Audio signal processing method and audio signal processing device

Abstract

The invention provides an audio signal processing method and an audio signal processing apparatus for performing the audio signal processing method. The audio signal processing method comprises the following steps: acquiring an audio signal, and compressing the audio signal to generate a first compressed signal; calculating the duration when the power value of the first compressed signal is equal to the first power threshold value; judging whether the duration is greater than a first time threshold; and when judging that the duration is greater than the first time threshold, compressing the first compressed signal to generate a second compressed signal, and amplifying and outputting the second compressed signal.

Description

Technical Field

[0001] This application relates to the field of audio signal processing technology, and in particular to an audio signal processing method and an audio signal processing apparatus. Background Technology

[0002] With the rapid development of technology, audio signal processing has transformed from analog audio signal processing to digital audio signal processing.

[0003] In digital audio signal processing, compressors / limiters are typically used in speaker systems to compress the dynamic range and control the power of digital audio signals, thereby preventing unpleasant sounds such as hissing and noise. However, when a speaker system operates at full power input for extended periods, or when the digital audio signal output exceeds the system's maximum power handling capacity, it can easily damage the power amplifier or speakers. Under extreme conditions, the electronic components within the speaker system may smoke or catch fire, directly impacting consumer safety and experience. Summary of the Invention

[0004] Based on the foregoing, this application provides an audio signal processing method and an audio signal processing apparatus to solve the problem of damage to power amplifiers or speakers caused by a speaker system being in a full-power input state for a long time.

[0005] Based on the foregoing, this application provides an audio signal processing method, executed by an audio signal processing device, comprising: acquiring an audio signal and compressing the audio signal to generate a first compressed signal, wherein the power value of the first compressed signal is less than or equal to a first power threshold; calculating the duration for which the power value of the first compressed signal is equal to the first power threshold; determining whether the duration is greater than a time threshold; when the duration is determined to be greater than the time threshold, compressing the first compressed signal to generate a second compressed signal, and amplifying and outputting the second compressed signal, wherein the power value of the second compressed signal is less than or equal to a second power threshold, and the second power threshold is less than the first power threshold.

[0006] Based on the foregoing, this application provides an audio signal processing apparatus, including a first limiter, a second limiter, a limiter triggering time component, and a power amplifier. The first limiter acquires an audio signal and compresses it to generate a first compressed signal; wherein the power value of the first compressed signal is less than or equal to a first power threshold. The limiter triggering time component is connected to the first limiter and calculates the duration for which the power value of the first compressed signal equals the first power threshold, and determines whether the duration is greater than the time threshold. The second limiter is connected to the limiter triggering time component, and when the limiter triggering time component determines that the duration is greater than the time threshold, it compresses the first compressed signal to generate a second compressed signal. The power value of the second compressed signal is less than or equal to a second power threshold, and the second power threshold is less than the first power threshold. The power amplifier is connected to the second limiter and the first limiter, and amplifies and outputs the second compressed signal.

[0007] In summary, the audio signal processing method and audio signal processing apparatus of this application, by configuring two limiters, reduce excessively loud sounds and prevent damage to electronic components caused by the speaker system operating at maximum power for extended periods.

[0008] Furthermore, the audio signal processing method and audio signal processing apparatus of this application can be applied to subwoofer systems. Even when the subwoofer system operates at high power for extended periods, the audio signal processing method and audio signal processing apparatus of this application can still prevent damage to the speaker and power amplifier caused by high-power operation, and do not affect the output capability of large dynamic signals for short periods.

[0009] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this invention and to implement it in accordance with the contents of the specification, the following describes the invention in detail with reference to preferred embodiments and accompanying drawings. Attached Figure Description

[0010] Figure 1 A block diagram of an audio signal processing apparatus according to an embodiment of this application is shown.

[0011] Figure 2 A flowchart illustrating an audio signal processing method according to an embodiment of this application is provided.

[0012] Figure 3 A flowchart illustrating an audio signal processing method according to another embodiment of this application is provided.

[0013] Figure 4A This is a schematic diagram illustrating the output of a second compressed signal in an audio signal processing method according to another embodiment of the present application.

[0014] Figure 4BThis is a schematic diagram illustrating the output of a first compressed signal in an audio signal processing method according to another embodiment of the present application.

