CN102893633B - Audio system equalization for portable media playback devices - Google Patents

Abstract

The present invention discloses methods, devices, systems, and logic encoded in a computer-readable storage medium to instruct a processing system to implement the method. The method includes applying correction filters directly in the portable media device to perform corrections, such as equalization, for the entire system including the portable media device and its attached playback system. Further disclosed is a method of determining a correction filter when recording the resulting sound field on a portable media device by playing back one or more calibration signals on a playback system.

Description

Audio System Equalization for Portable Media Playback Devices

Cross references to related patent applications

This application claims priority to US Provisional Patent Application No. 332,159, filed May 6, 2010, which is hereby incorporated by reference in its entirety.

technical field

The present disclosure relates generally to audio signal processing, and in particular to audio system equalization for portable media devices.

Background technique

Portable media devices have become a very common way to playback media. Devices for playing back digitally stored audio (such as and mobile phones) are used to playback both music and audiovisual content. A growing trend for such devices is that they attach to a wide variety of reproduction devices and systems for playback of audio. For example, a user might attach her iPod to a home theater system that includes speakers, a TV with speakers, or a stand-alone docking station with speakers. Each of these is an example of a different playback system to which the same portable device might be attached.

Even though portable playback devices for digitally stored audio have been available for more than a decade, and portable devices for playing back digitally stored audio on disc or tape have been around for decades, there is still a need for such devices to connect to a The need for equalization of audio from such devices when playing back one of the possible playback systems. As an example of how long such devices have been commercially available, Diamond Multimedia of California manufactures Portable playback devices were introduced in 1998 for MP3 playback. The PJB-100 Personal Jukebox manufactured by HanGo Electronics Co., Ltd of Korea is generally recognized as the first hard drive based device and was introduced commercially in 1999. The Apple IPOD was introduced in 2001. Each of these devices includes a digital processor to decompress and render the digitally stored compressed audio.

It would be advantageous to include an equalization filter in the portable media device that is to be applied to the audio signal directly in the portable media device in order to equalize for the entire system, including the portable media device and its attached A playback system for an improved listening experience. It would be further advantageous to include multiple sets of equalization filters in the portable media device, each set being applicable to a different one of the playback systems to which the portable device may be attached, in order to equalize for the overall system comprising A portable media device and its attached playback system. It would also be advantageous to have an end user operated method of using a portable media device to determine a set of equalization filters for use with a particular playback system in the portable media device to equalize for an overall system comprising A portable media device and its attached playback system.

Description of drawings

1A and 1B each show a simplified view of a user, a portable media device, and a playback system to which the portable media device can be coupled, wherein FIG. 1A shows the components in calibration mode, and FIG. components.

Figure 2 shows a simplified block diagram of an example embodiment of a portable media device that includes at least one feature of the present invention.

Figure 3 shows a simplified block diagram of one example embodiment of a playback system to which a portable media device may be connected, and when so connected, be used in implementing the features of the present invention.

Figure 4 shows a simplified flowchart of an embodiment of a calibration method.

Figure 5 shows a simplified flowchart of a method of operating a portable media device for or storing data for a set of correction filters on the portable media device.

Figure 6 shows a simplified block diagram of an arrangement according to some embodiments of the invention including remote storage of data for a set of one or more banks of correction filters.

Detailed ways

overview

Embodiments of the invention include methods, devices, systems, and logic encoded in a computer-readable storage medium to instruct a processing system to implement the method. The method includes applying corrective filtering (eg, equalization filtering) directly in the portable media device, at least for correcting, eg, equalizing, the overall system including the portable media device and its attached playback system.

Some embodiments include methods of operating portable media devices. The method includes applying at the portable media device one or more selected from a set of one or more sets of pre-stored correction filters, or data therefor, while the portable media device is coupled to a particular playback system. The audio signal is played back on a combination of a portable media device in a particular listening arrangement and a particular playback system when a particular set of multiple correction filters is selected. The set of one or more sets of correction filters, or data therefor, is pre-stored in or for the portable media device. Each of the one or more groups of sets is associated with a corresponding listening arrangement and a corresponding playback system. The particular set of one or more correction filters is determined by a calibration process comprising the steps of: recording on the portable media device the sound field resulting from one or more predefined calibration signals being played back on the particular playback system , utilizing a microphone built into or connected to the portable media device to make the recording while the microphone is at one or more listener positions of a particular listening arrangement, analyzing the recording of the sound field to determine at least A specific set of one or more corrective filters for equalization for a specific playback system, and storing in or for the portable media device the specific set for the one or more corrective filters for the specific playback system group of data.

Some embodiments include a method of operating a portable media device comprising: recording on the portable media device a sound field resulting from one or more predefined calibration signals being played back on a particular playback system, utilizing a built-in The recording is made at one or more listener positions of the microphone in a particular listening arrangement or with a microphone connected to the portable media device. The method includes analyzing a recording of the sound field to determine at least a particular set of one or more corrective filters for equalizing at least for a particular playback system, and storing in or for the portable media device the specific set of correction filters for the particular playback system. Data for a particular set of one or more corrective filters such that when the portable media device is coupled to a particular playback system, when the portable media device applies the determined particular set of one or more corrective filters , the audio signal can be played on a combination of a portable media device and a specific playback system in a specific listening arrangement.

In some aspects, data for a particular set of one or more corrective filters is stored to a pre-stored set of one or more sets of corrective filters stored in or for the portable media device Or in data therefor, each of the one or more groups of sets is associated with a corresponding listening arrangement and a corresponding playback system.

Some embodiments include a portable media device comprising: a playback subsystem configured to play back a selected audio signal; and a filtering subsystem coupled to the playback subsystem and configured to filter one or more audio signals during playback of the audio signal. A bank of multiple correction filters is applied to the audio signal. The portable media device also includes: a coupler configured to couple the portable media device with a mating coupler included in the playback system; a user interface configured to accept input from a user; and a microphone or a connection to the microphone coupler. The filtering subsystem is configured to, when the portable media device is coupled to the particular playback system in the particular listening arrangement, apply a filter associated with the particular playback system and the particular listening arrangement during playback of the audio signal via the particular playback system. A specific set of one or more correction filters. The particular set of one or more corrective filters is a set of one or more sets of corrective filters pre-stored in or for the portable media device or part of data therefor, and one of the set Each of the or more groups is associated with a corresponding listening arrangement and a corresponding playback system. In some aspects, the portable media device is configured to: record the sound field resulting from one or more predefined calibration signals being played back on a particular playback system, using a microphone in the portable media device or a The microphone makes this recording while the microphone is at one or more listener positions of a particular listening arrangement. In such aspects, the portable media device is further configured to: analyze a recording of the sound field to determine a particular set of one or more correction filters for at least equalizing for a particular playback system; and in the portable media device or Data for a particular set of one or more correction filters for a particular playback system is stored for the portable media device.

Some embodiments include a portable media device comprising: means for playing back an audio signal; means for filtering configured to apply the set of one or more corrective filters during playback of the audio signal by the means for playback for audio signals; for coupling the portable media device to a playback system; for accepting input from a user; and for recording a sound field. The means for filtering is configured to apply the specific playback during playback of an audio signal via the specific playback system when the portable media device is coupled by the means for coupling to the specific playback system in the specific listening arrangement. A specific set of one or more correction filters associated with a system and a specific listening arrangement. The particular set of one or more corrective filters is a set of one or more sets of corrective filters pre-stored in or for the portable media device or part of data therefor, and one of the set Each of the or more groups is associated with a corresponding listening arrangement and a corresponding playback system. Some aspects of the portable media device further include: means for analyzing a recording of the sound field obtained by the one or more predefined calibration signals in order to determine one or more banks of correction filters; or more components that correct the data for the set of filters. The means for recording is configured to record a sound field resulting from one or more predefined calibration signals being played back on a particular playback system at one or more listener positions of a particular listening arrangement, for The means for analyzing is configured to analyze the recording of the sound field to determine at least a particular set of one or more corrective filters for equalization for a particular playback system; and the means for storing is configured to be in the portable media device or Data for a particular set of one or more correction filters for a particular playback system is stored for the portable media device.

