Modular digital control of audio analog functionality

Abstract

The audio signal processing device comprises at least one controllable element (90, 91, 92) for performing an analog audio processing function. The controllable elements (90, 91, 92) are operable with a digital controller (58) that controls an analog audio processing function performed by the controllable elements (90, 91, 92). The at least one audio processing module (52, 54) includes partial audio processing circuitry for audio processing operations. The modules (52, 54) are operable with controllable elements (90, 91, 92) to intact the audio processing circuitry and thereby enable audio processing operations. In this manner, audio processing operations may be controlled by a digital controller. A switch array (96) selectively couples the audio processing modules (52, 54) and the controllable elements (90, 91, 92). The power supply (66) is operable to selectively supply power to the module (52, 54) or the audio processing circuitry of each module (52, 54).

Description

Technical Field

[0001] An audio signal processing device, an audio processing module, an audio signal processing system, and a method for processing an analog audio signal. Background Art

[0002] Audio processing modules are used together with various audio signal sources to apply sound effects to audio. Audio processing modules and various audio signal sources are used in analog synthesizers and audio mixers or mixing desks. Audio processing modules and various audio signal sources are used with electric guitars, where they are called fuzz boxes. Fuzz boxes are usually used alone. However, they can also be used in multiple combinations.

[0003] In practice, the fuzzy sound device and other audio processing modules are connected in series, in parallel, or in combination to achieve different sound effects. The fuzzy sound device is sometimes placed on the stage before the performance and has a switch and a dial that is large enough to be operated by the foot during the performance. When the module is used in conjunction with an analog synthesizer, an audio mixer, a mixing desk, etc., the module is usually placed on a shelf.

[0004] Figure 1 Schematic diagram of the electrical components in the analog audio processing module 10. The electrical components can be configured in many different ways. Figure 1 Module 10 is shown in FIG. 1 , which includes any selected elements representative of those found in a typical module. These elements include an input connection 11 (typically a socket) coupled to an input stage or buffer 12 .

[0005] Input connections 11 enable an audio signal source (e.g., a microphone, a pickup in a guitar, or a tape recorder) to be connected to provide an electrical signal that is a simulation of speech or musical notes. Depending on the intended use of module 10, input stage 12 may be used to present a specified impedance at the input, to isolate the input from subsequent components in module 10, or to condition the signal prior to further processing by the module.

[0006] The signal from the input stage 12 is passed to the processing stage 14, which processes the signal using a transfer function fx to modify the audio represented by the signal. The fx stage 14 may include such elements as attenuators, filters, delay circuits, preamplifiers, signal amplifiers, limiting amplifiers, etc. In practice, depending on the sophistication or complexity of the audio processing, the module 10 may include a combination of these elements (not shown) that together apply the desired processing to the electrical audio signal provided to the module 10.

[0007] In some modules, one or more control switches, dials or knobs 15 are provided to allow the user to change the effects that the fx applies to the audio signal. In practice, a rotary switch or dial is typically provided. The switches and dials allow the user to turn the module on or off or include or bypass circuit elements in the module (such as the fx stage 14) to change the processing effects on the input signal.

[0008] The knob 15 may be coupled to a potentiometer or similar element having a variable impedance, which may be used, for example, to control signal attenuation or the operation of more active elements such as filters or amplifiers. Knobs are typically included for volume control and tone control. But they are also used to modify the transfer function of the filter to change the effect applied by the module 10 to the analog audio signal.

[0009] The processed signal from the fx stage 14 is provided to an output stage or buffer 17 which operates in a similar manner to the input buffer 12 (e.g., matching impedance or conditioning the signal) to conform to a specified or expected output current or voltage range. A socket 19 allows the processing module 10 to be connected to another module for additional processing of the signal or to a power amplifier, such as driving a loudspeaker, in an auditorium, theater or other performance venue. The socket 19 may be used as a connection to a signal storage device, such as a tape recorder for long-term storage of analog audio signals.

[0010] Figure 2 A processing module 20 is shown that includes another arbitrarily selected element. An audio signal is input at plug 21, which is connected to an isolation transformer 22, which outputs a signal for a preamplifier 23. The conditioned signal is applied to a filter 24, which modifies the signal according to the characteristics of the filter and the position of a control knob 25 and outputs the modified signal for another output stage 27. For the purpose of variety - and to illustrate that there is no fixed design for analog audio processing modules - the output stage is shown as a variable preamplifier 27, which works with another isolation transformer 28 to output the audio signal via a socket 29 for further processing, amplification, or storage. Typically, the preamplifier here will be connected via a similar Figure 1 The knob 15 in the module 20 is controlled, but it does not need to be controlled depending on, for example, the intended use of the module 20.

[0011] The module 20 includes a tap or connection 26 between the filter 24 and the preamplifier 27, which can be connected via a wire (not shown) to provide a feedback signal at the input 21 or a feedforward signal at the output 29. This provides the user with further control over the effect the module applies to the audio signal. Additional taps (not shown) may be provided between other stages in the module to provide the user with further control over the effect.

[0012] Figure 3 A series of modules are shown connected to each other using feedback paths 35 and feed forward paths 36 which are created in the module by interconnections between taps 26. This allows the user to modify the effects produced by the cascaded modules between input connections 37 and output connections 38. Taps may also be connected to the inputs and outputs of individual modules 32 to 34 or to the inputs 37 or outputs 38 of the cascade as required. Such connections are used in analog synthesizers (not shown), although they can be and are sometimes used in associated mixing consoles (not shown).

[0013] Figure 4 An example of one way these processing modules are used in an audio mixer in a recording studio is shown. In this case, Figure 4 As shown in FIG. 1 , a rack 40 is provided to accommodate a plurality of processing modules 42 to 45. The rack 40 provides a common power supply (not shown) when necessary, and the settings in each module can be adjusted via the control knobs and switches 15 on the front of each module 42 to 45. The sockets 26, 29 provided on the front of some of the modules 43, 45 provide connections to the interior of the module, such as Figure 2 A similar arrangement associated with analog synthesizers may also be used.

[0014] Analog audio signal processing modules have existed in a variety of different forms for decades. As with all products, some models come and go, while others remain popular over the years. Despite the possibility of digital devices that serve roughly the same function, analog modules continue to be widely used.

[0015] Recently, but still counting decades, digital signal processing has been widely used in the field of audio signal processing. Analog signals are converted into digital form by sampling them at regular intervals. This produces a series of numbers that represent the audio signal. The digital signal processor modifies these numbers to modify the audio represented by these numbers. In this way, audio can be obtained in a digital environment with the same effect as in an analog environment.

[0016] In fact, many effects produced by analog processing modules (fuzz devices, etc.) are now available in a digital environment. In some cases, the effects of the analog modules are simulated by a computer or digital signal processor. The effects are all satisfactory. This is consistent with the advancement of electronically based audio technology into a digital environment.