[0015] Figure 5 A block diagram of an audio signal processing apparatus is shown according to another embodiment of this application.

[0016] Figure 6 A schematic diagram illustrating the reduction of audio signal power by a second limiter according to an embodiment of this application is shown.

[0017] Explanation of reference numerals in the attached figures:

[0018] 1A, 1B: Audio signal processing device

[0019] 10: Signal Input Interface

[0020] 20: Mixer

[0021] 30: Signal Amplifier

[0022] 40: Equalizer

[0023] 50: First limiter

[0024] 60: Processor

[0025] 60A: Limiting Trigger Time Component

[0026] 60B: Limiting runtime component

[0027] 70: Second limiter

[0028] 80: Power Amplifier

[0029] S11~S15, S21~S30: Steps Detailed Implementation

[0030] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the accompanying drawings and embodiments. To enable those skilled in the art to better understand the solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0033] The audio signal processing apparatus of this application includes a first limiter, a limiter triggering time component, a second limiter, and a power amplifier. The first limiter acquires an audio signal and compresses it to generate a first compressed signal; wherein the power value of the first compressed signal is less than or equal to a first power threshold. The limiter triggering time component is connected to the first limiter and calculates the duration for which the power value of the first compressed signal equals the first power threshold, and determines whether the duration is greater than the time threshold. The second limiter is connected to the limiter triggering time component and, when the limiter triggering time component determines that the duration is greater than the time threshold, compresses the first compressed signal to generate a second compressed signal, wherein the power value of the second compressed signal is less than or equal to a second power threshold, and the second power threshold is less than the first power threshold. The power amplifier is connected to the second limiter and the first limiter, and amplifies and outputs the second compressed signal. Through the limiter triggering time component and the second limiter, the first compressed signal is selectively compressed to avoid damage to the speaker or power amplifier. Detailed embodiments are described below.

[0034] Please see Figure 1 This is a block diagram illustrating an audio signal processing apparatus according to an embodiment of this application. Figure 1 As shown, the audio signal processing device 1A is used in a speaker system and includes a signal input interface 10, a mixer 20, a signal amplifier 30, an equalizer 40, a first limiter 50, a processor 60, a second limiter 70, and a power amplifier 80.

[0035] The signal input interface 10 acquires a single-track audio signal. Specifically, the signal input interface 10 is an input interface with multiple audio jacks and multiple USB (Universal Serial Bus) jacks. The signal input interface 10 is connected to an audio playback device, such as a portable playback device or microphone, via an audio source cable or USB cable to acquire a single-track audio signal. The portable playback device can be a CD player, mobile phone, MP3 player, etc. In this embodiment, the audio signal processing device 1 further includes a mixer 20, which connects the signal input interface 10 and the signal amplifier 30; in other words, the mixer 20 is located between the signal input interface 10 and the signal amplifier 30. The audio playback device transmits the left channel audio signal and the right channel audio signal to the signal input interface 10 via the audio source cable or USB cable. The signal input interface 10 transmits the left channel audio signal and the right channel audio signal to the mixer 20. The mixer 20 mixes the left channel audio signal and the right channel audio signal into a single-track audio signal and transmits the single-track audio signal to the signal amplifier 30. In another embodiment, the audio playback device directly transmits a single-track audio signal to the signal input interface 10 via an audio source cable or a USB cable, and the signal input interface 10 transmits the single-track audio signal to the signal amplifier 30.

[0036] Signal amplifier 30 is connected to signal input interface 10. For example, signal amplifier 30 may be an operational amplifier, voltage amplifier, or differential amplifier. In this embodiment, signal amplifier 30 is connected to signal input interface 10 through mixer 20, obtains a single-track audio signal from mixer 20, and amplifies the single-track audio signal to generate an amplified audio signal. In another embodiment, signal amplifier 30 is directly connected to signal input interface 10, obtains a single-track audio signal from signal input interface 10, and amplifies the single-track audio signal to generate an amplified audio signal. Through the action of the signal amplifier, the amplitude of the amplified audio signal (e.g., voltage amplitude) is greater than the amplitude of the single-track audio signal.

