Patent Description:
Other relevant prior art is illustrated in <CIT> and in <NPL>.

The scope of the present invention is defined in the appended claims.

A data processing system according to the disclosure includes a speaker, a processor, and a computer-readable medium. The computer-readable medium stores executable instructions for causing the processor to perform operations including obtaining a first input signal to be output by the speaker; determining a first volume level associated with the first input signal; selecting a first Linkwitz Transform and a first Multiband Compressor (MBDRC) from volume-dependent configuration data based on the first volume level; generating a first intermediate signal by applying the first Linkwitz Transform to the first input signal to increase a low-frequency response of the speaker; generating a first output signal by applying the first MBDRC to the first intermediate signal by compressing the at least a portion of the first intermediate signal; and driving the speaker to produce first audio output using the first output signal.

An example method for operating a speaker disposed within a sealed enclosure according to the disclosure includes obtaining a first input signal to be output by the speaker; determining a first volume level associated with the first input signal; selecting a first Linkwitz Transform and a first Multiband Compressor (MBDRC) from volume-dependent configuration data based on the first volume level; generating a first intermediate signal by applying the first Linkwitz Transform to the first input signal to increase a low-frequency response of the speaker; generating a first output signal by applying the first MBDRC to the first intermediate signal by compressing at least a portion of the first intermediate signal; and driving the speaker to produce first audio output using the first output signal.

In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. In some instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

Techniques for compensating for a reduction in low frequency output in speakers disposed in a sealed enclosure are provided. These techniques solve the technical problem in which speakers disposed within a sealed enclosure will experience a reduction in low frequency output caused by the resonance of the driver with the air within the enclosure. In a microspeaker, this resonance is typically much higher than a standard full range driver. The techniques disclosed herein provide a technical solution to this problem by compensating for this reduction in low frequency output to provide improved low frequency output for such speakers. These techniques use a set of volume-dependent Linkwitz transforms (LT) and a set of volume-dependent Multiband Compressors (MBDRC) to optimally process the audio for each of a set of different device volume levels.

A Linkwitz Transform is a method for cancelling out the driver-enclosure resonance in the audio signal and replacing it with a much lower frequency resonance, effectively emulating a larger speaker with better low frequency response. A dynamic range compressor is an algorithm that applies a different level of gain to a signal based on the level of that signal. A multiband compressor splits the audio stream through a filter bank, applies a compressor on each stream, then mixes the result back together. At a given volume level, the LT is configured to provide the lowest frequency extension using the available volume headroom, plus a configurable amount of overboost. The MBDRC for that volume level is configured to only apply compression to frequency bands that are being overboosted by the LT while leaving the other bands uncompressed. Furthermore, the amount of compression applied by the MBDRC is volume-dependent, and the MBDRC does not compress as aggressively at higher volume levels.

The techniques disclosed herein provide distinct advantages over conventional approaches to improving bass extension. One approach utilizes a low shelf filter. The low shelf filter is similar to an LT filter, but the low shelf filter is not exactly matched to cancel out the resonances of the speaker. The low shelf filter is instead an approximation. Accordingly, this approach alone cannot provide as much bass extension as the techniques disclosed herein, because the low shelf filter cannot use more headroom that is available. Most musical content is not a full scale most of time, and the use of the low shelf filter does not take advantage of this to improve bass extension. Another conventional approach is to use a single MBDRC that is configured to extend the low frequency response as low as possible based on a real content signal level. However, this approach is limited compared to the techniques disclosed herein, because the single MBDRC approach will noticeably compress audio content at higher volume levels. In contrast, the techniques disclosed herein use a volume dependent MBDRC which will not compress as aggressively at higher volume levels.

<FIG> is a block diagram showing a computing environment <NUM> in which the techniques disclosed herein may be implemented. The computing environment <NUM> is divided into a development environment <NUM> and a deployment environment <NUM>. In the development environment <NUM>, the speaker configuration information <NUM> is generated based on a speaker model <NUM> of a speaker <NUM>. In the deployment environment <NUM>, the speaker configuration information <NUM> is deployed to a computing device <NUM> to operate a speaker <NUM> of the computing device <NUM>. The speaker <NUM> of the of the computing device <NUM> is of the same type as the speaker <NUM>, and the speaker configuration information <NUM> may be used to operate the speaker <NUM> to cancel out the driver-enclosure resonance in the audio signal and provide a much lower frequency resonance. Using this approach, the speaker <NUM> of the computing device <NUM> may emulate a larger speaker with better low frequency response. The development environment <NUM> and the deployment environment <NUM> of the computing environment <NUM> may be implemented by the same or by separate entities. For example, a manufacturer of the computing device <NUM> may implement both the development environment <NUM> and the deployment environment <NUM>. Alternatively, a manufacturer of the speaker <NUM> may implement the development environment <NUM> in which the speaker configuration information <NUM> is generated, and a separate entity, such as a manufacturer of the computing device <NUM> may implement the deployment environment <NUM>.