[0017] However, it is often said that equivalent digital effects often lack the warmth and intimacy of their analog originals. While this is subjective and difficult to quantify, it is still a real issue in the audio world. The digital version may be equivalent, but it is not the same as analog. In short, musicians, sound engineers, and producers like analog modules because their sound and warmth (however quantified) are familiar - many modules have been popular for decades. Users know what they will get from a given module.

[0018] Still, it is useful to be able to take advantage of digital control techniques when working with audio processing modules. In a fully analog environment, where several modules are linked together to achieve a specific sound, it is necessary to pay attention to how the modules are connected and what settings are provided. If you don't do this, it will be difficult to reproduce the same sound again in the future.

[0019] Changing between one complex set of setups and another is time-consuming during a show. Simple changes (turning a module on or off, adjusting a few dials, and switching a few connections) may be all that can be done between songs. Naturally, a studio has the ability to stop and reset all equipment before continuing recording. But even here, relying entirely on notes to record various setups takes time to keep the current or up-to-date setup, which increases production costs. Summary of the invention

[0020] The invention provides an audio signal processing device, an audio processing module, an audio signal processing system and a method for processing an analog audio signal.

[0021] An audio signal processing system comprises: an audio signal processing device, which includes a digital controller and at least one controllable element, the controllable element is used to perform an analog audio processing function, the controllable element can be operated together with the digital controller, the digital controller is used to control the analog audio processing function performed by the controllable element; and an audio processing module, which includes a partial audio processing circuit for audio processing operations, the module is connected to the at least one controllable element to complete the audio processing circuit, thereby realizing the audio processing operation.

[0022] The invention is defined by the claims.

[0023] The above and other features of the present invention are particularly set forth in the claims and, together with the advantages of the present invention, will become more apparent from a consideration of the following description given with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the electrical components in the analog audio processing module.

[0025] Figure 2 The processing module including another arbitrarily selected element is shown in more detail.

[0026] Figure 3 Modules are shown connected to each other in series with feedback paths and feedforward paths.

[0027] Figure 4 An example of using multiple processing modules on a rack is shown.

[0028] Figure 5 is a schematic diagram of an audio processing system having a control platform and an analog audio processing module.

[0029] Figure 6 Examples of graphical representations of modules for display on a user interface are shown.

[0030] Figure 7 Shows the suitability for Figure 5 Details of the modules used in the system.

[0031] Figure 8 Shows Figure 7 The modules are connected to controllable elements.

[0032] Fig. 9 Shows Figure 7 The module is connected to two controllable elements.

[0033] Fig.10 Modules comprising controllable elements are shown.

[0034] Fig.11 Elements of the platform are shown in more detail.

[0035] Fig.12 is a schematic diagram of a power supply.

[0036] Fig.13 The information and control paths in the system are shown.

[0037] Fig.14 Shows the movement of information within the system.

[0038] Fig.15 It is a schematic diagram of the controllable components.

[0039] Fig.16 A switch matrix coupled to the audio processing module is shown.

[0040] Fig.17 A switch matrix coupling the various elements in the system is shown.

[0041] Fig.18 Represents one way in which modules and controllable elements can be connected via a matrix.

[0042] Fig.19 The transfer of data to the user interface is shown.

[0043] Fig. 20 Data transfer from a user interface is shown.

[0044] Fig.21 Data delivery to an audio workstation is shown. DETAILED DESCRIPTION

[0045] Figure 5 is a schematic diagram of an audio processing system 50 having a platform (PFM) 56 and analog audio processing modules 52, 53, 54. The audio processing modules 52, 53, 54 are controlled and connected via the platform 56. The operation of the platform 56 is controlled by a central processing unit (CPU) 58, which is connected to the platform via a digital bus 60, which is also connected to each of the modules 52 to 54.

[0046] For ease of description and understanding, CPU 58 is shown as being external to platform PFM 56. In practice, CPU 58 is typically included as part of PFM 56. The operations described below for CPU 58 may be performed by a dedicated processor in the platform as shown. However, there is no technical reason why the CPU could not be provided as a unit external to the platform. Instead, the operations may be performed by, for example, a personal computer (not shown) coupled to the platform via bus 60. Either way, the operations are essentially the same.

[0047] The CPU 58 receives commands from a user interface (UI) 62 that enables a user to set operating parameters within each of the modules 52 to 54. The UI 62 may be provided, for example, by any of a mobile phone, tablet, or personal computer coupled to the CPU 58 via a suitable data connection 64 (e.g., USB, Wi-Fi, Bluetooth, or similar connection).

[0048] The user interface 62 provides a way for the user to input commands to the system 50. Typically, the commands will be in the form of Figures 1 to 4 The operation of the modules 52, 53, 54 is adjusted in the same manner as the dials and knobs 15, 25 discussed above. While any form of representation may be used for the modules - including control input via a keyboard or mouse - it is now common to have a graphical representation displayed on a touch-sensitive screen such as found on a touch tablet device.

[0049] Figure 6 Shows the displayed Figure 5 52, 53, 54 in FIG. 5 . Each module has a selector dial 15 'and other indicators 25 ', which are equivalent to the modules 52, 53, 54 in FIG. Figure 1 , Figure 2 and Figure 4 The user can manipulate these visual input elements 15', 25' to change the settings in the corresponding module. The user interface UI 62 responds to the manipulation by generating control data for use by the CPU 58, as will be described in more detail below.

[0050] For reasons that will become clear later in this document, modules 52, 53, 54 can be designed directly from existing audio processing modules by their current manufacturers. Starting with the original module, the circuits can be modified and adjusted to make them suitable for use with system 50. This allows popular and historical models to be included in the system, making their operation familiar to many users. After this is done, the graphical representation displayed on UI 62 can be a replica of the original module front panel, with the same representation of knobs, buttons and dials as on the original module.

[0051] Back to Figure 5 , the system 50 also includes a power supply (PS) 66 that supplies power to the system 50 via a power line 68. Although the power supply PS 66 is shown external to the platform for illustrative purposes, it is typically included as part of the platform 56. The power supply 66 is coupled to the processor (CPU) 58 via the digital bus 60 and is controlled by the processor (CPU) 58. The power supply PS 66 is connected to the processor (CPU) 58 via the supply line ( Figure 5 ) provides power to the various components and modules 52 , 54 on the platform 56 .

[0052] The platform (PFM) 56 includes a switch or a connection device ( Figure 5), the switch or connection device is used to connect the system analog input line and output line 72 to the module analog line 74. These analog lines 72, 74 are connected to the module analog line 74. Figure 5 50, but this has no significance other than to illustrate that the analog lines can be provided individually or in groups of several lines as desired. The analog lines 72 provide an input point for audio signals to the system 50, such as from a microphone or a pickup in a musical instrument (not shown), and an output point for audio signals from the system 50 to, for example, an amplifier (not shown).