[0037] Equalizer 40 is connected to signal amplifier 30; in other words, signal amplifier 30 is positioned between equalizer 40 and mixer 20, or between equalizer 40 and signal input interface 10. Specifically, equalizer 40 may be a multi-band variable equalizer, a linear equalizer, a decision feedback equalizer, or other types of equalizer. Equalizer 40 performs an equalization process on the amplified audio signal to produce a balanced audio signal. Details of the equalization process will be described in detail in the section on audio signal processing methods.

[0038] The first limiter 50 is connected to the equalizer 40, the power amplifier 80, and the processor 60; in other words, the first limiter 50 is positioned between the equalizer 40 and the processor 60, and between the power amplifier 80 and the equalizer 40. For example, the first limiter 50 may be a VCA (voltage-controlled amplifier) ​​compressor, a field-effect transistor compressor, a tube compressor, an optical compressor, or other types of compressor. The first limiter 50 has a first power threshold. In this embodiment, a balanced audio signal is used as the audio signal received by the first limiter 50, and the first limiter 50 compresses the balanced audio signal to generate a first compressed signal; the power value of the first compressed signal is less than or equal to the first power threshold. Details of generating the first compressed signal will be described in detail in the audio signal processing method section. In another embodiment, the configuration of the equalizer 40 and the signal amplifier 30 may be omitted; a single-track audio signal may be used as the audio signal received by the first limiter 50, and the first limiter 50 compresses the single-track audio signal to generate the first compressed signal. It should be noted that the audio signal received by the first limiter 50 can be any type of audio signal, and there is no limitation on the type of audio signal received by the first limiter 50.

[0039] Processor 60 is connected to second limiter 70, and power amplifier 80 is connected to both second limiter 70 and first limiter 50. In other words, second limiter 70 is located between processor 60 and power amplifier 80, and power amplifier 80 is located between second limiter 70 and first limiter 50. For example, processor 60 may be a microcontroller unit (MCU), central processing unit (CPU), or other type of processor; second limiter 70 may be a VCA (voltage-controlled amplifier) ​​compressor, field-effect transistor compressor, vacuum tube compressor, optical compressor, or other type of compressor; and power amplifier 80 may be a Class A amplifier, Class B amplifier, Class AB amplifier, Class C amplifier, Class D amplifier, or other type of amplifier.

[0040] In this embodiment, the processor 60 calculates the duration for which the power value of the first compressed signal equals a first power threshold, and determines whether the duration is greater than a first time threshold to generate a determination result; the second limiter 70 has a second power threshold. Subsequently, the processor 60 controls the first limiter 50 to output the first compressed signal to the power amplifier 80 or the second limiter 70 according to the determination result. The second limiter 70 further compresses the first compressed signal to generate a second compressed signal, the power value of which is less than or equal to the second power threshold. Finally, the power amplifier 80 amplifies and outputs the first compressed signal or the second compressed signal to the audio playback device. The details of determining the duration and selecting the first or second compressed signal for amplification and output will be described in detail in the audio signal processing method section.

[0041] In another embodiment, processor 60 calculates the duration for which the power value of the first compressed signal equals a first power threshold, and determines whether the duration is greater than a first time threshold to generate a first determination result; second limiter 70 has a second power threshold. Subsequently, processor 60 controls first limiter 50 to output the first compressed signal to power amplifier 80 or second limiter 70 according to the first determination result. When processor 60 transmits the first compressed signal to second limiter 70, processor 60 calculates the entry time of the first compressed signal into second limiter 70, and determines whether the entry time is greater than the second time threshold to generate a second determination result. Processor 60 selectively activates second limiter 70 according to the second determination result to further compress the first compressed signal. The compressed first compressed signal becomes the second compressed signal, and the power value of the second compressed signal is less than or equal to the second power threshold. Finally, power amplifier 80 amplifies and outputs the first compressed signal or the second compressed signal to audio playback device. The details of determining the duration, the entry time, and generating the second compressed signal will be described in detail in the audio signal processing method section.

[0042] Please see Figure 2 This is a flowchart illustrating an audio signal processing method according to an embodiment of this application. Figure 2 As shown, the audio signal processing method includes steps S11 to S15. Figure 2 The audio signal processing method shown can be applied to audio signal processing devices including a first limiter, a limiter trigger time component, a second limiter, and a power amplifier. Figure 1 The audio signal processing apparatus shown is not limited to this. The following examples illustrate... Figure 1 The audio signal processing apparatus shown will be used to illustrate steps S11 to S15.

