WO2020143473A1

WO2020143473A1 - Audio device and electronics apparatus

Info

Publication number: WO2020143473A1
Application number: PCT/CN2019/128815
Authority: WO
Inventors: Thomas Beierholm
Original assignee: Goertek Inc.
Priority date: 2019-01-08
Filing date: 2019-12-26
Publication date: 2020-07-16

Abstract

An audio device and an electronics device are disclosed. The audio device comprises: a loudspeaker; a sensing circuit, which senses a voltage and/or a current in the loudspeaker; a first processing circuit, which determines changes of acoustic radiation character based on the sensed voltage and/or current and determines an adjustment parameter based on the changes of acoustic radiation character; and a second processing circuit, which adjusts an audio signal to be played by the loudspeaker based on the adjustment parameter or is triggered to perform a higher precision measurement of changes for the loudspeaker by the adjustment parameter.

Description

AUDIO DEVICE AND ELECTRONICS APPARATUS

FIELD OF THE INVENTION

The present disclosure relates to loudspeaker, and more specifically, to an audio device and an electronics apparatus.

BACKGROUND OF THE INVENTION

The low-frequency response of a loudspeaker is dependent on the position of the loudspeaker in a room and it is dependent on characteristics of the room such as size, distance to reflecting surfaces, absorption coefficients, furniture, etc. ) . So, the low-frequency response of the loudspeaker shall be adjusted according to a listening environment.

Traditional ways of correcting the low-frequency part of a loudspeaker response that is impacted by a loudspeakers position in a given room is by means of measuring the acoustic radiation impedance (or just the real part of the impedance, i.e. resistance) . Microphones are normally used for measuring the radiation impedance. Typically, one or more microphones are used to measure the pressure close to the loudspeaker diaphragm. This measurement may be combined with a microphone placed in the back cavity of the loudspeaker or with an accelerometer mounted on the loudspeaker diaphragm.

Traditionally, acoustical and mechanical sensors have been used to determine the radiation impedance/resistance or changes of the loudspeaker.

The article of “Adaptive Bass Control -The ABC Room Adaptation System” byPedersen, Jan A. proposes a system for adapting a loudspeaker to its position and to the acoustic properties of the listening room, which is hereby incorporated herein by reference.

US patent No. 9,992,595 B1 describes an acoustic change detection solution which uses a number of pairs of microphones, which is hereby incorporated herein by reference.

The article of “Adaptive Control of Loudspeaker Frequency Response at Low Frequencies” by G.J. Adams proposes a method for monitoring and adjusting the acoustic power-output/frequency response of a direct-radiator type loudspeaker system at low frequencies, which is hereby incorporated herein by reference.

SUMMARY OF THE INVENTION

This disclosure provides a new solution for correcting low-frequency response of a loudspeaker.

According to a first aspect of the present invention, there is provided an audio device, comprising: a loudspeaker; a sensing circuit, which senses a voltage and/or a current in the loudspeaker; a first processing circuit, which determines changes of acoustic radiation character based on the sensed voltage and/or current and determines an adjustment parameter based on the changes of acoustic radiation character; and a second processing circuit, which adjusts an audio signal to be played by the loudspeaker based on the adjustment parameter or is triggered to perform a higher precision measurement of changes for the loudspeaker by the adjustment parameter.

According to a second aspect of the present invention, there is provided an electronics apparatus, which includes the audio device according to an embodiment.

According to various embodiment of this disclosure, a new solution for correcting low-frequency response of a loudspeaker is provided.

Further features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments according to the present invention with reference to the attached drawings.

BRIEF DISCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention.

Figure 1 shows a schematic block diagram of an audio device according to an embodiment.

Figure 2 shows a schematic block diagram of asensing circuit according to an embodiment.

Figure 3 shows a schematic block diagram of afirst processing circuit according to an embodiment.

Figure 4 shows a schematic block diagram of asecond processing circuit according to an embodiment.

