Audio system and method for providing saturation processing of audio output

Abstract

An audio system includes an amplifier that includes at least one controller and is programmed to: receive an audio input signal; apply saturation processing to at least the audio input signal by introducing nonlinear distortion to provide an audio output signal; and transmit the audio output signal to one or more speakers to play audio from a first speaker among the one or more speakers.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 788,426, filed April 14, 2025, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The aspects disclosed herein generally relate to an audio system and method for providing saturation processing for audio output. These and other aspects will be discussed in more detail below. Background Technology

[0004] An audio amplifier (or power amplifier) ​​typically amplifies a low-power audio input signal received from an audio source. In this case, the audio amplifier increases the output level of the powerful audio input signal high enough to drive one or more speakers in the listening environment. Generally, an audio amplifier can be the last electronic device in the audio playback chain before the amplifier's audio output is transmitted to the speakers. The preamplifier stage of an audio amplifier may include an equalizer and / or a mixer that combines various input signals. Summary of the Invention

[0005] In at least one embodiment, an audio system is provided. The audio system includes an amplifier that includes at least one controller and is programmed to: receive an audio input signal; apply saturation processing to at least the audio input signal by introducing nonlinear distortion to provide an audio output signal; and transmit the audio output signal to one or more speakers to play audio from a first speaker among the one or more speakers.

[0006] In at least another embodiment, a method is provided. The method includes: receiving an audio input signal; applying a saturation process to at least the audio input signal to generate a saturated signal and providing an audio output signal; and playing the audio output signal via one or more speakers.

[0007] In at least another embodiment, a computer program product is provided, embodied in a non-transitory computer-readable medium stored in memory and programmed and executable by at least one controller in an audio system. The computer program product includes instructions for performing: receiving an audio input signal; applying saturation processing to at least the audio input signal to generate a saturated signal and providing an intermediate signal; and mixing the intermediate signal with the audio input signal to generate an audio output signal. Attached Figure Description

[0008] The embodiments of this disclosure are specifically pointed out in the appended claims. However, other features of the various embodiments will become more apparent and best understood by referring to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0009] Figure 1 A general description is provided of an audio system for providing saturation processing to an audio output signal according to one embodiment; and

[0010] Figure 2 The overall description is based on an implementation plan. Figure 1 The amplifier for the audio system.

[0011] Figure 3 A flowchart of an audio processing method according to one implementation scheme is generally described. Detailed Implementation

[0012] As requested, detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the invention that may be embodied in various alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show details of specific components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art to employ the invention in different ways.

[0013] The aspects disclosed herein generally provide, in particular, an amplifier including an audio signal processor that adds auditory excitation to an audio input signal. Auditory excitation typically corresponds to a process of adding saturation processing and dynamic enhancement based on the envelope of the audio input signal. The amplifier (e.g., or exciter) utilizes a full-wave (or half-wave) rectifier to track the envelope of the audio input signal. In one example, the audio input signal may be saturated (non-linear operation) to produce distortion and compression. A saturator may be included as part of the amplifier.

[0014] An audio signal processor can actually be used as a distortion envelope follower, which tracks the dynamic changes associated with the audio input signal. This is mixed with the original audio signal (or audio input signal), thus providing a degree of distortion and dynamics (which provide enhancement), and is pleasing, resulting in an enhanced listening experience. Furthermore, the audio input signal and sound characteristics can vary significantly based on input gain (e.g., volume). This generally means that the audio signal processor has a dynamic effect on the sound.

[0015] One intended use of the disclosed system and / or method can be performed by an automotive amplifier microprocessor located external to the main digital signal processor (DSP) for sound tuning. However, it should be recognized that the disclosed system / method can be used in other areas of sound tuning / audio calibration. The disclosed embodiments can provide:

[0016] 1. A signal stream used in an audio signal processor (or amplifier) ​​that utilizes a full-wave rectifier and a cubic function to provide saturation distortion; and

[0017] 2. Sound Characteristics of Car Amplifiers. Traditionally, car amplifiers are implemented to require clean input and output characteristics. The disclosed implementations add distortion / color to the audio input signals processed by the car amplifier.

[0018] Generally, the disclosed implementation can add sonic characteristics to the amplifier that are not present in automotive amplifier solutions, and also add dynamic characteristics that are beneficial to audio quality. These benefits may include:

[0019] 1. Adding sonic characteristics to car amplifiers can certainly be related to branded audio.

[0020] 2. Distortions common in audio signals and possessing "pleasant" characteristics (e.g., in tube amplifiers). Therefore, this sound was introduced into the automotive field, as otherwise including such circuitry would be both expensive and impractical.

