Apparatus and method for adjusting volume of audio signal in audio system
By introducing a determining and adjusting unit into the audio system, combined with an attenuation unit, the sound quality problem caused by abrupt changes in volume level is solved, achieving stable volume output and improving the listening experience.
Patent Information
- Application Number
- CN202510629292.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-05-17
- Filing Date
- 2025-05-16
- Publication Date
- 2025-11-18
AI Technical Summary
When audio signals switch or level jumps, existing technologies struggle to effectively prevent sudden changes in volume, leading to a decrease in sound quality or a poor listening experience.
By introducing a determining unit and an adjusting unit into the audio system, the loudness of the audio signal is determined, and the volume is rapidly attenuated using an attenuation unit to avoid over-adjustment.
It achieves smooth output when the volume level changes, avoiding sound quality degradation and improving the listening experience.
Smart Images
Figure CN120977332A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The invention relates to a device for adjusting the volume of audio signals in a motor vehicle audio system according to claim 1 and to a motor vehicle having such a device according to claim 8. Furthermore, the invention relates to a method for adjusting the volume of audio signals in a motor vehicle audio system according to claim 9. BACKGROUND
[0002] In today's vehicles, audio signals from different audio sources, such as a radio, an external device via an interface, etc., can be played within the vehicle. Here, the volume of the output signal can be set by the user. However, the audio signals of these or one audio source can have different volume levels. This leads to the fact that, for example, upon switching between audio sources or upon switching within an audio signal, for example from one musical piece to another or within one musical piece, the output volume can change even if the user setting is unchanged. This can be compensated by a function of the audio system which balances the level differences of the audio signals. Here, the level of the input signals is adjusted towards a target value so that all audio signals, in particular from different audio sources, are played within the vehicle with the same loudness.
[0003] However, it has been found that, with musical pieces having level jumps, although this function balances the level of the output signal, an overshoot occurs which affects the sound quality or the listening experience. This means that, with musical pieces which contain different levels or level jumps, for example a very quiet intro followed by a very loud part, after a jump-like change in the volume of the input signal, the output signal does not directly reach the desired set value (target level) but overshoots the set value and is then adjusted to the desired value. SUMMARY
[0004] It is therefore the task of the invention to provide the possibility of being able to output audio signals which are balanced in terms of volume even in the case of a jump-like change in the volume level.
[0005] This task is achieved by the device for adjusting the volume of audio signals in a motor vehicle audio system according to claim 1, the motor vehicle having such a device according to claim 8 and the method for adjusting the volume of audio signals in a motor vehicle audio system according to claim 9.
[0006] The device is used to adjust the volume of an audio signal in a motor vehicle audio system. The audio system has an input for receiving an audio signal from an input source and an output for outputting the audio signal. The audio system can play music or other audio signals (for example navigation voice announcements) from different external or integrated input sources in the audio system. In this regard, an input source can be understood as an audio source through which entertainment content, for example music or an audio book, can be output in the form of an audio signal, but also telephone calls or voice announcements of a navigation device can be output in the form of an audio signal. Furthermore, internal input sources, for example input sources in the vehicle interior, can be a radio, a CD player integrated in the audio system, a hard disk integrated in the audio system or a memory card connected for example via a USB interface ("USB stick"). External input sources can be connected to the audio system for example via Bluetooth or an AUX input. External input sources can be for example a smartphone or an MP3 player.
[0007] The audio signals of the external and internal input sources are output via a loudspeaker system of the audio system. The volume of the audio signals output by the audio system can be set directly in the audio system here by a regulator provided there.
[0008] As already explained above, level jumps can occur between the audio signals of different sources or also within one audio signal. These changes can be prevented by the determining unit and the adjusting unit of the proposed device. The determining unit is configured to determine the loudness of the audio signal. The loudness of the audio input signal can be measured as an LKFS value (Loudness, K-weighted, relative to full scale). The LKFS value is a loudness standard which implements a standardization of the audio level for television transmissions and other audio / video transmissions. The measured LKFS value can be understood in particular as an average LKFS value, that is to say a value which is obtained by averaging over a plurality of measurements taken in succession over short time periods. If the entire music work range is considered (from very quiet, for example classical music, to very loud, for example rock music), the LKFS value usually varies between approximately -14 and -30 (so-called normal LKFS value range). The determining unit determines the LKFS value at the input of the audio system, that is to say ascertains a value which depends on the input audio source and not on the set volume.
