Headphones with automatic volume limitation

Abstract

In audio playback devices, circuits for volume limitation are prescribed in certain cases. In this case, together with wireless headphones, the maximum volume which can be reproduced can be unnecessarily reduced. According to the invention, a volume limitation in wireless headphones (100) can be modified or suspended by virtue of the fact that the wireless headphones check (330) the type of audio source, the wireless headphones wirelessly receiving at least one parameter, and automatically select (340) an operating mode according to the parameter. The wireless headphones can choose between a first operating mode (350) and a second operating mode (360), the first operating mode (350) corresponding to a first volume characteristic curve (210) having a first maximum volume (250) which is prescribed for open systems. The second operating mode (360) corresponds to a second volume characteristic curve (220) having a higher second maximum volume which is selected only if the parameter indicates that a closed system is concerned. On the basis of the volume characteristic curve (210, 220) corresponding to the chosen operating mode, a user can set a playback volume of the headphones by means of a user interface (4202).

Description

[0001] Headphones with automatic volume limiter

[0002] The invention relates to a headset with automatic volume limitation and a method for automatic volume limitation in headsets.

[0003] background

[0004] Safety requirements for audio / video, information, and communication technology equipment for the voluntary and intentional listening to entertainment, information, or communication content are governed by the international standard IEC 62368-1. This standard also covers audio playback via headphones. A maximum volume of 100 dB(A) / sqm is specified to protect users' hearing from damage.

[0005] Audio playback devices often contain corresponding volume-limiting circuits. One example is known from EP2224749 B1. This describes a method for controlling a maximum signal level output to a headset connected to a wireless device via cable. For this purpose, an impedance of the headset and a wearer-specific maximum signal level for headphones with this impedance are determined. An audio amplifier of the wireless device connected to the headset is adjusted to limit the maximum signal level output to the headset to the wearer-specific maximum value.

[0006] In recent times, however, headphones are usually connected wirelessly to an audio playback device. Volume limits are often set independently on both the playback device and the headphones. This can lead to the maximum permissible volume not being reached.

[0007] A problem that is increasingly common among headphone users is a perceived insufficient volume level in certain situations. In addition to the aforementioned dual limitation, this can be due to a user not wearing a hearing aid despite already having mild hearing loss. It can also be the case that a user isn't using their hearing aid because it's incompatible with the headphones, and they prefer headphones.

[0008] Typically, the problem can occur in a noisy environment, for example, or when an audio playback device such as a television isn't producing a sufficiently loud signal. However, for headphones, further increasing the volume may be unacceptable due to the validity of the standard and the general potential for hearing damage.

[0009] It is therefore an object of the present invention to enable at least one maximum permissible volume for headphones. Furthermore, it may be desirable to modify or suspend a volume limit in certain cases where the standard does not apply or where (further) hearing damage is not expected. In other cases, however, the volume limit should remain in place.

[0010] This object is achieved by headphones according to claim 1. Claim 12 relates to a method according to the invention. According to the invention, the maximum playback volume in headphones is automatically limited to either a first sound pressure level or a higher second sound pressure level depending on the type of audio signal source (or audio source).

[0011] Further advantageous embodiments are described in the dependent claims.

[0012] Short description of the drawings

[0013] Further details and advantageous embodiments are shown in the drawings.

[0014] Fig. 1 various typical use cases for headphones;

[0015] Fig. 2 a) a characteristic diagram;

[0016] Fig. 2 b) a schematic representation of the switching between characteristics;

[0017] Fig. 3 is a flowchart of a method; and

[0018] Fig. 4 is a block diagram of a headphone.

[0019] Detailed description of the invention

[0020] Fig. 1 shows two typical use cases for headphones or headsets. In the first case, shown on the left, a user wears wireless headphones 100a to listen to music, make phone calls, etc., while on the go and from any location (e.g., with a personal music player, PMP). The headphones use a standard wireless connection 110, e.g., Bluetooth, to a playback device 120 in an "open system." This is understood to be a system in which products, usually sold separately, can be universally combined with one another and exchange standardized data. A prescribed volume limit of a maximum of 100 dB is observed to protect hearing and avoid noise pollution for other people in the vicinity. In the second case, shown on the right, a user wears headphones 100b in their home environment to follow the program on a television 140 ("TV listener" mode).A wireless connection 130 is used, which forms a closed system with the headphones 100b and the television 140. A closed system exists between defined devices, in this case in a domestic (non-public) environment: the headphones according to the invention can form a closed system with a specific, individual device or with any device of a specific device class. Different regulations apply to a closed system than to an open system, at least with regard to the maximum reproducible volume. The headphones 100b according to the invention, which can be the same headphones 100a, 100 as in the first case, recognizes the individual device or device class of the audio source, i.e., the television 140, based on the data transmitted via the wireless connection 130 and switches from an "open" to a "closed" operating mode. This can offer different technical features.Optionally, the device serving as the audio source can also be individually defined as a device approved for a closed connection, so that a closed connection can only exist with the "own" television, for example. This identification as a device approved for a closed connection can be achieved, for example, by a predefined UUID transmitted via packets of the wireless connection 130.

