Sound system and electronic device with improved vibration compensation

Abstract

The invention provides a sound system and an electronic device with improved vibration compensation. An acoustic system is disclosed that includes a speaker, an exciter, and a coupling device for mechanically coupling the exciter to the speaker. The sound system further comprises a signal influencing circuit designed to feed a first electrical signal to the speaker for moving the speaker diaphragm along the first axis and to feed a second electrical signal to the exciter for moving the movable mass along the shifted second axis based on the audio signal. The signal influencing circuit is designed to vary the amplification of the second electrical signal in the frequency range of the acoustic system and / or to set a phase shift between the first electrical signal and the second electrical signal, the phase shift being not equal to 0 DEG and 180 DEG in at least a part of the frequency range of the acoustic system. In addition, the invention further discloses the electronic equipment with the sound system.

Description

Technical Field

[0001] The present invention relates to a sound system, which includes a loudspeaker, an actuator, and a coupling device for mechanically coupling the actuator to the loudspeaker. The loudspeaker has a diaphragm and a loudspeaker motor coupled to the diaphragm, wherein the loudspeaker motor is designed to move the diaphragm along a first axis. The actuator has a moving mass and an actuator motor coupled to the moving mass, wherein the actuator motor is designed to move the moving mass along a second axis, and wherein the second axis is displaced from the first axis. Furthermore, the present invention relates to an electronic device, which includes a sound system of the above type. The sound system is built into the housing and / or frame of the electronic device, wherein the coupling device for mechanically coupling the actuator to the loudspeaker is at least partially formed by the housing and / or frame. Background Art

[0002] Sound systems and electronic devices of the aforementioned type are generally known in the prior art. In a common design, the vibrations caused by the loudspeaker motor of the loudspeaker also cause vibrations in the electronic device in which the loudspeaker is built based on the actio-reactio principle. Since these vibrations are unwanted in some applications, vibration compensation for the above devices has been proposed. For example, the moving mass of the actuator motor moves in antiphase with the movement of the loudspeaker motor. However, the vibration compensation is only achieved to a certain extent, and there are still some unwanted vibrations in the common design, which may cause clicking sounds in the movable elements (such as buttons, etc.) of the sound system or the electronic device. Summary of the Invention

[0003] Therefore, the object of the present invention is to overcome the disadvantages of the prior art and provide an improved sound system and an improved electronic device. In particular, the vibration compensation should be improved, and the clicking sounds of the movable elements of the sound system or the electronic device should be avoided or at least reduced.

[0004] The problem of the present invention is solved by the sound system defined in the opening paragraph, wherein the sound system further includes a signal influencing circuit,

[0005] -) The signal influencing circuit has an audio input, a loudspeaker output, an actuator output, a first signal path from the audio input to the loudspeaker output, and a second signal path from the audio input to the actuator output,

[0006] -) The signal influencing circuit is designed to feed a first electrical signal to the loudspeaker motor via the loudspeaker output and a second electrical signal to the actuator motor via the actuator output based on the audio signal received at the audio input, and

[0007] -) The signal influencing circuit is designed to vary the amplification (synonymously "gain") of the second electrical signal within the frequency range of the sound system and / or to introduce a phase shift between the first electrical signal and the second electrical signal This phase shift is different from 0° and 180° in at least a part of the frequency range of the sound system (i.e., and ).

[0008] Accordingly, a method of operating the above-described sound system may include the steps of:

[0009] - feeding a first electrical signal to the speaker motor via a speaker output based on an audio signal received at an audio input, and feeding a second electrical signal to the actuator motor via an actuator output, and

[0010] - varying the amplification of the second electrical signal and / or introducing a phase shift between the first electrical signal and the second electrical signal within the frequency range of the sound system, the phase shift being different from 0° and 180° in at least a part of the frequency range of the sound system.

[0011] The problem of the present invention is also solved by an electronic device including a sound system of the above type, wherein the sound system is built into a housing and / or a frame of the electronic device, and wherein a coupling means for mechanically coupling the actuator to the speaker is at least partially formed by the housing and / or the frame.

[0012] By using the proposed measures, the disadvantages of the prior art are overcome. By providing an appropriate amplification and / or an appropriate phase shift (other than in-phase or anti-phase), vibration compensation can be improved for a sound system in which the diaphragm of the speaker is displaced along a first axis from the axis along which the moving mass moves along a second axis.

[0013] For example, the signal influencing circuit in the operating setting may be arranged such that in at least a part of the frequency range of the sound system, the amplitude of the mechanical oscillation at a specific point of the housing and / or the frame of the electronic device is less than 50% of the amplitude of the mechanical oscillation at the said specific point of the housing and / or the frame in a reference setting in which the actuator is disconnected. Accordingly, a method of tuning the signal influencing circuit of a sound system may include the steps of arranging the signal influencing circuit in the operating setting such that in at least a part of the frequency range of the sound system, the amplitude of the mechanical oscillation at a specific point of the housing and / or the frame of the electronic device is less than 50% of the amplitude of the mechanical oscillation at the said specific point of the housing and / or the frame in a reference setting in which the actuator is disconnected.

[0014] By means of the proposed measures, the sound system (strictly speaking, its signal influencing circuit) can be tuned in such a way that vibrations at specific points of the housing and / or frame of the electronic device are significantly reduced. Preferably, these points are located at movable elements (such as buttons) which would otherwise undesirably click or generate other unwanted noises. For this purpose, during the tuning process, the amplification and / or phase shift is changed until a suitable value is found.

[0015] In an alternative embodiment, the signal influencing circuit is set in the operating setting in such a way that in at least a part of the frequency range of the sound system, a) the maximum amplitude or b) the average amplitude of the mechanical oscillations of the housing and / or frame of the electronic device is, in case a), below 50% of the maximum amplitude of the mechanical oscillations of the housing and / or frame in a reference setting in which the actuator is disconnected, or, in case b), below 50% of the average amplitude of the mechanical oscillations of the housing and / or frame in a reference setting in which the actuator is disconnected. Thus, an alternative method of tuning the signal influencing circuit of a sound system can include the step of setting the signal influencing circuit in the operating setting in such a way that in at least a part of the frequency range of the sound system, a) the maximum amplitude or b) the average amplitude of the mechanical oscillations of the housing and / or frame of the electronic device is, in case a), below 50% of the maximum amplitude of the mechanical oscillations of the housing and / or frame in a reference setting in which the actuator is disconnected, or, in case b), below 50% of the average amplitude of the mechanical oscillations of the housing and / or frame in a reference setting in which the actuator is disconnected.

[0016] Here, the sound system or its signal influencing circuit can be tuned separately in such a way that vibrations of the entire housing and / or frame of the electronic device are significantly reduced. Again, during the tuning process, the amplification and / or phase shift is changed until a suitable value is found. The tuning can be performed in such a way that the maximum amplitude of the housing and / or frame is significantly reduced (case a) or the average amplitude of the mechanical oscillations of the housing and / or frame is significantly reduced (case b).

[0017] Preferably, the above conditions hold in the steady state of the sound system (i.e., in the steady state of the oscillations of the loudspeaker and the actuator). In addition, the above conditions hold in particular for harmonic or sinusoidal sound signals at the audio input.

[0018] The reference setting can also be referred to as the "initial setting" or "default setting". In general, the test can be performed by closing the second signal path, by disconnecting the actuator from the signal influencing circuit or by setting zero gain in a matching filter or in an additional (energy-saving) filter of the signal influencing circuit.

[0019] In the above context, it should be noted that the point at which the maximum amplitude is measured in the operating setting is not necessarily the point at which the maximum amplitude is measured in the reference setting. Instead, the maximum amplitude can occur at different locations in the operating and reference settings. For example, mechanical oscillations of the housing and / or frame or points thereof can typically be measured with a laser during the tuning process.

[0020] Typically, the frequency range of an audio system can reach from 20 Hz to 20 kHz. In this way, the frequency range of sounds audible to humans is covered.

[0021] The coupling means for mechanically coupling the actuator to the loudspeaker can be provided by a dedicated elastic element between the actuator and the loudspeaker, such as a rod or plate made of metal and / or plastic. However, the coupling means can also be formed by the housing and / or frame of an electronic device in which the loudspeaker and the actuator are incorporated. However, it should be noted that in this context, using the housing and / or frame as a coupling between the actuator and the loudspeaker does not exclude the use of a dedicated elastic element between the actuator and the loudspeaker. In this case, the coupling means is formed by both the elastic element and the housing and / or frame of the electronic device.

[0022] Advantageously, the coupling means for mechanically coupling the actuator to the loudspeaker is formed by an elastic element having a natural resonance greater than 1 kHz. The proposed frequency range provides a sufficient coupling between the actuator and the loudspeaker for the housing of common electronic devices, which housing or its elements audibly click above said frequency substantially without vibration compensation.

