Mechanical protection and non-linear compensation method and system for loudspeaker system

Abstract

A speaker protection system includes: a speaker having a driver and a passive radiator or vent; and a controller determining at least one of a displacement of the driver, a displacement of the passive radiator, and a velocity of airflow through the vent based on an input voltage representative of an audible sound, and determine an output voltage at which the speaker reproduces the audible sound based on a single type of compression applied to both the driver displacement and the passive radiator displacement or the vent airflow velocity. An output voltage provided to the speaker limits the driver displacement within a driver displacement range and simultaneously limits the passive radiator displacement within a passive radiator displacement range or the vent airflow velocity within an airflow velocity range to mechanically protect the speaker and reduce distortion of the reproduced audible sound.

Description

Technical Field

[0001] The present disclosure relates to a method and system for mechanical protection and non - linear compensation of a speaker system. Background Art

[0002] Consumer audio products or consumer electronic devices with embedded audio (such as smartphones, tablet computers, laptop computers, soundbars, smart speakers, and portable speakers) have shown a trend of being designed smaller, thinner, and more compact in the past decade. This trend is mainly driven by industrial design considerations. However, it has a negative impact on the acoustic performance of such devices. Due to the size constraints of the speaker system, its maximum bass output, overall loudness, and sound quality are limited.

[0003] The problem is how to squeeze more bass and overall loudness from a given speaker system without damaging it or generating too much distortion. In doing so, three limitations of the speaker system can be considered, namely, mechanical limitations, non - linear distortion, and thermal limitations. The present disclosure describes methods and systems for addressing mechanical limitations and non - linear distortion to improve the maximum bass output and sound quality of a given speaker system. Summary of the Invention

[0004] In a non - limiting exemplary embodiment, the present disclosure provides a speaker protection system. The system includes a speaker that includes a driver and a passive radiator or a vent. The system further includes a controller configured to determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on an input voltage representative of an audible sound, and configured to determine an output voltage of the speaker reproducing the audible sound based on a single type of compression applied to both the driver displacement and the passive radiator displacement or the vent air flow velocity. The output voltage provided to the speaker limits the driver displacement within a driver displacement range and simultaneously limits the passive radiator displacement within a passive radiator displacement range or the vent air flow velocity within a vent air flow velocity range to mechanically protect the speaker and reduce distortion of the audible sound reproduced by the speaker.

[0005] In another non-limiting, exemplary embodiment, the present disclosure provides a method for mechanically protecting a loudspeaker including a driver and a passive radiator or vent. The method includes: determining at least one of a displacement of the driver, a displacement of the passive radiator, and an air flow velocity through the vent based on an input voltage representative of an audible sound; and determining an output voltage of the loudspeaker reproducing the audible sound based on a single type of compression applied to both the driver displacement and the passive radiator displacement or the vent air flow velocity. The method further includes providing the output voltage to the loudspeaker to limit the driver displacement within a driver displacement range and, simultaneously, limit the passive radiator displacement within a passive radiator displacement range or limit the vent air flow velocity within a vent air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

[0006] In another non-limiting, exemplary embodiment, the present disclosure provides a non-transitory computer-readable medium storing computer-executable instructions for mechanically protecting a loudspeaker including a driver and a passive radiator or vent. Executing the instructions causes a controller to: determine at least one of a displacement of the driver, a displacement of the passive radiator, and an air flow velocity through the vent based on an input voltage representative of an audible sound; determine an output voltage of the loudspeaker reproducing the audible sound based on a single type of compression applied to both the driver displacement and the passive radiator displacement or the vent air flow velocity; and provide the output voltage to the loudspeaker to limit the driver displacement within a driver displacement range and, simultaneously, limit the passive radiator displacement within a passive radiator displacement range or limit the vent air flow velocity within a vent air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

[0007] The following detailed description of these and other non-limiting, exemplary embodiments of the systems and methods of the present disclosure is set forth with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figures 1A to 1C is a cross-section of a non-limiting, exemplary closed-box passive radiator and vented-box loudspeaker system;

[0009] Figure 2 is a cross-section of a non-limiting, exemplary loudspeaker driver;

[0010] Figure 3 is a graph showing an example of a displacement-related BI factor in a loudspeaker;

[0011] Figure 4A and Figure 4B are schematic diagrams regarding mechanical protection for bass enhancement in a loudspeaker;

[0012] Figure 5A and Figure 5B shows the measured loudspeaker driver displacement over time in a commercial product using a known voltage-controlled limiter;

[0013] Figure 6 is a simplified block diagram of a non-limiting exemplary embodiment of a method and system according to the present disclosure;

[0014] Figure 7 is a simplified block diagram of a model-driven side-chain dynamic range controller (DRC) of a non-limiting exemplary embodiment of a method and system according to the present disclosure;

[0015] Figure 8 is a simplified block diagram of direct compression of a mechanical signal of a non-limiting exemplary embodiment of a method and system according to the present disclosure;

[0016] Figure 9 is a simplified block diagram of a model-driven side-chain dynamic range controller (DRC) of a passive radiator loudspeaker of a non-limiting exemplary embodiment of a method and system according to the present disclosure;

[0017] Figures 10A to 10G shows Figure 9 an example of a music input of a model-driven side-chain DRC;

[0018] Figure 11A and Figure 11B shows Figure 9 an example of a music input of a model-driven side-chain DRC of the passive radiator loudspeaker shown in;

[0019] Figure 12 is a simplified block diagram of a model-driven side-chain DRC of a vented-box loudspeaker of a non-limiting exemplary embodiment of a method and system according to the present disclosure;

[0020] Figure 13A and Figure 13B is a simplified block diagram of direct mechanical compression of a passive radiator loudspeaker of a non-limiting exemplary embodiment of a method and system according to the present disclosure;

[0021] Figures 14A to 14F is a signal diagram showing an example of a music input of direct mechanical compression of the passive radiator loudspeaker shown in FIG. 13;

[0022] Figure 15 is a simplified block diagram of a direct mechanical compression system with voltage limiting of a non-limiting exemplary alternative embodiment of a system and method according to the present disclosure;

[0023] Figure 16is a simplified block diagram of a direct mechanical compression system of a vented box loudspeaker system according to a non - limiting exemplary alternative embodiment of the systems and methods of the present disclosure;

[0024] Figure 17 is an exemplary graph of the magnitude of the displacement transfer function of a passive radiator loudspeaker system;

[0025] Figure 18 is a table describing various features of a model - driven side - chain DRC and direct compression method and system according to the present disclosure;

[0026] Figure 19 is a simplified block diagram of a non - limiting exemplary embodiment of a hybrid signal processing method and system for providing mechanical protection in a PR loudspeaker system according to the present disclosure;

[0027] Figure 20 is a simplified block diagram of another non - limiting exemplary embodiment of a hybrid signal processing method and system for providing mechanical protection in a PR loudspeaker system according to the present disclosure;

[0028] Figures 21A to 21F is a signal diagram showing an example of a music input of a hybrid signal processing method for providing mechanical protection in a passive radiator loudspeaker system shown in Figure 19 ;

[0029] Figure 22 depicts a signal diagram showing an example of a music input of a hybrid signal processing method for providing mechanical protection in a passive radiator loudspeaker system shown in Figure 19 ;

[0030] Figure 23 is a simplified block diagram of multi - band and multi - stage protection of a PR loudspeaker system according to a non - limiting exemplary alternative embodiment of the systems and methods of the present disclosure;