Particular embodiments may provide all, some, or none of these aspects, features, or advantages. Particular embodiments may provide one or more other aspects, features or advantages, one or more of which may be readily apparent to those skilled in the art from the drawings, description and claims in this application.

some examples

1A and 1B each show a simplified view of a user 141, a portable media device 121, and a playback system 103 to which the portable media device can be coupled. These are example elements of an example embodiment of the invention. FIG. 1A shows the elements in calibration mode, and FIG. 1B shows the elements in playback mode.

Portable media device 121 includes a coupler 127 configured to couple the portable media device to a mating coupler included within a playback system (in this case, playback system 103 ). Portable media device 121 also includes user interface 123 , which typically includes a display device and a user input mechanism configured to accept commands from user 141 . Portable media device 121 also includes a playback subsystem 128 configured to play back the selected audio signal and a filtering subsystem 129 coupled to the playback subsystem and configured to A bank of one or more correction filters is applied to the audio signal during playback. Other elements that are not shown in these figures but are shown in more detailed figures of the apparatus include processors and storage subsystems, elements of which are included in playback subsystem 128 and filtering subsystem 129 in some embodiments. Inside. The storage subsystem is configured to store one or more sets of data for calibrating the filter, and to apply a particular set of data to the filtering subsystem.

The playback system 103 includes at least one speaker 105 (two are shown in this example playback system), and a playback module 107 including one or more audio amplifiers.

FIG. 1B illustrates an aspect of the present invention that includes data from data stored in portable media device 121 when portable media device 121 is coupled to playback system 103 via couplers 127 and 113 on media device 127 and playback system 103, respectively. Normal playback of the audio signal of the media file. User 141 is at a particular listener location. The specific listening environment and the location of the listener and playback system define the listening arrangement. One or more corrective filters selected from a set of one or more sets of pre-stored corrective filters for that particular playback system 103 and listening arrangement are applied at the portable media device 121 by using the filtering subsystem 129. playback of audio signals on a combination of a portable media device and a specific playback system when a specific set of speakers is selected.

As described in more detail below, a set of one or more sets of correction filters are pre-stored in or for the portable media device 121 and listening arrangement (e.g., with form of data). Each set of one or more corrective filters of the set is associated with a corresponding playback system and a corresponding listening arrangement.

FIG. 1A illustrates another aspect of the invention: a specific set of one or more correction filters for determining at least one or more correction filters for equalization for a playback system and listening arrangement (in this example, a specific playback system 103 ). calibration process. The portable media device 121 includes at least one microphone 125 built in, or is connectable to at least one microphone 125 . The calibration process includes recording on the portable playback device 121 the at least one predefined calibration signal 111 being played back on the particular playback system 103 while the microphone 125 is at one or more desired listener positions of the listening arrangement. get the sound field. The calibration process includes analyzing recordings of the sound field to determine data for a specific set of one or more correction filters to be used at least for equalization for a specific playback system (and possibly also for a listening environment), and Data for a particular set of one or more correction filters for a particular playback system (and listening arrangement) is stored in the device 121 or for the portable media device 121 . Note that in some embodiments, the calibration process includes recording from several locations and averaging the results. There may thus be more than one desired listening position associated with the listening arrangement.

In this way, data for a set of sets of correction filters is pre-stored in or for the portable media device, each set of the set being associated with a corresponding playback system and listening arrangement.

device

The invention does not limit the type of portable media device. The minimum requirements are: be able to play digitally stored audio, have or be able to connect to one or more microphones, and be able to couple to any of a number of playback systems. Examples of portable media devices include, but are not limited to: audio playback devices, such as Apple Sandisk Creative ZEN Microsoft And other models from other manufacturers too many to list. Examples also include, but are not limited to, cellular phones with audio storage and playback capabilities made by virtually every manufacturer of cellular phones, and so-called "smart" cellular phones such as the Apple IPHONE, Google NEXUS ONE, and Many other "smart" cellular phones are too numerous to list. Many of these are capable of playback not only digitally stored audio data but also audiovisual content, such as digitally stored video files which may include digitally stored audio data.

The invention is also not limited to the type of playback system. The minimum requirement is to include one or more speakers and be capable of docking directly with the portable playback device, via a wired connection, via a wireless connection, and via a wired or wireless network connection. The minimum requirements also include the ability to receive at least one signal comprising at least audio content from the portable playback device when connected to the portable playback device, and to play back at least the audio of that signal. The minimum requirements also include the ability to play back one or more calibration files stored in the playback system, loaded into a storage subsystem in the playback system, or sent to the playback system from an external calibration signal source. Examples of playback systems include, but are not limited to, so-called docking speakers designed to include connectors for a particular model or models of portable media devices. For example, Amazon.com, a popular shopping website in the United States, listed 1953 items for the search "iPod speaker" and 1295 items for the search "docking speaker" in the category electronic devices on March 16, 2010. Examples of playback systems also include, but are not limited to: home theater systems that include home theater receivers, some of which also include connectors for a specific model or models of portable media devices, while others include common input connections connectors such as phonograph (RCA) connectors and for TRS (tip, ring, sleeve) or TRRS (tip, ring, ring, sleeve) connectors jack. Examples of playback systems also include, but are not limited to, televisions that include or are connected to speakers. Such televisions usually include connectors for external audio. Examples also include, but are not limited to: car audio systems, which in 2010 typically include connectors for a specific model or models of portable media devices and/or common input connectors, such as for TRS (tip, Ring, Sleeve) or TRRS (Tip, Ring, Ring, Sleeve) connector.

Embodiments of the present invention are particularly useful because a particular portable media device can be connected to more than one playback system.

Example Portable Media Device

Figure 2 shows a simplified block diagram of an example embodiment of a portable media device that includes at least one feature of the present invention. It will be clear to those skilled in the art that not all elements shown in FIG. 2 will be included in all portable media device embodiments, and further, some portable media devices may include additional components not shown in FIG. element.

The digital components of portable media device 121 include components coupled by bus subsystem 241 (only shown as a single bus for simplicity). These digital components include at least one processor 243, storage subsystem 245, user interface 123, at least one digital interface 231 coupled to the main connector 211, and for converting digital information, such as digitized audio signals, into One or more digital-to-analog converters (DACs) for playback of analog audio signals via one or more audio amplifiers in analog subsystem 225, and one or more digital-to-analog converters for converting the analog audio signals to digitized analog signals an analog-to-digital converter (ADC). The DAC and ADC are shown as module 233 along with their associated interfaces. DAC and ADC 233 are coupled to analog subsystem 225. The portable media device 121 also includes at least one wireless interface 249, such as, but not limited to, a wireless network interface, a Bluetooth interface, an infrared interface, and the like. One such wireless interface is the common Wi-fi IEEE 802.11 wireless network interface. Some embodiments of portable media device 121 also include a cellular phone wireless network interface, enabling the device to function as a cellular phone. Some embodiments also include other wireless network interfaces, such as a Bluetooth interface.

Portable media device 121 also includes a battery and associated electronics subsystem 215 , which is coupled to main connector 211 in one embodiment.

In some embodiments, the analog subsystem 225 is connected to the main connector 211 such that, for example, an analog audio signal is available at the main connector 211 . Main connector 211 is also coupled to bus subsystem 241 and at least one digital interface 231 such that signals are provided to and available from any device connected to main connector 211 .