[0053] The platform also includes a digital audio port 77 for receiving and / or outputting audio signals in digital form. This enables the platform to receive signals from a digital source or output digital signals to a digital destination. Thus, for example, the system can convert an incoming digital signal to an analog signal, pass the analog signal through modules 52, 53, 54, and then output the resulting processed signal in digital form.

[0054] Figure 7 , Figure 8 and Fig. 9 Details of modules 52, 53, 54 suitable for use in system 50 are shown. Modules 52 to 54 are analog devices that are Figure 1 and Figure 2 The modules 10, 20 described above and shown in FIG. 1 have much in common. In fact, when the modules are based on original analog designs suitable for use in the system, they actually retain access to popular designs of the past. The modules (such as module 52) still include an input connection 11' coupled to an input stage 12' and an output stage 17' (here a variable amplifier) ​​coupled to an output connection or socket 19'.

[0055] Each module 52 to 54 has an information storage or data element 70 which is connected to the platform 56 and hence to the CPU 58 via the digital bus 60. The data element 70 stores operational information characterizing the operation of the module. The operational information is initially used to set up the manner in which the module is to interface with the platform and defines the manner in which the module and the platform interact during use.

[0056] Thus, the operational information includes the characteristics or functions of one or more parts of the module that have been removed and the required characteristics of the controllable elements CE 90, 92 that will replace the one or more parts of the module that have been removed. Depending on the specifics of the module, the information may include: the impedance of the input terminals 21', 21", and the output terminals 29', 29", to ensure signal balance between modules; signal voltage levels; and power supply requirements. Broadly speaking, the information includes anything required to configure the controllable element CE to operate with the module.

[0057] This information is stored in digital form. Figure 7 As shown in detail in the upper left portion of FIG. 1 , the information storage or data element 70 includes a memory storage device (S) and a digital interface circuit (IF) which communicates with the Figure 5 The bus 60 shown is connected (interface). This enables the platform (including CPU 58) to obtain operating information and work accordingly. The digital interface circuit IF can be a dedicated interface circuit. However, in practice, it is convenient to provide a programmable controller that is configured to communicate with CPU 58 via the digital bus 60. And thereby operate as a data element 70.

[0058] A microcontroller (μ) typically includes a memory for storing applications, program routines, and for saving operational data. When designing a module, data defining the various characteristics of the module are saved in the memory of the microcontroller, which enables the module to be connected to a platform and operate therein as the designer intended.

[0059] Therefore, a small microprocessor or microcontroller (μ) 70 is a suitable way to implement the memory S and interface IF. Depending on the implementation details, the microcontroller μ will generally provide an efficient way for the module to communicate with the CPU 58 and other parts of the platform 56 and thereby operate therein as part of the system 50. Of course, a separate memory may be used in conjunction with or in place of the microcontroller's memory, depending on design preference. In the following, it is assumed that the information storage or data element 70 includes a microcontroller μ, but it should be kept in mind that this is a matter of design choice.

[0060] like Figure 7 As shown in FIG. 5 , the processing stage fx 14 ′ and the control knob 15 ′ have been removed from the module 52 . This is indicated by the dashed lines. In place of these elements are terminals 80 , 82 , the internal connection lines L from the input stage 12 ′ out and to the output stage 17' L in Connected to these terminals. It can be seen that these internal connection lines L out and L in Similar to connecting to Figure 2 and Figure 3 Therefore, some internal components (fx) of the module 52 have been removed, and the internal connection terminals L out and L in 80, 82 enable access to the rest of the module. Thus, modules 52, 53, 54 comprise part of the audio processing circuitry for audio processing operations.

[0061] In practice, the platform will typically include a mounting member, such as a rack, to which the modules 52, 53, 54 can be removably mounted. Figure 7 The connectors of the terminals 11 ′, 19 ′, 80 , 82 shown in the figure are connected with corresponding connectors on the rack to couple the electronic devices and modules on the rack to each other.

[0062] exist Figure 8 , the module 53 is shown connected to a controllable element CE 90 via terminals 80, 82. This connection is via the connection line L mentioned above. out and L in Complete. The controllable element CE 90 is not part of the module 52, but it is provided in the platform PFM56 and will be described in detail below. As a matter of design choice, the controllable element CE 90 can be controlled by the processor CPU 58 or the information storage device 70 or both. When the information storage device is implemented as a microcontroller μ70, it is convenient to arrange the control together with μ70.

[0063] CE 90 can be configured by CPU 58 to perform the same analog functions as the components removed from the module (e.g., processing stage fx 14' and control knob 15'). As will be further explained below, CE 90 includes analog components that are controlled by CPU 58 based on operational data for the associated module from microcontroller 70, which are equivalent to the components removed from the module. Thus, controllable element CE 90 completes the audio processing circuits of modules 52, 53, 54, and thereby enables audio processing operations previously performed by the module to be performed by the remaining elements in the module in conjunction with CE.

[0064] exist Fig. 9 In the module 54, the output preamplifier 27 (see Figure 7 ) has been moved to a second controllable element CE 92 at the output 29" of the module 54. The output 29" is connected to the second controllable element CE 92 via a line 94. The controllable element CE 92, like the controllable element 90, is located in the platform 56 (see Figure 5 ). The output (out) of the CE provides a path 95 for outputting signals to other parts of the system or external connections (not shown).

[0065] exist Figures 7 to 9In each of the analog audio processing modules 52 to 54 in the platform 56, some functionality (typically but not necessarily variable functionality) is removed from the module and replaced by connectors 80, 82, 94 that connect to controllable elements 90, 92 in the platform 56. The reasons for this should become clearer from the following description. Among other things, this approach allows the manufacturer of analog modules to take their existing designs and modify the analog modules by removing selected portions of the module 52 (e.g., the processing stage fx 14) and providing connectors 80, 82, 94 in their place to connect to appropriately configured controllable elements 90, 92.

[0066] As will become apparent from the following description, placing the controllable element CE 90 outside the module and in the platform 56 provides flexibility in the use of the system 50. The module construction is simplified because at least some of the analog functions fx are removed from the module. During the use of the system 50, one module can be easily replaced by another module, and the operation of one or more related CEs can be adjusted according to the needs of the newly added module. Costs are lower because the system only needs a few CEs in the platform, rather than one in each module.

[0067] However, it is possible to place the controllable element CE 90 inside the module 55, such as Fig.10 shown. Fig.10 The components in module 55 are the same as Fig. 9 The elements in module 54 in are identical and are labeled accordingly. The controllable element 90' is coupled to bus 60, either directly as shown or via microcontroller μ70, and can therefore be controlled by CPU 58.