[0031] Figure 24 is a simplified block diagram of the non - linear compensation concept of a loudspeaker;

[0032] Figure 25 is a simplified block diagram of non - linear compensation of a PR loudspeaker system according to a non - limiting exemplary embodiment of the present disclosure;

[0033] Figure 26 is a simplified block diagram of the integration of non - linear compensation and direct mechanical compression in a PR loudspeaker system according to a non - limiting exemplary embodiment of the methods and systems of the present disclosure;

[0034] Figure 27is a simplified block diagram integrating the direct compression mixing method of side-chain limiting of non-linear compensation with speaker driver displacement and speaker passive radiator displacement in a PR speaker system according to a non-limiting exemplary embodiment of the method and system of the present disclosure; and

[0035] Figure 28 is a simplified block diagram integrating non-linear compensation and mechanical protection in a PR speaker system according to another non-limiting exemplary embodiment of the method and system of the present disclosure. DETAILED DESCRIPTION

[0036] As needed, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present invention, which can be embodied in various alternative forms. The drawings are not necessarily to scale; some features may be enlarged or minimized to show details of particular components. Thus, 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 practice the present invention in various ways.

[0037] Due to the size constraints of the speaker system in consumer audio products, its maximum bass output is limited. More specifically, there are displacement limitations of the speaker diaphragm and passive radiator, as well as velocity limitations of the ventilated air. Additionally, the speaker driver generates distortion at significant displacements, thus acting as a "soft" limit to displacement. Therefore, many consumer audio products lack bass due to the mechanical limitations of their speaker systems. Furthermore, common post-processing methods usually cannot fully utilize the available mechanical dynamic range.

[0038] The present disclosure describes methods and systems for improving the bass performance of a speaker system by fully utilizing the available mechanical dynamic range. The present disclosure describes signal processing-based methods and systems for providing mechanical protection and non-linear compensation for a speaker system. Through accurate protection, peaks in displacement or velocity response are suppressed. In this way, the input gain can be safely increased to push the speaker system towards its mechanical limits. The rms value of the acoustic output also increases, as does the subjective loudness. Additionally, non-linear compensation is incorporated to actively reduce distortion at high volumes.

[0039] The method is based on real-time modeling of the speaker system. The parameters of the model can be updated in real time through voltage and current measurements to track parameter changes and compensate for production differences. If the model parameters are known or more protection margin is allowed, real-time parameter updates can be omitted.

[0040] The present disclosure describes methods and systems for mechanical protection and non-linear compensation of vented box or PR speaker systems. Using these methods and systems, a speaker system can be safely pushed to its mechanical limits without risk of damage. Non-linear distortion can be actively reduced to utilize the non-linear operating range. Compared to known methods and systems, the methods and systems according to the present disclosure can protect the displacement and venting speed of both the speaker driver and the passive radiator and are fully integrated with non-linear compensation.

[0041] The methods and systems of the present disclosure provide protection and compensation for a speaker system. More specifically, the methods and systems of the present disclosure increase the maximum bass output and improve the sound quality of a given speaker system at high volumes. In this regard, the methods and systems of the present disclosure enhance the bass and overall loudness in a given speaker system without damaging it or producing too much distortion. The methods and systems of the present disclosure described herein can be used for speaker systems of any size from portable products to large subwoofers and result in powerful and pure bass from a speaker with a relatively small form factor, the performance of which exceeds user expectations. The methods and systems of the present disclosure increase the maximum bass output of a given speaker system, protect the speaker system from any mechanical damage, and are able to reduce the size of the speaker system while maintaining bass performance.

[0042] Figures 1A to 1C is a cross-section of a non-limiting exemplary speaker system 100 that includes a closed box system 102, a passive radiator (PR) system 104, and a vented box system 106. Each of systems 102, 104, 106 includes a speaker driver 108. The PR system 104 also includes a passive radiator 110, and the vented box system 106 also includes a vent or port 112. Figure 2 A cross-section of a non-limiting exemplary speaker driver 108 shared by each of systems 102, 104, 106 is shown.

[0043] As Figures 1A to 1C shown, the operation of each of systems 102, 104, 106 causes displacement of the driver 108. As Figure 1B shown, the operation of the PR system 104 causes displacement of the passive radiator 110. As Figure 1C shown, the operation of the vented box system 106 causes an air flow with a certain speed to pass through the vent 112. In this regard, the common symbols and abbreviations used herein are as follows:

[0044]

[0045] Mechanical limitations associated with one or more of the speaker systems 102, 104, 106 include: (1) the physically allowable range of movement of the moving parts (before hitting other components or full extension of the suspension), i.e., the limitation on the displacement of the speaker driver ( ) and the displacement of the passive radiator ( ); and (2) large air velocities can cause turbulent noise, i.e., the limitation on the air velocity at the vent ( ). Since large , and all occur in the low-frequency range, the mechanical limitations affect the maximum bass output the most.

[0046] Regarding nonlinear distortion, speakers are inherently nonlinear because many parameters depend on the state of the systems 102, 104, 106. The most significant non-linearities are: (1) Bl(x) (the force factor or speaker motor strength, which is the product of the magnetic field strength (B) in the voice coil and the voice coil length (l)); (2) Kms(x) (the speaker suspension stiffness (the reciprocal of compliance)); (3) Le(x) (the voice coil inductance); and (4) Rms(v) (the mechanical resistance). Nonlinear distortion affects the full-band sound quality due to the harmonic and intermodulation distortion generated at large signals. Since the non-linearity is mainly related to displacement, it is also a limiting factor for the maximum bass output. Figure 3 is a graph showing an example of the displacement-dependent BI factor in a speaker.

[0047] Music content has a very large dynamic range and crest factor, i.e., they have large peaks and relatively low root mean square (rms) values. , and The corresponding waveforms are the same. The maximum bass output of the speaker system is limited by the peaks that can cause mechanical overload and excessive distortion. However, the loudness perceived by humans is more related to the rms value over a longer period.

[0048] The basic idea of the present disclosure is to reduce the , and dynamic range through mechanical overload protection, which can be regarded as a special DRC that suppresses peaks and increases the rms value. Additionally, nonlinear compensation can be used to actively reduce distortion at large displacements. Figure 4A and Figure 4B are schematic diagrams regarding mechanical protection for bass enhancement in a speaker. Figure 4A shows the variation of the maximum displacement xd of the driver over time (0 to 40 seconds) without mechanical protection, while Figure 4BShows the variation of the driver displacement xd of the same input over time with additional gain and mechanical protection. With protection, the input gain can be safely increased. In the example shown, the displacement is limited to ±4 mm, and the rms value is increased by 4 dB.

[0049] Known voltage-controlled limiters divide and compress the low-frequency band based on the peak voltage. Methods using voltage-controlled limiters are disclosed in US9380385B1, US9917565B2, and US9967655B2, the entire contents of which are incorporated herein by reference. However, problems associated with such methods include not considering or oversimplifying the dynamics of the speaker system. The protection cannot be accurate. It is essentially tuned for the worst-case scenario, leaving a large safety margin. Additional problems are that they are difficult to tune, rely on trial and error, and they are powerless against nonlinear distortion. Figure 5A and Figure 5B Shows the measured speaker driver displacement over time in a commercial product using a known method with a voltage-controlled limiter. In this regard, Figure 5A Shows a medium volume with a small amount of compression, while Figure 5B Shows the maximum volume. As Figure 5B shown, the dynamic range is not fully utilized, and the displacement is overcompressed most of the time.