[0043] Step S11: Compress the audio signal to generate a first compressed signal. Specifically, the first limiter 50 compresses the audio signal according to a first attack time, a first release time, a first compression threshold, and a first compression ratio. The maximum signal level of the compressed audio signal is lower than the first compression threshold. The compressed audio signal serves as the first compressed signal. The dynamic range of the first compressed signal is smaller than the dynamic range of the audio signal, and the power value of the first compressed signal is less than or equal to a first power threshold. Furthermore, the first attack time, first release time, first compression threshold, and first compression ratio are preset in the first limiter. It should be noted that audio amplification signals, single-track audio signals, or other types of audio signals can be used as the audio signals received by the first limiter 50; therefore, the type of audio signal received by the first limiter 50 is not limited.

[0044] When the audio signal exceeds a threshold, the limiter begins to compress the audio signal. The trigger time is the time at which the limiter begins compression when the audio signal exceeds the threshold. The release time is the time it takes for the audio signal to go from being compressed to being uncompressed. The compression ratio specifies the amount of compression used to compress the audio signal. The values ​​of the threshold, trigger time, release time, and compression ratio can vary depending on the compression requirements of the audio signal; however, there are no fixed values ​​for these parameters.

[0045] Step S12: Calculate the duration during which the power value of the first compressed signal equals the power threshold. Specifically, the processor 60 obtains the first compressed signal and the first power threshold from the first limiter 50, and calculates the duration during which the power value of the first compressed signal equals the power threshold.

[0046] Step S13: Determine whether the duration is greater than a time threshold. Specifically, the processor 60 determines whether the duration is greater than a time threshold to generate a determination result, and selects whether to further compress the first compressed signal based on the determination result.

[0047] If the determination result is that the duration is greater than the time threshold, the speaker system has been operating at high power for a long time or is in a full-power input state, and the first compression signal needs to be further compressed, then proceed to step S14. If the determination result is that the duration is not greater than the time threshold, the speaker system is operating normally, and the first compression signal does not need to be further compressed, then proceed to step S15.

[0048] Step S14: Compress the first compressed signal to generate a second compressed signal, and amplify and output the second compressed signal. Specifically, the processor 60 transmits the first compressed signal to the second limiter 70. The second limiter 70 compresses the first compressed signal according to a second compression threshold, decay rate, and hold time. The compressed first compressed signal becomes the second compressed signal. The dynamic range of the second compressed signal is smaller than that of the first compressed signal, and the power value of the second compressed signal is less than or equal to a second power threshold, which is less than the first power threshold. In other words, the power value of the second compressed signal is less than the power value of the first compressed signal. Subsequently, the second limiter 70 transmits the second compressed signal to the power amplifier 80. The power amplifier 80 amplifies and outputs the second compressed signal to the speaker according to the driving requirements of the speaker in the speaker system.

[0049] Furthermore, the second compression threshold is preset in the second limiter 70. When the power value of the second compression signal drops to the second power threshold, the processor 60 controls the second limiter 70 to stop compression and maintain the output of the second compression signal. When it is determined that the signal level of the first compression signal has decreased, the processor 60 stops determining whether the duration exceeds the time threshold.

[0050] Step S15: Amplify and output the first compressed signal. Specifically, the power amplifier 80 obtains the first compressed signal from the first limiter 50, and amplifies and outputs the first compressed signal to the speaker according to the driving requirements of the speaker system.

[0051] The audio signal processing method of this application can not only protect the subwoofer system from damage caused by long-term high-power operation, but also does not affect the output capability of large dynamic signals in a short period of time.

[0052] Please see Figure 3 This is a flowchart illustrating an audio signal processing method according to an embodiment of this application. Figure 3 As shown, the audio signal processing method includes steps S21 to S30. Steps S25 to S26 are... Figure 2 Steps S12 to S13 shown are the same. Figure 3 and Figure 2The similarities will not be repeated here. Steps S21 to S23 further describe the generation of the balanced audio signal, and steps S28 to S29 further determine whether to activate the second limiter 70. Additionally, the time threshold in step S26 is the determination of duration, and the time threshold in step S29 is the determination of entry time. The time thresholds in steps S26 and S29 are not the same; to distinguish between the time thresholds in steps S26 and S29, the time threshold in step S26 is the first time threshold, and the time threshold in step S29 is the second time threshold. The following examples illustrate... Figure 1 The audio signal processing apparatus shown is used to illustrate steps S21 to S23 and steps S27 to S30.