Figure 5 shows aschematic block diagram of an electronics device according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods and apparatus as known by one of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all of the examples illustrated and discussed herein, any specific values should be interpreted to be illustrative only and non-limiting. Thus, other examples of the exemplary embodiments could have different values.

Notice that similar reference numerals and letters refer to similar items in the following figures, and thus once an item is defined in one figure, it is possible that it need not be further discussed for following figures.

As shown in Figure 1, the audio device 10 comprises: aloudspeaker 14, a sensing circuit 15, a first processing circuit 16 and a second processing circuit 11.

The sensing circuit 15 senses a voltage and/or a current in the loudspeaker. The first processing circuit 16 determines changes of acoustic radiation character based on the sensed voltage and/or current and determines an adjustment parameter based on the changes of acoustic radiation character. The second processing circuit 11 adjusts an audio signal to be played by the loudspeaker based on the adjustment parameter or is triggered to perform a higher precision measurement of changes for the loudspeaker by the adjustment parameter.

This disclosure relates to determination of acoustic radiation impedance/resistance or changes thereof by means of VI-sensing. In such a manner, a microphone for correction may be omitted, which could simplify the hardware of an audio device. We find that changes in acoustic radiation impedance (such as impedance phase or resistance) can be detected by analyzing or processing of the sampled current and voltage waveforms in the electrical circuit part of a loudspeaker. If a change is detected, it can be used for correction of the low-frequency response of the loudspeaker or it can be used for triggering another system that makes a higher precision measurement that is then used for correction of the low-frequency response.

The audio device may further comprise a digital-to-analog converter 12 and an amplification circuit 13. The digital-to-analog converter 12 receives digital audio signals to be played by the loudspeaker and converts the digital audio signals into analog audio signals. The amplification circuit 13 receives the analog audio signals, amplifies the analog audio signals and sends the amplified analog audio signals to the loudspeaker for playing.

The sensing circuit 15can sense the voltage and current by sampling the voltage and current in an electrical circuit part of the loudspeaker 14. Although in Figure 1, two lines from loudspeaker 14 to the sensing circuit 15 are shown, the sensing circuit 15 can just sense one of voltage and current in some situation.

The voltage and/or current may be the voltage and/or current of a signal being played by the loudspeaker 14. The sensing circuit 15 senses the voltage and current, and the first processing circuit determines the changes based on the sensed voltage and current.

The signal being played by the loudspeaker is an analog signal.

Figure 2 shows a schematic block diagram of asensing circuit according to an embodiment. The sensing circuit 15 further includes: asampling circuit 151 and an analog-to-digital converter 152. The sampling circuit 151 samples the voltage and/or current signals. Theanalog-to-digital converter 152 converts the sampled voltage and/or current signals into digital voltage and/or current signals. For example, the sampling circuit may be a switch.

The first and second processing circuits16, 11 can be implemented in various manners.

In the example of Figure 3, the first processing circuit 16 further includes: afirst processor 161 anda first memory 162. The first memory 162stores first instructions. When the first instructions are executed by the first processor 161, the first instructions control the first processor 161to determine the changes of acoustic radiation character based on the sensed voltage and/or current.

Figure 4 shows a schematic block diagram of a second processing circuit according to an embodiment.

In the example of Figure 4, the second processing circuit 11 further includes: asecond processor 111 anda second memory 112. The second memory 112 stores second instructions. When the second instructions are executed by the second processor 111, the second instructions control the second processor 111 to adjust an audio signal to be played by the loudspeaker 14 based on the adjustment parameter or to be triggered to perform a higher precision measurement of changes for the loudspeaker 14by the adjustment parameter.

In some designs, the first and second processors can be combined together. They are the same processor, and the first and second memories are a same memory. The first and second instructions are stored in the same memory.

Alternatively, the second processing circuit may be an equalization filter, and the first processing circuit determines filter coefficients for the equalization filter based on the changes of acoustic radiation character.