[0050] Model-based methods for closed-box systems use a real-time speaker model to predict and compress (limit) the driver displacement. These methods can be broadly divided into two categories: (1) variable low-frequency EQ or side-chain DRC driven by the speaker model, such as those described in US7372966B2, US9980068B2, US10206038B2, US10462565B2, US10536774B2, and US10701485B2, the entire contents of which are incorporated herein by reference; and (2) direct compression, followed by inverse modeling, such as those described in US8712065B2, US9837971B2, US9967663B2, and US10165361B2, the entire contents of which are incorporated herein by reference. Such methods have been widely applied to closed-box micro speakers on devices such as smartphones and tablet computers. They are commonly referred to as SmartPA technology. Nonlinear compensation can also be integrated with driver displacement protection, as described in US10547942B2, the entire contents of which are incorporated herein by reference. However, the problem with existing technology models and systems using direct compression, followed by inverse modeling, is that they are only applicable to closed-box systems.

[0051] Model-based vented-box and PR system methods can be classified into the following categories. For vented-box and PR systems, a trajectory planning block that gives the target displacement and a feedforward control block that converts the target displacement into a control voltage are combined, as described in US10506347B2, the entire content of which is incorporated herein by reference. However, there is no description of how to generate a target displacement that matches the system limitations, and the limitations of port velocity are not considered. For vented-box systems, an alternative is to limit the port velocity through a side-chain DRC driven by the total port energy, as described in US10797666B2, the entire content of which is incorporated herein by reference. Although the energy-driven DRC described there may have a smoother gain curve, its computational cost is slightly higher, and there is no mention of how to limit both simultaneously at the same time. Another alternative for vented-box systems is to concentrate on protecting the displacement of the speaker driver without considering the vent velocity, as described in US2022 / 0201386A1, the entire content of which is incorporated herein by reference. For PR systems, an alternative is to directly compress the modeled and convert it back to voltage, as described in US11399247B2, the entire content of which is incorporated herein by reference. However, as described therein, there is no mention of how to limit both simultaneously at the same time.

[0052] In contrast, Figure 6 is a simplified block diagram of a non-limiting exemplary embodiment of the method and system according to the present disclosure. As shown therein, the speaker protection method and system according to the present disclosure generally includes a DRC or controller 200, such as a digital signal processor (DSP), which is configured to receive a varying input voltage representing an audio signal of audible sound. The controller 200 includes a software-based solution that includes a feedforward process 202 for mechanical overload protection and non-linear compensation and a parameter estimation 204 for real-time updating of model parameters. According to this software-based solution, the controller 200 provides a varying output voltage of the audio signal to reproduce audible sound through the speaker 206.

[0053] In this regard, the present disclosure focuses on the real-time modeling of speaker systems. A parameter estimation block 204 is provided to correct model parameter errors caused by various time-varying effects and production variations. The present disclosure provides the following features: (1) applicable to PR and vented-box speaker systems; (2) protecting both simultaneously, ; (3) maximized bass output; and (4) reduced distortion without reducing the output. The present disclosure also increases the maximum bass output of a given speaker system, protects the speaker system from any mechanical damage, and is able to reduce the size of the speaker system while maintaining the bass performance.

[0054] The methods and systems according to the present disclosure can be based on two fundamental ideas. First, Figure 7 is a simplified block diagram of a model-driven side-chain DRC of a non-limiting exemplary embodiment of the methods and systems according to the present disclosure. As shown therein, the mechanical protection method and system for the loudspeaker 300 can include a loudspeaker model module 302 and a side-chain peak limiter 304. Second, Figure 8 is a simplified block diagram of a direct compression of mechanical signals of a non-limiting exemplary embodiment of the methods and systems according to the present disclosure. As shown therein, the mechanical protection method and system for the loudspeaker 400 can include a loudspeaker model module 402, a peak limiter 404, and an inverse loudspeaker model module 406. It should be noted that these two types of methods and systems are not mutually exclusive and can be combined in various ways.

[0055] Figure 9 is a simplified block diagram of a model-driven side-chain DRC of a PR loudspeaker system of a non-limiting exemplary embodiment of the methods and systems according to the present disclosure. As shown therein, the model-driven side-chain DRC for the mechanical protection of the PR loudspeaker system 500 can include a PR system model module 502, which is a digital model that generates x d and x p from the input voltage. The module 502 may or may not receive model parameter updates from the outside and may be linear or non-linear as required. The model-driven side-chain DRC may further include an optional group delay compensation block 504, which compensates for group delay differences. In this regard, since the group delay is frequency-dependent, an average value in the frequency band of interest can be used.

[0056] The model-driven side-chain DRC may further include a side-chain block 506 for calculating x p 、x d and the voltage (v) side-chain. The side-chain block 506 can take the absolute value of each signal (xp, xd, v) and then normalize it by a corresponding threshold (limiter). The maximum value among these three (xp, xd, v) is the side-chain input of the peak limiter 508, which detects peaks exceeding the corresponding threshold and calculates the gain accordingly. Since the side-chain has been normalized, the threshold can be set to 1 (0 dB).

[0057] Figures 10A to 10G The signal diagram of Figure 9 shows an example of the music input of the model-driven side-chain DRC of d In the example shown, the protection settings include x d limits of + / -3 millimeters (mm), x p limits of + / -4 mm, and voltage limits of + / -20 volts (V). AtFigure 9 Are marked with the numbers 1 to 11 in the figure Figures 10A to 10G The signal shown as a function of time in the figure. Therefore, Figure 10A Shows the input voltage 1, and Figure 10B Shows the unprotected x d Value 2 and x p Value 3, and these values may exceed the protection setting limits. Figure 10C Shows the x calculated by the side-chain block 506 d 4, x p 5 and the normalized values of the voltage (v) 6, while Figure 10D Shows the maximum side-chain value (x d 、x p Or v) 7. Figure 10E Shows the gain applied to the voltage 8, while Figure 10F Shows the output voltage 9 provided to the PR speaker 500. It can be seen that this output voltage is always within the protection setting voltage limits. Finally, Figure 10G Shows the protected x d Value 10 and x p Value 11, and they are also within the protection setting limits.

[0058] Figure 11A And Figure 11B Also shows in the figure Figure 9 The same example of the music input of the model-driven side-chain DRC. Again, in the example shown, the protection settings include x limits of + / -3 mm d 、x limits of + / -4 mm p And voltage limits of + / -20 V. In Figure 9 Are marked with the numbers 1 to 3 and 8 to 11 in the figure Figure 11A And Figure 11B The signal shown as a function of time in the figure. Therefore, Figure 11A The upper right figure of shows the input voltage 1 that may exceed the + / -20 V limit together with the output voltage 9 provided to the PR speaker 500, and this output voltage is also always within this voltage limit. Figure 11A The upper left figure of shows the unprotected x d Value 2 that may exceed the + / -3 mm limit together with the protected x d Value 10 that is always within this driver displacement limit. Figure 11A The lower left figure of shows the unprotected x p Value 3 that may exceed the + / -4 mm limit together with the protected x p Value 11 that is always within this RP displacement limit. Finally, Figure 11A The lower right figure of shows the calculated gain 8.