[0053] Step S21: Obtain a single-track audio signal. As mentioned above, the signal input interface 10 obtains a single-track audio signal from the audio playback device; or, the signal input interface 10 obtains the left channel audio signal and the right channel audio signal from the audio playback device, and the mixer 20 obtains the left channel audio signal and the right channel audio signal from the signal input interface 10, and generates a single-track audio signal based on the left channel audio signal and the right channel audio signal.

[0054] Step S22: Amplify the single-track audio signal to generate an amplified audio signal. As previously described, the signal amplifier 30 obtains the single-track audio signal from the signal input interface 10 or the mixer 20 and amplifies it, increasing the signal level of the single-track audio signal and thus increasing its amplitude. The amplified single-track audio signal serves as the amplified audio signal, with a higher signal level than the single-track audio signal, resulting in a larger amplitude. Subsequently, the signal amplifier 30 transmits the amplified audio signal to the equalizer 40.

[0055] Step S23: Perform an equalization process on the amplified audio signal to generate a balanced audio signal. Specifically, equalizer 40 adjusts multiple gain values ​​corresponding to multiple frequency bands of the amplified audio signal, and adjusts the signal level of the amplified audio signal in multiple frequency bands according to the adjusted multiple gain values. The adjusted amplified audio signal is then used as the balanced audio signal. Subsequently, equalizer 40 transmits the balanced audio signal to the first limiter 50.

[0056] For example, there are three frequency bands: low frequency, mid frequency, and high frequency. The low frequency band can be represented by a piano, the mid frequency band by a singer's voice, and the high frequency band by a flute. Equalizer 40 appropriately adjusts the three gain values ​​corresponding to the low, mid, and high frequency bands of the amplified audio signal. After adjustment, the three gain values ​​are different from each other, and the three signal levels of the amplified audio signal in the low, mid, and high frequency bands are also different. Through the adjustment of equalizer 40, the piano sound becomes richer, the singer's voice becomes clearer, and the brightness of the flute sound is increased.

[0057] Step S24: Compress the balanced audio signal to generate a first compressed signal. Specifically, the first limiter 50 compresses the balanced audio signal according to a first attack time, a first release time, a first compression threshold, and a first compression ratio. The maximum signal level of the compressed balanced audio signal is lower than the first compression threshold. The compressed balanced audio signal serves as the first compressed signal. The dynamic range of the first compressed signal is smaller than that of the balanced audio signal, and the power value of the first compressed signal is less than or equal to a first power threshold. Furthermore, the first attack time, first release time, first compression threshold, and first compression ratio are preset in the first limiter 50.

[0058] Step S27: Receive the first compressed signal and calculate the arrival time of the first compressed signal. Specifically, the second limiter 70 receives the first compressed signal from the processor 60, and the processor 60 calculates the arrival time of the first compressed signal entering the second limiter 70.

[0059] Step S28: Amplify and output the first compressed signal. Specifically, as follows: Figure 4B As shown, the power amplifier 80 obtains the first compressed signal from the first limiter 50, and amplifies and outputs the first compressed signal to the speaker according to the driving requirements of the speaker in the speaker system.

[0060] Step S29: Determine whether the entry time is greater than the second time threshold. Specifically, the processor 60 determines whether the entry time is greater than the second time threshold to generate a second determination result, and selects whether to further compress the first compression signal based on the second determination result.

[0061] If the second judgment result indicates that the entry time is greater than the second time threshold, the speaker system has been operating at high power for a long time or is in a full-power input state, and the first compression signal needs to be further compressed. The processor 60 controls the second limiter 70 to start and continues to execute step S20. If the second judgment result indicates that the entry time is not greater than the second time threshold, there is no need to further compress the first compression signal, and the process returns to step S28.