[0068] This approach is advantageous, for example, when module 55 provides a complex or highly specific function that cannot be easily performed by a general purpose controllable element CE. An equalizer that provides different attenuation across multiple frequency bands would require multiple filters, one for each band, which would require a complex CE that would have limited appeal to many users. It would therefore be more cost effective to use a CE designed specifically for this multi-band function and place it in or with module 55. The benefits of digital control of the analog functions of the controllable elements can still be achieved, although the cost of the module has not been reduced to the same extent.

[0069] Fig.11 The platform 56 is shown in more detail. In this figure, the CPU 58 is shown as part of the platform, Figure 5Similarly, a power supply unit PS 66 is included within the platform 56. Here, the bus 60 provides a path for control data between the CPU 58, the microprocessors (μ) 70 in the modules 52, 54, the power supply PS 66 and the controllable elements CE 90, 91, 92, 94 also located in the platform.

[0070] The structure of bus 60 is implementation dependent and is influenced by issues such as design efficiency and cost effectiveness. Fig.11 60 is shown as a single path, but in reality it may include multiple different buses. There are many available buses suitable for system control and communication. The USB (Universal Serial Bus) standard is well known, making it suitable for a system such as where the platform may be manufactured by one vendor and the modules by another vendor. USB hardware is widely available, making it a cost-effective choice for implementing bus 60. Therefore, bus 60 may include a USB for communicating data between CPU 58 and microcontroller 70.

[0071] Of course, other bus standards are available and may be better suited to the transfer of control data.When the CPU is provided by an externally connected personal computer or the like, the external computer will typically be connected via an external bus such as Ethernet or USB.

[0072] The controllable elements CE 90, 91, 92 have unique identifiers such as addresses, which enable the system control CPU 58 to identify the unique identifiers. Therefore, from a design perspective, it is convenient to use a bus based on the serial peripheral interface (SPI) bus standard to pass information between the CPU 58 and the CE 90, 91, 92, 94. Many microcontrollers include GPIO pins (general purpose input output) that provide a logic 1 or 0 output that can be used to directly control the on / off type operations performed by the controllable elements. This is done in the system shown in the figure and will be discussed further below.

[0073] Because the use of a particular bus is an implementation detail, the description will generally refer to bus 60 in a generic sense. Where the context requires or permits, the suitability of a particular bus will be identified.

[0074] The number of modules 52, 54 in the system is a matter of design choice determined by, among other things, user requirements, including the processing power required by the user, and budget. From a technical point of view, it is perfectly acceptable to provide a system 50 comprising only a single module 52 connected to a platform PFM 56, although such a system may not take advantage of all the features of a multi-module system.

[0075] An entry-level system can be provided, which can include, for example, two or three modules 52, 54, which are installed in a platform together with an appropriate number of controllable elements 90, 94. If necessary, more modules can be included, and the ellipsis (...) between the modules 52 and 54 shown is intended to indicate that the system can be increased to more than the two modules shown in the figure. For clarity, these additional elements have been omitted in the figure. Similarly, the ellipsis (...) between CE 92 and CE 94 indicates that the platform 56 can include additional control elements (CE) depending on the specific needs of the design.

[0076] In a larger system, the platform and modules may be manufactured and sold by different suppliers. Thus, the platform will include a rack (not shown) in which the individual modules can be mounted. Suitable connectors in the rack and modules will provide the necessary connections for the data bus 60 and the various analog lines for the modules.

[0077] Still refer to Fig.11 The switch array 96 controls the movement of analog signals within the platform 56, the movement of analog signals to and from the modules 52, 54, and the movement of analog signals between modules. The movement of analog signals within the system is accomplished by the switch array 96 along analog lines, most of which are located here. Fig.11 There are many analog audio signal lines between the switch array 96 and the controllable elements 90 to 94. For the sake of clarity, these analog audio signal lines have also been omitted in the figure. They include lines 100, 102 connecting the module 52 and the controllable element CE 90 and lines 104, 105 between the module 54 and the CE 94.

[0078] The switch array 96 is Fig.11 And in the following figures, it is identified as a switch matrix MX. The matrix provides flexibility in connecting modules 52, 53, 54 and controllable elements 90, 91, 92 to each other. However, in some cases, such as the system is relatively small, it has only two or three modules, and the matrix may not be the best solution. A simpler switch array may be more design or cost-effective. Depending on the implementation requirements, the switch array can be provided by CMOS analog switches, multiplexers, relays, etc., as long as they can route signals between different input and output terminals on the platform, controllable elements and modules. However, for consistency and clarity, the remaining description will be given with reference to the switch matrix MX.

[0079] Although the system is designed to keep the audio signal in its analog form-while providing computer control, i.e., digital control, sometimes the user may wish to receive audio from a digital source or provide audio to a digital system. The analog-to-digital converter and the digital-to-analog converter ADC / DAC 108 provide a path 77 for the digital audio signal to be input to or output from the platform 56. The ADC and DAC are shown as a single unit, but they can be provided as separate components. Regardless of the configuration, the ADC / DAC 108 is connected to the bus 60 so that the ADC / DAC can be controlled by the CPU 58. The analog port of the ADC / DAC 108 is connected or connected to the switch matrix 96 via an analog line 109.

[0080] The power supply PS 66 delivers power to the platform 56 and modules 52, 54 under the control of the CPU 58. In addition to providing power to the microcontrollers 70 (the digital control portion of the system) in the platform and modules, the power supply 66 also separately and selectively provides power to the analog components of the modules 52, 54. This is necessary because each manufacturer has made its own decisions over the years regarding the voltage levels within its equipment - there is no uniformity.

[0081] Therefore, the information stored in the microcontroller μ70 also specifies the power characteristics of the module. This includes information about how much power the module requires and what voltage it requires. The power supply 66 uses this information to supply power to the module via power lines p1, p2, p3, ..., p n The correct level of power is provided to the analog circuits in each module. This enables specific power to be provided to the module at the required power level, which is necessary if the system is to support a variety of modules of different designs made by different manufacturers.

[0082] Typically, the power supply PS 66 is capable of supplying power within a voltage range of, for example, ±48 volts, where the specific voltage supplied depends on the individual requirements of each module. Some modules 52 to 54 may require a voltage higher than the voltage range of the power supply 66. Here, the design of the module will include a booster that is used to take the available voltage from the power supply and increase it to the level required by the analog audio processing portion of the module.

[0083] Fig.12 The power supply 66 is shown in more detail. As shown, the power supply 66 includes two power conversion paths 121 and 121', which are coupled to receive an AC power signal (e.g., 110V AC to 240VAC, not shown) from a multi-tap transformer 120 that can be connected to a main power outlet. The power supply 66 provides power to each controllable element CE 90, 91 (see Fig.11) provide separate power outputs, and therefore the power supply 66 includes separate power conditioning paths 121, 121' for each CE. However, for clarity, only two power paths 121, 121' are shown. Since the two paths 121, 121' operate in substantially the same manner, they will be described together.