The development environment <NUM> may include a speaker <NUM>, a speaker model <NUM>, a speaker configuration data module <NUM>, and a speaker configuration data store <NUM>. The development environment <NUM> may be implemented on one or more data processing systems. The data processing systems may be a local data processing system that is present in a location where the speaker <NUM> is being tested to produce the speaker model <NUM>. Alternatively, the development environment <NUM> may include one or more remote data processing systems, such as one or more server devices.

The speaker <NUM> is a microspeaker disposed within a sealed enclosure. The speaker <NUM> may experience a reduction in low frequency output caused by the resonance of the driver within the enclosure. The speaker model <NUM> may be determined based on design parameters determined during the speaker design process. Alternatively, the speaker performance may be tested for a predetermine range of frequencies to determine the speaker response. The speaker model <NUM> may be stored in a persistent data store, such as the speaker configuration data store <NUM>. The speaker configuration data store <NUM> may be a database or other persistent data store that is configured to store one or more speaker models, such as the speaker model <NUM>, and speaker configuration information, such as the speaker configuration information <NUM>. The speaker configuration information <NUM> may be derived from speaker model <NUM> by the speaker configuration data module <NUM>. The speaker model <NUM> may provide a model of the frequency response of the speaker for each of a plurality of volume levels. The speaker model <NUM> may be used to predict the frequency response of the speaker <NUM> over a predetermined frequency range in response to a test input signal. The frequency response of the of the speaker <NUM> may be predicted for multiple volume levels.

The speaker configuration data module <NUM> may be configured to analyze the speaker model <NUM> and to output speaker configuration information <NUM>, which may be stored in the speaker configuration data store <NUM>. The speaker configuration information <NUM> may include configuration information that may be used for driving the speaker at each of the multiple volume levels. The speaker configuration information <NUM> may include Linkwitz Transform (LT) information and Multiband Compressor (MBDRC) information for each of plurality of volume levels. The LT information and the MBDRC information can be used to compensate for the reduction in the low frequency output caused by the resonance of the driver within the enclosure for each volume level. LT information and MBDRC information are included for each of the volume levels because the reduction in low frequency output is impacted by the volume level of the output.

The LT information includes a Linkwitz Transform configured to receive a signal input at a respective volume level and to generate an intermediate signal input in which a low-frequency response of the speaker is increased. The speaker model <NUM> provides a mathematical description of the speaker <NUM> that defines the frequency response of the speaker <NUM> over a range of frequencies. As discussed above, the speaker <NUM> is an enclosed speaker that is subject to driver-enclosure resonance in the audio signal which causes low frequency rolling off of the frequency response. The term "roll off" or "rolling off" as used herein refers to a reduction in frequency response.

<FIG> illustrates and example of such a low frequency rolling off. The graph <NUM> shows a representation of the frequency response of an example speaker, such as the speaker <NUM>. The graph <NUM> plots the frequency along the X-axis (horizontal axis) and the speaker output in decibels (dB) along the Y-axis (vertical axis). The curve <NUM> represents the speaker response before applying the Linkwitz Transform. As can be seen from the curve <NUM>, the speaker output drops rapidly as the frequency decreases, while in an ideal situation, the frequency response should remain relatively flat across the frequency domain. The shape of the curve <NUM> is characterized by two parameters associated with the speaker model: the tuning frequency (F) and the quality factor (Q). The Linkwitz Transform is a mathematical operation that can be applied to the speaker model <NUM> to change the effective F and Q values of the speaker model <NUM> to different values that provide an improved low frequency response. For example, the F value may be decreased to provide greater bass output and/or the Q value may be decreased to cause the speaker model <NUM> to behave as if the speaker enclosure were larger. Decreasing the Q value effectively reduces the impact of resonance of the driver with air in the speaker enclosure. The graph <NUM> of <FIG> illustrates an example curve <NUM> of a Linkwitz Transform which can be used to boost low the low frequency response by applying more gain at lower frequencies. The graph <NUM> includes an example curve <NUM>, which shows the improved low frequency response after the Linkwitz Transform has been applied.