[0023] The electronic device can be, for example, a mobile phone, a tablet computer or a laptop computer.

[0024] Typically, an "actuator" converts electrical power into movement and force. In contrast, a "loudspeaker" converts electrical power into sound. For the purposes of this disclosure, the actuator motor is not designed to move the diaphragm along a second axis. In other words, the loudspeaker is designed to convert an electric current into sound pressure, while the actuator is designed to convert an electric current into movement of a mass without generating a dedicated or significant sound. The generation of sound in view of the actuator is merely a side effect. In particular, the average sound pressure level of the loudspeaker measured at a perpendicular distance of 10 cm from the sound-emitting surface of the diaphragm can be at least 50 dB_SPL, and the average sound pressure level of the actuator measured at the same distance in the same direction can be at most 20 dB_SPL in the same frequency range.

[0025] Typically, the above device can also be intended to generate vibrations for haptic feedback.

[0026] An electronic device may include a frame and / or a housing. The housing encloses a more or less enclosed volume. The housing will protect the internal components from external influences such as dust, humidity, etc. In some cases, the housing is hermetically sealed. In contrast, the frame does not have an obvious sealing function but is intended to hold the components of the electronic device together.

[0027] Similar considerations can be made for loudspeakers, exciters, and audio systems, each of which may include a frame and / or a housing having the above-described characteristics.

[0028] Generally, the signal-influencing circuit may include a (digital) matching filter in the second signal path for setting amplification and phase shift. The matching filter has proven to be a device for setting amplification and phase shift, especially depending on the frequency of the audio signal received at the audio input.

[0029] In particular, the signal-influencing circuit may include:

[0030] - a phase shifter or an all-pass filter in the first signal path respectively, and

[0031] - a (digital) matching filter in the second signal path having a complex transfer function.

[0032] In particular, the phase shifter or the all-pass filter provides a time delay for the first signal such that the processing time or the maximum group delay of the matching filter is considered respectively, and a desired phase shift can be provided between the first signal and the second signal.

[0033] It should be noted that throughout the disclosure, "gain" is generally a similar term or synonym for "amplification" respectively.

[0034] Additional advantageous embodiments are disclosed in the claims, the description, and the drawings.

[0035] Preferably, the phase shift satisfies the conditions in at least a part of the frequency range of the audio system and In this way, the advantages of the proposed audio system are even more obvious.

[0036] Advantageously, the signal influencing circuit may additionally include a non-linear actuator model of the actuator and an actuator resistance detector for detecting the DC resistance of the actuator, wherein the actuator model has a first actuator model input connected to an input path leading to the matched filter, a second actuator model input connected to the output of the actuator resistance detector, and an output coupled to a second signal path before the input path to the matched filter. In particular, the actuator model may output an actuator resonance characteristic signal representing the resonance characteristics of the actuator (i.e., a signal representing the resonance frequency and / or quality factor or Q-factor of the actuator). More specifically, the actuator model may output a modeled back electromotive force of the actuator as the actuator resonance characteristic signal. The actuator resonance characteristic signal output by the actuator model is negatively coupled to the second signal path before the input path to the matched filter. If the actuator model outputs a negative actuator resonance characteristic signal or a negative modeled back electromotive force, it is positively coupled to the second signal path. Thereby, the resonance of the actuator is (actively) damped.

[0037] In another advantageous embodiment of the audio system, the signal influencing circuit may additionally include a non-linear speaker model of the speaker, a speaker resistance detector for detecting the DC resistance of the speaker, and a movement difference detector for detecting the difference between the speaker movement parameter and the actuator movement parameter.

[0038] - wherein the speaker model has a first speaker model input connected to an input path leading to the phase shifter or all-pass filter and a second speaker model input connected to the output of the speaker resistance detector.

[0039] - wherein the movement difference detector has a first input connected to the output of the speaker model, a second input connected to the output of the actuator model, and an output coupled to the second signal path before the input path to the said matched filter.

[0040] The speaker movement parameter and the actuator movement parameter may be selected from the group: offset, velocity, acceleration, or momentum. Thus, the movement difference detector may be referred to as an "offset difference detector", "velocity difference detector", "acceleration difference detector", or "momentum difference detector". Of course, the movement difference detector calculates the difference of the same type of parameters. Thus, the offset difference detector calculates the difference between the speaker offset and the actuator offset, the velocity difference detector calculates the difference between the speaker velocity and the actuator velocity, etc. Specifically, the movement difference detector may be a modeled movement difference detector that detects the difference between the modeled speaker movement parameter and the modeled actuator movement parameter.

[0041] It should be noted that if the output of the movement difference detector reflects the difference between the speaker movement parameter and the actuator movement parameter, then the output is negatively connected to the second signal path before the input path to the matched filter. In contrast, if the output reflects the difference between the actuator movement parameter and the speaker movement parameter, then the output is positively connected to the second signal path. Thus, in view of the resonance of the speaker, the resonance of the actuator is (actively) damped.

[0042] It should also be noted that the output of the actuator model in this embodiment outputs the actuator movement parameter (e.g., modeled actuator offset, modeled actuator velocity, modeled actuator acceleration, or modeled actuator momentum), while in the foregoing embodiment, the actuator model preferably outputs the modeled actuator resonance characteristic signal (e.g., back electromotive force of the modeled actuator). In the case of combining the two embodiments, the actuator model can have two different outputs, one for the actuator movement parameter and the other for the modeled actuator resonance characteristic signal.

[0043] Generally, the signal influencing circuit can respectively have optional driver stages or amplifiers in the first signal path and the second signal path to provide the first signal and the second signal that are powerful enough for the speaker and the actuator.

[0044] During the operation of the actuator, its resonance characteristics including harmonics may change, which is particularly caused by the temperature change of the actuator and / or the change in the level of the second electrical signal fed into the actuator. By feeding back the actuator resonance characteristic signal (e.g., back electromotive force of the actuator), these changes are respectively considered and compensated. Thus, the signal influencing circuit better adapts to the actual conditions.

[0045] The same is true for the speaker, whose resonance characteristics (including harmonics) may also change, which is particularly caused by the temperature change and / or the change in the level of the first electrical signal fed into the speaker. By feeding back the output signal of the movement difference detector, the differences in the behaviors of the speaker and the actuator are respectively considered and compensated. Thus, the movement of the moving mass of the actuator better adapts to the movement of the moving mass of the speaker. Thus, the signal influencing circuit better adapts to the actual conditions.

[0046] In this case, it is advantageous to use the offsets of the speaker and the actuator as the movement parameters because a very clear output signal of the movement difference detector is then obtained for low frequencies, which is particularly relevant for vibration compensation.

[0047] In particular, the non-linear exciter model in the above-described embodiments can be provided to calculate physical quantities of a second-order system based on Thiele / Small parameters related to the exciter (with or without non-linear parameters) and based on the signal fed into the matched filter in the second signal path. One of the calculated physical quantities can be an exciter resonance characteristic signal (e.g., the back electromotive force of the exciter), and another mechanical physical quantity can be the displacement, velocity, acceleration, or momentum of the exciter.

[0048] In a very similar manner, a loudspeaker model can be provided to calculate physical quantities of a second-order system based on Thiele / Small parameters related to the loudspeaker (with or without non-linear parameters) and based on the signal fed into the phase shifter / all-pass filter in the first signal path.

[0049] In particular, the exciter resistance detector can be designed to detect the DC resistance of the exciter, and the loudspeaker resistance detector can be designed to detect the DC resistance of the loudspeaker. Generally, the behavior of the exciter or loudspeaker is affected by its (ohmic) DC resistance. Therefore, the DC resistance can be used to adapt the exciter model and the loudspeaker model to real and actual conditions, in particular to obtain as accurate modeling values as possible and to avoid signal-induced circuit instability.

[0050] For example, the DC resistance can be obtained by measuring the current and voltage at the exciter or loudspeaker or at the component driving the exciter or loudspeaker (e.g., at the driver stage or amplifier). The DC resistance depends respectively on the temperature of the exciter voice coil or the loudspeaker voice coil. Therefore, if the DC resistance at a specific temperature and its dependence on temperature are known, the (actual) DC resistance can also be obtained by measuring the temperature of the exciter or loudspeaker. Alternatively, the (actual) DC resistance can also be obtained by measuring the electric power delivered to the exciter or loudspeaker, since the electric power has a direct influence on its temperature.

[0051] More specifically, an exciter resistance detector or a loudspeaker resistance detector can be provided to extract a low-frequency pilot tone signal from both the voltage and current fed into the exciter or loudspeaker. In this case, the instantaneous DC resistance value can be obtained by dividing the voltage of the pilot tone by the instantaneous RMS value of the current. The instantaneous DC resistance value can then be output at the exciter resistance detector output or the loudspeaker resistance detector output, respectively.