[0084] A plurality of taps 122, 122' from the transformer 120 are provided to multiplexers 124, 124'. Each tap provides a different AC power voltage to the multiplexers 124, 124'. Although taps 122, 122' are shown separately for each power conversion path 121, 121', the corresponding tap for each path will generally be from the same location in the transformer 120. The AC output from the multiplexers 124, 124' is converted to a rail-to-rail DC supply 126, 126' by a bridge rectifier 127, 127' (or the like) and a regulator R 128, 128', which receives a reference voltage V from a digital-to-analog converter DAC 130, 130'. ref .

[0085] The operation of the multiplexers 124, 124' is controlled by a controller 132 which is connected to the bus 60 and receives control information from the control processor CPU 58 (see Fig.11 ). Conveniently, a microcontroller μ (similar to the microcontroller 70 in the module) is deployed as the controller 132. The controller μ132 provides a signal to the multiplexers 124, 124', so that the multiplexers 124, 124' select one of the taps to which the transformer 120 is input. The controller μ132 also provides a signal to the DACs 130, 130', so that the DACs 130, 130' output a reference voltage V ref For use by regulators R 128, 128'.

[0086] The selection of the tap and the reference voltage V ref The generation of is determined based on the characteristic data of the module. The module data is static (it remains static for the module in question) and is therefore stored in the module's microcontroller or associated storage. As will be explained in more detail below, static data (such as the power requirement data) is provided from the module to the CPU, which passes the static data to the microcontroller μ132 in the power supply. Thus, each DC supply 126, 126' is generated at a level specified by the information passed from the microcontroller by the CPU 58 for a given module 52, 54 (see Fig.11 ).

[0087] Power is not initially supplied to the respective modules by the power conversion paths 121, 121'. Prior to this, the platform 56 must be powered together with the microcontroller 70 in the module (i.e. the digital part of the system 50). This is necessary, among other things, so that information about the requirements of each module can be obtained from the modules 23, 54 for setting the output voltage to the level required by the module.

[0088] Thus, the power supply 66 also includes an additional power conversion path 135 for providing power to the digital portion of the system 50, including the platform 56 and portions of the modules connected to the platform via the bus 60 (i.e., the microcontroller 70). Thus, the power conversion path 135 includes: a bridge rectifier 137, which is connected to receive the AC power signal from the transformer 120; and a regulator 138, which is used to provide a voltage V to the digital portion of the system. dd This portion of the power supply 66 provides output when the system is turned on. Of course, the power supply 66 can be provided as a separate component when it is convenient to do so, as the power supplied by the power supply 66 is not dependent on the module being plugged into or otherwise coupled to the platform.

[0089] In from Fig.12 Before proceeding, note that a second bus 150 is shown coupled to the controller μ 132. The purpose of this bus 150 will be described below.

[0090] Fig.13 It shows how the components of the system (particularly the CPU 58, PSU 66 and modules 52, 54, including microcontroller 70) are connected to each other to enable power to be supplied to the modules. When the system is first turned on, the analog parts of the modules remain unpowered. Similarly, when the modules are first added to the powered system, power will be applied to the microcontroller 70, but not to the analog parts of the modules.

[0091] Bus 60 is used for initial communication between CPU 58 and microcontroller 70. Fig.11 As mentioned, this communication can be provided via a USB bus. The USB bus is suitable for a platform such as Figure 5 The PFM in the bus can be made by one vendor and the modules by another. USB hardware is widely available, making it a cost-effective choice for implementing bus 60.

[0092] Reference Fig.13 and Fig.14 , the memory S of the microcontroller μ70 ( Figure 7) or in a memory S connected to the microcontroller μ70 includes a known form of "signature" or "signature certificate" for identifying the module. This signature data 140 is passed to the CPU 58 via the bus 60. The CPU 58 verifies the signature in a handshake 142 between the microcontroller μ70 in the module 52, 54 and the CPU 58 in the platform.

[0093] While the combined platform and modular design allow different manufacturers to contribute to the system, there is also the risk of manufacturing parts that are not fully compatible. Modules that fail to work, break down after a short period of time, or cause physical damage to the system can be damaging to the reputation of the product and its supplier. The use of signatures aids in quality control, making it less likely that inferior equipment will be able to cause damage to the system.

[0094] When the modules are mounted on the rack, they can be placed anywhere on the rack. Once the initial system data has been verified by the CPU 58, a handshake 140 is completed, wherein the CPU 58 sends instructions to the microcontroller μ70 to provide a signal identifying the location of the microcontroller μ70 in the system 50. This can be done via the USB bus 60. However, there is a simpler method.

[0095] As about Fig.11 As mentioned, microcontrollers typically include GPIO pins (general purpose input output). These pins are hardwired to the connection pins of the backplane of the rack mount. When the microcontroller 70 receives a command to send an identification signal, it does so by setting a signal (e.g., logic 1) on the relevant pin. This action is Fig.14 It is represented by the arrow 144 between the module M / μ and the CPU. Fig.13 148, 149 in the figure, which connects the microcontroller 70 in each module 52, 54 with the CPU 58. The microcontroller μ then sends the power requirement data 147 to the power supply PSU 66. This can of course be done via the bus 60. However, this need not be the case. The CPU 58 does not need to know this information, so that it does not need to be passed through the CPU.

[0096] like Fig.12 and 13 As shown in , an alternative is for the microcontroller μ to send the power requirement data directly to the PSU 66 via a separate bus. SPI (Serial Peripheral Interface) buses 150, 151 connect the microcontrollers 52, 54 and the microcontroller 132 in the PSU 66 to facilitate the transfer of data. Note that this is the above Fig.12 The bus mentioned at the end of the description.

[0097] Power data can be encrypted during transmission, providing an additional way, in addition to signed certificates, to check that a module is “legitimate,” i.e., ensuring that its construction is compatible with the system.

[0098] exist Fig.14 At the end of the information exchange shown in , the power supply has all the information necessary to supply the correct level of power to each module 52, 54. Fig.12 Once confirmed, the microcontroller 132 in the PSU 66 will use the power requirement data to select the appropriate tap 122 via the multiplexer and the microcontroller 132 in the PSU 66 will use the power requirement data to set the correct reference voltage V from the DAC 130 ref to drive regulator R 128. Appropriate power is provided via line 126 (also Fig.14 ) is output from the regulator to module 52, thereby energizing the analog components of the module.

[0099] Fig.15 The controllable element CE 90 is shown in more detail. Therefore, the controllable elements are designed so that their functions are adjustable to match the requirements of the various individual modules 52. The controllable element 90 includes a microcontroller 160, which has a unique identifier such as an address, which enables the system control CPU 58 to recognize the unique identifier. The microcontroller 160 is connected to the CPU via a (SPI) bus 60, and the microcontroller 160 controls the elements in the CE 90 through internal buses 162, 164, 166, 168.