The MBDRC may apply a further boost to the intermediate signal output by the LT. The MBDRC may analyze the actual content of the audio signal in real time and can add an additional boost in gain (also referred to herein as a "overboost") to the audio signal that has already been boosted by the LT. The MBDRC may consider the amount of headroom within a particular frequency range, the MBDRC may boost the gain up to the amount of headroom. The MBDRC may boost the gain more where there is more headroom and boost the gain less where there is less available headroom. <FIG> illustrates an example of such an overboost. The graph <NUM> shows a plot <NUM> of an example Linkwitz Transform and a plot <NUM> of the Linkwitz Transform with the overboost applied. As can be seen from the examples illustrated in <FIG>, the overboost further boosts the lower frequencies to provide further improved low frequency response. The graph <NUM> shows a plot <NUM> of the frequency response curve of an example speaker <NUM> and a plot <NUM> of the frequency response curve of the example speaker <NUM> with the overboosted Linkwitz Transform <NUM> having been applied to improve the low frequency response of the speaker <NUM>.

The speaker configuration data module <NUM> may be configured to generate multiple LT transforms as illustrated in <FIG>. The graph <NUM> illustrates an example of volume specific Linkwitz Transforms that may be used boost the low frequency response of the speaker <NUM> at each volume level of a set of volume levels. As can be seen in the graph <NUM>, the curve associated with the Linkwitz Transforms boosts the low frequency response less for lower volume levels and more for higher volume levels. The graph <NUM> of <FIG> illustrates the resulting speaker response curves after the Linkwitz Transforms have been applied to at each volume level. The low frequency response has been improved for each of the volume levels. The number of volume levels for which the LT is calculated may vary from implementation to implementation. The number of levels may be determined based on a signal threshold of the speaker divided by a predetermined number of volume intervals. In other implementations, each interval may be a predetermined decibel increment. In other implementations, the number of intervals may be specified by a user. For example, the data processing system may provide a user interface that allows the user to configure one or more attributes of the speaker configuration information <NUM>, including but not limited to the number of volume levels for which the Linkwitz Transforms are to be determined.

At a given volume level, the LT is configured to provide the lowest frequency extension using the available volume headroom, plus a configurable amount of overboost. This overboost may result in the generation of an intermediate signal output that exceeds the signal threshold of the speaker. As a result, portions of an audio signal that exceed the signal threshold of the speaker may be clipped where portions of the audio signal that exceed the signal threshold are limited to the signal threshold of the speaker. Clipping may introduce significant amounts of distortion into the audio output of the speaker.

The speaker configuration data module <NUM> also addresses the overboosting problem by configuring a Multiband Compressor (MBDRC) for each volume level that processes the intermediate signal output by the LT. The MBDRC splits the frequency domain of the speaker <NUM> into multiple frequency bands. The number of frequency banks that the frequency domain may be divided into may be configurable. For example, the data processing system may provide a user interface in which the user may configure one or more attributes of the speaker configuration information <NUM>, including but not limited to the number of frequency bands into which the frequency domain of the speaker <NUM> may be subdivided. The MBDRC may alter the dynamic range of the signal in each frequency band by reducing the volume of louder parts of the signal and/or by amplifying the quieter parts of the signal. Thus, the MBDRC may identify frequency bands of the intermediate signal output by the LT that are overboosted and may compress those signals sufficiently so that they do not exceed the dynamic range of the speaker and end up being clipped. The MBDRC outputs a calibrated signal based on the intermediate signal in which the overboosted frequency bands have been compressed. The MBDRC is configured to only apply compression to frequency bands that are being overboosted for that volume level by the LT while leaving the other bands uncompressed for that volume level. The speaker configuration data module <NUM> is configured to add MBDRC configuration information for each volume level to the speaker configuration information <NUM>.