Analog subsystem 225 is coupled to microphone 125, which in this embodiment is built-in. Other embodiments may be connected to the microphone 125 . This embodiment also includes at least one speaker 227 connected to the analog subsystem 225 . A set comprising at least one input/output connector 213 enables an external set of speakers (for example, speakers incorporated into a headset) to be connected and also enables different analog audio signals to be transmitted via an analog subsystem 225 enter.

In some embodiments, the user interface 123 includes a display screen 261 operable to display information to the user, one or more buttons 264 for accepting input from the user, and a keypad/keypad also for accepting input from the user. Keyboard 263. In some embodiments, display screen 261 includes a touch-sensitive surface for accepting input from a user, and in some such embodiments, at least some of buttons 264 are so-called soft A particular area of the screen 261 results from displaying a button (possibly with a message for the user), and having the user touch that particular area causes the same input as displaying a hardware button. Similarly, while separate modules are shown for keypad/keyboard 263 , some or all of these elements may include soft buttons on display screen 261 .

Storage subsystem 245 includes programs in the form of executable instructions that, when executed by at least one processor 243, cause the conventional functions of portable media device 121 to be implemented and for implementing aspects of the present invention. For example, some of programs 251 when executed provide such functionality as causing display and accepting input from buttons 264 (including soft buttons displayed in display screen 261), and in some embodiments, accepting gestures with multi-touch Form input, as is common in 2010. Storage subsystem 245 is also configured to store digital content, shown in FIG. 2 as stored audio-visual (AV) content 253 , but it may include only digitally stored audio. The content in stored content 253 is typically stored as a compressed data file, eg, in the case of audio, as an AAC or MP3 file, such as audio file 254 . Program 251 also includes instructions that, when executed, cause the digitally stored audio file to be played back to form a digital signal that is converted to analog form by the DAC in module 233 and amplified by at least one amplifier in analog subsystem 225 . Accordingly, portable media device 121 includes a playback subsystem configured to playback the selected audio signal. In the illustrated embodiment, the playback system consists of the elements of the analog subsystem 225, the DAC of the module 233, and the program 251 in the storage subsystem 245 which when executed cause the playback of the audio content forming the selected audio signal. command composition.

As will be described in more detail below, storage subsystem 245 is also configured to store a plurality of correction filter profiles (eg, equalization profiles) 257 including data required to implement the bank of correction filters. In one embodiment, each corrective filter profile 258 of corrective filter profile set 257 provides the data needed to implement a particular set of one or more corrective filters for a particular playback system. Since the corrective filter profile 258 provides the data needed to implement a particular set of one or more corrective filters for a particular playback system, the terms "corrective filter profile 258" and " Data for a set of one or more correction filters" will be used synonymously. However, having a profile is only one way of implementing a bank of one or more correction filters, so using the same language is not intended to limit the invention to using a profile.

Accordingly, portable media device 121 includes a filtering subsystem coupled to the playback subsystem and configured to apply a set of one or more corrective filters to the audio signal during playback of the selected audio signal.

Storage subsystem 245 is comprised of several types of storage devices, and includes solid-state memory and may include magnetic memory, such as hard disks. Many variations are possible, as will be apparent to those skilled in the art.

Some of the elements of portable media device 121 may be provided as part of a larger integrated circuit. Functions may be distributed among more than one device. Additionally, there may be one or more discrete components. The function of at least one element may be provided by executing one or more programs on one or more of at least one processor 243 . One or more processors 243 may include the functionality of a DSP device, eg, in the form of the DSP portion of an integrated circuit, or in some embodiments, in the form of a separate DSP device. Alternatively or additionally, a general purpose processor may be used. Many such variations are possible. In order not to obscure the inventive aspects, no further details regarding the possible architecture of the portable media device 121 are provided in this application.

Example playback system

FIG. 3 shows a simplified block diagram of an example embodiment of playback system 103 . A portable media device can be connected to more than one playback system. The playback system shown is one example. It will be apparent to those skilled in the art that not all elements shown in FIG. 3 will be included in all playback system embodiments, and further that some playback systems may include additional elements not shown in FIG. 3 . For example, the playback system of FIG. 3 includes a number of digital components, including storage for digital media files, and includes interfaces for connecting the playback system to a wireless network as well as for having a wired network connection. Many playback systems will not have this element.

The playback system includes a coupler (shown as coupler 113 in FIGS. 1A and 1B ) to a portable media device, such as media device 121 . In the embodiment of FIG. 3 , coupler 113 has the form of a main connector 311 configured to connect with a portable media device (eg, device 121 ). Main connector 311 includes a connection to accept analog audio signals from a connected portable media device. The main connector 311 is connected to an analog subsystem 325 comprising one or more audio amplifiers for playback of audio signals via a coupled set of one or more speakers 105 .

A set comprising at least one input/output connector 313 enables different analog audio signals to be input via an analog subsystem 325 . Thus, instead of or in addition to main connector 311, the analog input connector in 313 can also serve as a coupler to a portable media device (shown as coupler in FIGS. 1A and 1B ). 113). Of course, some embodiments do not include such additional inputs, while other embodiments do not include a main connector configured to accept analog input signals. In some embodiments, an output terminal is also included within element 313, enabling the connection of an external set of speakers, eg, headphones comprising a speaker arrangement.

In the embodiment shown, control of volume etc. is effected via a user interface 347 which in this case comprises digital elements. A user interface for a playback system may of course also include one or more analog elements, such as an analog fader.

The digital components of playback system embodiment 103 include components coupled by bus subsystem 341 (only shown as a single bus for simplicity). These digital components include at least one processor 343, a memory subsystem 345, a user interface 347, at least one digital interface 331 coupled to the main connector 311, and one or more digital-to-analog converters (DACs), the one or Further digital-to-analog converters (DACs) are used to convert digital information, such as digitized audio signals from AV content stored in storage subsystem 345, into The audio amplifier plays back the analog audio signal on at least one speaker 105 . The DACs are shown together with their associated interfaces as module 333 , and are coupled with analog subsystem 325 .

In some aspects, the playback system 103 also includes at least one wireless interface 349, such as, but not limited to, a wireless network interface, a Bluetooth interface, an infrared interface, and the like. One such wireless interface is the common Wi-fi IEEE 802.11 wireless network interface. The wireless network interface enables connection to a network, eg a home network, which in turn can be connected to an external network, eg the Internet. Some embodiments of the playback system 103 also include an infrared interface configured to accept commands from the remote control device 315 as well as a Bluetooth interface.

Some embodiments also include one or more other network interfaces 335 to enable playback system 103 to connect to a wired network, such as a wired home network, which in turn can connect to an external network, such as the Internet.

In some embodiments, the main connector is also coupled to a charging circuit 317 configured to supply power to charge a connected portable playback device and to accept control signals related to charging.

In some embodiments, the main connector 311 is also coupled to a bus subsystem 341 and at least one digital interface 331, so that signals are provided to and from any device connected to the main connector 311. The device is obtained.

In some embodiments that include one or more processors 343 and a storage subsystem 345, the storage subsystem 345 includes programs in the form of executable instructions that, when executed by at least one processor 343, cause the The normal function of the playback system 103 . In some such embodiments, storage subsystem 345 is also configured to store digital content, shown in FIG. 3 as stored audiovisual (AV) content 353 , but which may include only digitally stored audio. The content in stored content 353 is typically stored as a compressed data file, eg, in the case of audio, as an AAC or MP3 file, such as audio file 354 .

While the invention is not limited to such embodiments, in some embodiments, a digitally activated user interface 347 is included. In an example embodiment, the user interface 347 includes a display screen 361 operable to display information to the user, and one or more buttons and knobs 364 for accepting input from the user. In some embodiments, display screen 361 includes a touch-sensitive surface for accepting input from a user, and in some such embodiments, at least some of buttons or knobs 364 are so-called soft buttons because they are Having a particular area of the display screen 361 display a button (possibly with a message for the user) results, and causing the user to touch that particular area causes the same input as displaying a hardware button. Thus, some of the programs 351 when executed, for example, provide such functionality as causing display and accepting input from buttons 364 (including soft buttons displayed in display screen 361 ).