[0059] Figure 11Ashows the signal recorded over a time period from 0 to 10 seconds, while Figure 11B shows those same signals magnified at approximately 6.8 seconds. Thus, Figure 11B The upper right diagram of again shows the input voltage 1 that may exceed the + / -20 V limit, along with the output voltage 9 provided to the PR speaker 500, which always remains within this voltage limit. Figure 11B The upper left diagram of again shows the unprotected x d value 2 that may exceed the + / -3 mm limit, along with the protected x d value 10 that always remains within this driver displacement limit. Figure 11B The lower left diagram of again shows the unprotected x p value 3 that may exceed the + / -4 mm limit, along with the protected x p value 11 that always remains within this RP displacement limit. Finally, Figure 11A The lower right diagram of shows the calculated gain 8.

[0060] Figure 12 is a simplified block diagram of a model-driven side-chain dynamic range controller (DRC) for a vented-box loudspeaker, which is a non-limiting exemplary embodiment of the method and system according to the present disclosure. As shown therein, for the vented-box loudspeaker system 600, the system and method of the present disclosure are substantially the same as those Figure 9 shown in. In this regard, the PR speaker model module can simply be replaced with a vented-box model module 602, and the predicted vent velocity can be used as one of the side-chains, rather than the predicted PR displacement xp.

[0061] Therefore, as Figure 12 shown in, the model-driven side-chain DRC for mechanical protection of the vented-box loudspeaker system 600 can include a vented-box system model module 602, which is a digital model that generates x d and x p from the input voltage. Module 602 may or may not receive model parameter updates from the outside, and may be linear or non-linear as needed. The model-driven side-chain DRC may also include an optional group delay compensation block 604, which compensates for group delay differences. In this regard, since group delay is frequency-dependent, the average value in the frequency band of interest can be used.

[0062] The model-driven side-chain DRC may further include a side-chain block 606 for calculating u p 、x d and the voltage (v) side-chain. The side-chain block 606 can process each signal (u p 、x d, v) Take the absolute value and then normalize it by a corresponding threshold (limit). The maximum of these three (x p , x d , v) is the side-chain input to the peak limiter 608, which detects peaks exceeding the corresponding threshold and calculates the gain accordingly. Since the side-chain has been normalized, the threshold can be set to 1 (0 dB).

[0063] Although the side-chain method is simple and has a short audio delay compared to direct mechanical compression methods, it can have two drawbacks. First, due to speaker non-linearity, the side-chain gain can be biased. If a linear speaker model is used in the side-chain, the gain will be overestimated (reduced too much). On the other hand, using a non-linear speaker model will underestimate the gain (reduced not enough). Second, due to the phase difference between the voltage in the side-chain and the mechanical overshoot may still occur in the compressed voltage. The group delay compensation described above can significantly mitigate this problem for and . However, it may not be very effective for because its group delay varies too much within the frequency band of interest.

[0064] Figure 13 is a simplified block diagram of the direct mechanical compression of a passive radiator speaker according to a non-limiting exemplary embodiment of the method and system of the present disclosure. As shown therein, the direct mechanical compression of the PR speaker system 700 includes a two-stage DRC system that directly compresses the modeled and , and then converts it back to voltage. The order of these two stages can be switched. The system may include a linear PR system model module 702 that generates xp based on the input voltage of an audio signal representing audible sound and may or may not receive parameter updates from the outside. The system may also include: a first-stage peak limiter 704 for compressing the xp signal; and an xp-to-xd model module 706 for converting the compressed xp signal into a corresponding xd signal. The system may also include: a second-stage peak limiter 708 for compressing the xd signal; and a non-linear inverse PR system model module 710 for converting xd back to the output voltage for providing to the PR speaker system 700 to reproduce audible sound. The non-linear inverse PR system model module 710 may or may not receive model parameter updates from the outside and may alternatively be linear instead of non-linear as needed.

[0065] Figures 14A to 14F shows Figure 13A and Figure 13BA signal diagram of an example of a music input of direct mechanical compression of a PR speaker, as described above, the PR speaker including a two-stage DRC system for direct mechanical compression of the PR speaker system 700. In the example shown, the protection settings include an x d limit of + / - 3 mm and an x p limit of + / - 4 mm. Figures 14A to 14F The signals shown as a function of time in Figure 13B correspond to the signals labeled xd_0, xp_0, xd_1, xp_1, xd_2, and xp_2 in Figure 14A and Figure 14B show the unprotected x d and x p values (xd_0 and xp_0) output by the linear PR system model module 702 after converting the varying input voltage to x d and x p values, both of which may exceed their respective protection limits. Figure 14C and Figure 14D show the compressed x p value (xp_1) output by the first-stage peak limiter 704 and the compressed xd value (xd_1) output by the x p to x d converter 706, where the compressed x p value is always within the x p protection limit. Finally, Figure 14E and Figure 14F show the protected x d value (xd_2) output by the second-stage peak limiter 708 and the protected x p value (xp_2) output by the non-linear inverse PR system model module 710, both of which are always within their respective protection limits.

[0066] Figure 15 is a simplified block diagram of a direct mechanical compression system with voltage limit, which is a non-limiting exemplary alternative embodiment of the system and method according to the present disclosure. As shown therein, an extension of direct mechanical compression using voltage limit can also be employed. More specifically, as Figure 15 shown, voltage limit can be included by cascading another peak limiter 712 either before or after the system shown in Figure 13A In this regard, it should be noted that cascading such a voltage peak limiter after the inverse model requires the inverse model to be linear.

[0067] Figure 16is a simplified block diagram of a direct mechanical compression system of a vented box loudspeaker system 800 according to a non-limiting exemplary alternative embodiment of the systems and methods of the present disclosure. As shown therein, for the vented box loudspeaker system 800, the modeled and signals can be compressed. More specifically, as shown in Figure 16 , the direct mechanical compression of the vented box loudspeaker system 800 includes a two-stage DRC system that directly compresses the modeled and , and then converts it back to voltage. The order of these two stages can be switched. The system can include a linear vented box system model module 802 that generates up based on a varying input voltage of an audio signal representing an audio sound and can or cannot receive parameter updates from the outside. The system can also include: a first-stage peak limiter 804 for compressing the up signal; and an up-to-xd model module 806 for converting the compressed up signal into a corresponding xd signal. The system can also include: a second-stage peak limiter 808 for compressing the xd signal; and a non-linear inverse vented box system model module 810 for converting xd back to an output voltage for providing to the PR loudspeaker system 800 to reproduce audible sound. The non-linear inverse vented box system model module 810 can or cannot receive model parameter updates from the outside and can alternatively be linear rather than non-linear as needed.

[0068] Direct mechanical compression is very accurate for protection. It is also naturally related to the non-linear compensation described herein. However, it is computationally intensive. Compared with the side-chain method, this method additionally requires two limiters and two loudspeaker models. Additionally, since each of the cascaded peak limiters introduces its own look-ahead delay, this method introduces a long audio delay. Finally, special processing is required to ensure that the gain applied to and is smooth enough, otherwise the inverse model can produce click noise or even large spikes in the voltage. In this regard, Figure 17 is an exemplary graph of the magnitude of the displacement transfer function of a PR loudspeaker system. As shown therein, the inverse model has a large high-frequency gain. It essentially takes a high-order derivative of the mechanical signal under the high-frequency band, thereby revealing the high-order discontinuities introduced by the compression of xd, xp.