[0052] Finally, the moving difference detector is explained in more detail. It can be embodied as or regarded as an inverse actuator model, which calculates the physical quantity of a second-order system based on the mechanical physical quantities provided by the actuator model and the speaker model (strictly speaking, based on the difference of the said mechanical physical quantities), based on the same Thiele / Small parameters as the actuator model (with or without non-linear parameters), and outputs the calculated voltage at its output.

[0053] It should also be noted that the outputs of the actuator resistance detector and / or the speaker resistance detector, as well as the second actuator model input and / or the second speaker model input, can be provided as multi-dimensional inputs and outputs. This means that not only can one parameter be transmitted via such an input or output, but more parameters can also be transmitted. For example, the actuator resonance parameter can be (additionally) transmitted via the actuator resistance detector output and the second actuator model input, or the speaker resonance parameter can be (additionally) transmitted via the speaker resistance detector output and the second speaker model input. In this way, the external effects on the resonance of the actuator and / or the speaker that are independent of temperature or signal level can also be considered and compensated for respectively. For example, if an electronic device with an audio system built in is linked to a heavy mass, such as when the user holds the electronic device in his hand or touches the display screen of the electronic device with his finger, the resonance of the actuator and / or the speaker can change. The actuator resonance parameter can directly be the resonance frequency of the actuator, the phase shift between the voltage and current of the second electrical signal (which is also a measure of the resonance frequency of the actuator), or the phase shift deviation relative to 0° between the voltage and current of the second electrical signal (which is a measure of the change in the resonance frequency of the actuator). Very similarly, the speaker resonance parameter can directly be the resonance frequency of the speaker, the phase shift between the voltage and current of the first electrical signal (which is also a measure of the resonance frequency of the speaker), or the phase shift deviation relative to 0° between the voltage and current of the first electrical signal (which is a measure of the resonance frequency shift of the speaker). For example, a phase shift of 0° means operating at the resonance frequency. It should be noted that at this time, the phase shift between the voltage and current of the first electrical signal and the phase shift between the voltage and current of the second electrical signal must never be confused with the phase shift between the first electrical signal and the second electrical signal.

[0054] Preferably, the ratio of the moving mass of the speaker to the moving mass of the actuator is in the range of 0.5 to 5. In this way, the offset of the actuator is kept within a beneficial range and is neither too high nor too low. The moving mass of the speaker can be, for example, the mass of the speaker voice coil plus the mass of the movable part of the diaphragm.

[0055] In another preferred embodiment of the sound system, the angle α between the first axis and the second axis can be in the range of 0° ≤ α ≤ 45°. In this way, under certain conditions, the layout space of the loudspeaker and the actuator can be saved.

[0056] In yet another preferred embodiment of the sound system, the loudspeaker includes a rear cavity volume, wherein the actuator is arranged outside or inside the rear cavity volume. If the actuator is arranged outside the rear cavity volume, the rear cavity volume is independent of the size and shape of the actuator. If the actuator is arranged inside the rear cavity volume, a compact and robust sound system can be obtained. In particular, in this case, the housing surrounding the rear cavity volume can form a coupling device.

[0057] Advantageously, the sound system can additionally include an input for a supply voltage or a disconnect signal and an energy-saving control, which is designed to reduce the amplitude of the second electrical signal compared to the normal operating setting, or to switch off the generation of the second electrical signal below a threshold value of the supply voltage or upon receipt of the disconnect signal.

[0058] If the input is connected to the supply voltage for the sound system, the sound system itself can reduce the amplitude of the second electrical signal or switch off the generation of the second electrical signal in case of a low supply voltage. However, changing the amplitude of the second electrical signal between the energy-saving mode and the normal operating setting or switching the generation of the second electrical signal on and off between the energy-saving mode and the normal operating setting can also be triggered by a disconnect signal provided by the electronic device in which the sound system is integrated.

[0059] In particular, the generation of the second electrical signal can be affected by changing the parameters of the matched filter through the energy-saving control. For example, the gain of the matched filter can be set to a lower value or even zero in some frequency ranges or all frequency ranges for energy saving. Alternatively, for the same reason, an additional energy-saving filter can be provided in series with the matched filter. For example, the gain of the energy-saving filter can be set to a low value or even zero in some frequency ranges or all frequency ranges in the energy-saving mode and to "1" in all frequency ranges in the normal operating mode.

[0060] Advantageously, changing the amplitude of the second electrical signal or turning the generation of the second electrical signal on and off does not change the sound output by the loudspeaker or only changes it to a very small extent. The only influence of the actuator on sound generation is the possible movement of the entire loudspeaker caused by the movement of the actuator being transmitted to the loudspeaker via the coupling means. Strictly speaking, sound generation is based on the movement of the diaphragm relative to the loudspeaker frame or housing caused by the loudspeaker motor plus the movement of the entire loudspeaker caused by the actuator motor. However, as described above, the second movement is very small, and thus the influence on sound generation is also very small. If the loudspeaker frame or housing is fixed in space, for example if it is mounted to a heavy mass, this influence is even zero.

[0061] It should be noted in this context that in the case of turning off the generation of the second electrical signal in the energy-saving mode, the energy-saving mode is equal to the reference setting in the tuning of the aforementioned operating settings to obtain a significant reduction in vibration at specific points of the housing and / or frame of the electronic device or the entire housing and / or frame. In this case, therefore, the above conditions can be tested by switching the electronic device to the energy-saving mode.

[0062] Therefore, the considerations regarding sound generation in the energy-saving mode also apply to the tuning of the operating settings. This means that the sound output by the loudspeaker is not affected or not much affected during the tuning process or when the electronic device is transferred to the reference mode or reference setting. If the loudspeaker frame or housing is fixed in space, for example if it is mounted to a heavy mass, this influence can even be drawn to zero. Description of the Drawings

[0063] These and other aspects, features, details, utilities, and advantages of the present invention will become more apparent from the following detailed description, the appended claims, and the drawings, in which the drawings illustrate the features of exemplary embodiments according to the present invention, and in which:

[0064] Figure 1 A schematic diagram of an exemplary audio system is shown;

[0065] Figure 2 A cross-sectional view of the audio system is shown, in which the actuator is arranged outside the rear cavity volume of the loudspeaker;

[0066] Figure 3 A cross-sectional view of the audio system is shown, in which the actuator is arranged inside the rear cavity volume of the loudspeaker;

[0067] Figure 4 A schematic diagram of a signal influence circuit with an actuator model and an actuator resistance detector is shown;

[0068] Figure 5 Similar Figure 4, but with an additional speaker model, speaker resistance detector, and moving difference detector;

[0069] Figure 6 Shows a schematic diagram of a signal influence circuit with energy-saving control;

[0070] Figure 7 Shows a top view of an exemplary electronic device;

[0071] Figure 8 Is an exemplary curve graph showing the phase shift between the first signal and the second signal varying with frequency;

[0072] Figure 9 Is the exemplary gain of the second signal in frequency; and

[0073] Figure 10 Shows a schematic cross-sectional view of an audio system with a tilted first axis.

[0074] In multiple views, the same reference numerals represent the same or equivalent parts.

[0075] List of Reference Numerals

[0076] 1, 1a..1f Audio system

[0077] 2 Speaker

[0078] 3 Diaphragm

[0079] 4 Speaker voice coil

[0080] 5a Speaker magnet

[0081] 5b Speaker cone

[0082] 5c Speaker top plate

[0083] 6 Speaker motor

[0084] 7 Speaker housing / speaker frame

[0085] 8 Actuator

[0086] 9a, 9b Actuator voice coil

[0087] 10 Outer actuator ring

[0088] 11a Actuator magnet

[0089] 11b Actuator base plate

[0090] 11c Actuator top plate

[0091] 12 Moving mass

[0092] 13 Actuator motor

[0093] 14 Spring

[0094] 15 Actuator Housing / Actuator Frame

[0095] 16 Connecting Device

[0096] 17, 17a..17d Signal Influence Circuit

[0097] 18 Phase Shifter / All-Pass Filter

[0098] 19 Matching Filter

[0099] 20 Speaker Amplifier / Speaker Driver Stage

[0100] 21 Actuator Amplifier / Actuator Driver Stage

[0101] 22a..22c Electronic Device

[0102] 23 Housing or Frame of Electronic Device

[0103] 24 Display Screen of Electronic Device

[0104] 25 Sound Port

[0105] 26 Common Speaker and Actuator Housing or Frame

[0106] 27 Air Connection

[0107] 28 Nonlinear Actuator Model

[0108] 29 Actuator Model Amplifier

[0109] 30 Summing Unit

[0110] 31 Actuator Resistance Detector

[0111] 32 Nonlinear Speaker Model

[0112] 33 Speaker Resistance Detector

[0113] 34 Moving Difference Detector

[0114] 35 Energy Saving Control

[0115] 36 Energy Saving Switch

[0116] 37a..37d Button

[0117] α: Angle between the first axis and the second axis

[0118] A1, A1’ First Axis

[0119] A2 Second Axis

[0120] BV rear cavity volume

[0121] SES sound emission surface

[0122] P1..P3 points of the housing / frame

[0123] I1 audio input I2 first exciter model input I3 second exciter model input I4 exciter resistance detector input I5 first speaker model input I6 second speaker model input I7 speaker resistance detector input I8 first input of the moving difference detector I9 second input of the moving difference detector I10 power supply voltage or disconnect signal input O1 speaker output O2 exciter output O3 (first) exciter model output O4 exciter resistance detector output O5 speaker model output O6 speaker resistance detector output O7 second exciter model output O8 output of the moving difference detector O9 first energy-saving switch output O10 second energy-saving switch output SP1 first signal path SP2 second signal path AUD audio signal SPS first electrical signal ACS second electrical signal VCC power supply voltage or disconnect signal f frequency Phase shift