[0062] Step S30: Compress the first compressed signal according to the running time conditions to generate a second compressed signal, and amplify and output the second compressed signal. Specifically, as follows... Figure 4A As shown, processor 60 transmits a first compressed signal and a runtime condition to second limiter 70. The runtime condition includes hold time and decay rate. Second limiter 70 compresses the first compressed signal according to a second compression threshold, decay rate, and hold time. The compressed first compressed signal then becomes the second compressed signal. The dynamic range of the second compressed signal is smaller than that of the first compressed signal, and the power value of the second compressed signal is less than or equal to a second power threshold, which is less than the first power threshold. In other words, the power value of the second compressed signal is less than the power value of the first compressed signal. Subsequently, second limiter 70 transmits the second compressed signal to power amplifier 80. Power amplifier 80 amplifies and outputs the second compressed signal to the speaker according to the driving requirements of the speaker system.

[0063] In addition, the second compression threshold is preset in the second limiter 70. When the power value of the second compressed signal drops to the second power threshold, the processor 60 controls the second limiter 70 to stop compression and maintain the output of the second compressed signal. When it is determined that the signal level of the single-track audio signal drops, the processor 60 stops judging whether the duration is greater than the first time threshold, and the power of the single-track audio signal gradually returns to full power.

[0064] In the audio signal processing method of this embodiment, the maximum power of the audio signal is adjusted for a short period of time through compression by the first limiter. After the speaker system has been operating at full power for a period of time, the second limiter is activated to compress the audio signal after it has been compressed by the first limiter. The power of the entire speaker system begins to decrease, so as to ensure that the speaker system can provide the ability to operate for a long time under full power input and avoid damage to the speaker system.

[0065] Please see Figure 5Figure 4 is a block diagram illustrating an audio signal processing apparatus according to another embodiment of this application. As shown in Figure 4, the audio signal processing apparatus 1B includes a signal input interface 10, a mixer 20, a signal amplifier 30, an equalizer 40, a first limiter 50, a limiter trigger time component 60A, a limiter run time component 60B, a second limiter 70, and a power amplifier 80. The configuration of the signal input interface 10, mixer 20, signal amplifier 30, equalizer 40, first limiter 50, second limiter 70, and power amplifier 80 is shown in Figure 4. Figure 1 The configuration shown is the same and will not be repeated here. It should be noted that... Figure 5 The audio signal processing device shown can perform Figure 2 and Figure 3 The audio signal processing method shown is illustrated. Figure 2 The multiple steps executed by the processor 60 can be performed through the limiting trigger time component 60A and the limiter, but the limiting run time component 60B is not used. Figure 3 The multiple steps executed by the processor 60 can be performed through the limiting trigger time component 60A, the limiting run time component 60B, and the limiter.

[0066] Limiting trigger time component 60A and limiting run time component 60B are located in processor 60, meaning they are functional units executed by processor 60. Limiting trigger time component 60A is connected to the first limiter 50 and the second limiter 70; in other words, limiting trigger time component 60A is located between the first limiter 50 and the second limiter 70. Limiting trigger time component 60A calculates the duration for which the power value of the first compressed signal equals a first power threshold, and determines whether the duration is greater than the first time threshold, which is set to N seconds. The determination that the duration is greater than N seconds is trigger condition C1.

[0067] The limiting runtime component 60B is connected to the second limiter 70. In other words, the second limiter 70 is located between the limiting trigger time component 60A and the limiting runtime component 60B, and between the limiting runtime component 60B and the power amplifier 80. The limiting runtime component 60B stores runtime conditions, calculates the entry time of the first compression signal into the second limiter 70, and determines whether the entry time is greater than a second time threshold.

[0068] An electronic audio playback device provides a left-channel audio signal and a right-channel audio signal to a mixer 20, wherein the electronic audio playback device can be a portable playback device such as a CD player / mobile phone / microphone / broadcasting system. The mixer 20 mixes the left-channel and right-channel audio signals into a single-track audio signal with only one track and transmits the single-track audio signal to a signal amplifier 30. The signal amplifier 30 amplifies the signal level of the single-track audio signal to a suitable value through gain adjustment and transmits the amplified single-track audio signal to an equalizer 40. The equalizer 40 performs an equalization process on the amplified single-track audio signal to produce a balanced audio signal. A first limiter 50 receives the balanced audio signal from the equalizer 40 and compresses the balanced audio signal to produce a first compressed signal, the power of which is limited within the design power range of the first limiter 50.