[0069] According to another non-limiting exemplary embodiment of the present disclosure, the two methods of model-driven side-chain DRC and direct compression can be combined in a hybrid manner. The basic idea is to maintain the direction compression and apply the and The protection is moved to the side chain. In this regard, Figure 18 is a table that describes various features of a model-driven side-chain DRC and direct compression method and system according to the present disclosure. Since inverts to have a smaller high-frequency gain compared to voltage and the smoothing problem is smaller. Accurate protection and capabilities are also maintained for non-linear compensation with medium complexity and audio latency.

[0070] Figure 19 is a simplified block diagram of a non-limiting exemplary embodiment of a hybrid signal processing method and system for providing mechanical protection in a PR speaker system 900 according to the present disclosure. As shown therein, the hybrid method and system can include a side-chain limiter block 902 for x p and voltage, and a direct compression block 904 for x d . The side-chain limiter block 902 can include a PR system model module 906 that generates a digital model of x p from a varying input voltage of an audio signal representing audible sound. The module 906 may or may not receive model parameter updates from the outside and can be linear or non-linear as needed. The side-chain limiter block 904 can also include a group delay block 908 for compensating group delay differences for x p , and a side-chain block 910 for calculating the side-chain of x p and voltage (v). The side-chain block 910 can take the absolute value of each signal (xp, v) and then normalize it by a corresponding threshold (limiting). The maximum of the two (xp, v) is the side-chain input to a peak limiter 912 that detects peaks exceeding the corresponding threshold.

[0071] The direct compression block 904 can include: a linear PR system model module 914 that converts the signal received from the peak limiter 912 into x d ; and a peak limiter 916 that receives x d and produces a compressed x d . The direct compression block can also include a non-linear inverse PR system model module 918 that converts the compressed x d from the peak limiter 912 into a varying output voltage for providing to the PR speaker system 900 to reproduce audible sound. The module 918 may or may not receive model parameter updates from the outside and can alternatively be linear as needed.

[0072] Figure 20is a simplified block diagram of another non - limiting exemplary embodiment of a hybrid signal processing method and system for providing mechanical protection in a PR loudspeaker system 1000. As shown therein, the hybrid method and system can include a voltage limiter 1002 and a direct compression block 1004 that takes x p (and x d ) as a side - chain. The voltage limiter 1002 can include a peak limiter 1006 for limiting and / or compressing the varying input voltage of an audio signal representing audible sound. The direct compression block 1004 can include a linear PR system model module 1008 that generates digital models of x d and x p based on the input voltage received from the voltage limiter 1002. The module 1008 may or may not receive model parameter updates from the outside and may be linear or non - linear as needed.

[0073] The direct compression block 1004 can further include a side - chain block 1010 for calculating the side - chain of x p and x d . The side - chain block 1010 can take the absolute value of each signal (xp, xd) and then normalize it by a corresponding threshold (limitation). The maximum of the two (x p , x d ) is the side - chain input of a peak limiter 1012 that detects peaks exceeding the corresponding threshold and outputs the compressed x d . The direct compression module 1004 can further include a non - linear inverse PR system model module 1014 that converts the compressed x d received from the peak limiter 1012 into a varying output voltage that is provided to the PR loudspeaker system 1000 to reproduce the audible signal. The module 1014 may or may not receive model parameter updates from the outside and may alternatively be linear as needed.

[0074] Figures 21A to 21F is a signal diagram showing an example of a music input of a hybrid signal processing system and method for providing mechanical protection in the PR loudspeaker system 900 shown in Figure 19 . In the example shown, the protection settings include x d limitations of + / - 3 mm, x p limitations of + / - 4 mm, and a voltage limitation of 15 V. The signals as a function of time show the unprotected voltages xd and xp, and the protected voltages xd and xp after signal processing according to the Figure 19 hybrid system and method. More specifically, Figure 21AShows an unprotected varying input voltage representing an audible sound received by the side-chain limiter block 902, which may exceed the voltage protection limit (+ / -15 V). Figure 21B Shows a protected varying output voltage generated by the non-linear inverse PR system model module 918 and provided to the PR speaker 900 to reproduce the audible sound, which always remains within the voltage protection limit.

[0075] Figure 21C Shows an unprotected x d value generated by the linear PR model module 914, which may exceed the x d protection limit (+ / -3 mm), while Figure 21D shows a protected x d value generated by the peak limiter 916 and the non-linear inverse PR system model module 918, which always remains within the x d protection limit. Finally, d Figure 21E shows an unprotected x value generated by the linear PR model module 906, which may exceed the x p protection limit (+ / -4 mm), while p shows a protected x Figure 21F value generated by the side-chain block 910, which always remains within the x p protection limit. p p p

[0076] Figure 22 Figure 19 Depicts a signal diagram showing an example of a music input of a hybrid signal processing method for providing mechanical protection in the passive radiator speaker system shown in Figure 19 . Figures 21A to 21F Shows the signal recorded over the time from 0 to 10 seconds, while Figure 22 shows the same signal amplified at approximately 3.2 seconds. Thus, Figure 22 The upper left figure of Figure 22 again shows the unprotected xd value 920 that may exceed the xd protection limit (+ / -3 mm) together with the protected xd value 930 that always remains within the xd protection limit. p The lower left figure of p again shows the unprotected x Figure 22 value 940 that may exceed the xd protection limit (+ / -4 mm) together with the protected x p value 950 that always remains within the xp protection limit. Figure 22The upper right figure shows the gain 980 calculated by the side-chain (first stage) and the gain 990 calculated by the directional compression (second stage).

[0077] According to another non-limiting exemplary embodiment, the present disclosure also provides multi-band and multi-stage protection. In this regard, it is preferred to perform dynamic range processing (i.e., multi-band DRC) separately for each band using different tuning parameters. This avoids problems such as pumping effects and gain modulation. All of the mechanical protection methods and systems previously introduced according to the present disclosure can be used for multi-band structures.

[0078] Figure 23 is a simplified block diagram of the multi-band and multi-stage protection of the PR speaker system 2000 according to a non-limiting exemplary alternative embodiment of the systems and methods of the present disclosure. As shown therein, the first stage block 2002 may include an intermediate band model-driven side-chain limiter module 2004 and a low band model-driven side-chain limiter module 2006, such as those described previously herein. After the first stage block 2002 has multi-band limiters 2004, 2006, a wider band protection is employed in the second stage block 2008 to ensure that the total signal is within mechanical limits. In this regard, the second stage block 2008 may include a hybrid protection method 2010, such as those described previously herein. Since most of the compression occurs in the first stage block 2002, the gain at the second stage block 2008 does not produce any audible artifacts. The protection limit for each band at the first stage block 2002 may be fixed or adaptive, depending on the input signal.

[0079] The systems and methods according to the present disclosure also provide non-linear compensation. In this regard, Figure 24 is a simplified block diagram of the non-linear compensation concept of a speaker. As shown therein, a non-linear filter or non-linear controller 3000 provides non-linear compensation to pre-distort the varying input signal (in volts) input to the speaker 3002 such that the distortion of the entire system (i.e., the sound pressure output in Pascals (Pa)) is reduced compared to the non-distorted input signal provided to the speaker 3004. Non-linear compensation improves the sound quality at high volumes and extends the maximum bass output by exploiting the non-linear operating range of the speaker. Non-linear compensation is essentially accomplished by first finding the algebraic relationship between the input and output (model), and then deriving an expression (control law) for the inverse operation of that relationship. The application of non-linear compensation in speakers is well known to those of ordinary skill in the art. The specific methods vary depending on the model used to derive the control law and the manner in which the state information is obtained.