[0100] Although bus 60 may be coupled to elements in CE 90 to enable control of the elements in CE 90 by CPU 60, the use of one or more buses internal to CE 90 enables the CE to operate independently. This makes it easier for individual module companies to specify their own CE for use in the system, among other things. As a matter of design choice, the bus within the CE is Fig.15 Shown in FIG. 1 are these individual connections 162 , 164 , 166 , 168 between the microcontroller 160 and the various elements of the CE controlled by the microcontroller.

[0101] At connection point 170, the signal from the module (e.g. Figure 7 The connecting line L out and L in) is input to a controllable element and applied to the input of a fixed gain amplifier 172. The amplifier 172 buffers the signal, thereby conditioning the signal to a form suitable for the CE. This is necessary in the case where the signal level from the module is different from one module to another. The conditioned signal is passed to a switch passive attenuator (SwA) 174, which provides signal attenuation from zero to high before the signal is passed to a programmable gain amplifier PGA 176.

[0102] The switch passive attenuator typically includes an array of resistive attenuators (also called pads) that can be selected individually or in combination to provide the desired attenuation of the signal. The switch passive attenuator 174 is controlled by the microcontroller 160 via bus 162. When the selection is limited to "on / off" or "high / low", the GPIO pins on the microcontroller are suitable for the selection. When a range is available, a data bus (such as an I2C bus (inter-integrated circuit)) may be more suitable. The programmable gain amplifier PGA 176 is controlled by the microcontroller via bus 164, which is conveniently an I2C bus that is capable of transmitting data representing a range of different amplification values. The data is used to select the pads and thereby control the operation of the switch passive attenuator SwA 174.

[0103] The programmable gain amplifier PGA 176 provides variable gain control over a range, and its use in conjunction with the switching attenuator SwA 174 allows variable gain to be achieved over a wider range than using the PGA alone. When the microcontroller 160 receives operational data for the SwA 174 and PGA 176 from the CPU 58 via the bus 60, it is simply passed to the SwA and PGA, which then operate accordingly. Naturally, the PGA can be constructed in many different ways. No one programmable gain amplifier is more desirable than another. The choice is simply a matter of meeting the design criteria depending on the specifics of the system.

[0104] The audio signal from the PGA 176 is applied to a filter 178 which is controlled by a digital potentiometer 179 (also referred to as a "digital potentiometer"). Typically, a digital potentiometer is CMOS based and includes a serial string of resistors having a digitally addressable electronic switch that can be used as a wiper. The digital potentiometer is controlled by the microcontroller 160 via bus 166, although bus 166 is a single bus shown as two separate parts to avoid cluttering the diagram. Bus 166 for the digital potentiometer 179 is conveniently an I2C bus as is bus 164 for the PGA, which allows data representing a range of resistance values ​​to be sent to the digital potentiometer 179. Again, the microcontroller 160 simply passes data obtained from the CPU to the digital potentiometer 179, which then sets the digital potentiometer 179 accordingly.

[0105] Filter 178 includes a plurality of filters, typically two filters to separate high and low frequencies, wherein a corresponding digital potentiometer controls the relative amplitude of each filter and thereby the frequency response characteristics of filter 178. Filter 178 provides tone control. As with the PGA, the filter can naturally be constructed in many different ways. No one filter is preferred over another. The choice is simply a matter of meeting the design criteria depending on the specifics of the system.

[0106] While cost can be a factor, there is no technical reason why there cannot be more filters and associated digital potentiometers to provide frequency control of signals over multiple frequency points (frequency ranges or bands). Fig.10 As mentioned in , an alternative solution for module designers is to place the CE inside the module to meet the specific needs of the module.

[0107] The filtered signal is applied to an output op amp 180, which acts to buffer the output before the signal is returned to the module via connection point 182. A bypass switch 184 associated with filter 178 is connected to microcontroller 160 via bus 168, which is conveniently a GPIO pin on microcontroller 160. Switch 184 shorts filter 178 when closed, thereby bypassing the tone control. This is very useful when the design of the module requires no or only minimal changes to the frequency response. It can also improve audio quality by removing undesirable artifacts from, for example, digital potentiometer 179.

[0108] The above description is one example of a controlled element 90. It should be understood that other circuit configurations are possible, and may indeed be desirable, depending on the characteristics of the modules 52, 54 to which the CE 90 is to be coupled. Fig.15 The CE shown in is a voltage controlled and voltage source device. However, the CE and module can be changed to accommodate a current controlled / current source module.

[0109] In current-based circuits, providing a termination resistor at the output of the module provides a path for the output current, where the voltage drop across the resistor is used as the signal input to the CE 90. This termination resistor (not shown) together with the high dynamic range and low noise of the output buffer amplifier 180 maintains satisfactory audio quality of the signal passing through the CE. In addition, the output buffer amplifier 180 has a known impedance, and this known impedance together with the input impedance of the current control module allows the correct output level to be calculated and set accordingly. In addition, as long as the source has sufficient drive capability and the impedance is known, the input can be modeled as a voltage input in many current-controlled audio systems.

[0110] Other variations may also be desirable. Additional bypass switches (not shown) may be provided, where the module does not require signal processing, but only connects the module connection line L out and L in The path (see Figure 7 ). This allows selective use of the module and may be useful, for example, where all that is required of the CE is to maintain a balanced output.

[0111] Fig.16 The switch matrix MX 96 is shown in more detail. Conceptually, the matrix 96 is shown as an array comprising horizontal lines and vertical lines, which is a common representation of a switch matrix. These lines are connected by means of switches 162, as shown in the enlarged cross-sectional view 160. The switch is closed so that a connection is made between the horizontal line 164 and the vertical line 166. The operation of the switch 162 is controlled by the CPU. As mentioned above, the matrix 96 does not need to be so complicated. A simpler switch array may be more design or cost-effective. Nevertheless, the switch matrix as shown will continue to be described below.

[0112] The switch matrix 96 is connected via the input terminals M of the modules 52 and 54. in (equivalent to Figure 7 and Figure 8 The connecting piece 11') and the output terminal M out (equivalent to 19') connected to two modules 52, 54. Input signal S in Applied to line 170, line 170 is connected to connection point 172 in matrix 96. Switches are closed or opened in response to commands from CPU 58 via bus 60 to form path 174 to connection point 176.

[0113] The module input terminal Min The output terminal M of the module 52 is connected to the connection point 176 via the line 11'. out The connection is made to the connection 177 via the line 19' and this connection point passes through the matrix along the path 178 to the input terminal M of the module 54. in In addition, the output terminal M of module 54 out is transmitted to the output terminal S from the system via path 179 out .

[0114] In other words, the input signal S in is applied to the input terminal M of the module 52 in The output terminal of module 52 is connected to the input terminal M of module 54. in The output terminal M from module 54 out Connect to the system output terminal S out This simple module linking example shows how to use the matrix 96 to connect modules to each other in a system without the involvement of the CE.