Storage subsystem 345 is comprised of several types of storage devices, and includes solid-state memory and may include magnetic memory, such as hard disks. Many variations are possible, as will be apparent to those skilled in the art.

An aspect of an embodiment of the invention is playback of one or more calibration signals by a playback system. In some aspects, the calibration signal may be input, for example, via an external connector or via a wireless or wired connection. In other arrangements, the calibration signal may be pre-stored in digital form in the memory subsystem. In an alternative arrangement, the calibration signal may be obtained through the connection and then stored in digital form in the storage subsystem 355 for playback. The digitally stored calibration signal is shown as calibration signal 355 in the example embodiment of FIG. 3 .

Some of the elements of playback system 103 may be provided as part of a larger integrated circuit. Functions may be distributed among more than one device. Additionally, there may be one or more discrete components. The function of at least one element may be provided by executing one or more programs on one or more of at least one processor 343 . Many such variations are possible. In order not to obscure the inventive aspects, no further details regarding the possible architecture of the playback system 103 are provided in this application.

An inventive aspect of embodiments of the present invention is that a single portable media device can be connected to several different playback devices, or even one device that can be listened to in different locations. Thus, while only one playback system example has been shown here, those skilled in the art will appreciate that there are many possible playback devices to which a portable media device may be connected. Some such playback devices are relatively simple, while others are more complex.

The disclosed invention provides mechanisms and methods for applying corrective filtering (eg, equalization) to each of the various playback systems to which a portable media device may be attached by applying the corrective filtering directly in the portable media device. The invention is not limited to any particular type of corrective filtering, and equalization is an example of corrective filtering that can be applied as described in this application.

example method

Some embodiments include methods of operating portable media device 121 . The method includes, while the portable media device 121 is coupled to a particular playback system 103 and in a particular listening arrangement, playing back an audio signal on the portable media device 121/playback system combination. During playback, the portable media device applies a particular set of one or more corrective filters selected from a pre-stored set of data for at least one set of one or more corrective filters.

Data for the set of one or more sets of correction filters is pre-stored in or for portable media device 121 . Data for each group of sets is associated with a corresponding playback system (and listening arrangement). In the example of FIG. 2 , a particular set of one or more correction filters is shown as a profile 258 that includes a or more programs to implement the data required for the bank of filters.

Note that the term "listening arrangement" may cover a specific position, or may cover a range of listening positions or any listening position for a particular playback system. For example, a correction filter may be designed to equalize the listening of a playback system with a particular loudspeaker 105, and may be available for a range of listening positions as may be determined for a specific listener position. Furthermore, measurements (records) can be made from multiple locations in order to determine a single averaged correction filter for a range of locations. Accordingly, the term "listening arrangement" should not be considered to imply only a single listening position using a particular playback system, ie not applicable to other positions using a particular playback system. Firstly, a correction filter determined from one or more records from a single location can be used for a range of locations, and secondly, in some calibration method embodiments, measurements can be taken from several locations in order to determine the appropriate range for a location A single group of "average" correction filters.

Example Calibration Method

A particular set of one or more correction filters is determined through a calibration process. FIG. 4 shows a simplified flowchart of an embodiment of a calibration method 400 . Method 400 includes: at 403, playing back one or more predefined calibration signals 111 on a particular playback system 103, and, at 405, during playback, recording on a portable playback device 121 The sound field resulting from one or more predefined calibration signals 111 played back on the system 103 . The recording is made using the microphone 125 built into or connected to the portable media device 121 while the microphone 125 is at one or more desired listener positions as part of the listening arrangement. As previously noted, there may be more than one location associated with the listening arrangement, and the recording may include recordings made at more than one location. The method comprises analyzing a recording of the sound field in 407 to determine a specific set of one or more correction filters for equalizing at least for a specific playback system (and possibly also for a listening environment), and in 409, A specific set of one or more correction filters for a specific playback system (and listening environment) is stored in or for the portable media device.

In one set of embodiments, stored on portable media device 121 . In another set of embodiments, it is stored (though possibly temporarily) on portable media device 121, and then or later stored remotely for portable media device 121, eg, on a remote storage system on a remote server. Thus, storage is made "in or for" the portable media device 121 for a particular playback system 103 (and listening environment).

In one embodiment, portable media device 121 includes a user interface that presents a 'Calibrate' button among buttons 264 or presents a recording, analysis, or other function for enabling the user to instruct a particular set of one or more correction filters to be implemented. And some other functions of storage. The calibration method includes receiving an indication from a user on a user interface to enable recording, analysis and storage of a particular set of one or more correction filters, and performing these steps in response to such receiving.

Furthermore, in some embodiments where portable media device 121 includes its own microphone, embodiments of the method provide a very easy-to-use, self-contained form factor for calibration. The user can simply tap the 'Calibrate' button in the buttons 264 and hold the portable media device 121 in a listening position, for example, in front of the playback system speakers 105.

The calibration signal in one embodiment is pre-stored in portable media device 121 (e.g., in storage subsystem 245 of portable media device 121 as calibration signal 255) and loaded into playback system 103 for storage. in the playback system. In other embodiments, the portable media device 121 is connected to the playback system from the listening position by wire or wirelessly, and the calibration signal is sent to the playback system 103 and played back, while the resulting sound field is recorded for analysis in order to determine the A particular set of one or more correction filters for the combination of the portable media device 121 and the playback system. In yet another embodiment, the one or more calibration signals are provided by some other mechanism for playback on the playback system, eg, pre-loaded in the playback system, or provided in real-time by another source. The invention is not limited to any particular manner of providing one or more calibration signals to a playback system. Nor is the invention limited to any manner in which the calibration signal is provided to the playback system, eg in digital form or as an analog signal.

An example method of operating a portable media device,

5 shows a simplified flowchart of a method 500 of operating a portable media device (eg, device 121) for or on which data for a set of correction filters (eg, In the form of data for implementing correction filters), each group is associated with a corresponding playback system (and listening arrangement).

The method includes connecting the portable media device 121 to a specific playback system 103 in a specific listening environment in 503 . The method also includes selecting in 505 (manually or automatically) specific values of at least one or more correction filters pre-stored for equalization for a specific playback system 103 (and possibly also for a listening environment). Group. In the absence of locally stored data for the set of sets of correction filters, 505 includes loading at least the selected particular set of one or more correction filters. This may occur separately and at a different time than this selection. 507 includes playing back the audio signal on the portable media device 121 when the portable media device 121 is connected to the particular playback system 103 . The playback includes applying a particular set of one or more correction filters.

Select a bank of one or more correction filters

In the case of a manual selection in 505, in some embodiments the portable media device includes a user interface 123 that includes, for example, as button 264, a set of one or more pre-stored correction filters to the user instructions. The method includes the media portable device 121 receiving an indication from a user, eg, via the user interface 123, to use a particular set of one or more correction filters for playback.

Some embodiments provide for automatic selection of banks of one or more correction filters. In some embodiments, for example, with some so-called "docking speaker" playback systems, the playback system may be configured to provide an indication to the attached portable media device, for example, via the main connector to indicate the type of playback device and/or or model signal. In some embodiments, method 500 includes the portable media device receiving an indication from the particular playback system that the particular portable media device is coupled with the particular playback system. Some embodiments of the portable media device are configured such that, in response to the indication, the method includes automatically selecting for playback a particular set of one or more correction filters associated with the particular portable media device.

Additionally, some embodiments of the portable media device have a predefined set of correction filters predefined for a particular class of playback system. For example, simple "docking speaker" playback systems could form a category, television receivers could form a category, home stereo receivers with connected speakers could form a category, and home stereo receivers with connected subwoofers could form a category. Receivers could form a category, car playback systems in cars could form a category, and so on. In some embodiments, at least one of the sets of correction filters is a predefined default set for a type of playback system.