[0080] Figure 25is a simplified block diagram of the non - linear compensation of the PR loudspeaker system 4000 according to a non - restrictive exemplary embodiment of the present disclosure. As shown therein, the non - linear compensation block 4002 may include a linear PR system model module 4004, which converts the input voltage that varies with the audio signal representing the audible sound into the desired linear driver displacement x d . The linear PR system model module 4004 may or may not receive model parameter updates from the outside. The non - linear compensation block 4002 may further include a non - linear inverse PR system model module 4006, which converts the desired linear x d into a varying output voltage, which is provided to the PR loudspeaker system 4000 to reproduce the audible signal. The non - linear inverse PR system model module 4006 may or may not receive model parameter updates from the outside. Thus, the linear model provides the desired linear displacement, while the inverse model can specify the voltage required to produce the target displacement.

[0081] Figure 25 The systems and methods of the present disclosure shown in provide a novel extension for PR and vented box systems and a tight integration with mechanical protection, which is based on the known algorithm in which the loudspeaker system is first discretized and then inverted. In this regard, the low - frequency dynamics of the PR system can be described by a lumped - parameter model. The model of the vented box is very similar. According to the present disclosure, by extending the known method, the physical model can be discretized to calculate , and its inverse. However, it should be noted that the loudspeaker modeling methods and algorithms proposed herein are not the only types that can be utilized. Any other method or algorithm that can model the loudspeaker system and its inverse model with sufficient accuracy can be used to implement the systems and methods of mechanical protection and non - linear compensation described herein.

[0082] According to the present disclosure, non - linear compensation can be integrated with mechanical protection. Figure 26 is a simplified block diagram of the integration of non - linear compensation and direct mechanical compression in the PR loudspeaker system 5000 according to a non - restrictive exemplary embodiment of the method and system of the present disclosure. As shown herein, the system may include a linear PR system model module 5002, which generates x p based on the input voltage of the audio signal representing the audible sound, and may or may not receive parameter updates from the outside. The system may further include: a peak limiter 5004, which is used to compress the x p signal; and an x p to x d model module 5006, which is used to convert the compressed x p signal into the corresponding x dsignal. The system can further include: a peak limiter 5008, which is used to compress x d signal; and a non-linear inverse PR system model module 5010, which is used to convert x d back to the output voltage for providing to the PR speaker system 5000 to reproduce audible sound. The non-linear inverse PR system model module 5010 may or may not receive model parameter updates from the outside. In this regard, it should be noted that by inserting limiters 5004 and 5008 between the linear model module 5002 and the inverse model module 5010, the non-linear compensation becomes substantially the same as the Figure 13A and Figure 13B direct mechanical compression method for mechanical protection shown. The main difference is that, in order to achieve the Figure 13A and Figure 13B mechanical protection purposes, the inverse model module 710 can be linear, while the Figure 26 inverse model module 5010 of must be non-linear in order to achieve non-linear compensation.

[0083] Figure 27 is a simplified block diagram of the integration of non-linear compensation in the PR speaker system 6000 of a non-limiting exemplary embodiment of the method and system according to the present disclosure and the direct compression hybrid method of side-chain limiting for and for . As shown therein, the system can include a voltage limiter 6002 and a direct compression block 6004 with xp (and xd) as the side-chain. The voltage limiter 6002 can include a peak limiter 6006 for limiting and / or compressing the varying input voltage of the audio signal representing audible sound. The direct compression block 6004 can include a linear PR system model module 6008, which is a digital model that generates xd and xp according to the input voltage received from the voltage limiter 6002. The module 6008 may or may not receive model parameter updates from the outside, and can be linear or non-linear as needed.

[0084] The direct compression block 6004 can further include a side-chain block 6010 for calculating the x p and x d side-chain. The side-chain block 6010 can take the absolute value of each signal (x p , x d ), and then normalize it through the corresponding threshold (limitation). The maximum value of these two (x p , x d ) is the side-chain input of the peak limiter 6012, which detects the peak exceeding the corresponding threshold and outputs the compressed x d。The direct compression module 6004 may further include a non-linear inverse PR system model module 6014 that converts the compressed x received from the peak limiter 6012 into a varying output voltage that is provided to the PR loudspeaker system 6000 to reproduce an audible signal. The module 6014 may or may not receive model parameter updates from the outside. d Here, it should be noted again that by inserting the side-chain blocks 6010, 6012 between the linear model module 6008 and the non-linear inverse model module 6014, the non-linear compensation becomes substantially the same as the direct mechanical compression method for mechanical protection shown in. The main difference is again that for the purpose of mechanical protection in, the inverse model module 1014 can be linear, while the inverse model module 6014 in must be non-linear in order to achieve non-linear compensation.

[0085] Here, it should be noted again that by inserting the side-chain blocks 6010, 6012 between the linear model module 6008 and the non-linear inverse model module 6014, the non-linear compensation becomes Figure 20 substantially the same as the direct mechanical compression method for mechanical protection shown in. The main difference is again that, for the purpose of Figure 20 mechanical protection in, the inverse model module 1014 can be linear, while Figure 27 the inverse model module 6014 in must be non-linear in order to achieve non-linear compensation.

[0086] Figure 28 is a simplified block diagram of the integration of non-linear compensation and mechanical protection in a PR loudspeaker system 7000 according to another non-limiting exemplary embodiment of the method and system of the present disclosure. As shown therein, the non-linear compensation block 7002 (which may include the linear PR system model module 7004 and the non-linear inverse PR system model module 7006 as described above) may be cascaded after the mechanical protection block 7008. In this regard, the mechanical protection block 7008 may be side-chain based or direct mechanical compression, as described above, and must be located before the non-linear compensation block 7002. Additionally, generally, there should be no linear or non-linear processing between the non-linear inverse model module 7006 and the PR loudspeaker system 7000, other than a simple gain such as an amplifier.

[0087] Those skilled in the art should understand that the loudspeakers, controllers, blocks, models, modules, limiters, converters, compensators, compressors, technologies, and any other components, systems, subsystems, units, methods, interfaces, sensors, devices, etc. described herein may individually, jointly, or in any combination include appropriate circuitry, such as one or more appropriately programmed processors (e.g., one or more microprocessors, including a central processing unit (CPU)) and associated memory, which may include stored operating system software, firmware, and / or application software that can be executed by the processor to control its operation, any loudspeaker, block, model, module, limiter, converter, compensator, component, compressor, technology, system, subsystem, unit, method, interface, sensor, device, etc. described herein, and / or to perform specific algorithms represented by the various methods, functions, technologies, and / or operations described herein (including interactions and / or collaborations between each other).