Referring to <FIG>, the deployment environment <NUM> may be implemented on one or more data processing systems. As discussed above, the deployment environment <NUM> may be implemented by the same entity as the development environment <NUM>, while in other implementations separate entities may implement the development environment <NUM> and the deployment environment <NUM>. The deployment environment <NUM> includes a device configuration module <NUM> that may be implemented as an application on a data processing system. The device configuration module <NUM> may be configured to configure a computing device <NUM> that includes a speaker <NUM>, which is the same type of speaker as speaker <NUM>. The device configuration module may obtain from the speaker configuration data store <NUM> a copy of the speaker configuration information <NUM> for the speaker <NUM>. In some implementations, the speaker configuration data store <NUM> may be located on a remote servers or servers from the device configuration module <NUM>. The device configuration module <NUM> may be configured to send a request to the speaker configuration data store <NUM> over one or more networks to obtain the speaker configuration information <NUM>. In some implementations, the speaker configuration data store <NUM> may be configured to store speaker configuration information <NUM> for multiple types of speakers, and the device configuration module <NUM> may be configured to send a request to the speaker configuration data store <NUM> to obtain the speaker configuration information <NUM> for a particular type of speaker.

The computing device <NUM> may be a mobile phone, a tablet computing device, a wearable computing device, a portable game console, a portable speaker device, or other electronic device, where the size and/or form factor of the device limits the size of the speakers that may be integrated into the device. The computing device <NUM> may include hardware and/or software elements for driving the speaker <NUM>. The device configuration module <NUM> may be configured to use the speaker configuration information <NUM> to configure hardware and/or software-based digital signal processing elements of the computing device <NUM> to use the volume specific LT and MBDRC to provide improved low frequency response for the speaker <NUM> of the computing device <NUM>.

<FIG> is a flow diagram of a process <NUM> that may be implemented by the data processing system for generating speaker configuration information, such as the speaker configuration information <NUM>. The process <NUM> may be implemented by the development environment <NUM> described above in <FIG>. The process <NUM> may be used to generate speaker configuration information <NUM> that may be used when operating the speaker <NUM> of the computing device <NUM> to provide for improve low frequency output by the speaker <NUM>.

The process <NUM> may include an operation <NUM> of obtaining a model of the frequency response of the speaker for each of a plurality of volume levels. The frequency response represents an output of the speaker over a frequency range in response to a test input signal at a respective one of the plurality of volume levels. <FIG> illustrates an example of such a frequency response in the graph <NUM>. The plot <NUM> shows an example of the reduction in low frequency output caused by the resonance of the driver with the air within the enclosure.

The process <NUM> may include an operation <NUM> of determining Linkwitz Transform information for the speaker including, for each respective volume level of the plurality of volume levels, a Linkwitz Transform for increasing a low-frequency response of the speaker at the respective volume level. The Linkwitz Transform receives a signal input and to generates an intermediate signal output. The LT is configured to use available volume headroom to boost the low frequency response of the speaker <NUM>. The LT may also add a configurable amount of overboost to further increase the low frequency response of the speaker <NUM>. The overboost amount may be defined in terms of decibels and may be added to the overall signal output of the LT to provide an additional boost to the low frequency performance. The overboost may be specified in the model information <NUM> in some implementations. In other implementations, the data processing system on which the process <NUM> is performed may provide a user interface that allows a user to input a value for the overboost parameter. As a result of the overboost, the intermediate signal may exceed a signal threshold capability of the speaker <NUM> for at least a portion of the frequency domain of the speaker <NUM>.

The process <NUM> may include an operation <NUM> of determining Multiband Compressor (MBDRC) information including, for each respective volume level of the plurality of volume levels, a MBDRC configuration configured to receive the intermediate signal output and to generate a calibrated signal output, the calibrated signal output compensating for the low frequency response of the speaker at the respective volume level. The MBDRC may subdivide the frequency domain of the speaker into a plurality of frequency bands. Each band may be compressed by the MBDRC, as necessary, to prevent the signal within that frequency band from exceeding the signal threshold of the speaker <NUM>. The signal threshold of the speaker <NUM> may be defined in the speaker model <NUM>.

The process <NUM> may include an operation <NUM> of generating speaker configuration information based on the Linkwitz Transform information and the MBDRC information for calibrating the speaker. The speaker configuration information <NUM> described above may be output and stored in the speaker configuration data store <NUM>. An entity configuring a computing device <NUM> that includes a speaker <NUM> that is of the same or similar type as the speaker <NUM> for which the LT and MBDRC configuration information was determine may obtain the speaker configuration information <NUM> and use that information to configure the computing device <NUM> to utilize the speaker configuration information <NUM> when operating the speaker <NUM>.