[0115] Fig.17 A switch matrix 96 is shown for connecting the controllable elements CE and the modules M to each other. in Again, this is applied to line 170, which is connected to connector 172. Other lines to and from modules 52, 54 shown in the figure include internal connecting lines L out 80 and L in 82. Several controllable elements CE 181 to CE 184 are shown connected to the matrix 96. However, the internal paths in the matrix are not shown, as this would increase clutter. Fig.16 As depicted, the CPU 58 activates switches 162 within the matrix to make the desired connections.

[0116] The controllable elements 181 to 184 are identified by their position (i.e. their location on the bus), wherein the CPU 58 can obtain this information. When the modules 52, 54 are connected to the platform 56, the data sent to the CPU 58 are used by the CPU to configure the CEs 181 to 184 and connect them to the relevant connectors (11', 21', 19', 11", 12", 29", 80, 82, see Figures 7 to 9 ) to form a complete circuit of the module.

[0117] Fig.18 1 shows one way in which the modules 52, 54 and the controllable elements 181 to 184 can be connected via the matrix 96. The controllable element CE 181 is connected to the L of the first module 52. out With L inTypically, this connection will replace an internal function fx in the module 52 with a controllable element CE in the platform.

[0118] The output terminal M of the first module 52 out The second module 54 is connected to the input terminal M through the controllable element 182. in This can be done, among other things, so that the output terminals M of the modules 52, 54 out and input terminal M in The controllable element 183 is connected in a similar manner to the CE 181 and typically replaces an internal functional component in the second module 54. And the CE 184 is the same as the CE 182, when the signal is sent from the system to the S out Before being output, signal conditioning (amplification, adjustment of dynamic range or VU level, etc.) is performed.

[0119] To avoid overly complex diagrams and to make them easier to understand, Fig.16 Module links in and Fig.16 and Fig.17 The component connections of the controllable element CE in have been shown and described separately. Naturally, these two types of connections can be done together. In addition, such as Figure 3 The feedforward path shown in (which may include controllable elements) is also easy to implement.

[0120] Go to Fig.19 For completeness, the information transferred via the bus 60 during the above-mentioned handshake (HS) is represented by the arrow 190 between the HS on the module side and the HS on the UI side. As explained herein above, the CPU 58 uses the electrical data in the XML file to generate the power supply ( Figures 11 to 13 ) and controlled element 90( Fig.15 ) of operable data. When there is a module link - such as Fig.16 In the example, two or more modules 52, 54 are connected to each other - the CPU 58 uses the data from two or all modules to control the switch array 96 to establish the required links. Similarly, the connection mode of the modules 52, 54 and the controllable elements CE 90, 91, 92 is included in the XML file and used by the CPU to establish the required connection through the matrix 96.

[0121] exist Fig.19 In the example, user controls are provided by means of a user interface UI 68 (see Figure 5). The data from the module 52 also includes an XML file 192 that includes UI information that defines the graphics 194 displayed by the UI. This includes the characteristics of the graphical user interface for the module for display. Although the graphics information from the modules 52, 54 can provide a complete definition of the graphical image of the module, it is generally more efficient to store the graphics for each module 52 in a library in the CPU 58. In practice, the library can be stored in an online server (in the cloud) and retrieved by the CPU 58 via an online connection (not shown) based on the data from each module.

[0122] The CPU 58 operates as a user interface service module UI Srvc including a web class server SRV 196, which is arranged to generate graphics for a web client Clnt 198 (e.g., a web browser). The web client 198 sends a web request to the web server 196 included in the UI Srvc. The web class server 196 responds with a web page, which the web client 198 receives and uses to display a user interface on the display 194. The web page shows information about the installed modules 52, 54, such as their names, their physical locations, graphics corresponding to their brands, and their available controls. Using the graphics for the modules displayed on the UI 194, manipulation of the images enables the user to change the operation of the system.

[0123] As can be seen from the above description of CPU 58 and UI 68, the functions of CPU or UI or both can be provided by a personal computer (not shown) connected to bus 60. Therefore, CPU 58 and UI 68 shown in the figure can be implemented by a computer outside system 10, and can be connected to a computer outside system 10. Figure 5 The description and display are consistent.

[0124] exist Fig. 20 In the example, UI 60 is shown to include user input I / P 202. When display 194 has touch input capability, dragging and clicking the display is used as user input 202. In a PC-based arrangement, user input I / P 202 may be provided by a mouse (not shown) that drives a cursor on the display, the movement of which as well as clicks and single clicks are used as user input. In both examples, the user's manipulation of the image is interpreted by user interface UI 68 as a command for changing the operation of the system.

[0125] The UI client Clnt 204 converts the command into a command Web request, which is sent to the Web server 196. The UI Srvc in the CPU 58 converts the command into actionable data, which is sent to the driver DVR 206 for each module 52 to change its operation. The driver 206 is provided by the data element 70 of the module. Fig.15 , the module's microcontroller 160 uses the operational data to generate new data for the switching attenuator 174, programmable gain amplifier 176, etc., thereby changing the operation of the module.

[0126] exist Fig.21 In the embodiment, the user interface 68 is provided by a digital audio workstation DAW running on a personal computer. Since the workstation is digital, the audio data can be in digital form. The digital audio data can be transmitted through Fig.11 The analog-to-digital converter ADC 108 shown in FIG. 1 is communicated digitally between the system and the DAW.

[0127] The UI 68 is provided as a plug-in inside a digital audio workstation DAW. The plug-in is client software, and it will be a corresponding DAW plug-in server running inside the UI service. The DAW plug-in includes a graphical user interface P / GUI 210 and a client P / Clnt 212, which is equivalent to Fig. 20 The DAW plug-in P / Clnt 212 is connected to the UI Srvc in the CPU 58 via a bus 214, which may be provided as an Ethernet connection. The command flow between the DAW plug-in P / Clnt 212 and the UI Srvc in the CPU 58 is similar to that previously described with reference to FIG. Fig.18 and Fig.19 Describes the command flow.

[0128] In summary, the audio signal processing device includes at least one controllable element 90,91,92, which is used to perform analog audio processing functions. The controllable element can be operated together with a digital controller 58, which controls the analog audio processing functions performed by the controllable elements 90,91,92. At least one audio processing module 52,54 includes a partial audio processing circuit for audio processing operations. Modules 52,54 can be operated together with controllable elements 90,91,92 to complete the audio processing circuit and thereby enable audio processing operations. In this way, the audio processing operation can be controlled by the digital controller. The switch array 96 selectively connects the audio processing modules 52,54 and the controllable elements 90,91,92. The power supply 66 can be operated to selectively supply power to the audio processing circuit of the module 52,54 or each module 52,54.