[0088] Clause 1: According to one embodiment, the present disclosure provides a loudspeaker protection system, which includes: a loudspeaker, which includes a driver and a passive radiator or a vent; and a controller, which is configured to determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on an input voltage representing an audible sound, and determine an output voltage of the loudspeaker reproducing the audible sound based on a single type of compression applied to both the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent; wherein the output voltage provided to the loudspeaker limits the displacement of the driver within a driver displacement range, and simultaneously limits the displacement of the passive radiator within a passive radiator displacement range or limits the air flow velocity of the vent within a vent air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

[0089] Clause 2: In another embodiment, the present disclosure provides the loudspeaker protection system according to Clause 1, wherein the controller includes a dynamic range controller, and the single type of compression includes side-chain dynamic range compression, and the dynamic range controller includes: a loudspeaker model module, which is configured to convert the input voltage into the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent; and a side-chain peak limiter, which is configured to determine the output voltage of the loudspeaker based on the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent.

[0090] Clause 3: In another embodiment, the present disclosure provides the loudspeaker protection system according to Clause 1, wherein the controller includes a dynamic range controller, and the single type of compression includes direct compression. The dynamic range controller includes: a loudspeaker model module configured to convert the input voltage into the passive radiator displacement or the vent air flow velocity; a first peak limiter configured to compress the passive radiator displacement or the vent air flow velocity; a converter configured to convert the compressed passive radiator displacement or the compressed vent air flow velocity into the driver displacement; a second peak limiter configured to compress the driver displacement; and an inverse loudspeaker model module configured to convert the compressed driver displacement into the output voltage of the loudspeaker.

[0091] Clause 4: In another embodiment, the present disclosure provides the loudspeaker protection system according to any one of Clauses 1 to 3, further including a compensator configured to apply non-linear compensation to the output voltage to generate a compensated output voltage for the loudspeaker.

[0092] Clause 5: In another embodiment, the present disclosure provides the loudspeaker protection system according to any one of Clauses 1 to 4, wherein the input voltage includes a plurality of input voltages, each input voltage representing a frequency in a different frequency band of the plurality of frequency bands of the audible sound, and wherein the controller is configured to determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on each of the plurality of input voltages.

[0093] Clause 6: In another embodiment, the present disclosure provides the loudspeaker protection system according to Clause 2, wherein the loudspeaker model module receives updated loudspeaker parameters.

[0094] Clause 7: In another embodiment, the present disclosure provides the loudspeaker protection system according to Clause 3, wherein the loudspeaker model module and the inverse loudspeaker model module receive updated loudspeaker parameters.

[0095] Clause 8: According to one embodiment, the present disclosure provides a method for mechanically protecting a loudspeaker including a driver and a passive radiator or a vent, the method comprising: determining at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on an input voltage representative of audible sound; determining an output voltage of the loudspeaker for reproducing the audible sound according to a single type of compression applied to both the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent; and providing the output voltage to the loudspeaker to limit the displacement of the driver within a driver displacement range and, simultaneously, limit the displacement of the passive radiator within a passive radiator displacement range or limit the air flow velocity of the vent within a vent air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

[0096] Clause 9: In another embodiment, the present disclosure provides the method for mechanically protecting a loudspeaker according to Clause 8, wherein the single type of compression includes side-chain dynamic range compression, and the method further comprises: converting the input voltage into the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent via a loudspeaker module; and determining the output voltage of the loudspeaker based on the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent via a side-chain peak limiter.

[0097] Clause 10: In another embodiment, the present disclosure provides the method for mechanically protecting a loudspeaker according to Clause 8, wherein the single type of compression includes direct compression, and the method further comprises: converting the input voltage into the displacement of the passive radiator or the air flow velocity of the vent via a loudspeaker module; compressing the displacement of the passive radiator or the air flow velocity of the vent; converting the compressed displacement of the passive radiator or the compressed air flow velocity of the vent into the displacement of the driver; compressing the displacement of the driver; and converting the compressed displacement of the driver into the output voltage of the loudspeaker via an inverse loudspeaker model module.

[0098] Clause 11: In another embodiment, the present disclosure provides the method for mechanically protecting a loudspeaker according to any one of Clauses 8 to 10, further comprising: applying non-linear compensation to the output voltage to generate a compensated output voltage for the loudspeaker.

[0099] Clause 12: In another embodiment, the present disclosure provides a method for mechanically protecting a speaker according to any one of Clauses 8 to 11, wherein the input voltage comprises a plurality of input voltages, each input voltage representing a frequency in a different frequency band of the plurality of frequency bands of the audible sound, and wherein determining at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on the input voltage representing the audible sound comprises: determining at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on each of the plurality of input voltages.

[0100] Clause 13: In another embodiment, the present disclosure provides a method for mechanically protecting a speaker according to Clause 9, wherein the speaker model is based on updated speaker parameters.

[0101] Clause 14: In another embodiment, the present disclosure provides a method for mechanically protecting a speaker according to Clause 10, wherein the speaker model and the inverse speaker model are based on updated speaker parameters.

[0102] Clause 15: According to one embodiment, the present disclosure provides a non-transitory computer-readable medium storing computer-executable instructions for mechanically protecting a speaker including a driver and a passive radiator or a vent, wherein executing the instructions causes the controller to: determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on the input voltage representing the audible sound; determine an output voltage of the speaker for reproducing the audible sound according to a single type of compression applied to both the driver displacement and the passive radiator displacement or the vent air flow velocity; and provide the output voltage to the speaker to limit the driver displacement within a driver displacement range and, simultaneously, limit the passive radiator displacement within a passive radiator displacement range or limit the vent air flow velocity within a vent air flow velocity range to mechanically protect the speaker and reduce distortion of the audible sound reproduced by the speaker.

[0103] Clause 16: In another embodiment, the present disclosure provides the non-transitory computer-readable medium according to Clause 15, wherein the single type of compression comprises side-chain dynamic range compression, and wherein executing the instructions further causes the controller to: convert the input voltage into the driver displacement and the passive radiator displacement or the vent air flow velocity via a speaker module; and determine the output voltage of the speaker based on the driver displacement and the passive radiator displacement or the vent air flow velocity via a side-chain peak limiter.

[0104] Clause 17: In another embodiment, the present disclosure provides the non-transitory computer-readable medium according to Clause 15, wherein the single type of compression includes direct compression, and wherein executing the instructions further causes the controller to: convert the input voltage to the passive radiator displacement or the vent air flow velocity via a speaker module; compress the passive radiator displacement or the vent air flow velocity; convert the compressed passive radiator displacement or the compressed vent air flow velocity to a driver displacement; compress the driver displacement; and convert the compressed driver displacement to the output voltage of the speaker via an inverse speaker model module.

[0105] Clause 18: In another embodiment, the present disclosure provides the non-transitory computer-readable medium according to any one of Clauses 15 to 17, wherein executing the instructions further causes the controller to: apply non-linear compensation to the output voltage to produce a compensated output voltage for the speaker.

[0106] Clause 19: In another embodiment, the present disclosure provides the non-transitory computer-readable medium according to Clause 16, wherein the speaker model is based on updated speaker parameters.

[0107] Clause 20: In another embodiment, the present disclosure provides the non-transitory computer-readable medium according to Clause 17, wherein the speaker model and the inverse speaker model are based on updated speaker parameters.

[0108] The present disclosure provides methods and systems for mechanical protection and non-linear compensation of vented or PR speaker systems. Using the methods and systems of the present disclosure, such speaker systems can be safely pushed to their mechanical limits without risk of damage. Non-linear distortion can be actively reduced to utilize the non-linear operating range. Compared with known methods or systems, the methods and systems of the present disclosure can protect the displacements of both the speaker driver and the PR and the vent air velocity simultaneously and are fully integrated with non-linear compensation. The methods and systems of the present disclosure can potentially be used for speaker systems of any size from portable products to large subwoofers and result in powerful and pure bass from speakers with a relatively small form factor, the performance of which exceeds user expectations.