<FIG> is a flow diagram of a process <NUM> that may be implemented by the data processing system for operating a speaker of a computing device using speaker configuration information, such as the speaker configuration information <NUM>. The process <NUM> may be implemented by the computing device <NUM>. In the process <NUM>, the speaker configuration information <NUM> generated by the process <NUM> may be used to operate the speaker <NUM> of a computing device <NUM>. The speaker configuration information <NUM> may include volume-specific pairs of Linkwitz Transforms and MBDRCs that process an input signal to be output by the speaker <NUM> to provide improved low frequency output by the speaker <NUM>.

The process <NUM> may include an operation <NUM> of obtaining a first input signal to be output by a speaker <NUM> of a computing device <NUM>. The speaker <NUM> is disposed within a sealed enclosure and may experience a reduction in low frequency output caused by resonance of the speaker driver with air in the enclosure. The computing device <NUM> may be a portable computing device, such as but not limited to a mobile phone, a tablet computing device, a laptop computing device, a wearable computing device, or portable game consoles, where the size and/or form factor of the device limits the size of the speakers that may be integrated into the device. Thus, the speaker <NUM> may be a microspeaker to fit within the form factor of such a computing device. The small size of the sealed enclosures of such speakers may be impacted by resonance of the speaker driver with air within the enclosure more significantly than speakers having a larger enclosure.

The process <NUM> may include an operation <NUM> of determining a first volume level associated with the first input signal. The first volume level may a device volume level set by a user of the device and/or set automatically by a software or hardware component of the device. The device volume level may by selected by a user via a software user interface of the computing device <NUM>. For example, where the computing device <NUM> is a tablet computing device or a laptop computing device, the computing device <NUM> may provide a graphical user interface for controlling the volume of audio output by the computing device. The volume control user interface may be rendered on a touchscreen that permits the graphical user interface to be manipulated via tactile input. The volume control user interface may be rendered on a non-touch screen and the graphical user interface may be controlled via a mouse or other inputs means. In other implementations, the computing device <NUM> may include one or more physical control knobs, buttons, sliders, switches, or other physical control means that may be used to adjust the volume of audio output of the computing device <NUM>. The volume level information may be obtained from an operating system of the computing device <NUM> and/or determined by hardware and/or software based digital signal processing components that are configured to process digital audio content and output analog audio signal to the driver of the speaker <NUM>.

The process <NUM> may include an operation <NUM> of selecting a first Linkwitz Transform and a first MBDRC from volume-dependent configuration data <NUM> based on the first volume level. The computing device <NUM> may include the volume-dependent configuration data in speaker configuration information <NUM> that may have been generated using the various techniques disclosed in the preceding examples. The speaker configuration information <NUM> may include parameters that may be used to configured hardware and/or software-based digital signal processing components that can implement the Linkwitz Transform and the MBDRC. The speaker configuration information <NUM> may include parameters that may be used to configure the LT and MBDRC for execution by digital signal processing components of the computing device <NUM>. As discussed in the preceding examples, the speaker configuration information <NUM> may be implemented as a lookup table that is indexed by volume level. The computing device <NUM> may look up a volume specific entry associated with a volume level that is closest to the device volume level determined in the operation <NUM>. In some implementations, the computing device <NUM> may be configured to round up to the next nearest volume level or to round down to the next nearest volume level. Once an entry in the lookup table has been determined, the configuration parameters for the LT and MBDRC associated with that entry may be obtained.

The process <NUM> may include an operation <NUM> of generating a first intermediate signal by applying the first Linkwitz Transform to the first input signal to increase a low-frequency response of the speaker. The first input signal obtained in operation <NUM> may be processed using the Linkwitz Transform that was determined in operation <NUM>. The output from the first Linkwitz Transform boosts the low frequency response and may include an overboost component that may cause at least a portion of the first intermediate signal resulting from the first LT to exceed the signal threshold of the speaker <NUM>, which would result in those portions of the first intermediate signal being clipped. This would result in distortion in the signal that would degrade the quality of the audio output by the speaker <NUM>. However, the MBDRC may resolve this issue through selective compression those portions of the intermediate signal that exceed the signal threshold of the speaker <NUM>.