[0124] G amplification / gain Detailed implementation

[0125] This document describes various embodiments for various devices. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments described in the specification and illustrated in the figures. However, those skilled in the art will understand that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be understood that the specific structural and functional details disclosed herein may be representative and not necessarily limit the scope of the embodiments, the scope of which is defined only by the appended claims.

[0126] References throughout this specification to "various embodiments", "some embodiments", "one embodiment", or "an embodiment" etc. mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in various embodiments", "in some embodiments", "in one embodiment", or "in an embodiment" etc. throughout this specification are not necessarily all referring to the same embodiment. Additionally, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be included in whole or in part in one or more other embodiments, without limitation, so long as such combination is not illogical or non-functional.

[0127] It must be noted that, as used in this specification and the appended claims, unless otherwise expressly specified, the singular forms "a", "an", and "the" include plural referents.

[0128] The terms "first", "second", etc. (if any) in the specification and claims are used to distinguish between similar elements and not necessarily to describe a particular order or temporal sequence. It should be understood that such terms are interchangeable under appropriate circumstances so that the embodiments of the invention described herein, for example, can be operated in an order different from that illustrated or otherwise described herein. Additionally, the terms "comprising", "having", and any variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to the process, method, article, or apparatus.

[0129] All directional references (e.g., "plus", "minus", "up", "down", "upward", "downward", "left", "right", "leftward", "rightward", "front", "back", "top", "bottom", "above", "below", "over", "under", "vertical", "horizontal", "clockwise", and "counterclockwise") are for identification purposes only to assist the reader in understanding the present disclosure and do not impose limitations, particularly as to the position, orientation, or use in any aspect of the present disclosure. It should be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein, for example, can operate in other orientations different from those illustrated or otherwise described herein.

[0130] As used herein, the phrases "configured to", "configured for", and like phrases mean that the stated device, apparatus, or system is designed and / or constructed (e.g., by appropriate hardware, software, and / or components) to achieve one or more particular object purposes and not that the stated device, apparatus, or system is merely capable of performing that object purpose.

[0131] Joinder references (e.g., "attached", "coupled", "connected", etc.) shall be construed broadly and may include intermediate members between the connections of elements and relative movement between elements. Thus, a joinder reference does not necessarily infer that two elements are directly connected and in a fixed relationship to each other. All content included in the foregoing description or shown in the accompanying drawings is intended to be construed as merely exemplary and not limiting. Changes in details or structure may be made without departing from the spirit of the invention as defined by the appended claims. However, the term "connected" in the present disclosure may specifically mean "directly connected" (without an intermediate part), and the term "coupled" in the present disclosure may specifically mean "directly or indirectly connected" (with or without an intermediate part).

[0132] All numbers representing measures, etc. used in the specification and claims shall be understood in all cases to be modified by the term "about" or "substantially", which particularly means a deviation of ±10% from the reference value.

[0133] Figure 1Schematic diagram showing a first example of an audio system 1a. The audio system 1a includes a speaker 2 having a diaphragm 3 and a speaker voice coil 4, a speaker magnet 5a (magnetized in the axial direction along a first axis A1), a speaker pot 5b, and a speaker top plate 5c. The speaker magnet 5a, the speaker pot 5b, and the speaker top plate 5c form a speaker magnetic circuit system. Both the voice coil 4 and the speaker magnetic circuit system form a speaker motor 6. In addition, the speaker 2 includes a speaker housing or speaker frame 7 that houses the speaker magnetic circuit system. The diaphragm 3 is attached to the speaker housing or speaker frame 7 and to the speaker voice coil 4.

[0134] The current passing through the speaker voice coil 4 and the magnetic flux generated by the speaker magnet 5a and guided by the speaker pot 5b and the speaker top plate 5c cause the movement of the speaker voice coil 4, thereby causing the movement of the diaphragm 3. Generally, the speaker motor 6 is designed to move the diaphragm 3 up and down along the first axis A1.

[0135] In addition, the audio system 1a includes an exciter 8 having exciter voice coils 9a, 9b, an outer exciter ring 10, an exciter magnet 11a (magnetized in the axial direction along a second axis A2), an exciter bottom plate 11b, and an exciter top plate 11c. The outer exciter ring 10, the exciter magnet 11a, the exciter bottom plate 11b, and the exciter top plate 11c together form an exciter magnetic circuit system. In this example, the outer exciter ring 10 forms a fixed part of the exciter magnetic circuit system, and the exciter magnet 11a, the exciter bottom plate 11b, and the exciter top plate 11c together form a movable part and a moving mass 12 of the exciter magnetic circuit system, respectively. The exciter voice coils 9a, 9b are attached here to the outer exciter ring 10. The exciter voice coils 9a, 9b together with the magnetic circuit system (i.e., together with the fixed part of the exciter magnetic circuit system and the movable part of the exciter magnetic circuit system) form an exciter motor 13. In addition, the exciter 8 includes a spring 14, and the moving mass 12 is movably coupled to the fixed part of the exciter 8 (here coupled to the exciter voice coils 9a, 9b) through the spring 14. Finally, the exciter 8 includes an exciter housing / exciter frame 15 that houses the outer exciter ring 10.

[0136] The current passing through the exciter voice coils 9a, 9b and the magnetic flux generated by the exciter magnet 11a and guided by the outer exciter ring 10, the exciter bottom plate 11b, and the exciter top plate 11c cause the movement of the moving mass 12. Generally, the exciter motor 13 is designed to move the moving mass 12 up and down along the second axis A2, and the second axis A2 is displaced from the first axis A1 and is parallel to the first axis A1 in this example.

[0137] In addition, the sound system 1a includes a coupling device 16 for mechanically coupling the actuator 8 to the loudspeaker 2. For example, a dedicated elastic element, in particular a rod or plate made of metal and / or plastic, can be provided between the actuator 8 and the loudspeaker 2 for this purpose.

[0138] In general, it should be noted that the loudspeaker 2, the actuator 8 and the coupling member 16 are only schematically drawn and other embodiments are possible. For example, the proportions of the loudspeaker 2 and its parts can be different. In addition, in an alternative design, the loudspeaker magnet 5a can be larger and / or the loudspeaker 2 can have more than one loudspeaker voice coil 4 (for example, two). In addition, the actuator magnetic circuit system can have a different design and / or the actuator 8 can have a different number of actuator voice coils 9a, 9b. For example, the actuator 8 can have only one actuator voice coil 9a, 9b. It should also be noted that the proportions of the actuator 8 and its parts are also exemplary. For example, in an alternative design, the actuator magnet 11a can be larger.

[0139] It should also be noted that the loudspeaker 2 is used to convert electrical power into sound, while the actuator 8 should only convert electrical power into movement and force. Figure 1 It is conceivable that the actuator 8 does not have a diaphragm 3, so the actuator motor 13 is not designed to move the diaphragm 3 along the second axis A2. In other words, the actuator 8 is designed to convert an electric current into the movement of the moving mass 12 without generating a dedicated or significant sound. Given that the actuator 8 generating sound is only an unused side effect. In particular, the average sound pressure level of the loudspeaker 2 measured at a vertical distance of 10 cm from the sound-emitting surface SES of the isolation diaphragm 3 can be at least 50 dB_SPL, and the average sound pressure level of the actuator 8 measured at the same directional distance can be at most 20 dB_SPL in the same frequency range.

[0140] In addition, the sound system 1a includes a signal influencing circuit 17a, which has an audio input I1, a loudspeaker output O1, an actuator output O2, a first signal path SP1 from the audio input I1 to the loudspeaker output O1, and a second signal path SP2 from the audio input I1 to the actuator output O2. The signal influencing circuit 17a is designed to feed a first electrical signal SPS to the loudspeaker motor 6 via the loudspeaker output O1 and a second electrical signal ACS to the actuator motor 13 via the actuator output O2 based on the audio signal AUD received at the audio input I1.