[0069] Then, the limiting trigger time component 60A calculates the duration for which the power value of the first compressed signal equals the first power threshold, and determines whether the duration corresponding to the first compressed signal meets the trigger condition C1. When the limiting trigger time component 60A determines that the duration corresponding to the first compressed signal does not meet the trigger condition C1, it outputs the first compressed signal to the power amplifier 80, which amplifies and outputs the first compressed signal to the speaker. When the limiting trigger time component 60A determines that the duration corresponding to the first compressed signal meets the trigger condition C1, it outputs the first compressed signal to the second limiter 70. The limiting operation time component 60B calculates the entry time of the first compressed signal into the second limiter 70 and determines whether the entry time is greater than the second time threshold. When the entry time is greater than the second time threshold, the second limiter 70 starts and compresses the first compressed signal according to the operation time condition of the limiting operation time component 60B to generate the second compressed signal, and the power of the second compressed signal decreases. When the power of the second compressed signal decreases to the condition set by the second limiter 70, the second limiter 70 stops compressing and maintains the output of the second compressed signal. If the signal level of the left or right channel audio signal drops, the limiting trigger time component 60A turns off, and the power of the signal output by the power amplifier 80 gradually returns to full power.

[0070] The audio signal processing device in this embodiment, through the configuration of the limiting trigger time component 60A, the limiting run time component 60B, and the second limiter 70, can not only protect the subwoofer system from damage caused by long-term high-power operation, but also does not affect the output capability of large dynamic signals in a short period of time.

[0071] Please see Figure 6 This is a schematic diagram illustrating a second limiter reducing the power of an audio signal, based on an embodiment of this application. Figure 6 As shown, and paired with Figure 1The speaker system's power is approximately 1600W between 0 and 40 seconds. After 40 seconds, the second limiter 70 is triggered, and the speaker system's power gradually decreases, dropping to 800W within 2 minutes. When 1600W represents the speaker system's full power, the power drops to half of its full power within 2 minutes. Therefore, through the audio signal processing method and device of this application, the performance of the speaker and power amplifier is ensured without damage while the speaker system remains at full power, allowing the speaker system to operate normally under continuous full power conditions, providing early protection and a better user experience.

[0072] In summary, the audio signal processing method and audio signal processing apparatus of this application, by configuring two limiters, reduce excessively loud sounds and prevent damage to electronic components caused by the speaker system operating at maximum power for extended periods.

[0073] Furthermore, the audio signal processing method and audio signal processing apparatus of this application can be applied to subwoofer systems. Even when the subwoofer system operates at high power for extended periods, the audio signal processing method and audio signal processing apparatus of this application can still prevent damage to the speaker and power amplifier caused by high-power operation, and do not affect the output capability of large dynamic signals for short periods.

Claims

1. A method of audio signal processing, characterized by, comprising: obtaining an audio signal and compressing the audio signal to produce a first compressed signal, wherein a power value of the first compressed signal is less than or equal to a first power threshold; calculating a duration that the power value of the first compressed signal is equal to the first power threshold; determining whether the duration is greater than a time threshold; and compressing the first compressed signal to produce a second compressed signal when it is determined that the duration is greater than the time threshold, wherein a power value of the second compressed signal is less than or equal to a second power threshold, the second power threshold being less than the first power threshold.

2. The audio signal processing method of claim 1, wherein, further comprising: amplifying and outputting the first compressed signal when it is determined that the duration is not greater than the time threshold.

3. The audio signal processing method of claim 1, wherein, compressing the audio signal to produce the first compressed signal comprises: compressing the audio signal to produce the first compressed signal according to a first compression threshold and a first compression ratio, wherein a dynamic range of the first compressed signal is less than a dynamic range of the audio signal.

4. The audio signal processing method of claim 1, wherein, the time threshold is a first time threshold, and the step of compressing the first compressed signal to produce the second compressed signal when it is determined that the duration is greater than the first time threshold further comprises: receiving the first compressed signal and calculating an entry time of the first compressed signal when it is determined that the duration is greater than the first time threshold; determining whether the entry time is greater than a second time threshold; compressing the first compressed signal to produce the second compressed signal according to a run-time condition and amplifying and outputting the second compressed signal when it is determined that the entry time is greater than the second time threshold.