[0021] 3. Enhance the original audio input signal by adding clarity, impact, and power while providing an audio output signal through any number of speakers.

[0022] 4. Improve the performance of high-volume amplifiers by providing audio saturation processing instead of distortion / clipping.

[0023] Current implementations attempt to maintain a clean audio path and achieve non-linear behavior through component overload. However, alternatively, static processors or processors that operate in a fixed manner (e.g., equalizers, compressors, limiters) can traditionally be used to create sound effects.

[0024] Generally, the disclosed amplifier can provide dynamic equalization and includes an audio processor, which may be a non-linear processor. For a desired application, an amplifier that enhances transient response, clarity, harmonics, and perceived loudness can be provided (e.g., a car amplifier). Similarly, the disclosed amplifier can amplify the aforementioned enhancements, thereby increasing the gain volume supplied to the processor. Therefore, the disclosed amplifier can operate in real-time / near real-time and respond dynamically as the volume (the gain supplied to the amplifier on the audio input signal) can increase or decrease.

[0025] The disclosed amplifier can be implemented using analog circuitry or other implementations, with a digital signal processor (DSP) located within a microcontroller (or audio processor) directly preceding the amplifier's power stage. Therefore, positioning the audio DSP processing before (or upstream of) the amplifier's power IC / output stage can be advantageous for providing auditory stimulation. One implementation of audio amplification, particularly in the automotive field, is the transparent amplification of the raw sound signal.

[0026] The disclosed amplifier intentionally incorporates distortion / non-linear characteristics to improve sound quality. The amplifier's audio signal processor can be positioned at a predetermined location within the amplifier. In one example, the audio signal processor could be located directly before the power IC amplification circuitry and operate on one or more channels with identical settings across all amplifier channels. Generally, a use case for saturators / exciters is during music composition, rather than in sound reproduction.

[0027] Figure 1 An audio system 100 for providing saturation processing of an audio output signal, according to one embodiment, is generally described. System 100 includes an audio source 102, an amplifier 104, and one or more speakers 106 (hereinafter referred to as speakers 106). Generally, an audio controller 102 provides an audio input signal to the amplifier 104. The amplifier 104 amplifies the audio input signal to provide an audio output signal, which is provided to the speakers 106. The speakers 106 play the audio output signal in a listening environment 109 (e.g., the cab of a vehicle 111).

[0028] Amplifier 104 includes at least one controller (“controller”) (e.g., a microcontroller or audio input processor) 108 and a power integrated circuit (IC) 110. The power IC 110 serves as an output amplification stage and provides power amplification operation for amplifier 104. It should be recognized that the power IC 110 may be a discrete output circuit for automotive or other applications, such as home audio. Controller 108 includes a first circuit 112 and a tracking power supply 114. Generally, the tracking power supply 114 allows amplifier 104 to operate more efficiently by supplying the desired amount of voltage to reproduce the audio signal. This may be considered necessary in automotive amplifiers, as thermal efficiency and power efficiency can be critical factors. Although Figure 1 Typically, the first circuit 112 is shown located directly before the tracking power supply 114; however, it should be recognized that the first circuit 112 may be located within the power IC 110. Generally, the first circuit 112 (e.g., an exciter or saturation circuit) can add harmonics to the audio input signal provided by the audio source 102 to provide the effect of applying saturation processing based on the dynamics of the audio input signal. This will combine Figure 2 Let's have a more detailed discussion.

[0029] Figure 2 The overall description is based on an implementation plan. Figure 1 A detailed block diagram of amplifier 104 in the audio system 100. Specifically, Figure 2 The general aspects relating to the first circuit 112 are shown. The first circuit 112 includes an input gain block 202, a first filter (e.g., a high-pass filter) 204, a second filter (e.g., an input tuning filter) 206, a rectifier 210, a third filter (e.g., a low-pass filter) 212, a harmonic pre-gain block 214, a saturator circuit 216, a harmonic post-gain circuit 218, an output mixer 220, a fifth filter (e.g., an output tuning filter) 222, and an output gain 224. It should be appreciated that the input tuning filter 206 and / or the output tuning filter 222 may include any number of filters.

[0030] The amplifier 104 operates as described below. Input gain block 202 is typically used to adjust the input level of the audio input signal received from audio source 102. Amplifier 104 includes a first path 250 (e.g., an effects path or wet path), where the output of the first gain block 250 passes through a first filter 204, a second filter 206, a rectifier 210, a third filter 212, a harmonic pre-gain block 214, a saturator circuit 216, and a multiplier circuit 270. Amplifier 104 includes a second path 252 (e.g., a dry path), where the output of the input gain block 202 is directly transmitted to the output mixer 220. On wet path 250, the first filter 204 high-pass filters the output of the input gain block 202 such that the effect applied on wet path 250 operates only on frequencies above a predetermined cutoff frequency. In one example, the first filter 204 may be a tunable high-pass filter. Second block 206 receives the high-pass filtered output of the first filter 204. The second block 206 (or input tuning filter 206) may include a dual second-order filter block that can be tuned on the wet path 250. For example, the input tuning filter 206 may include a set of tunable dual second-order filters, allowing the spectral quality to be adjusted only on the wet path 250.