[0141] It should be noted that although the actuator 8 in this example includes two actuator voice coils 9a, 9b, Figure 1 only a single exemplary signal line to the actuator 8 is shown. Thus, in reality, there can be two signal lines leading to the actuator 8 (also see in this context Figure 2 andFigure 3 )。It should also be noted that the directions of the currents flowing through the two actuator voice coils 9a, 9b are anti-parallel. This can be achieved either by opposite winding directions or by inverting the second electrical signal ACS.

[0142] The signal influencing circuit 17a is designed to change the amplification or gain of the second electrical signal ACS and / or set the phase shift between the first electrical signal SPS and the second electrical signal ACS within the frequency range of the audio system 1a Within at least a part of the frequency range of the audio system 1a, the phase shift is not equal to 0° and 180° (or in other words, within and ).

[0143] In this example, the signal influencing circuit 17a includes a phase shifter or all-pass filter 18 in the first signal path SP1 and a (digital) matched filter 19 in the second signal path SP2. The matched filter 19 is used here to set the amplification and / or phase shift, in particular depending on the frequency of the audio signal AUD received at the audio input I1, and can have a complex transfer function. The matched filter 19 is used to take into account and compensate for the physical differences between the loudspeaker 2 and the actuator 8. More specifically, the matched filter 19 can be provided to match the force generated by the actuator 8 with the force generated by the loudspeaker 2.

[0144] In particular, the phase shifter or all-pass filter 18 provides a time delay for the first signal SPS such that the processing time or maximum group delay of the matched filter 19 is taken into account and compensated for, and a desired phase shift can be provided between the first signal SPS and the second signal ACS even taking into account the said processing time or maximum group delay.

[0145] Finally, the audio system 1a includes an optional loudspeaker amplifier / loudspeaker driver stage 20 and an optional actuator amplifier / actuator driver stage 21, which are designed to amplify the signals from the phase shifter or all-pass filter 18 and the matched filter 19 to an appropriate signal level for the first signal SPS and the second signal ACS.

[0146] Generally, the actuator 8 (specifically its moving mass 12) is provided to compensate for the vibrations of the loudspeaker motor 6, which will be explained in detail later. Preferably, the ratio between the moving mass of the loudspeaker 2 (in this case the mass of the loudspeaker voice coil 4 plus the mass of the movable part of the diaphragm 3) and the moving mass 12 of the actuator 8 is in the range of 0.5 to 5. In this way, the offset of the actuator 8 remains within a beneficial range and is neither too high nor too low.

[0147] Figure 2A schematic cross-sectional view shows a second example of the audio system 1b, which is built into the electronic device 22a here. The electronic device 22a includes a housing and / or frame 23 having an optional display 24 and an optional sound port 25. For example, the electronic device 22a can be embodied as a mobile phone, a tablet computer, or a laptop computer. In addition, for example, the signal influencing circuit 17 can be embodied as Figure 1 the signal influencing circuit 17a depicted in

[0148] The audio system 1b includes a dedicated coupling device 16 for mechanically coupling the actuator 8 to the speaker 2. However, the speaker 2 and the actuator 8 are also mounted to the housing and / or frame 23, which forms an additional coupling device for the speaker 2 and the actuator 8. Thus, the mechanical coupling between the actuator 8 and the speaker 2 is partly formed by the housing and / or frame 23. It should also be noted that Figure 2 Two dedicated signal lines to the actuator voice coils 9a, 9b are shown.

[0149] The sound generated by the speaker 2 exits the housing and / or frame 23 through the sound port 25. However, other possibilities for sound transmission are also conceivable. From Figure 2 It can also be recognized that the actuator 8 does not contribute to sound generation because it does not compress or decompress the air volume within the housing and / or frame 23. Instead, the space between the moving mass 12 and the actuator voice coils 9a, 9b and the central hole in the moving mass 12 substantially form a sound short circuit. However, it should be noted that the actuator 8 will also function in the case where there is no such central hole in the moving mass 12 and will then have an even higher force factor.

[0150] In Figure 2 the example of Figure 3 the actuator 8 is arranged outside the rear cavity volume BV of the speaker 2. However, the actuator 8 can also be arranged within the rear cavity volume BV, as is the case in

[0151] Specifically, Figure 3 an audio system 1c built into the electronic device 22 is shown. Similarly, the electronic device 22 includes a housing and / or frame 23 having an optional display 24 and an optional sound port 25. In addition, the audio system 1c includes a common speaker and actuator housing or frame 26 and an air connection 27 to the air volume behind the diaphragm 3. Similarly, the sound generated by the speaker 2 exits the housing and / or frame 23 through the sound port 25, and for the reasons stated previously, the actuator 8 also does not contribute to sound generation. It should be noted that in this example, the outer actuator ring 10 is arranged on a dedicated holder, but it can also be arranged on a suitably shaped common speaker and actuator housing or frame 26.

[0152] In Figure 3 the example, there is no dedicated coupling device 16, but the mechanical coupling between the loudspeaker 2 and the actuator 8 is accomplished by the housing and / or the frame 23 and additionally by the common loudspeaker and actuator housing or frame 26. Again, in Figure 3 two dedicated signal lines to the actuator voice coils 9a, 9b are shown.

[0153] Figure 4 Now another embodiment of the sound system 1d is shown, which sound system 1d is similar to Figure 1 the sound system 1a, but wherein the signal influencing circuit 17b additionally includes a non-linear actuator model 28 of the actuator 8, an actuator model amplifier 29, a summing unit 30 and an actuator resistance detector 31. The non-linear actuator model 28 includes a first actuator model input I2 and a second actuator model input I3 as well as an actuator model output O3, and the actuator resistance detector 31 includes an actuator resistance detector input I4 and an actuator resistance detector output O4.

[0154] The actuator resistance detector input I4 is connected to the output of the actuator amplifier / actuator driver stage 21 and is designed to detect the DC resistance of the actuator 8. The DC resistance of the actuator 8 is output at the actuator resistance detector output O4 and fed via the second actuator model input I3 into the non-linear actuator model 28. The first actuator model input I2 is connected to the input path leading to the matching filter 19 (downstream of the summing unit 30). The actuator model output O3 is coupled to a second signal path SP2 before the input path to the matching filter 19. In this example, the actuator model output O3 is connected to the summing unit 30 via the actuator model amplifier 29. Furthermore, in this example, the actuator model 28 outputs an actuator resonance characteristic signal representing the resonance characteristics of the actuator 8 (i.e., a signal representing the resonance frequency and / or the quality factor or Q-factor of the actuator 8) at the actuator model output O3. More specifically, the actuator model 28 may output the modeled back electromotive force of the actuator 8 as the actuator resonance characteristic signal at the actuator model output O3. The actuator resonance characteristic signal output at the actuator model output O3 is negatively coupled to the second signal path SP2 by the summing unit 30 before the input path to the matching filter 19. However, if the actuator model 28 outputs a negative actuator resonance characteristic signal (e.g., a negative modeled back electromotive force), it is positively coupled to the second signal path SP2. Thereby, the resonance of the actuator 8 is (actively) damped.

[0155] During operation of the actuator 8, its resonant characteristics, which include harmonics, may change, particularly due to temperature variations of the actuator 8 and / or due to variations in the level of the second electrical signal ACS fed into the actuator 8. By feeding back the actuator resonance characteristic signal (e.g., the back electromotive force of the actuator 8), these variations are taken into account and compensated for respectively. As a result, the signal influencing circuit 17b better adapts to the actual conditions.

[0156] In particular, a non-linear actuator model 28 can be provided to calculate physical quantities of a second-order system based on Thiele / Small parameters (with or without non-linear parameters) associated with the actuator 8 and based on the input signal at the first actuator model input I2. One of the calculated physical quantities is the actuator resonance characteristic signal (e.g., the back electromotive force of the actuator 8), which is output at the actuator model output O3.

[0157] As described above, the actuator resistance detector 31 is designed to detect the DC resistance of the actuator 8. The (ohmic) DC resistance of the actuator 8 depends on the temperature of the actuator voice coils 9a, 9b and influences the behavior of the actuator 8. Therefore, the DC resistance is used herein to adapt the actuator model 28 to the real and actual conditions, particularly to obtain as accurate a value as possible of the actuator resonance characteristic signal or the back electromotive force respectively from the actuator model 28.