The process <NUM> may include an operation <NUM> of generating a first output signal by applying the first MBDRC to the first intermediate signal by compressing the at least a portion of the first intermediate signal. As described in the preceding examples, the MBDRC may divide the frequency domain of the speaker into a plurality of frequency bands. The configuration parameters for the volume level may define which frequency bands are to be used for that respective volume level. The MBDRC receives the first intermediate signal output by the LT, divides the first intermediate signal into the specified frequency bands, and applies compression to those frequency bands of the first intermediate signal that would otherwise exceed the signal threshold of the speaker <NUM>. The MBDRC mixes the frequency bands back to together and outputs a first output signal. As a result, the computing device <NUM> may utilize much smaller sized speakers that fit within the compact form factor of the computing device without having to sacrifice on audio quality.

The process <NUM> may include an operation <NUM> of driving the speaker to output audio content using the first output signal. The first output signal provides improved low frequency response resulting from the LT and MBDRC processing of the first input signal. The speaker <NUM> may then provide significantly improved frequency response that would otherwise not be realized without the processing by the LT and MBDRC.

The detailed examples of systems, devices, and techniques described in connection with <FIG> are presented herein for illustration of the disclosure and its benefits. Such examples of use should not be construed to be limitations on the logical process embodiments of the disclosure, nor should variations of user interface methods from those described herein be considered outside the scope of the present disclosure. It is understood that references to displaying or presenting an item (such as, but not limited to, presenting an image on a display device, presenting audio via one or more loudspeakers, and/or vibrating a device) include issuing instructions, commands, and/or signals causing, or reasonably expected to cause, a device or system to display or present the item. In some embodiments, various features described in <FIG> are implemented in respective modules, which may also be referred to as, and/or include, logic, components, units, and/or mechanisms. Modules may constitute either software modules (for example, code embodied on a machine-readable medium) or hardware modules.

In some examples, a hardware module may be implemented mechanically, electronically, or with any suitable combination thereof. For example, a hardware module may include dedicated circuitry or logic that is configured to perform certain operations. For example, a hardware module may include a special-purpose processor, such as a field-programmable gate array (FPGA) or an Application Specific Integrated Circuit (ASIC). A hardware module may also include programmable logic or circuitry that is temporarily configured by software to perform certain operations and may include a portion of machine-readable medium data and/or instructions for such configuration. For example, a hardware module may include software encompassed within a programmable processor configured to execute a set of software instructions. It will be appreciated that the decision to implement a hardware module mechanically, in dedicated and permanently configured circuitry, or in temporarily configured circuitry (for example, configured by software) may be driven by cost, time, support, and engineering considerations.

Accordingly, the phrase "hardware module" should be understood to encompass a tangible entity capable of performing certain operations and may be configured or arranged in a certain physical manner, be that an entity that is physically constructed, permanently configured (for example, hardwired), and/or temporarily configured (for example, programmed) to operate in a certain manner or to perform certain operations described herein. As used herein, "hardware-implemented module" refers to a hardware module. Considering examples in which hardware modules are temporarily configured (for example, programmed), each of the hardware modules need not be configured or instantiated at any one instance in time. For example, where a hardware module includes a programmable processor configured by software to become a special-purpose processor, the programmable processor may be configured as respectively different special-purpose processors (for example, including different hardware modules) at different times. Software may accordingly configure a processor or processors, for example, to constitute a particular hardware module at one instance of time and to constitute a different hardware module at a different instance of time. A hardware module implemented using one or more processors may be referred to as being "processor implemented" or "computer implemented.

Where multiple hardware modules exist contemporaneously, communications may be achieved through signal transmission (for example, over appropriate circuits and buses) between or among two or more of the hardware modules. In embodiments in which multiple hardware modules are configured or instantiated at different times, communications between such hardware modules may be achieved, for example, through the storage and retrieval of information in memory devices to which the multiple hardware modules have access. For example, one hardware module may perform an operation and store the output in a memory device, and another hardware module may then access the memory device to retrieve and process the stored output.

In some examples, at least some of the operations of a method may be performed by one or more processors or processor-implemented modules. For example, at least some of the operations may be performed by, and/or among, multiple computers (as examples of machines including processors), with these operations being accessible via a network (for example, the Internet) and/or via one or more software interfaces (for example, an application program interface (API)). The performance of certain of the operations may be distributed among the processors, not only residing within a single machine, but deployed across several machines. Processors or processor-implemented modules may be in a single geographic location (for example, within a home or office environment, or a server farm), or may be distributed across multiple geographic locations.