Types of Correction Filters

The invention is not limited to any particular type of correction filter or how such a correction filter is implemented or specified. In the near future, portable media devices may have sufficient processing power to implement more complex correction filters than a set of multi-band equalization filters. Some possible types of correction filters are described below. These are provided as examples only and do not limit the invention to any particular type of correction filter.

multi-band equalization filter

Some embodiments of the bank of one or more correction filters include a bank of multi-band equalization filters. The frequency range of listening is divided into a set of frequency bands, and each filter of the set of multi-band equalization filters sets a relative gain for one of the frequency bands. Such multi-band equalization filters are well known in the art. The number of frequency bands for any particular portable media device can be fixed, or settable, and is typically a relatively small number, eg, 6, 9, or 12. There are many ways of implementing such a filter, and one embodiment uses a digital signal processing method implemented by a program in program 251 executing on processor 243 (eg, on a DSP element). That is, applying the particular set of one or more corrective filters when the portable media device is coupled to a particular playback system includes processing the digital signal on at least one of the one or more processors of the portable media device. digital processing. In some embodiments, the multi-band equalization filter is implanted as a set of digital parametric filters at each frequency band. Such parametric filters are defined by a set of parameters. In one embodiment, each set of parameters is stored as a corrective filter profile 258 of a corrective filter profile set 257 and can be used to implement a particular set of one or more corrective filters for a particular playback system. .

In an alternative embodiment, playback circuitry in portable media device 121 implements a variable set of gain controls based on respective gain parameters for a predefined number of frequency bands. A set of gain settings is stored as corrective filter profile 258 of corrective filter profile set 257 and can be used to implement a particular set of one or more corrective filters for a particular playback system.

multi-channel audio

More complex correction filters are suitable for playback via playback systems comprising more than two speakers, eg, playback systems providing surround sound, as is common in home theater receivers today. A correction filter for such a playback system can include more complex settings that provide relative gains for signals produced by the portable media device 121 for the different speakers 105 in the playback system.

Perceptual domain processing

Recently, perceptual domain processing has been invented, which takes into account changes in the perception of audio depending on the reproduction level of the audio signal. The represented time-sampled audio signal is preprocessed to produce a time-varying spectrum indicative of signal levels within a number of frequency bands (critical bands), for example, 40 bands, each band represented by a band number, and varying over time blocks. The time-varying spectrum of an audio signal can be generated in many ways, but advantageously the bands are separated so as to simulate the frequency resolution of human hearing. A quantity called the excitation signal is calculated, which approximates the distribution of energy along the basilar membrane of the human inner ear at critical frequency bands during time blocks. While other transforms, such as the Modified Discrete Cosine Transform (MDCT), can also be used, by using the frequency responses of filters that simulate audio transmission through the human outer and inner ears and a selected set of bandpass filters (e.g., chosen as A bandpass filter that mimics the critical band filtering observed along the basilar membrane in the human ear at each critical frequency band of interest) to compute a running short-time discrete Fourier transform (STDFT) of the audio signal, allowing efficient Realize perceptual field stimulation. The example embodiment uses a set of filters with a spacing of 1 ERB, resulting in a total of 40 bands.

Distortion-reducing multi-band compressor with timbre preservation

In a playback device, audio playback can be perceptibly distorted, and often dramatically distorted as the playback level increases during playback. This distortion is often frequency dependent for the playback device. One form of corrective filtering is to apply multiband compression to the audio signal prior to playback in order to reduce distortion and try to maximize playback levels. A simple method consists of specifying distortion thresholds, which are specified for each frequency band of the compressor. The compressor applies different gain values to each frequency band independently in order to ensure that the output signal does not exceed any of the corresponding distortion thresholds.

An improved set of correction filters includes timbre preservation in the multiband compressor. Timbre preservation is determined by depending on (i) the respective fixed thresholds for the frequency band and at least in part on (ii) the audio signal level in the second frequency band (digital or analog audio signal) and (iii) the fixed threshold in the second frequency band implemented with time-varying thresholds in each of the multiple frequency bands. Therefore, each time-varying threshold is input signal adaptive. If a particular frequency band receives a significant gain reduction due to being above (or, approaching) its fixed threshold, the time-varying threshold of one or more other frequency bands is also reduced in order to receive some gain reduction.

An example embodiment of applying such timbre-preserving multi-band compressor corrective filtering includes providing or determining a fixed threshold for a first frequency band and determining a first level of an audio signal within the first frequency band. The first level can be less than a fixed threshold. The method further includes determining a second level of the audio signal also for the second frequency band, and calculating a time-varying threshold for the first frequency band by using the second level. The time-varying threshold is smaller than the fixed threshold. The method includes attenuating the audio signal in the first frequency band to be equal to or less than the time-varying threshold, or alternatively attenuating the audio signal in the first frequency band more and more as the time-varying threshold is approached. A time-varying threshold can be calculated from the average difference of the audio input signal in each frequency band and its corresponding fixed threshold. Optionally, a second fixed threshold for the second frequency band can be further determined. The second level of the audio signal can exceed the second fixed threshold, resulting in an attenuation of the audio signal in the second frequency band to the second fixed threshold. A set of correction filters for implementing this method includes a multi-band filter bank, a compression function element and at least one timbre preserving element. Each compression function element can be dedicated to a frequency band. The tone preserving element is coupled to the multi-band filter bank and the compression function element. The timbre hold element receives a fixed threshold for each frequency band and provides a time-varying threshold for each frequency band. The time-varying threshold for a frequency band is determined in part by the level of the out-of-band audio signal.

For more details on this corrective filtering, see U.S. Provisional Patent Application 61/315,172, entitled "TECHNIQUES FOR DISTORTION REDUCING MULTI-BANDCOMPRESSOR WITH TIMBRE PRESERVATION," filed March 18, 2010, the contents of which are incorporated by reference at hereby, and a copy of which is attached hereto as Appendix A.

Inverse filtering for matching target responses

Another form of corrective filtering applies an inverse filter in order to alter the frequency response of the speakers of the playback system in an effort to match the inverse filtered speaker output to a target frequency response. As in the perceptual-based processing described above, the method is applied to a "critical frequency band" - a frequency band of the full frequency range determined from consideration of perceptual actuation. Typically, critical frequency bands dividing the audible frequency range have widths that increase with frequency across the audible frequency range. The method uses "critically banded" data, implying that the full frequency range includes the critical bands, and that the data includes subsets, each subset consisting of data representing the audio content in a different one of the critical bands.

The target frequency response may be flat or may have some other predetermined shape.

In some embodiments, the calibration method includes determining inverse filters for speakers of the playback system. Calibration involves measuring the impulse response of the loudspeaker at each of many different spatial locations in the listening arrangement, time aligning and averaging the measured impulse responses to determine the average impulse response, and using Critical band smoothing to determine the inverse filter from the averaged impulse response and the target frequency response. For example, critical band smoothing may be applied to the averaged impulse response and optionally also to the target frequency response during determination of the inverse filter, or may be applied to the determination of the target frequency response. Measurement of the impulse response at multiple spatial locations enables determination of the frequency response of the loudspeaker for various listening positions. In some embodiments, time alignment of the measured impulse responses is performed using real cepstrum and minimum phase reconstruction techniques.