[0158] For example, the DC resistance can be obtained by measuring the current and voltage at the actuator voice coils 9a, 9b or at the elements driving the actuator voice coils 9a, 9b (e.g., at the actuator amplifier / actuator driver stage 21). If the DC resistance at a specific temperature and its dependence on temperature are known, the (actual) DC resistance can also be obtained by measuring the temperature of the actuator 8 (particularly by measuring the temperature of its actuator voice coils 9a, 9b). Alternatively, the (actual) DC resistance can also be obtained by measuring the electrical power transferred to the actuator voice coils 9a, 9b via the second signal ACS, since the power has a direct influence on the temperature of the actuator voice coils 9a, 9b. In Figure 4 the example, the actuator resistance detector input I4 receives current values and voltage values from the actuator amplifier / actuator driver stage 21. However, the actuator resistance detector input I4 can also alternatively be connected to a temperature sensor of the actuator 8. By the proposed measures, instability of the control loop formed by the actuator resistance detector 31, the non-linear actuator model 28, the actuator model amplifier 29, the summing unit 30, and the matching filter 19 can be avoided.

[0159] More specifically, an exciter resistance detector 31 can be provided to extract a low-frequency pilot tone signal from both the voltage measured at the exciter output O2 and the current measured in the exciter amplifier / exciter driver stage 21. In this case, the instantaneous DC resistance value can be obtained by dividing the voltage of the pilot tone by the instantaneous RMS value of the current. Then the instantaneous DC resistance value can be output at the exciter resistance detector output O4.

[0160] Figure 5 Another embodiment of an audio system 1e is shown, which is similar to Figure 4 the audio system 1d, but in which the signal influence circuit 17c additionally includes a non-linear speaker model 32 of the speaker 2, a speaker resistance detector 33 for detecting the DC resistance of the speaker 2, and a movement difference detector 34 for detecting the difference between the speaker movement parameter and the exciter movement parameter. The speaker model 32 has a first speaker model input I5 connected to the input path leading to the phase shifter or all-pass filter 18 and a second speaker model input I6 connected to the output O6 of the speaker resistance detector 33. The movement difference detector 34 has a first input I8 connected to the output O5 of the speaker model 32, a second input I9 connected to the (second) output O7 of the exciter model 28, and an output O8 connected to the second signal path SP2 before the input path to the matched filter 19.

[0161] The speaker movement parameter and the exciter movement parameter can be selected from the group: offset, speed, acceleration, or momentum. Thus, the movement difference detector 34 can be referred to as an "offset difference detector", a "speed difference detector", an "acceleration difference detector", or a "momentum difference detector". Of course, the movement difference detector 34 calculates the difference of the same type of parameters. Thus, the offset difference detector calculates the difference between the speaker offset and the exciter offset, the speed difference detector calculates the difference between the speaker speed and the exciter speed, etc. In particular, the movement difference detector 34 can be a modeled movement difference detector that detects the difference between the modeled speaker movement parameter and the modeled exciter movement parameter.

[0162] It should be noted that if the movement difference detector output O8 reflects the difference between the speaker movement parameter and the exciter movement parameter (as in Figure 5 ), then the movement difference detector output O8 is negatively connected to the second signal path SP2 before the input path to the matched filter 19, and if the movement difference detector output O8 reflects the difference between the exciter movement parameter and the speaker movement parameter, then the movement difference detector output O8 is positively connected to the second signal path SP2. Thereby, considering the resonance of the speaker 2, the resonance of the exciter 8 is (actively) damped.

[0163] It should also be noted that the first output O3 of the actuator model 28 and the second output O7 of the actuator model 28 do not necessarily output the same type of parameter. Instead, the first actuator model output O3 can output a modeled actuator resonance characteristic signal (e.g., the modeled back electromotive force of the actuator 8), while the second actuator model output O7 can output a modeled actuator offset, a modeled actuator velocity, a modeled actuator acceleration, or a modeled actuator momentum.

[0164] As previously described, during the operation of the actuator 8, its resonance characteristics including harmonics may change. The same is true for the loudspeaker 2, whose resonance characteristics including harmonics may also change, particularly also caused by temperature changes and / or by changes in the level of the first electrical signal SPS fed to the loudspeaker 2. By feeding back the output signal of the movement difference detector 34, the differences in loudspeaker behavior and actuator behavior are considered and compensated for separately. Thereby, the movement of the moving mass 12 of the actuator 8 better adapts to the movement of the moving mass of the loudspeaker 2 (here the mass of the loudspeaker voice coil 4 plus the mass of the movable part of the diaphragm 3). Thus, the signal influence circuit 17c better adapts to the actual situation.

[0165] In this case, it is advantageous to use the offsets of the loudspeaker 2 and the actuator 8 as movement parameters, because a very clear output signal of the movement difference detector 34 is then obtained for low frequencies, which is particularly relevant for vibration compensation.

[0166] More specifically, the actuator model 28 calculates physical quantities of a second-order system based on Thiele / Small parameters (with or without non-linear parameters) associated with the actuator 8 and based on the input signal at the first actuator model input I2 as previously indicated. One of the calculated physical quantities is the actuator resonance characteristic signal (e.g., the back electromotive force of the actuator 8) output at the actuator model output O3, and another mechanical physical quantity (offset, velocity, acceleration, or momentum) is output at the second actuator model output O7.

[0167] In a very similar manner, a loudspeaker model 32 can be provided to calculate physical quantities of a second-order system based on Thiele / Small parameters (with or without non-linear parameters) associated with the loudspeaker 2 and based on the input signal at the first loudspeaker model input I5. One of the calculated mechanical physical quantities (offset, velocity, acceleration, or momentum) is output at the loudspeaker model output O5.

[0168] In addition, the loudspeaker resistance detector 33 operates very similarly to the actuator resistance detector 31 and is provided for similar reasons. Specifically, the loudspeaker resistance detector 33 is designed to detect the DC resistance of the loudspeaker 2. The (ohmic) DC resistance of the loudspeaker 2 depends on the temperature of the loudspeaker voice coil 4 and affects the behavior of the loudspeaker 2. Therefore, the DC resistance is used herein to adapt the loudspeaker model 32 to the real and actual conditions.

[0169] For example, the DC resistance can be obtained by measuring the current and voltage at the loudspeaker voice coil 4 or at the element driving the loudspeaker voice coil 4 (e.g., at the loudspeaker amplifier / loudspeaker driver stage 20). If the DC resistance at a specific temperature and its dependence on temperature are known, the (actual) DC resistance can also be obtained by measuring the temperature of the loudspeaker 2, in particular by measuring the temperature of its loudspeaker voice coil 4. Alternatively, the (actual) DC resistance can also be obtained by measuring the electrical power that is transferred to the loudspeaker voice coil 4 via the first signal SPS, since the power has a direct influence on the temperature of the loudspeaker voice coil 4. In Figure 5 the example of, the loudspeaker resistance detector input I7 receives current values and voltage values from the loudspeaker amplifier / loudspeaker driver stage 20. However, the loudspeaker resistance detector input I7 can also alternatively be connected to a temperature sensor of the loudspeaker 2.

[0170] More specifically, the loudspeaker resistance detector 33 can be set to extract the low-frequency pilot tone signal from both the voltage measured at the loudspeaker output O1 and the current measured in the loudspeaker amplifier / loudspeaker driver stage 20. In this case, the instantaneous DC resistance value can be obtained by dividing the voltage of the pilot tone by the instantaneous RMS value of the current. Then the instantaneous DC resistance value can be output at the loudspeaker resistance detector output O6.

[0171] Finally, the moving difference detector 34 is explained in more detail. It can be embodied or regarded as an inverse actuator model, which calculates the physical quantities of a second-order system based on the mechano-physical quantities provided by the actuator model 28 and the loudspeaker model 32 (strictly speaking, based on the difference of the mechano-physical quantities), based on the same Thiele / Small parameters as the actuator model 28 (with or without non-linear parameters), and outputs the calculated voltage at the moving difference detector output O8.

[0172] It should also be noted that the exciter resistance detector output O4 and / or the speaker resistance detector output O6, as well as the second exciter model input I3 and / or the second speaker model input I6, can be set to multi-dimensional inputs and outputs. This means that not only can one parameter be transmitted via such inputs I3, I6 or outputs O4, O6, but more parameters can also be transmitted. For example, the exciter resonance parameter can be (additionally) transmitted via the exciter resistance detector output O4 and the second exciter model input I3, or the speaker resonance parameter can be (additionally) transmitted via the speaker resistance detector output O6 and the second speaker model input I6. In this way, the external effects on the resonance of the exciter 8 and / or the speaker 2 that are not related to temperature or signal level can also be considered and compensated for separately. For example, the resonance of the exciter 8 and / or the speaker 2 may change if the electronic devices 22a, 22b in which the audio system 1e is built are linked to a heavy mass, as is the case when the user holds the electronic devices 22a, 22 in his hand or touches the electronic devices 22a, 22 and the display screen 24 with his finger. The exciter resonance parameter can directly be the resonance frequency of the exciter, the phase shift between the voltage and current of the second electrical signal ACS (which is also a measure of the resonance frequency of the exciter 8), or the phase shift deviation relative to 0° between the voltage and current of the second electrical signal ACS (which is a measure of the change in the resonance frequency of the exciter 8). Very similarly, the speaker resonance parameter can directly be the resonance frequency of the speaker, the phase shift between the voltage and current of the first electrical signal SPS (which is also a measure of the resonance frequency of the speaker 2), or the phase shift deviation relative to 0° between the voltage and current of the first electrical signal SPS (which is a measure of the resonance frequency offset of the speaker 2). For example, a phase shift of 0° means operation at the resonance frequency. It should be noted that at this time, the phase shift between the voltage and current of the first electrical signal SPS and the phase shift between the voltage and current of the second electrical signal ACS must not be confused with the phase shift between the first electrical signal SPS and the second electrical signal ACS be confused with.