<FIG> is a block diagram <NUM> illustrating an example software architecture <NUM>, various portions of which may be used in conjunction with various hardware architectures herein described, which may implement any of the above-described features. <FIG> is a nonlimiting example of a software architecture and it will be appreciated that many other architectures may be implemented to facilitate the functionality described herein. The software architecture <NUM> may execute on hardware such as a machine <NUM> of <FIG> that includes, among other things, processors <NUM>, memory <NUM>, and input/output (I/O) components <NUM>. A representative hardware layer <NUM> is illustrated and can represent, for example, the machine <NUM> of <FIG>. The representative hardware layer <NUM> includes a processing unit <NUM> and associated executable instructions <NUM>. The executable instructions <NUM> represent executable instructions of the software architecture <NUM>, including implementation of the methods, modules and so forth described herein. The hardware layer <NUM> also includes a memory/storage <NUM>, which also includes the executable instructions <NUM> and accompanying data. The hardware layer <NUM> may also include other hardware modules <NUM>. Instructions <NUM> held by processing unit <NUM> may be portions of instructions <NUM> held by the memory/storage <NUM>.

The frameworks <NUM> (also sometimes referred to as middleware) provide a higher-level common infrastructure that may be used by the applications <NUM> and/or other software modules. For example, the frameworks <NUM> may provide various graphic user interface (GUI) functions, high-level resource management, or high-level location services. The frameworks <NUM> may provide a broad spectrum of other APIs for applications <NUM> and/or other software modules.

The applications <NUM> include built-in applications <NUM> and/or third-party applications <NUM>. Examples of built-in applications <NUM> may include, but are not limited to, a contacts application, a browser application, a location application, a media application, a messaging application, and/or a game application. Third-party applications <NUM> may include any applications developed by an entity other than the vendor of the particular platform. The applications <NUM> may use functions available via OS <NUM>, libraries <NUM>, frameworks <NUM>, and presentation layer <NUM> to create user interfaces to interact with users.

Some software architectures use virtual machines, as illustrated by a virtual machine <NUM>. The virtual machine <NUM> provides an execution environment where applications/modules can execute as if they were executing on a hardware machine (such as the machine <NUM> of <FIG>, for example). The virtual machine <NUM> may be hosted by a host OS (for example, OS <NUM>) or hypervisor, and may have a virtual machine monitor <NUM> which manages operation of the virtual machine <NUM> and interoperation with the host operating system. A software architecture, which may be different from software architecture <NUM> outside of the virtual machine, executes within the virtual machine <NUM> such as an OS <NUM>, libraries <NUM>, frameworks <NUM>, applications <NUM>, and/or a presentation layer <NUM>.

<FIG> is a block diagram illustrating components of an example machine <NUM> configured to read instructions from a machine-readable medium (for example, a machine-readable storage medium) and perform any of the features described herein. The example machine <NUM> is in a form of a computer system, within which instructions <NUM> (for example, in the form of software components) for causing the machine <NUM> to perform any of the features described herein may be executed. As such, the instructions <NUM> may be used to implement modules or components described herein. The instructions <NUM> cause unprogrammed and/or unconfigured machine <NUM> to operate as a particular machine configured to carry out the described features. The machine <NUM> may be configured to operate as a standalone device or may be coupled (for example, networked) to other machines. In a networked deployment, the machine <NUM> may operate in the capacity of a server machine or a client machine in a server-client network environment, or as a node in a peer-to-peer or distributed network environment. Machine <NUM> may be embodied as, for example, a server computer, a client computer, a personal computer (PC), a tablet computer, a laptop computer, a netbook, a set-top box (STB), a gaming and/or entertainment system, a smart phone, a mobile device, a wearable device (for example, a smart watch), and an Internet of Things (IoT) device. Further, although only a single machine <NUM> is illustrated, the term "machine" includes a collection of machines that individually or jointly execute the instructions <NUM>.

The machine <NUM> may include processors <NUM>, memory <NUM>, and I/O components <NUM>, which may be communicatively coupled via, for example, a bus <NUM>. The bus <NUM> may include multiple buses coupling various elements of machine <NUM> via various bus technologies and protocols. In an example, the processors <NUM> (including, for example, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), an ASIC, or a suitable combination thereof) may include one or more processors 812a to 812n that may execute the instructions <NUM> and process data. In some examples, one or more processors <NUM> may execute instructions provided or identified by one or more other processors <NUM>. The term "processor" includes a multi-core processor including cores that may execute instructions contemporaneously. Although <FIG> shows multiple processors, the machine <NUM> may include a single processor with a single core, a single processor with multiple cores (for example, a multi-core processor), multiple processors each with a single core, multiple processors each with multiple cores, or any combination thereof. In some examples, the machine <NUM> may include multiple processors distributed among multiple machines.