[0009] The adjustment unit is configured to subsequently adjust the level of the audio signal to a target value. For example, a value of -14 dB can be chosen for the target value or target level. Thereby, input signals with a higher level are reduced, while input signals with a level below the target level are increased. The adjustment speed is usually relatively slow (1000 milliseconds) so that sudden volume fluctuations do not occur. In the case of a dynamic change in loudness, for example in a musical piece that contains a level jump (e.g. a very quiet intro and a very loud start of the band), the effect of this adjustment unit alone is not optimal: the level of the audio signal is very low at the beginning (intro). Thus, the adjustment unit increases the level of the audio signal. At the start of the band, a sudden level jump occurs after the intro. Since the adjustment unit adjusts slowly, it is still in the maximum boost state at the time of the level jump. Thereafter, the adjustment unit slowly reduces the level of the audio signal. Thus, the start of the band is played significantly louder than a few seconds later, resulting in an undesired overdrive.
[0010] Although the change in volume or loudness is reliably compensated by the adjustment unit in that the volume level of the audio signal is balanced accordingly, as explained above, overdrive occurs in this adjustment process. These overdrives can now be avoided in that the device also has a decay unit which is connected downstream of the adjustment unit and is configured to decay the audio signal adjusted by the adjustment unit by a predetermined decay value on the basis of the determined loudness. Since the decay value depends on the loudness of the audio signal, the decay unit can decay with a different decay value for high levels than for low levels. In this way, strong level rises caused by the adjustment unit can be blocked by the decay unit. Since the decay unit works independently of the adjustment unit, it can provide a faster response time and thus, in particular, can compensate for the overdrive described above.
[0011] According to an embodiment, the decay unit is configured to compare the determined loudness with stored loudness values and to select the predetermined decay value on the basis of the comparison. In particular, the device can have a storage unit in which predetermined decay values and the associated loudness values are stored. In this way, a very fast and simple decay of the output signal of the adjustment unit can be realized with low computing power. Since the respective decay value can simply be read from the storage unit, the overdrive described above can be quickly decayed.
[0012] For example, the loudness values and the decay values can be stored in a table. Such a table can for example look as follows:
[0013] These attenuation values are merely exemplary and different attenuation values can be provided. It is also possible to store a plurality of tables and to select the table or the respective attenuation values depending on whether a strong or a weak attenuation should be implemented. A strong attenuation, that is to say a large attenuation value, means that the occurring overmodulation is strongly attenuated and thus no longer or hardly exists. A weak attenuation, that is to say a small attenuation value, means that the overmodulation, although attenuated, still exists. The respective selection of the table can be made, for example, by a user input which determines the type of attenuation, i.e. strong, weak or intermediate levels.
[0014] For example, in the storage unit attenuation values for different degrees of attenuation (strong attenuation, weak attenuation, etc.) can be stored, for example in the form of the above-described table. In this case, the attenuation unit can be configured to select a degree of attenuation and the associated attenuation value based on a user input.
[0015] The attenuation unit can also be configured to determine a distance between the target value and the level value of the adjusted audio signal and to stop the attenuation of the audio signal adjusted by the adjustment unit when the distance is smaller than a threshold value. The threshold value can be zero here, in particular. In this way, the attenuation can be cancelled, for example, when there is no abrupt volume change or when the adjustment unit has completed the adjustment to the target value.
[0016] According to another embodiment, the attenuation unit is configured to attenuate the audio signal adjusted by the adjustment unit for a predetermined time. Preferably, the predetermined time is such that the attenuation unit attenuates the audio signal faster than the adjustment of the audio signal to the target value by the adjustment unit is required. In this way, the above-described overmodulation can be attenuated faster than by the adjustment unit.
[0017] The attenuation unit can be configured to select the predetermined time based on a user input. Thus, the user can select how much the occurring overmodulation should be attenuated. A short predetermined time, for example 10 milliseconds, means that the occurring overmodulation is quickly attenuated and thus short in time. A larger predetermined time, for example 30 milliseconds, means that the occurring overmodulation is attenuated more slowly and thus occurs for a longer time.