[0109] While the above describes exemplary embodiments, it is not intended that these embodiments describe all possible forms of the invention. In fact, the language used in the specification is 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. Additionally, the features of various embodiments can be combined to form further embodiments of the invention.

Claims

1. A loudspeaker protection system, comprising: A loudspeaker, said loudspeaker including a driver and a passive radiator or a vent; And A controller configured to determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on an input voltage representing audible sound, and to determine an output voltage of the loudspeaker for reproducing the audible sound based on a single type of compression applied to both the displacement of the driver and the displacement of the passive radiator or the air flow velocity through the vent; Wherein the output voltage supplied to the loudspeaker limits the displacement of the driver within a driver displacement range and simultaneously limits the displacement of the passive radiator within a passive radiator displacement range or limits the air flow velocity through the vent within a vent air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

2. The loudspeaker protection system according to claim 1, wherein the controller includes a dynamic range controller, and the single type of compression includes side-chain dynamic range compression, and the dynamic range controller includes: A loudspeaker model module configured to convert the input voltage into the displacement of the driver and the displacement of the passive radiator or the air flow velocity through the vent; And A side-chain peak limiter configured to determine the output voltage of the loudspeaker based on the displacement of the driver and the displacement of the passive radiator or the air flow velocity through the vent.

3. The loudspeaker protection system according to claim 1, wherein the controller includes a dynamic range controller, and the single type of compression includes direct compression, and the dynamic range controller includes: A loudspeaker model module configured to convert the input voltage into the displacement of the passive radiator or the air flow velocity through the vent; A first peak limiter configured to compress the displacement of the passive radiator or the air flow velocity through the vent; A converter configured to convert the compressed displacement of the passive radiator or the compressed air flow velocity through the vent into the displacement of the driver; A second peak limiter configured to compress the displacement of the driver; And An inverse loudspeaker model module configured to convert the compressed displacement of the driver into the output voltage of the loudspeaker.

4. The loudspeaker protection system according to claim 1, further comprising a compensator configured to apply non-linear compensation to the output voltage to generate a compensated output voltage for the loudspeaker.

5. The loudspeaker protection system according to claim 1, wherein the input voltage includes a plurality of input voltages, each input voltage representing a frequency in a different frequency band of a plurality of frequency bands of the audible sound, and wherein the controller is configured to determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on each of the plurality of input voltages.

6. The loudspeaker protection system according to claim 2, wherein the loudspeaker model module receives updated loudspeaker parameters.

7. The loudspeaker protection system according to claim 3, wherein the loudspeaker model module and the inverse loudspeaker model module receive updated loudspeaker parameters.

8. A method for mechanically protecting a loudspeaker including a driver and a passive radiator or a vent, the method comprising: Determining at least one of a displacement of the driver, a displacement of the passive radiator, and an air flow velocity through the vent based on an input voltage representing an audible sound; Determining an output voltage of the loudspeaker for reproducing the audible sound according to a single type of compression applied to both the displacement of the driver and the displacement of the passive radiator or the air flow velocity through the vent; And Providing the output voltage to the loudspeaker to limit the displacement of the driver within a driver displacement range and simultaneously limit the displacement of the passive radiator within a passive radiator displacement range or limit the air flow velocity through the vent within a vent air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

9. The method for mechanically protecting a loudspeaker according to claim 8, wherein the single type of compression includes side-chain dynamic range compression, and the method further comprises: Converting the input voltage into the displacement of the driver and the displacement of the passive radiator or the air flow velocity through the vent via a loudspeaker module; And Determining the output voltage of the loudspeaker based on the displacement of the driver and the displacement of the passive radiator or the air flow velocity through the vent via a side-chain peak limiter.

10. The method for mechanically protecting a loudspeaker according to claim 8, wherein the single type of compression includes direct compression, and the method further comprises: Converting the input voltage into the displacement of the passive radiator or the air flow velocity through the vent via a loudspeaker module; Compressing the displacement of the passive radiator or the air flow velocity through the vent; Converting the compressed displacement of the passive radiator or the compressed air flow velocity through the vent into a displacement of the driver; Compressing the displacement of the driver; And Converting the compressed displacement of the driver into the output voltage of the loudspeaker via an inverse loudspeaker model module.

11. The method for mechanically protecting a loudspeaker according to claim 8, further comprising: Applying non-linear compensation to the output voltage to generate a compensated output voltage for the loudspeaker.

12. The method for mechanically protecting a loudspeaker according to claim 8, wherein the input voltage comprises a plurality of input voltages, each input voltage representing a frequency in a different frequency band of the plurality of frequency bands of the audible sound, and wherein determining at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on the input voltage representing the audible sound comprises: Determining at least one of a displacement of the driver, a displacement of the passive radiator, and an air flow velocity through the vent based on each of the plurality of input voltages.

13. The method for mechanically protecting a loudspeaker according to claim 9, wherein the loudspeaker model is based on updated loudspeaker parameters.

14. The method for mechanically protecting a loudspeaker according to claim 10, wherein the loudspeaker model and the inverse loudspeaker model are based on updated loudspeaker parameters.

15. A non-transitory computer-readable medium storing computer-executable instructions for mechanically protecting a loudspeaker including a driver and a passive radiator or a vent, wherein execution of the instructions causes the controller: Determine at least one of the displacement of the driver, the displacement of the passive radiator, and the air flow velocity through the vent based on an input voltage representing an audible sound; Determine an output voltage of the loudspeaker for reproducing the audible sound according to a single type of compression applied to both the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent; and Provide the output voltage to the loudspeaker to limit the displacement of the driver within a driver displacement range and, simultaneously, limit the displacement of the passive radiator within a passive radiator displacement range or limit the air flow velocity of the vent within an air flow velocity range to mechanically protect the loudspeaker and reduce distortion of the audible sound reproduced by the loudspeaker.

16. The non-transitory computer-readable medium according to claim 15, wherein the single type of compression includes side-chain dynamic range compression, and wherein executing the instructions further causes the controller to: Convert the input voltage into the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent via a speaker module; and Determine the output voltage of the loudspeaker based on the displacement of the driver and the displacement of the passive radiator or the air flow velocity of the vent via a side-chain peak limiter.

17. The non-transitory computer-readable medium according to claim 15, wherein the single type of compression includes direct compression, and wherein executing the instructions further causes the controller to: Convert the input voltage into the displacement of the passive radiator or the air flow velocity of the vent via a speaker module; Compress the displacement of the passive radiator or the air flow velocity of the vent; Convert the compressed displacement of the passive radiator or the compressed air flow velocity of the vent into the displacement of the driver; Compress the displacement of the driver; And Convert the compressed displacement of the driver into the output voltage of the loudspeaker via an inverse speaker model module.

18. The non-transitory computer-readable medium according to claim 15, wherein executing the instructions further causes the controller to: apply non-linear compensation to the output voltage to generate a compensated output voltage for the loudspeaker.

19. The non-transitory computer-readable medium according to claim 16, wherein the speaker model is based on updated speaker parameters.

20. The non-transitory computer-readable medium according to claim 17, wherein the speaker model and the inverse speaker model are based on updated speaker parameters.

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