In some embodiments, the averaged impulse response is converted to the frequency domain via a discrete Fourier transform (DFT) or other time domain to frequency domain transformation. The resulting frequency components represent the measured average impulse response. These frequency components in each transform bin (bin) are combined into frequency domain data in a smaller number of critical frequency bands (eg 20 bins or 40 bands), as for other perceptual domain processing. The banding of the averaged impulse response data into critically banded data is designed to mimic the frequency resolution of the human auditory system. Band-splitting is typically performed by weighting the frequency components in the transformed frequency bank by applying thereto an appropriate critical band-splitting filter and by summing the band-weighted data to produce frequency components for each critical band. Typically, these filters exhibit an approximately rounded exponential shape and are evenly spaced at the scale of the Equivalent Rectangular Bandwidth (ERB). The spacing and overlap in frequency of the critical bands provides a degree of regularization of the measured impulse response comparable to the capabilities of the human auditory system. The application of a critical-band filter is an example of critical-band smoothing (a critical-band filter typically smooths out perceptually irrelevant irregularities in the impulse response such that the determined inverse filter does not need to spend resources correcting these detail).

The value used to determine the inverse filter is determined from the target response in a frequency bin (eg, critical band) and the averaged impulse response (eg, from a smoothed version thereof). The critically banded impulse response data are used to find an inverse filter that achieves the desired target response. In some embodiments, in order to maintain equal loudness when using an inverse filter, the inverse filter preferably normalizes to a reference signal (eg pink noise) whose spectrum is representative of a common sound.

In some embodiments, the inverse filter coefficients are calculated directly in the time domain.

The resulting inverse filters form a bank of correction filters applied to the signal in the playback system as described in this application.

For more details on this corrective filtering, see International Patent Application No. PCT/US2010/020846, entitled "METHOD FOR DETERMINING INVERSE FILTER FROMCRITICALLY BANDED IMPULSE RESPONSE DATA," filed January 13, 2010, the contents of which are incorporated by reference incorporated herein, and a copy of which is attached hereto as Appendix B.

store data for banks of correction filters

In some embodiments, a set of parameters for implementing a set of one or more corrective filters is stored on or for portable media device 121 as part of a set of sets. In some embodiments, the collection is stored in the form of a database. Each entry is a set of parameters for implementing a set of one or more corrective filters for a particular playback system, and includes an indicator that the particular set of one or more corrective filters is associated with a particular playback system . Thus, step 409 of FIG. 4 for such an embodiment includes storing an indicator that a particular set of one or more correction filters is associated with a particular playback system.

In some embodiments, data (eg, a database) for the set of one or more sets of correction filters is stored in a storage subsystem included within the portable media device. Thus, as shown in FIG. 2, in some embodiments, storage subsystem 245 includes correction filter profiles 257, and one such profile 258 is shown.

In other embodiments, the data for the set of one or more sets of correction filters is stored remotely from the portable media device. Figure 6 shows a simplified block diagram of an arrangement according to some embodiments of the invention including remote storage of data for a set of one or more banks of correction filters. During step 409, it may initially be temporarily stored in a storage device in the portable media device 121, and then stored remotely, for example, when the portable media device is connected to the network 625 (which can be any private or public network, Even Internet) coupled personal computer 623 when stored remotely. Server system 627 is also connected to network 625 . Server system 627 includes one or more processors and storage subsystem 645 . Storage subsystem 645 is configured to store data for one or more sets of banks of correction filters, each such set associated with a particular portable media device 121 or a particular user or both a particular user and a portable media device. are associated. In the example shown, data for a set 657 of one or more banks of correction filters is shown. Data for one group 658 is shown. In some embodiments, the data of the collection is in the form of a database. The data for each set of one or more corrective filters is stored in a database as an entry which we call a corrective filter profile comprising the parameters needed to implement the corrective filter. When portable media device 121 is connected to personal computer 623 connected to server 627 via a network, the particular set of correction filters in temporary memory in portable media device 121 is sent for storage in storage subsystem 645 of server 627 . Similarly, when portable media device 121 is connected to personal computer 623 connected via a network to server 627, one or more sets of correction filters stored in storage subsystem 645, e.g., as correction filter profiles, can be loaded. to the portable media device 121 for playback. Thus, for example, a particular set of correction filters for a particular playback system can be loaded from remote memory to the portable media device 121 for playback when the portable media device is coupled to the particular playback system.

analyze

Processing action 405 includes recording on portable media device 121 the sound field resulting from playback of the calibration signal on playback system 103 . Processing action 407 includes analyzing the recording to determine a particular set of one or more correction filters for equalizing at least for a particular playback system (and possibly also for a listening environment).

The present invention is not limited to any particular type of calibration signal(s) or to any particular method of analysis. In one embodiment, the calibration signal consists of the sum of different frequency tones of known amplitude at a predefined number of different frequencies. In one embodiment, the center frequency is the center frequency of the correction filter used in the portable media device 121 . The center frequencies of graphic equalizers are usually distributed logarithmically, eg in octaves. In some embodiments, the center frequencies of the components of the test signal are thus also expanded logarithmically. In some embodiments, the amplitudes of the different frequency components of the test signal are equal, while in other embodiments the amplitudes vary according to the inverse of the frequency.

The analysis process 407 includes determining the amplitudes at different frequencies of the recorded recording in order to determine gains at frequencies that would equalize the responses. The gain at the center frequency forms data for a particular set of one or more correction filters, for example, a correction filter profile stored for or in portable media device 121 for a particular playback system and listening environment. files.

An alternative embodiment uses a noise signal for the calibration signal. In one embodiment, the calibration signal is a white noise signal, ie a noise signal with the same power distribution for all frequencies. In another embodiment, the calibration signal is a pink noise signal, ie a noise signal with a power distribution proportional to the inverse of frequency. In some embodiments where a noise signal is used as the calibration signal, the noise signal is generated by using a digital synthesis method using pseudorandom noise.

In some embodiments where a noise signal is used as the calibration signal, analyzing 407 includes performing a discrete Fourier transform (DFT), for example by performing a fast Fourier transform (FFT) using methods known to those skilled in the art. ) to determine the spectrum of the recorded sound field.

Determining and storing data for a particular set of one or more correction filters based on the results of the transformation and a target reference spectrum for the signal after processing through the one or more sets of correction filters, the one or more sets of correction filters A specific set of corrective filters modifies the determined spectrum of the recorded sound field in order to match a target reference spectrum for a specific playback system and listening environment.

Although the use of digital methods for analysis 407 has been described above, in alternative embodiments some or all of this analysis may be performed by analog circuitry. The recorded signal is split into frequency bands, for example by means of a set of bandpass filters, and a level measurement circuit is used to determine a signal representative of the signal power in the frequency bands. These data values may then be digitized and a set of gains for the frequency band determined as data for storage for a set of one or more correction filters for a particular playback system and listening environment.

Methods and apparatus have thus been described. In some embodiments, the calibration signal is played back on a playback system. Using a built-in or attached microphone, the resulting sound field is recorded on the portable media device. The recorded sound field is analyzed and a set of one or more correction filters for the playback system is calculated. Data for the set of one or more correction filters is stored on or for the portable media device, the data being associated with the playback system. Data for the set of banks of correction filters is thus stored. The data stored for the particular set can then be retrieved and the particular set of one or more correction filters applied to any audio being played from the portable media device when the portable media device is attached to the corresponding playback system. Since embodiments of the present invention include applying equalization in portable media devices, such embodiments provide the benefit of room equalization for audio playback systems that do not include such features. Furthermore, some embodiments of the present invention provide a very easy-to-use, self-contained form factor for calibration when the portable media device includes its own microphone. The user simply hits the calibration knob and holds the portable media device in the listening position in front of the speakers of the playback system.

In the context of this document, the term "wireless" and its derivatives may be used to describe circuits, devices, systems, methods, techniques, channels, etc., that can communicate data through a non-solid medium through the use of modulated electromagnetic radiation.

Unless specifically stated otherwise, as is clear from the following description, it is understood that the use of terms such as "processing", "calculating", "operating", "determining", etc. in the discussion throughout the specification refers to manipulating and/or Or the act and/or processing of a computer or computing system or similar electronic computing device that transforms data expressed as a physical quantity (such as an electronic quantity) into other data similarly expressed as a physical quantity.