[0031] The harmonic exciter 268 includes a rectifier 210, a third filter 212, a harmonic pre-gain block 214, and a saturator circuit 216. The rectifier 210 converts the output of the input tuning filter 206 (which typically includes both positive and negative values) into a signal having only positive values. For example, the rectifier 210 converts an output signal (or audio signal) that typically includes both positive and negative values ​​into a signal having only positive values. The rectifier 210 functions as an absolute value function.

[0032] The third filter 212 (or low-pass filter) then smooths the signal. As mentioned, the third filter 212 may be a low-pass filter that includes a low cutoff frequency for smoothing the output signal of the rectifier 210. Generally, the rectifier 210 and the third filter 212 form an envelope follower that tracks the amplitude of the output of the input tuning filter 206. On the wet path 250, the input tuning filter 206 also provides an output to the harmonic pre-gain block 214 and the saturator block 216. Generally, the harmonic pre-gain block 214 controls the input level provided to the output of the saturator block 216.

[0033] The higher gain provided by the harmonic pre-gain block 214 can lead to more pronounced saturation. The saturator block 216 can be a nonlinear function that adds harmonics to the audio signal provided by the harmonic pre-gain block 214. The harmonic pre-gain block 214 controls the level of the added harmonics by “driving” the signal into the nonlinear function of the saturator block 216. The multiplier circuit 270 multiplies the output of the third filter 212 with the output of the saturator block 216. This multiplication has the effect of applying saturation processing based on the dynamics of the audio input signal, thus the output of the saturator block 216 is used as a transient enhancer. Generally, including the saturator block 216 has the effect of applying saturation processing only when the signal is loud. Therefore, the saturator block 216 is used as, for example, a transient enhancer. The output mixer 220 mixes the outputs of the wet path 250 and the clean path 252. Generally, the output mixer 220 mixes the outputs of the wet path 250 and the clean path 252 to reconstruct such outputs. Output mixer 220 is tunable and provides tunable wet / dry mixing. Fifth filter (e.g., output tuning filter) 222 includes another set of tunable dual second-order filters. Output gain block 224 adjusts the gain of the audio output signal from the fifth filter 222.

[0034] Figure 3 A flowchart of an audio processing procedure 300 according to one embodiment is generally described. See also... Figure 1 and Figure 2 The process 300 can be implemented via various components of the audio system 100. For simplicity, the following description will refer to amplifier 104.

[0035] In response to receiving an audio input signal, at operation 302, amplifier 104 performs a filtering operation on the audio input signal to generate a filtered signal. The filtering operation may be performed via one or more filters. For example, filtering operation 302 may include a high-pass filtering operation via high-pass filter 204, such that only signals with frequencies higher than a predetermined threshold frequency are processed. Alternatively, filtering operation 302 may include an input tuning filtering operation via input tuning filter 206, which includes a set of tunable bi-second-order filters to adjust the spectral quality of the audio input signal and output a filtered audio signal.

[0036] At operation 304, filter 104 rectifies the filtered audio signal via rectifier 210 to generate a rectified signal. For example, the rectifier can convert a filtered audio signal, which typically includes both positive and negative values, into a signal with only positive values. Additionally, the signal output from the rectifier can be further smoothed via low-pass filter 212.

[0037] While operation 304 is being performed, amplifier 104 applies saturation processing to the filtered audio signal via saturator 216 to generate a saturated signal. As discussed above, the saturator can be used as a transient enhancer and can apply saturation processing only to loud audio signals. Additionally, the filtered signal can be further preprocessed via harmonic pre-gain block 214, which controls the level of added harmonics to the signal by “driving” the signal into a nonlinear function of saturator block 216.

[0038] At operation 308, amplifier 104 combines the rectified audio signal with the saturated audio signal via multiplier 270 to generate a combined / intermediate audio signal.

[0039] At operation 310, amplifier 104 mixes the original input audio signal with the combined audio signal via output mixer 220 to generate an output audio signal. Mixer 220 can be adjusted according to user needs so that the ratio of the original input audio signal to the processed combined audio signal reaches a desired level.

[0040] At operation 312, one or more speakers 106 output audio sound using the output audio signal.

