a remote server. Storage608may store data as well as software components that control and manage, at a higher level, the different functions of the device600.

In addition to storage608, there may be memory614, also referred to as main memory or program memory, which provides relatively fast access to stored code and data that is being executed by the processor612. Memory614may include solid state random access memory (RAM), e.g., static RAM or dynamic RAM. There may be one or more processors, e.g., processor612, that run or execute various software programs, modules, or sets of instructions (e.g., applications) that, while stored permanently in the storage608, have been transferred to the memory614for execution, to perform the various functions described above.

The device600may include communications circuitry602. Communications circuitry602may include components used for wired or wireless communications, such as two-way conversations and data transfers. For example, communications circuitry602may include RF communications circuitry that is coupled to an antenna, so that the user of the device600can place or receive a call through a wireless communications network. The RF communications circuitry may include a RF transceiver and a cellular baseband processor to enable the call through a cellular network. For example, communications circuitry602may include Wi-Fi communications circuitry so that the user of the device600may place or initiate a call using voice over Internet Protocol (VOIP) connection, transfer data through a wireless local area network.

The device600may include a motion sensor604, also referred to as an inertial sensor, that may be used to detect movement of the device600. The motion sensor604may include a position, orientation, or movement (POM) sensor, such as an accelerometer, a gyroscope, a light sensor, an infrared (IR) sensor, a proximity sensor, a capacitive proximity sensor, an acoustic sensor, a sonic or sonar sensor, a radar sensor, an image sensor, a video sensor, a global positioning (GPS) detector, an RP detector, an RF or acoustic doppler detector, a compass, a magnetometer, or other like sensor. For example, the motion sensor600may be a light sensor that detects movement or absence of movement of the device600, by detecting the intensity of ambient light or a sudden change in the intensity of ambient light. The motion sensor600generates a signal based on at least one of a position, orientation, and movement of the device600. The signal may include the character of the motion, such as acceleration, velocity, direction, directional change, duration, amplitude, frequency, or any other characterization of movement. The processor612receives the sensor signal and controls one or more operations of the device600based in part on the sensor signal.

The device600also includes camera circuitry606that implements the digital camera functionality of the device600. One or more solid state image sensors are built into the device600, and each may be located at a focal plane of an optical system that includes a respective lens. An optical image of a scene within the camera's field of view is formed on the image sensor, and the sensor responds by capturing the scene in the form of a digital image or picture consisting of pixels that may then be stored in storage608. The camera circuitry600may also be used to capture video images of a scene.

Device600also includes primary power source610, such as a built in battery, as a primary power supply.

While certain embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive, and that the embodiments disclosed herein are not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. For example, although the drawings show an acoustic output pathway in the shape of a duct, it is contemplated that the acoustic output pathway may have any shape such as a rectangular, square, circular or elliptical shape that could be implement within various components of an electronic device, for example, under a computer keyboard. The description is thus to be regarded as illustrative instead of limiting.