5. The audio signal processing method of claim 4, wherein, the run-time condition comprises a decay rate and a sustain time, and compressing the first compressed signal to produce the second compressed signal according to the run-time condition comprises: compressing the first compressed signal to produce the second compressed signal according to a second compression threshold, the decay rate, and the sustain time, wherein a dynamic range of the second compressed signal is less than a dynamic range of the first compressed signal.

6. The audio signal processing method of claim 1, wherein, further comprising: obtaining a mono audio signal; amplifying the mono audio signal to produce an audio amplified signal; and performing an equalization process on the audio amplified signal to produce an equalized audio signal, the equalized audio signal being the audio signal.

7. The audio signal processing method of claim 6, wherein, obtaining the mono audio signal comprises: obtaining a left channel audio signal and a right channel audio signal; and mixing the left channel audio signal and the right channel audio signal to produce the mono audio signal.

8. The audio signal processing method of claim 6, wherein, stopping determining whether the duration is greater than the time threshold when a signal level of the mono audio signal decreases.

9. An audio signal processing apparatus, characterized by comprising: comprising: a first limiter that obtains an audio signal and compresses the audio signal to produce a first compressed signal, wherein a power value of the first compressed signal is less than or equal to a first power threshold; a limiter trigger time component that is coupled to the first limiter and calculates a duration that the power value of the first compressed signal is equal to the first power threshold and determines whether the duration is greater than a time threshold; a second clipper connected to the clip trigger time component and configured to compress the first compressed signal to generate a second compressed signal when the clip trigger time component determines that the duration is greater than the time threshold, the second compressed signal having a power value less than or equal to a second power threshold, the second power threshold being less than the first power threshold; and a power amplifier connected to the second clipper and the first clipper and configured to amplify and output the second compressed signal.

10. The audio signal processing device of claim 9, wherein, when the clip trigger time component determines that the duration is not greater than the time threshold, the power amplifier is configured to amplify and output the first compressed signal.

11. The audio signal processing device of claim 9, wherein, The step of compressing the audio signal to generate the first compressed signal performed by the first clipper includes: compressing the audio signal to generate the first compressed signal according to a first compression threshold and a first compression ratio, the first compressed signal having a dynamic range less than a dynamic range of the audio signal.

12. The audio signal processing device of claim 9, wherein, The apparatus further includes a clip run time component connected to the second clipper and configured to store a run time condition, the time threshold being a first time threshold; when the clip trigger time component determines that the duration is greater than the first time threshold, the second clipper receives the first compressed signal, the clip run time component calculates an entry time of the first compressed signal into the second clipper and determines whether the entry time is greater than a second time threshold, and when the clip run time component determines that the entry time is greater than the second time threshold, the second clipper activates and obtains the run time condition from the clip run time component and compresses the first compressed signal according to the run time condition to generate the second compressed signal.

13. The audio signal processing device of claim 12, wherein, The run time condition includes a sustain time and a decay rate, and the step of compressing the first compressed signal to generate the second compressed signal performed by the second clipper according to the run time condition includes: compressing the first compressed signal to generate the second compressed signal according to a second compression threshold, the decay rate, and the sustain time, the second compressed signal having a dynamic range less than a dynamic range of the first compressed signal.

14. The audio signal processing device of claim 12, wherein, The clip trigger time component and the clip run time component are disposed in a processor.

15. The audio signal processing device of claim 9, wherein, The apparatus further includes a signal input interface configured to obtain a single-track audio signal, a signal amplifier connected to the signal input interface and configured to amplify the single-track audio signal to generate an audio amplified signal, and an equalizer connected to the signal amplifier and the first clipper and configured to perform an equalization process on the audio amplified signal to generate and transmit an equalized audio signal to the first clipper, the equalized audio signal being the audio signal.

16. The audio signal processing device of claim 15, wherein, Further comprising a mixer connected between the signal input interface and the signal amplifier, the signal input interface obtains a left channel audio signal and a right channel audio signal from an audio playing device, the mixer mixes the left channel audio signal and the right channel audio signal into the single track audio signal, and transmits the single track audio signal to the signal amplifier.

17. The audio signal processing device of claim 15, wherein, When the signal level of the single track audio signal is lower than a signal level threshold, the clip trigger time component is turned off and stops determining whether the duration is greater than the time threshold.

Images