[0173] Figure 6 Now, an audio system 1f is shown, which is similar to Figure 1 the audio system 1a, but additionally includes an input I10 for the power supply voltage or disconnect signal VCC and an energy-saving control 35 having a first energy-saving switch output O9 and a second energy-saving switch output O10. The first energy-saving switch output O9 is connected to the energy-saving switch 36, and the second energy-saving switch output O10 is connected to the matching filter 19. It should be noted that one of the outputs O9, O10 is sufficient to provide the energy-saving function, but both can also be specifically implemented in the audio system 1f at the same time. The energy-saving control 35 is designed to reduce the amplitude of the second electrical signal ACS compared to the normal operation setting, or to turn off the generation of the second electrical signal ACS below the threshold of the power supply voltage VCC or upon receiving the disconnect signal VCC.

[0174] For example, the generation of the second electrical signal ACS can be turned off by turning on the energy-saving switch 36 in the second signal path SP2, as is the case in Figure 6 . Additionally or alternatively, the generation of the second electrical signal ACS can be affected by correspondingly changing the parameters of the matched filter 19, as indicated by the dashed line leading from the output 10 of the energy-saving control 35 to the matched filter 19. For example, the gain of the matched filter 19 can be set to a lower value or even zero in some or all frequency ranges to save energy. Alternatively, for the same reason, an additional energy-saving filter switched in series with the matched filter 19 can be provided. For example, the gain of the energy-saving filter can be set to a low value or even zero in some or all frequency ranges in the energy-saving mode and to "1" in all frequency ranges in the normal operation mode. In fact, setting the gain of the matched filter 19 or the additional energy-saving filter to zero is equivalent to turning off the generation of the second electrical signal ACS or turning on the energy-saving switch 36, respectively.

[0175] If the input I10 is connected to the supply voltage VCC for the audio system 1f, the audio system 1f itself can reduce the amplitude of the second electrical signal ACS or turn off the generation of the second electrical signal ACS in the case of a low supply voltage VCC. However, changing the amplitude of the second electrical signal ACS between the energy-saving mode and the normal operation setting or turning on and off the generation of the second electrical signal ACS between the energy-saving mode and the normal operation setting can also be triggered by a disconnect signal provided by the electronic devices 22a, 22B incorporating the audio system 1f.

[0176] Advantageously, changing the amplitude of the second electrical signal ACS or turning on and off the generation of the second electrical signal ACS does not change the sound output by the speaker 2 or only changes it to a very small extent. The only effect of the actuator 8 on sound generation is the possible movement of the entire speaker 2 caused by transferring the movement of the actuator via the mechanical coupling (e.g., via the coupling members 16, 23, 26) between the speaker 2 and the actuator 8. Strictly speaking, sound generation is based on the movement of the diaphragm 3 relative to the speaker frame or housing 7 caused by the speaker motor 6 plus the movement of the entire speaker 2 caused by the actuator motor 13. However, as described above, the second movement is very small, and thus the effect on sound generation is also very small. If the speaker frame or housing 7 is fixed in space, for example, if it is mounted to a heavy mass, this effect is even zero.

[0177] It should be noted that Figure 6 the energy-saving feature of

[0178] can be integrated into any one of the signal-influencing circuits 17, 17a..17c. Figures 7 to 9Explain in detail the function or use of vibration compensation. Figure 7 A top view of an exemplary electronic device 22c is shown, Figure 8 An exemplary graph of the phase shift between a first signal SPS and a second signal ACS over a frequency f is shown, and Figure 9 An exemplary gain G of the second signal ACS over the frequency f is shown.

[0179] Specifically, Figure 1 The exemplary electronic device 22c is embodied as a smartphone and includes a housing and / or frame 23 having a display screen 24 and a sound port 25. In addition, the electronic device 22c includes an audio system 1, which (which can be embodied as any one of the audio systems 1a..1f, for example) has a signal influencing circuit (not explicitly shown in Figure 7 ), which can be embodied as any one of the signal influencing circuits 17a..17d, for example. In addition, the electronic device 22c includes four buttons 37a..37d. Finally, Figure 7 Three exemplary points or positions P1..P3 on the electronic device 22c are depicted in

[0180] Advantageously, the audio system 1 or its signal influencing circuits 17, 17a..17d can be set in the operating settings in such a way that in at least a part of the frequency range of the audio system 1, the amplitude of the mechanical oscillation at specific points P1..P3 of the housing and / or frame 23 of the electronic device 22c is less than 50% of the amplitude of the mechanical oscillation at the specific points P1..P3 of the housing and / or frame 23 in the reference setting where the actuator 8 is disconnected.

[0181] Since the actuator 8 is disconnected in the reference setting, it is equal to the energy-saving mode in the case where the generation of the second electrical signal ACS is turned off there. In this case, accordingly, the above conditions can be tested by switching the signal influencing circuits 17, 17a..17d to the energy-saving mode. Generally, the test can be performed by disconnecting the second signal path SP2, by cutting off the actuator 8 from the signal influencing circuits 17, 17a..17d, or by setting a zero gain G in the matching filter 19 or in an additional energy-saving filter of the signal influencing circuits 17, 17a..17d.

[0182] It should be noted that the consideration of generating sound in the energy-saving mode also applies here. This means that during the test of the above conditions or when the signal influencing circuits 17, 17a..17d are transferred to the reference setting, the sound output by the speaker 2 is not affected or is affected little. If the speaker frame or housing 7 is fixed in space, for example, if it is mounted to a heavy mass block, the effect can even be attenuated to zero.

[0183] Thus, the sound system 1 (strictly speaking, its signal influencing circuits 17, 17a..17d) can be tuned in such a way that the vibrations of the housing and / or frame of the electronic device 22c at specific points P1..P3 are greatly reduced. To this end, during the tuning process, the amplification / gain G and / or the phase shift are changed until suitable values are found. These points P1..P3 can be located at movable elements, as is the case where point P3 is arranged at or on the button 37d. Alternatively, the points P1..P3 can be located at any position on the electronic device 22c, as is the case with points P1 and P2. Thus, unwanted clicking sounds or other unwanted noises can be suppressed or at least reduced.

[0184] In this context, Figure 8 and Figure 9 shows the results of an exemplary tuning process, namely the phase shift of the second signal ACS at the frequencies f of points P1..P3 and an exemplary graph of the gain G. It can be seen that tuning the sound system 1 to different points P1..P3 with reduced movement results in different graphs. Therefore, if the movement of more points P1..P3 is to be greatly reduced, a trade-off usually has to be made.

[0185] In this context, in an alternative embodiment, the signal influencing circuits 17, 17a..17d can be set in the operating settings in such a way that in at least a part of the frequency range of the sound system 1, a) the maximum amplitude or b) the average amplitude of the mechanical oscillations of the housing and / or frame 23 of the electronic device 22c is in case a) below 50% of the maximum amplitude of the mechanical oscillations of the housing and / or frame 23 in the reference setting where the actuator 8 is disconnected or in case b) below 50% of the average amplitude of the mechanical oscillations of the housing and / or frame 23 in the reference setting where the actuator 8 is disconnected.

[0186] Here, the sound system 1 or its signal influencing circuits 17, 17a..17d are tuned in such a way as to greatly reduce the vibrations of the entire housing and / or frame 23 of the electronic device 22c. Tuning can be carried out in the following ways: the maximum amplitude of the housing and / or frame 23 is greatly reduced (case a) or the average amplitude of the mechanical oscillations of the housing and / or frame 23 is greatly reduced (case b).

[0187] It should be noted in this context that the points P1..P3 at which the maximum amplitude is measured in the operating settings are not necessarily the points P1..P3 at which the maximum amplitude is measured in the reference setting. On the contrary, the points P1..P3 at which the maximum amplitude occurs in the two settings may be different from each other. It should also be noted that Figure 8 and Figure 9The curve graph is exemplary and only illustrates possible tuning results. However, under different conditions, the curve graph can be very different from the curve graphs shown in Figure 8 and Figure 9 .