In a similar manner, the term "processor" may refer to any device that processes electronic data, e.g., from registers and/or memory, to transform that electronic data into other electronic data, e.g., which may be stored in registers and/or memory or parts of the device. A "computer" or "computing machine" or "computing platform" may include one or more processors.

Note that where a method is described as comprising several elements (eg, several steps), no order of such elements (eg, steps) is implied unless specifically stated.

In some embodiments, a computer-readable storage medium is configured with (eg, encoded with) stored therein instructions that are processed by a processing system, such as a digital signal processing system that includes at least one processor element and a storage subsystem. device or subsystem) such that when executed, one or more processors implement the methods as described in this application.

The methodologies described in this application are, in some embodiments, executable by one or more processors receiving instructions, logic encoded on one or more computer-readable media. When executed by one or more processors, the instructions cause at least one of the methods described in this application to be implemented. Includes any processor capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken. Thus, one example is a typical processing system including one or more processors. Each processor may include one or more of a CPU or similar element, a graphics processing unit (GPU), and/or a programmable DSP unit. The processing system also includes a storage subsystem having at least one storage medium, which may include memory embedded in the semiconductor device, or include main RAM and/or static RAM, and/or ROM, and separate memory subsystems that also include cache memory system. The storage subsystem may also include one or more other storage devices, such as magnetic and/or optical and/or additional solid-state storage devices. A bus subsystem may be included for communication between components. The processing system may also be a distributed processing system having processors coupled through a network (eg, via a network interface device or a wireless network interface device). If the processing system requires a display, such a display may be included, for example, a liquid crystal display (LCD), an organic light emitting display (OLED), or a cathode ray tube (CRT) display. If manual data entry is required, the processing system also includes input devices such as one or more of an alphanumeric input unit such as a keyboard, a pointing control device such as a mouse, or the like. The term "storage", "storage subsystem" or "storage unit" as used in this application also includes a storage system such as a disk drive unit if clear from the context and unless expressly stated otherwise. The processing system in some configurations may include an audio output device, as well as a network interface device.

The storage subsystem thus includes a computer-readable storage medium configured with (e.g., encoded with) instructions, e.g., logic, e.g., software, which when executed by one or more processors When executed such that one or more of the method steps described in this application are carried out. The software may reside on the hard disk or also reside fully or at least partially in RAM and/or in the processor during its execution by the computer system. Accordingly, the memory and processor also constitute a computer-readable medium having encoded instructions thereon.

Furthermore, a computer readable storage medium may form a computer program product, or be included in a computer program product.

In alternative embodiments, one or more processors operate as stand-alone devices or may be connected (e.g., network-connected) to one or more other processors in a network-attached deployment, where one or more The processor can operate as a server or client machine in a server-client network environment, or as a peer machine in a peer-to-peer or distributed network environment. Unless expressly excluded in this application, the term "processing system" includes all such possibilities. One or more processors can form a personal computer (PC), portable media device, media playback system, tablet PC, set-top box (STB), personal digital assistant (PDA), game console, cellular phone, Web appliance (appliance) , network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) specifying actions to be taken by that machine.

Note that while some of the figures show only a single processor and a single storage subsystem, e.g., a single memory storing logic including instructions, those skilled in the art will understand that many of the components described above are included, but in order not to Aspects that are vague and inventive are not explicitly shown or described. For example, while a single machine is illustrated, the term "machine" should also be taken to include the execution of a set (or multiple sets) of instructions, independently or jointly, to perform any one or more of the methodologies discussed in this application. Any collection of machines.

Accordingly, one embodiment of each of the methods described in this application is in the form of a computer-readable storage medium configured with a set of instructions, e.g., a computer program, which is executed in one or The method steps are implemented when executed on more than one processor (eg, one or more processors that are part of a portable media device). Some embodiments are in the form of logic itself. Accordingly, as will be apparent to those skilled in the art, embodiments of the present invention may be embodied as methods, apparatus (such as special purpose apparatus), apparatus (such as data processing systems), logic (e.g., embodied in a computer-readable storage medium), or a computer-readable storage medium encoded with instructions (for example, a computer-readable storage medium configured as a computer program product). The computer readable medium is configured with a set of instructions which, when executed by one or more processors, cause the implementation of method steps. Accordingly, aspects of the invention may take the form of a method, an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. In addition, the present invention can be embodied, for example, as program logic in a computer-readable medium (for example, a computer program on a computer-readable storage medium) or a computer-readable medium (for example, a computer program product) configured with computer-readable program code. )form.

Although the computer-readable medium is shown in example embodiments as a single medium, the term "medium" should be taken to include a single medium or multiple media (e.g., several memories, a centralized or distributed databases, and/or associated caches and servers). Computer readable media may take many forms including, but not limited to, non-volatile media and volatile media. Non-volatile media include, for example, optical disks, magnetic disks, and magneto-optical disks. Volatile media includes dynamic memory, such as main memory.

It will also be understood that embodiments of the invention are not limited to any particular implementation or programming technique, and that the invention may be implemented using any suitable technique for implementing the functionality described in this application. Furthermore, embodiments are not limited to any particular programming language or operating system.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments, as would be apparent to one skilled in the art from this disclosure.

Similarly, it should be appreciated that in the foregoing description of example embodiments of the invention, various features of the invention are sometimes referred to for the purpose of simplifying the disclosure and facilitating an understanding of one or more of the various inventive aspects. are grouped together in a single embodiment, figure, or description thereof. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single previously disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, although some embodiments described in this application include some features contained in other embodiments but not others, combinations of features of different embodiments are intended to be within the scope of the invention and to form different embodiments. , as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Furthermore, some embodiments are described in this application as a method or a combination of elements of a method that can be implemented by a processor of a computer system or by other means implementing a function. Thus, a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method. Furthermore, the elements of the apparatus embodiments described in this application are examples of means for implementing the functions performed by the elements for the purpose of carrying out the invention.

In the description provided in this application, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.

Unless otherwise specified, as used herein, the use of the ordinal adjectives "first," "second," "third," etc. to describe a common object merely indicates that different instances of a similar object are being referred to, And it is not intended to imply that objects so described must have a given sequence temporally, spatially, hierarchically or in any other way.

All US patents, US patent applications, and international (PCT) patent applications designating the United States cited in this application are hereby incorporated by reference. In cases where patent regulations or statutes do not permit the incorporation by reference of material that is itself incorporated by reference, the incorporation of material in this application excludes the incorporation by reference of material in such incorporated by reference. any information incorporated, unless such information is expressly incorporated herein by reference.

Any discussion of prior art in this specification should in no way be taken as an admission that such prior art is generally known, is publicly known or forms part of the common general knowledge in the field.

In the following claims as well as in the description in this application, any of the terms "comprising", "consisting of" or "which includes" is an open term, which means including at least the following elements/features, but Others are not excluded. Therefore, when used in the claims, the term "comprising" should not be interpreted as being limited to the parts or elements or steps listed thereafter. For example, the scope of the expression "the device includes A and B" should not be limited to a device consisting of elements A and B only. Any of the terms "comprising" or "comprising" or "comprising of" as used herein is also an open term, which also means including at least the elements/features following the term, but not excluding others. Thus, "comprising" and "including" are synonymous and mean "including."

Similarly, it is to be noted that, when used in the claims, the term "coupled" should not be construed as being restricted to a mere direct connection. The terms "coupled" and "connected," along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Therefore, the scope of the expression "a device A is coupled to a device B" should not be limited to devices or systems in which the output of device A is directly connected to the input of device B. This means that between the output of A and the input of B there is a path which may be a path involving other devices or components. "Coupled" may mean that two or more elements are in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but still co-operate or interact with each other.