[0041] It will be appreciated that controllers disclosed herein may include various microprocessors, integrated circuits, memory devices (e.g., flash memory, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or other suitable variations thereof), and software that cooperate with each other to perform the operations disclosed herein. Additionally, such controllers disclosed herein may utilize one or more microprocessors to execute a computer program embodied in a non-transitory computer-readable medium programmed to perform any number of the disclosed functions. Furthermore, controllers provided herein include a housing and various numbers of microprocessors, integrated circuits, and memory devices (e.g., flash memory, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) located within the housing. One or more controllers disclosed may also include hardware-based inputs and outputs for receiving data from and transmitting data to other hardware-based devices discussed herein.

[0042] Although exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terms used in this specification are descriptive rather than limiting, and it should be understood that various changes can be made without departing from the spirit and scope of the invention. Furthermore, features of various embodiments can be combined to form other embodiments of the invention.

Claims

1. An audio system, comprising: An amplifier, the amplifier including at least one controller and programmed to: Receive audio input signals; An audio output signal is provided by saturating at least the aforementioned audio input signals by introducing nonlinear distortion. as well as The audio output signal is transmitted to one or more speakers to play audio from a first speaker among the one or more speakers.

2. The system of claim 1, wherein the at least one controller is further programmed to add harmonics to the audio input signal before applying saturation processing.

3. The system of claim 1, wherein the at least one controller is further programmed to rectify the audio input signal before applying saturation processing to the audio input signal.

4. The system of claim 3, wherein the at least one controller includes a first filter, the first filter being programmed to filter out frequencies above a first predetermined frequency on the audio input signal after rectification of the audio input signal to provide an intermediate audio signal.

5. The system of claim 4, wherein the intermediate audio signal indicates an envelope follower that tracks the amplitude of the audio input signal.

6. The system of claim 5, wherein the at least one controller is further programmed to multiply the intermediate audio signal with a signal including the saturation processing to provide the audio output signal.

7. The system of claim 1, wherein the amplifier defines a first path in which the audio input signal passes through at least one of a first filter, a second filter, a rectifier, a third filter, a harmonic pre-gain block, and a saturation circuit to provide a saturated audio signal.

8. The system of claim 7, wherein the amplifier defines a second path in which the audio input signal is mixed with the saturated audio signal from the first path to provide the audio output signal before the audio output signal is played by the one or more speakers.

9. The system of claim 1, wherein the amplifier is located in the vehicle.

10. A method comprising: Receive audio input signals; Saturation processing is applied to at least the aforementioned audio input signals to generate a saturated signal and provide an audio output signal; as well as The audio output signal is played through one or more speakers.

11. The method of claim 10, further comprising: Harmonics are added to the audio input signal before saturation processing is applied.

12. The method of claim 10, further comprising: The audio input signal is rectified to generate a rectified signal; The rectified signal is combined with the saturated signal to generate a combined signal; as well as The combined signal is mixed with the audio input signal to generate the audio output signal.

13. The method of claim 12, further comprising: After rectification, frequencies above a first predetermined frequency are filtered out to provide a rectified signal, wherein the rectified signal indicates an envelope follower that tracks the amplitude of the audio input signal.

14. A computer program product embodied in a non-transitory computer-readable medium, stored in a memory and programmed and executed by at least one controller in an audio system, the computer program product comprising instructions to perform the following: Receive audio input signals; Saturation processing is applied to at least the aforementioned audio input signals to generate a saturated signal and provide an intermediate signal; and The intermediate signal is mixed with the audio input signal to generate an audio output signal.

15. The computer program product embodied in the non-transitory computer-readable medium as claimed in claim 14, wherein the computer program product includes instructions to perform the following: The audio input signal is rectified to generate a rectified signal; The rectified signal is combined with the saturated signal to generate the intermediate signal.

16. The computer program product embodied in the non-transitory computer-readable medium as claimed in claim 14, wherein the computer program product includes instructions to perform the following: Harmonics are added to the audio input signal before saturation processing is applied.

17. The computer program product embodied in the non-transitory computer-readable medium as claimed in claim 14, wherein the computer program product includes instructions to perform the following: After rectification, frequencies above a first predetermined frequency are filtered out to provide a rectified signal, wherein the rectified signal indicates an envelope follower that tracks the amplitude of the audio input signal.

18. The computer program product embodied in the non-transitory computer-readable medium as claimed in claim 14, the computer program product comprising instructions to perform the following: Before applying the saturation processing and rectification, frequencies of the audio input signal below a predetermined first frequency are filtered out.

19. The computer program product embodied in the non-transitory computer-readable medium as claimed in claim 14, wherein the computer program product includes instructions to perform the following: The audio output signal is transmitted to one or more speakers for playback.

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