As used herein, "machine-readable medium" refers to a device able to temporarily or permanently store instructions and data that cause machine <NUM> to operate in a specific fashion, and may include, but is not limited to, random-access memory (RAM), read-only memory (ROM), buffer memory, flash memory, optical storage media, magnetic storage media and devices, cache memory, network-accessible or cloud storage, other types of storage and/or any suitable combination thereof. The term "machine-readable medium" applies to a single medium, or combination of multiple media, used to store instructions (for example, instructions <NUM>) for execution by a machine <NUM> such that the instructions, when executed by one or more processors <NUM> of the machine <NUM>, cause the machine <NUM> to perform and one or more of the features described herein. Accordingly, a "machine-readable medium" may refer to a single storage device, as well as "cloud-based" storage systems or storage networks that include multiple storage apparatus or devices. The term "machine-readable medium" excludes signals per se.

The I/O components <NUM> may include a wide variety of hardware components adapted to receive input, provide output, produce output, transmit information, exchange information, capture measurements, and so on. The specific I/O components <NUM> included in a particular machine will depend on the type and/or function of the machine. For example, mobile devices such as mobile phones may include a touch input device, whereas a headless server or IoT device may not include such a touch input device. The particular examples of I/O components illustrated in <FIG> are in no way limiting, and other types of components may be included in machine <NUM>. The grouping of I/O components <NUM> are merely for simplifying this discussion, and the grouping is in no way limiting. In various examples, the I/O components <NUM> may include user output components <NUM> and user input components <NUM>. User output components <NUM> may include, for example, display components for displaying information (for example, a liquid crystal display (LCD) or a projector), acoustic components (for example, speakers), haptic components (for example, a vibratory motor or force-feedback device), and/or other signal generators. User input components <NUM> may include, for example, alphanumeric input components (for example, a keyboard or a touch screen), pointing components (for example, a mouse device, a touchpad, or another pointing instrument), and/or tactile input components (for example, a physical button or a touch screen that provides location and/or force of touches or touch gestures) configured for receiving various user inputs, such as user commands and/or selections.

In some examples, the I/O components <NUM> may include biometric components <NUM>, motion components <NUM>, environmental components <NUM>, and/or position components <NUM>, among a wide array of other physical sensor components. The biometric components <NUM> may include, for example, components to detect body expressions (for example, facial expressions, vocal expressions, hand or body gestures, or eye tracking), measure biosignals (for example, heart rate or brain waves), and identify a person (for example, via voice-, retina-, fingerprint-, and/or facial-based identification). The motion components <NUM> may include, for example, acceleration sensors (for example, an accelerometer) and rotation sensors (for example, a gyroscope). The environmental components <NUM> may include, for example, illumination sensors, temperature sensors, humidity sensors, pressure sensors (for example, a barometer), acoustic sensors (for example, a microphone used to detect ambient noise), proximity sensors (for example, infrared sensing of nearby objects), and/or other components that may provide indications, measurements, or signals corresponding to a surrounding physical environment. The position components <NUM> may include, for example, location sensors (for example, a Global Position System (GPS) receiver), altitude sensors (for example, an air pressure sensor from which altitude may be derived), and/or orientation sensors (for example, magnetometers).

Claim 1:
A data processing system (<NUM>, <NUM>) comprising:
a speaker (<NUM>) disposed in a sealed enclosure;
a processor (<NUM>); and
a computer-readable medium (<NUM>) storing executable instructions (<NUM>) for causing the processor (<NUM>) to perform operations comprising:
obtaining a first input signal to be output by the speaker (<NUM>);
determining a first volume level associated with the first input signal;
selecting a first Linkwitz Transform and a first Multiband Compressor, MBDRC, from volume-dependent configuration data (<NUM>) based on the first volume level;
generating a first intermediate signal by applying the first Linkwitz Transform to the first input signal to increase a low-frequency response of the speaker (<NUM>);
generating a first output signal by applying the first MBDRC to the first intermediate signal by compressing at least a portion of the first intermediate signal that exceeds a signal threshold of the speaker (<NUM>); and
driving the speaker (<NUM>) to produce first audio output using the first output signal.