Therefore, while what are considered to be the preferred embodiments of the invention have been described, those skilled in the art will recognize that other and further modifications can be made thereto without departing from the spirit of the invention, and it is intended to claim All such changes and modifications are intended to come within the scope of the invention. For example, any formulas given above are merely representative of procedures that could be used. Functionality may be added to or deleted from the block diagrams and operations may be interchanged between functional blocks. Steps may be added or deleted to the described methods within the scope of the invention.

Claims (25)

1. A method of operating a portable media device comprising: Recording on a portable media device the sound field resulting from one or more predefined calibration signals being played back on a particular playback system that includes speakers and is external to the portable media device using built-in Or a microphone connected to the portable media device makes the recording while the microphone is at a number of different expected listener positions in a particular listening arrangement, thereby measuring a number of different spatial locations of the speakers in the particular listening arrangement the impulse response at each of the locations; averaging the measured impulse responses to determine the average impulse response; determining a specific set of one or more correction filters for at least equalizing for the specific playback system from the averaged impulse response and from the target response of the loudspeakers of the specific playback system, and storing data for a particular set of one or more correction filters for a particular playback system in or for the portable media device, wherein the combination of the portable media device and the particular playback system in a particular listening arrangement when the portable media device is coupled to the particular playback system, when the portable media device applies a particular set of one or more correction filters Play back the audio signal. 2. The method of claim 1, further comprising applying critical band smoothing to the averaged impulse response. 3. The method of claim 1, wherein the particular set of correction filters or data therefor is stored in a storage subsystem included within the portable media device. 4. The method according to any one of claims 1 to 3, wherein a specific set of one or more correction filters for a specific playback system is stored in or for the portable media device or used for the same The data includes storing an indicator that a particular set of one or more correction filters is associated with a particular playback system. 5. The method of any one of claims 1 to 3, wherein the portable media device includes a user interface, and wherein the calibrating method includes receiving an indication from a user on the user interface in order to implement a calibration of the one or more correction filters The recording, identification and storage of data for or for a particular group. 6. The method of any one of claims 1 to 3, wherein the portable media device is coupled to the remote processing system over a network, and wherein determining a particular group comprises: sending the recorded sound field or data related thereto to a remote processing system, identify specific groups in the remoting system, and The determined particular group or data therefor is received from the remote processing system via the network. 7. A method as claimed in any one of claims 1 to 3, wherein the step of determining the particular group is performed by one or more processors included in the portable media device. 8. The method of any one of claims 1 to 2, wherein a specific set of one or more correction filters or data therefor is stored in a storage subsystem remote from the portable media device such that at A particular set of correction filters, or data therefor, is loaded in the portable media device when the portable media device is coupled to a particular playback system for playback of an audio signal or before. 9. A method as claimed in any one of claims 1 to 3, wherein the portable media device is operable as a portable telephone. 10. An apparatus for operating a portable media device, comprising: Apparatus for recording on a portable media device a sound field resulting from one or more predefined calibration signals being played back on a particular playback system comprising loudspeakers and external to the portable media device using the portable media device A microphone built into the device or connected to the portable media device makes this recording while the microphone is at a number of different expected listener positions for a particular listening arrangement, thereby measuring how many speakers are in the particular listening arrangement. The impulse response at each of the different spatial locations; means for averaging the measured impulse responses in order to determine the averaged impulse response; means for determining at least a particular set of one or more correction filters for equalization for a particular playback system from the averaged impulse response and from a target response of loudspeakers of the particular playback system, and means for storing in or for a portable media device data for a particular set of one or more correction filters for a particular playback system, wherein the combination of the portable media device and the particular playback system in a particular listening arrangement when the portable media device is coupled to the particular playback system, when the portable media device applies a particular set of one or more correction filters Play back the audio signal. 11. The apparatus of claim 10, further comprising means for applying critical band smoothing to the averaged impulse response. 12. The apparatus of claim 10, wherein the particular set of correction filters or data therefor is stored in a storage subsystem included within the portable media device. 13. Apparatus as claimed in any one of claims 10 to 12, wherein for storing in or for a portable media device a specific set of one or more correction filters for a specific playback system or using The means for storing data thereon includes means for storing an indicator that a particular set of one or more correction filters is associated with a particular playback system. 14. The apparatus of any one of claims 10 to 12, wherein the portable media device includes a user interface, and wherein the calibration process includes receiving an indication from a user on the user interface in order to implement the one or more correction filters The recording, identification and storage of data for or for a particular group. 15. The apparatus of any one of claims 10 to 12, wherein the portable media device is coupled to the remote processing system via a network, and wherein the means for determining a particular group comprises: means for sending the recorded sound field or data relating thereto to a remote processing system, means for determining a particular group in the teleprocessing system, and Means for receiving the determined particular group or data therefor from a remote processing system via a network. 16. An apparatus as claimed in any one of claims 10 to 12, wherein the means for determining the particular group comprises one or more processors included in the portable media device. 17. Apparatus as claimed in any one of claims 10 to 11, wherein a specific set of one or more correction filters or data therefor are stored in a storage subsystem remote from the portable media device such that at A particular set of correction filters, or data therefor, is loaded in the portable media device when the portable media device is coupled to a particular playback system for playback of an audio signal or before. 18. Apparatus as claimed in any one of claims 10 to 12, wherein the portable media device is operable as a portable telephone. 19. A portable media device comprising: a playback subsystem configured to playback the selected audio signal; a filtering subsystem coupled to the playback subsystem and configured to apply a set of one or more corrective filters to the audio signal during playback of the audio signal; a coupler configured to couple the portable media device with a mating coupler included within a playback system; wherein the playback system includes speakers and is external to the portable media device; a user interface configured to accept input from a user; and A microphone or a coupler to a microphone; wherein the filtering subsystem is configured to be associated with the particular playback system and the particular listening arrangement during playback of the audio signal via the particular playback system when the portable media device is coupled to the particular playback system in the particular listening arrangement A specific set of one or more correction filters, wherein the portable media device is configured to determine the particular set of one or more correction filters through a calibration process comprising: Recording the sound field resulting from one or more predefined calibration signals being played back on a particular playback system, using a microphone in or connected to the portable media device when the microphone is in multiple locations in a particular listening arrangement This recording is made at a number of different expected listener positions, thereby measuring the impulse response of the loudspeaker at each of a number of different spatial positions in a particular listening arrangement; averaging the measured impulse responses to determine the average impulse response; determining a specific set of one or more correction filters for at least equalizing for the specific playback system based on the averaged impulse response and based on the target response of the loudspeakers of the specific playback system; and Data for a particular set of one or more correction filters for a particular playback system is stored in or for the portable media device. 20. The portable media device of claim 19, further comprising: at least one processor; and a storage subsystem coupled to the filtering subsystem and the at least one processor, Where applying the particular set of one or more corrective filters includes digitally processing the digital signal on at least one of the one or more processors. 21. The portable media device as claimed in any one of claims 19 to 20, wherein a specific set of one or more correction filters for a specific playback system is stored in or for the portable media device or used The data therein includes: storing an indicator that a particular set of one or more correction filters is associated with a particular playback system. 22. The portable media device of any one of claims 19 to 20, wherein the portable media device is configured to receive an indication from a user on a user interface in order to implement a particular set of one or more correction filters or to use Recording, determination and storage of data related to it. 23. The portable media device as claimed in any one of claims 19 to 20, wherein the portable media device comprises a network interface for coupling the portable media device to a remote processing system via a network, and wherein the portable media device is specific for determining Group handling is configured as: The recorded sound field, or data relating thereto, is sent to the remote processing system to enable the remote processing system to determine the particular group, and the determined particular group, or data therefor, is received from the remote processing system via the network. 24. The portable media device of claim 20, wherein the records are analyzed to determine that a particular set was performed by the at least one processor. 25. A portable media device as claimed in any one of claims 19 to 20, comprising components enabling the portable media device to operate as a cellular phone.