[0018] According to another aspect, a motor vehicle having a device for adjusting the volume of an audio signal as described above is proposed.
[0019] According to another aspect, a method for adjusting the volume of an audio signal in an audio system is proposed, wherein the audio system receives the audio signal from an input source and outputs the audio signal at an output. The method comprises determining the loudness of the audio signal and adjusting the level of the audio signal to a target value. The method further comprises attenuating the adjusted audio signal by a predetermined attenuation value based on the determined loudness.
[0020] The embodiments and features described for the proposed apparatus apply correspondingly to the proposed method.
[0021] Furthermore, a computer program product is proposed, which has program code configured to cause a performance of the method as described above on a computer.
[0022] A computer program product, for example a computer program medium, can be provided or delivered, for example as a storage medium, like a memory card, a USB stick, a CD-ROM, a DVD, or also in the form of a downloadable file from a server in a network. This can be realized, for example, in a wireless communication network by transmitting the respective file with the computer program product or computer program medium.
[0023] Further possible embodiments of the present application also include combinations of features or embodiments described before or after with respect to the examples, which are not explicitly mentioned. Here, the skilled person will also add individual aspects as improvements or supplements to the respective basic form of the present application.
[0024] Further advantages and advantageous embodiments are given in the description, the drawings and the claims. In particular, the combination of features given in the description and the drawings is here merely exemplary, so that the features can also exist individually or in other combinations.
[0025] Next, the present application will be described in more detail with reference to the embodiments shown in the drawings. Here, the embodiments and the combinations shown in the embodiments are merely exemplary and shall not define the scope of protection of the present application. The scope of protection of the present application is defined solely by the appended claims. BRIEF DESCRIPTION OF DRAWINGS
[0026] wherein is shown:
[0027] Figure 1 : a schematic block diagram of a device for adjusting the volume of an audio signal in an audio system,
[0028] Figure 2a and 2b : an exemplary diagram of audio signals with different attenuation values; and
[0029] Figure 3a and 3b : an exemplary diagram of audio signals with different attack times. DETAILED DESCRIPTION
[0030] Figure 1An audio system 1 is shown, which has means 2 for adjusting the volume of an audio signal A in the audio system 1. The audio system 1 has an input (not shown) for receiving the audio signal A from an input source and an output (not shown) for outputting the audio signal A'.
[0031] As explained above, the input source can be any audio input source, e.g. a radio or an external device like a smartphone, etc. In any case, the audio signal is received by the input source, which can vary in volume (e.g. at input source switching or also within the audio signal of one input source). In order to avoid such varying volumes of the output signal A', the means 2 have a determining unit 4, which is configured to determine the loudness L of the audio signal A. Based on the determined loudness L, an adjusting unit 6 can then adjust the level of the audio signal A to a target value. This target value can be set beforehand by a user, for example.
[0032] However, if now a stepwise change of the loudness L or a sudden level jump is contained in the audio signal A, the adjusting unit 6 can not be able to compensate these fast, stepwise changes quickly enough, because the adjusting unit makes slow adjustments. Thus, the adjusted audio signal A_c will first be louder than desired and then only be adjusted to the desired value.
[0033] This way, for example in a musical piece, the intro can be very quiet. Thus, the adjusting unit 6 will raise the level of the audio signal A. When the band starts playing, a sudden level jump occurs after the intro. Since the adjusting unit 6 adjusts slowly, at the time of the level jump the adjusting unit is still in the maximum boost state. Afterwards, the adjusting unit 6 will slowly decrease the level of the input source. Thus, the band starting to play will be played significantly louder than the piece a few seconds later. An over-adjustment of the audio signal A_c occurs, as can be seen in Figure 2a 、 2b , 3a, 3b.
[0034] In order to avoid such over-adjustments, the means 2 have an attenuation unit 8, which is connected downstream of the adjusting unit 6. This means that the attenuation unit 8 is used to attenuate the audio signal A_c, which has been adjusted by the adjusting unit 6, when necessary, in particular at the time of the over-adjustment described above. Based on the determined loudness L, the attenuation unit 8 attenuates the audio signal A_c, which has been adjusted by the adjusting unit 6, by a predetermined attenuation value in order to then output the adjusted and attenuated audio signal A'.