[0129] The present invention has been described by referring to an audio signal processing device, an audio processing module, an audio signal processing system, and a method for processing an analog audio signal. It should be understood that the audio signal processing device, the audio processing module, the audio signal processing system, and the method for processing an analog audio signal are described only by way of example, and that modifications and variations may be made by persons having appropriate knowledge and skills without departing from the spirit and scope of the present invention as set forth in the appended claims and their equivalents.

Claims

1. An audio signal processing device, the audio signal processing device comprising: Digital controller; at least one controllable element, the controllable element being used to perform an analog audio processing function, the controllable element being operable together with the digital controller, the digital controller being used to control the analog audio processing function performed by the controllable element, and the controllable element being operable together with an audio processing module including a partial audio processing circuit for an audio processing operation to complete the audio processing circuit and thereby implement the audio processing operation.

2. The audio signal processing device according to claim 1, wherein: The controllable element comprises a variable gain amplifier operable under digital control for varying the gain of the variable gain amplifier, the amplifier being coupled to the digital controller and the amplifier being responsive to commands from the digital controller to vary the gain.

3. The audio signal processing device according to claim 2, wherein: The controllable element includes an array of attenuators that can be selected individually or in combination to attenuate the signal, the array is connected to the variable gain amplifier to pass the audio signal to the variable gain amplifier, and the array is connected to the digital controller and responds to commands from the digital controller to vary the attenuation.

4. An audio signal processing device according to any preceding claim, wherein: The controllable element comprises a variable filter for filtering signals within a frequency range, the variable filter being operable to vary the filtering performed by the variable filter.

5. The audio signal processing device according to claim 4, wherein: The controllable element includes one or more variable resistors, which are connected to the variable filter and can be operated under digital control to change the resistance of the variable resistor, the variable resistor is connected to the digital controller and the variable resistor responds to commands from the digital controller to change the resistance and thereby change the filtering performed by the variable filter.

6. The audio signal processing device according to claim 4 or 5, wherein: The filter has an input and an output, the controllable element includes a switch coupled between the input and the output, the switch coupled to the digital controller and responsive to a command from the digital controller to bypass the filter.

7. An audio signal processing device according to any preceding claim, further comprising a power supply for selectively supplying power to the or each module.

8. The audio signal processing device according to claim 7, wherein: The power supply comprises, for the or each module: a digital-to-analog converter that responds to a command from the digital controller to output a reference voltage; and A regulator is used to change the supplied DC voltage to output a DC voltage for the module.

9. The audio signal processing device according to claim 8, wherein: The power supply includes a selector that responds to commands from the digital controller to select a voltage tap and output a voltage for the regulator.

10. The audio signal processing device according to any one of claims 7 to 9, wherein: The power supply includes a microcontroller coupled to the digital controller to receive commands from the digital controller, and the microcontroller is operable to issue commands for operation of the power supply.

11. An audio signal processing device according to any preceding claim, further comprising a switch array responsive to the digital controller to selectively couple the or each audio processing module and the or each controllable element.

12. An audio signal processing device according to any preceding claim, wherein: When the digital controller is coupled to an audio processing module, the digital controller is responsive to operational data from the audio processing module to provide control data for at least one of the controllable elements.

13. An audio signal processing device according to any preceding claim when dependent on claim 7, wherein: When the digital controller is coupled to an audio processing module, the digital controller is responsive to operational data from the audio processing module to provide control data for the power supply.

14. An audio signal processing device according to any preceding claim when dependent on claim 11, wherein When the digital controller is coupled to an audio processing module, the digital controller is responsive to operational data from the audio processing module to provide control data for the switch array.

15. An audio signal processing device according to any preceding claim, further comprising a user interface coupled to the digital controller, the user interface responsive to user manipulation to provide commands to the digital controller to change the operation of a controllable element or a switch array according to claim 11.

16. An audio processing module for use with the apparatus of any preceding claim, the module comprising a portion of an audio processing circuit for an audio processing operation, the module being capable of being coupled to at least one controllable element to complete the audio processing circuit, thereby implementing the audio processing operation.

17. The audio processing module according to claim 16, wherein: The analog audio processing module or each analog audio processing module comprises: a signal input terminal, the signal input terminal is used to receive the audio signal to be processed; and a signal output terminal, the signal output terminal is used to output the processed signal, the signal input terminal can be connected to a signal source, and the signal output terminal can be connected to a signal destination.

18. The audio processing module according to claim 16 or 17, wherein: The or each analog audio processing module comprises a data element for providing operational data for the module to the digital controller.

19. The audio processing module according to claim 18, wherein: The operational data from the data element includes control data for one or more of the controllable element, the power supply, and the switch array in the analog audio signal processing device.

20. The audio processing module according to claim 18 or 19, wherein: The data element comprises a microcontroller having at least one input-output pin coupled to the controllable element to provide some of the control data to the controllable element.

21. An audio signal processing system, the audio signal processing system comprising: The audio signal processing device according to any one of claims 1 to 15; as well as At least one audio processing module according to any one of claims 16 to 20.

22. A method for processing an analog audio signal, the method comprising: providing at least one controllable element for performing an analog audio processing function; providing at least one analog audio processing module, the analog audio processing module including a portion of an audio processing circuit for audio processing operations; completing the audio processing circuit using at least one of the controllable elements and at least one of the analog audio processing modules; as well as The analog audio processing function of the controllable element is controlled to enable the audio processing operation of at least one of the analog audio processing modules.

23. The method according to claim 22, comprising: A variable gain amplifier is provided in at least one of the controllable elements, and the gain of the variable gain amplifier is varied to change the analog function of the controllable element.

24. The method according to claim 23, comprising: providing an array of attenuators in at least one of the controllable elements, the array of attenuators being coupled to the variable gain amplifier; Attenuators in the array are selected, individually or in combination, to change the analog function of the controllable element.

25. The method according to claim 23 or 24, comprising: providing a variable filter for filtering a signal from the variable gain amplifier over a frequency range; Operation of the variable filter is varied to change the analog function of the controllable element.

26. The method according to claim 25, wherein: The filter comprises an input and an output, the method comprising coupling a coupled switch between the input and the output, and operating the switch to change an analog function of the controllable element.

27. The method according to any one of claims 22 to 26, further comprising: providing a power supply for supplying power to the or each module; as well as Power is selectively supplied to the modules or each module individually.

28. The method according to claim 27, further comprising: Providing a reference voltage; providing a regulator for varying the supplied DC voltage relative to the reference voltage; as well as A DC voltage is output for the or each module.

29. The method according to claim 27 or 28, further comprising: Providing multiple voltage taps; Selecting a voltage tap; as well as The selected voltage tap is used to generate the supplied DC voltage.

30. The method according to any one of claims 22 to 29, further comprising: providing a switch array; as well as The switch array is operable to selectively couple the or each audio processing module to the or each controllable element.

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