The acoustic radiation character can be acoustic radiation impedance and/or resistance for the loudspeaker 14.

The first processing circuit 16 can determine the changes based on waveforms of the sensed voltage and current.

The first processing circuit 16 can determine the changes by comparing the current acoustic radiation character determined based on the currently sensed voltage and/or current and the previous acoustic radiation character determined based on the previously sensed voltage and/or current.

The first processing circuit is a digital signal processor. The second processing circuit can also be a digital signal processor.

The first processing circuit determines filter coefficients of a low-frequency response for adjusting the audio signal, the second processing circuit adjusts the low-frequency response by using the filter coefficients.

The first processing circuit may determine changes by using a model of the loudspeaker. For example, the model is linear or non-linear. Optional, the model may be time-variant or time-invariant. The model may be statistical or deterministic. The model may be static or adaptive. The model may be based on an equation describing a behavior of a driver of the loudspeaker.

Changes in the electrical circuit part of the loudspeaker such as voice coil temperature changes and changes in the mechanical part of the loudspeaker such as suspension stiffness changeswill also present changes in the current-voltage relationship over time.

For example, the changes of acoustic radiation character are abrupt. For example, when moving the loudspeaker to a new position, the changes of acoustic radiation character are abrupt. As such, this kind of changes can be identified from others.

A loudspeaker model can be used to map a change in electrical impedance to a change in acoustic radiation impedance. If current measurements are too small to be measured accurately and thereby changes in acoustic radiation impedance cannot reliably be detected, then VI sensing can be used in combination with a microphone placed in-front of the loudspeaker diaphragm. The VI sensing is then used for obtaining the acceleration/velocity signal.

The audio device may be a loudspeaker cabinet or aspeaker.

Figure 5 shows a schematic block diagram of an electronics device according to an embodiment.

As shown in Figure 5, the electronics device 20 includes the audio device 10 as described above. The electronics apparatus 20 may be a TV, a smart speaker, and so on.

Although some specific embodiments of the present invention have been demonstrated in detail with examples, it should be understood bya personskilled in the art that the above examples are only intended to be illustrative but not to limit the scope of the present invention.

Claims

An audio device, comprising:

a loudspeaker;

a sensing circuit, which senses a voltage and/or a current in the loudspeaker;

a first processing circuit, which determines changes of acoustic radiation character based on the sensed voltage and/or current and determines an adjustment parameter based on the changes of acoustic radiation character; and

a second processing circuit, which adjusts an audio signal to be played by the loudspeaker based on the adjustment parameter or is triggered to perform a higher precision measurement of changes for the loudspeakerby the adjustment parameter.
The audio device according to claim 1, wherein the sensing circuit senses the voltage and current by sampling the voltage and current in an electrical circuit part of the loudspeaker.
The audio device according to claim 1, wherein the voltage and/or current is the voltage and/or currentof a signal being played by the loudspeaker.
The audio device according to claim 1, wherein the second processing circuit is an equalization filter, and the first processing circuit determines filter coefficients for the equalization filter based on the changes of acoustic radiation character.
The audio device according to claim 4, wherein the first processing circuit determines filter coefficients of a low-frequency response for adjusting the audio signal, the second processing circuit adjusts the low-frequency response by using the filter coefficients.
The audio device according to claim 1, wherein the acoustic radiation character is acoustic radiation impedance and/or resistance for the loudspeaker.
The audio device according to claim 1, wherein the first processing circuit determines the changes based on waveforms of the sensed voltage and current.
The audio device according to claim 1, wherein the first processing circuit determines the changes by comparing the current acoustic radiation character determined based on the currently sensed voltage and/or current and the previous acoustic radiation character determined based on the previously sensed voltage and/or current.
The audio device according to claim 1, wherein the changes of acoustic radiation character are abrupt.
An electronics apparatus, which includes the audio device according to any of claims 1-9.