[0188] Preferably, the above conditions are met in the steady state of the sound system 1 (i.e., in the steady state of the oscillations of the loudspeaker 2 and the actuator 8). In addition, the above conditions particularly hold for harmonic or sinusoidal sound signals AUD at the audio input I1. For example, the mechanical oscillations of the housing and / or the frame 23 can be measured with a laser during the tuning process.

[0189] Generally, the frequency range of the sound systems 1, 1a..1f can reach from 20 Hz to 20 kHz. In this way, the frequency range of the sounds audible to humans is covered.

[0190] Figure 10 A sectional view of the arrangement of the loudspeaker 2 and the actuator 8 built into the housing 23 is now shown. In this embodiment, there is an angle α between the first axes A1, A1’ and the second axis A2, which can save space under certain conditions. However, in order to obtain satisfactory vibration compensation, the angle α between the first axes A1, A1’ and the second axis A2 should be in the range of 0° ≤ α ≤ 45°.

[0191] In addition, in order to obtain satisfactory vibration compensation, it is useful if the coupling devices 16, 23, 26 for mechanically coupling the actuator 8 to the loudspeaker 2 are formed by elastic elements with a natural resonance greater than 1 kHz. The proposed frequency range provides sufficient coupling between the housing and / or the frame 23 of the common electronic devices 22a..22c between the actuator 8 and the loudspeaker 2, and these housings and / or frames 23 or their elements rattle above the said frequency f substantially without vibration compensation.

[0192] If the phase shift meets the conditions and in at least a part of the frequency range of the sound systems 1, 1a..1f, this is also advantageous. In this way, the advantages of the proposed sound systems 1, 1a..1f are even more obvious.

[0193] Finally, it is noted that the scope of the present invention is defined by the appended claims, including known equivalents and unforeseeable equivalents at the time of filing this application. Although many embodiments of the present invention have been described above with a certain degree of particularity, those skilled in the art can make various changes to the disclosed embodiments without departing from the spirit or scope of the present disclosure.

Claims

1. A sound system (1, 1a..1f), the sound system (1, 1a..1f) comprising: - a loudspeaker (2) having a diaphragm (3) and a loudspeaker motor (6) coupled to the diaphragm (3), wherein the loudspeaker motor (6) is designed to move the diaphragm (3) along a first axis (A1, A1'), - an exciter (8) having a mobile mass (12) and an exciter motor (13) coupled to the mobile mass (12), wherein the exciter motor (13) is designed to move the mobile mass (12) along a second axis (A2), and wherein the second axis (A2) is displaced from the first axis (A1, A1'), and - coupling means (16) for mechanically coupling the exciter (8) to the loudspeaker (2), The sound system (1, 1a..1f) further comprises a signal influencing circuit (17, 17a..17d), -) the signal influencing circuit (17, 17a..17d) has an audio input (I1), a loudspeaker output (O1), an actuator output (O2), a first signal path (SP1) from the audio input (I1) to the loudspeaker output (O1) and a second signal path (SP2) from the audio input (I1) to the actuator output (O2), -) the signal influencing circuit (17, 17a..17d) is designed to feed a first electrical signal (SPS) to the speaker motor (6) via the speaker output (O1) and to feed a second electrical signal (ACS) to the actuator motor (13) via the actuator output (O2), based on an audio signal (AUD) received at the audio input (I1), and -) the signal influencing circuit (17, 17a..17d) is designed to change the amplification (G) of the second electrical signal (ACS) and / or to set a phase shift between the first electrical signal (SPS) and the second electrical signal (ACS) within the frequency range of the sound system (1, 1a..1f) The phase shift unequal to 0° and 180° in at least a portion of the frequency range of the sound system (1, 1a..1f).

2. The sound system (1, 1a..1f) according to claim 1, wherein: The phase shift Satisfy the conditions and 3. The sound system (1, 1a..1f) according to claim 1, wherein: The signal influencing circuit (17, 17a..17d) comprises a matched filter (19) in the second signal path (SP2).

4. The sound system (1, 1a..1f) according to claim 1, wherein: The signal influencing circuit (17, 17a..17d) comprises: - a phase shifter or an all-pass filter (18), respectively, in said first signal path (SP1), and - a matched filter (19) having a complex transfer function in said second signal path (SP2).

5. The sound system (1, 1a..1f) according to claim 4, wherein: The signal influencing circuit (17, 17a..17d) further comprises a nonlinear actuator model (28) of the actuator (8) and an actuator resistance detector (31) for detecting the DC resistance of the actuator (8), - wherein the exciter model (28) has a first exciter model input (I2) connected to an input path to the matched filter (19), a second exciter model input (I3) connected to an output (O4) of the exciter resistance detector (31), and an output (O3) connected to the second signal path (SP2) before the input path to the matched filter (19).

6. The sound system (1, 1a..1f) according to claim 4 or 5, wherein: The signal influencing circuit (17, 17a..17d) further comprises a nonlinear loudspeaker model (32) of the loudspeaker (2), a loudspeaker resistance detector (33) for detecting the DC resistance of the loudspeaker (2) and a movement difference detector (34) for detecting the difference between a loudspeaker movement parameter and an exciter movement parameter, - wherein the loudspeaker model (32) has a first loudspeaker model input (I5) connected to an input path leading to the phase shifter or all-pass filter (18) and a second loudspeaker model input (I6) connected to an output (O6) of the loudspeaker resistance detector (33), -Wherein, the motion difference detector (34) has a first input (I8) connected to the output (O5) of the loudspeaker model (32), a second input (I9) connected to the output (O7) of the exciter model (28), and an output (O8) connected to the second signal path (SP2) before the input path to the matched filter (19).

7. The sound system (1, 1a..1f) according to claim 1, wherein The frequency range is up to 20 Hz to 20 kHz.

8. The sound system (1, 1a..1f) according to claim 1, wherein The ratio between the moving mass of the loudspeaker (2) and the moving mass (12) of the exciter (8) is in the range of 0.5 to 5.

9. The sound system (1, 1a..1f) according to claim 1, wherein: An angle (α) between the first axis (A1, A1′) and the second axis (A2) is in the range of 0°≤α≤45°.

10. The sound system (1, 1a..1f) according to claim 1, wherein The exciter motor (13) is not designed to move the diaphragm (3) along the second axis (A2).

11. The sound system (1, 1a..1f) according to claim 1, wherein: - the average sound pressure level of the loudspeaker (2) measured at a vertical distance of 10 cm from the sound emitting surface (SES) of the diaphragm (3) is at least 50 dB_SPL, and - The average sound pressure level of the exciter (8) measured at the same directional distance is at most 20 dB_SPL in the same frequency range.

12. The sound system (1, 1a..1f) according to claim 1, wherein The loudspeaker (2) comprises a back volume (BV), and wherein the driver (8) is arranged outside or inside the back volume (BV).

13. An audio system (1, 1a..1f) according to claim 1, further comprising an input (I10) for a supply voltage or a disconnect signal (VCC) and an energy saving control (35), the energy saving control (35) being designed to reduce the amplitude of the second electrical signal (ACS) compared to a normal operating setting or to switch off the generation of the second electrical signal (ACS) below a threshold of the supply voltage (VCC) or upon receipt of the disconnect signal (VCC).

14. The sound system (1, 1a..1f) according to claim 1, wherein The coupling means (16) for mechanically coupling the exciter (8) to the loudspeaker (2) are formed by an elastic element having a natural resonance greater than 1 kHz.

15. An electronic device (22a..22c), comprising the sound system (1, 1a..1f) according to claim 1 built into a housing and / or a frame (23) of the electronic device (22a..22c), wherein: The coupling means (16) for mechanically coupling the exciter (8) to the loudspeaker (2) are at least partially formed by the housing and / or frame (23).

16. The electronic device (22a..22c) according to claim 15, wherein The signal influencing circuit (17, 17a..17d) is arranged in an operating setting in such a way that in at least a part of the frequency range of the sound system (1, 1a..1f), the amplitude of the mechanical oscillations at a specific point (P1..P3) of the housing and / or frame (23) of the electronic device (22a..22c) is lower than 50% of the amplitude of the mechanical oscillations at the specific point (P1..P3) of the housing and / or frame (23) in a reference setting in which the exciter (8) is disconnected.

17. The electronic device (22a..22c) according to claim 15, wherein The signal influencing circuit (17, 17a..17d) is arranged in an operating setting in such a way that in at least a part of the frequency range of the sound system (1, 1a..1f), a) the maximum amplitude or b) the average amplitude of the mechanical oscillations of the housing and / or frame (23) of the electronic device (22a..22c) is lower than 50% of the maximum amplitude of the mechanical oscillations of the housing and / or frame (23) in a reference setting in which the exciter (8) is disconnected, or is lower than 50% of the average amplitude of the mechanical oscillations of the housing and / or frame (23) in the reference setting in which the exciter (8) is disconnected, in b).

Images