[0035] The attenuation unit 8 is used to quickly attenuate sudden level jumps. The attenuation value can be retrieved from a storage unit 10, e.g. based on a table which depends on the input loudness L.
[0036] As inFigure 2a , 2b As can be seen in 3a and 3b, even with the use of attenuation unit 8, a small overtone appears in the audio signal A'. However, this overtone is very short and small, and is imperceptible or almost imperceptible. Therefore, the horizontal jump is reliably blocked by attenuation unit 8, so that the overall dynamics remain more stable.
[0037] Not only the attenuation value, but also the time and the rate of attenuation can be set by the user or retrieved from storage unit 10 accordingly. The selection of these values affects the intensity of attenuation and the response time of attenuation unit 8. For example, if a small attenuation value is selected ( Figure 2a Over-adjustment will be more effective at larger decay values ( Figure 2b The decay is less pronounced. The same applies to time: at larger time values, overshoot is less pronounced than at smaller time values. Figure 3b ) Stay longer ( Figure 3a Figure 3a ).
[0038] Therefore, the device described above allows for the optimization and improved compensation of horizontal differences in the audio source. The attenuation unit provides rapid attenuation of sudden horizontal jumps, thereby avoiding or at least reducing over-pitch.
[0039] Figure label:
[0040] 1 Audio System
[0041] 2 devices
[0042] 4. Determine the unit
[0043] 6 adjustment units
[0044] 8 attenuation units
[0045] 10 storage units
[0046] A. Input audio signal
[0047] A_c is the audio signal adjusted by the adjustment unit.
[0048] A' Adjusted and attenuated output audio signal
[0049] L loudness value
Claims
1. A device (2) for adjusting the volume of an audio signal (A) in an audio system (1), wherein, The audio system (1) has an input terminal for receiving an audio signal (A) from an input source and an output terminal for outputting an audio signal (A'). The device (2) has a determining unit (4) and an adjusting unit (6). The determining unit is configured to determine the loudness (L) of the audio signal (A), and the adjusting unit is configured to adjust the level of the audio signal (A) to a target value. The device (2) is characterized in that it further comprises an attenuation unit (8) connected downstream of the adjustment unit (6), and the attenuation unit is configured to attenuate the audio signal (A_c) adjusted by the adjustment unit (6) by a predetermined attenuation value based on the determined loudness (L).
2. The apparatus according to claim 1, characterized in that, The attenuation unit (8) is configured to compare the determined loudness (L) with a stored loudness value and select the predetermined attenuation value based on the comparison.
3. The apparatus according to claim 2, characterized in that, The device (2) has a storage unit (10) in which a predetermined attenuation value and a corresponding loudness value are stored.
4. The apparatus according to claim 3, characterized in that, The storage unit (10) stores attenuation values for different attenuation levels, and the attenuation unit (8) is configured to select an attenuation level and a corresponding attenuation value based on user input.
5. The apparatus according to any one of the preceding claims, characterized in that, The attenuation unit (8) is configured to determine the distance between the target value and the level of the adjusted audio signal (A_c), and to stop attenuating the audio signal (A_c) adjusted by the adjustment unit (6) when the distance is less than a threshold.
6. The apparatus according to claim 5, characterized in that, The threshold is zero.
7. The apparatus according to any one of the preceding claims, characterized in that, The attenuation unit (8) is configured to attenuate the audio signal (A_c) adjusted by the adjustment unit (6) within a predetermined time.
8. The apparatus according to claim 7, characterized in that, The attenuation unit (8) is configured to select the predetermined time based on user input.
9. A motor vehicle having means (2) for adjusting the volume of an audio signal (A) according to any one of the preceding claims.
10. A method for adjusting the volume of an audio signal (A) in an audio system (1), wherein, The audio system (1) receives an audio signal (A) from an input source and outputs the audio signal at an output terminal. The method includes determining the loudness (L) of the audio signal (A) and adjusting the level of the audio signal (A) to a target value. The method is characterized by further comprising attenuating the adjusted audio signal (A_c) by a predetermined attenuation value based on the determined loudness (L).