[0021] In one embodiment, different characteristics apply to the two operating modes. Fig. 2 a) shows a characteristic diagram with two different characteristics, between which the headphones can automatically switch. The volume set by the user (in percent) is indicated on the abscissa, and the sound pressure level SPL (in dB) is indicated on the ordinate. If the headphones are in an open system, a first characteristic curve 210 applies, the values ​​of which are always below a first maximum value 250 (here: 100 dB). If, on the other hand, the headphones are in a closed system, a second characteristic curve 220 applies, which also has values ​​above the first maximum value 250. This can apply from 60%, as in this example, or in other examples only from a higher volume set by the user (e.g. 60-95%, especially 80-90%).At least in part of the control range, the values ​​of the second characteristic curve 220 are higher than those of the first characteristic curve 210, whereby the difference or distance 240 can be greater or smaller depending on the set volume. The second characteristic curve 220 is limited to a higher value, e.g., 120 dB or 110 dB, to protect the user's hearing and avoid overloading the headphones. In another perspective, which is technically identical, the second characteristic curve 220 can also be viewed as an extended first characteristic curve 210, which is then scaled accordingly by compressing the abscissa axis.

[0022] The headphones according to the invention are suitable for both open and closed systems, automatically detecting the type of system and switching accordingly. Therefore, the user can connect the headphones 100 to either the smartphone 120 or the television 140 at any given time, for example. When the headphones 100 are connected to the smartphone 120, the smartphone sends the standard data to the headphones 100 via the wireless connection 130; this data does not contain any explicit information about the type of system (open / closed), so the headphones 100 assume an open system and use the usual first characteristic curve 210. When the headphones 100 are connected to the television 140, the television informs the headphones 100 via the wireless connection 130 that it is in a closed system. The headphones 100 then automatically switch from the first characteristic curve 210 to the second characteristic curve 220.In order to avoid an unpleasant jump in volume for the user during this switching, the currently set volume of 230 can be maintained, ie the average sound pressure level remains constant.

[0023] If the user later uses the headphones 100 again in an open system, e.g., by connecting them to the smartphone 120, the headphones 100 automatically switch back to the first characteristic curve 210. When switching back from the second characteristic curve 220 to the first characteristic curve 210, the volume can also remain constant 230 if it is below the maximum value 250 before switching back. However, if it is above the maximum value 250 when switching back, it is reduced.

[0024] In one example, this reduction occurs to the maximum value of 250, as shown in Fig. 2 b). For example, in this open system, volume values ​​​​in a first range (here: between 1 and 5) are possible, whereas in a closed system, values ​​​​in a larger second range (here: between 1 and 8) are possible. The higher values ​​6-8 correspond to higher volumes, i.e. higher sound pressure levels. When switching from an open to a closed system (left), the volumes or sound pressure levels remain constant, and the user does not notice any difference except that the volume can be increased further. When switching back from a closed to an open system (right), the volumes or sound pressure levels also remain constant, provided they do not exceed the maximum value of 5. However, if the value previously set by the user is above the maximum value (here 6-8), the volume is reduced to the maximum value of 5.

[0025] In another example, the reduction occurs to a value corresponding to the same volume set by the user (in percent) or the same sound pressure level, i.e., following a vertical line 240 in diagram 200, or to a volume last set or preferred in an open system that has been stored in the headphones. Likewise, a preferred volume or the last volume set in a closed system can be stored in the headphones. In this case, however, an automatic increase in volume should be avoided when switching from the open to the closed system, or at least be stretched to a minimum period (e.g., 3-10 seconds) to avoid startling the user with a sudden increase in volume.

[0026] Fig. 3 shows a flowchart of a method 300 according to the invention for automatically limiting the volume in wireless headphones. When switched on, the headphones can optionally be in a standby state 310, where they can be connected to an audio source until audio playback is requested 320. The headphones check the type of audio source 330 and decide 340 whether it is a closed or open system. In the case of an open system, volumes up to the "normal" volume limit are permitted 350, e.g., according to a first characteristic curve 210. In the case of a closed system, higher volumes are also permitted 360, as described above, e.g., according to a second characteristic curve 220. Audio playback 370 can then begin. The selected setting applies until the headphones reconnect to another audio source 380.In a particular variant, in one embodiment of the invention, the signaling sent by the audio source can alternatively also change, for example if the type of use of the audio source changes over time, in that an actually mobile device is operated stationary or vice versa.

[0027] To check the type of audio source 330 and decide 340 whether it is a closed or an open system, the headphones evaluate a signal. The audio source can insert this signal at a suitable location, e.g., as a Bluetooth (BT) attribute, or in data packets used to establish the connection between the devices, or in the header of normal audio data packets according to BT or BT Low Energy (BLE). For example, a specific predefined UUID or UUID flag can indicate a closed system. This can also be transmitted when setting up the wireless connection, e.g., as advertising data. Furthermore, a multicast or broadcast connection is also possible, in which all connected headphones are participants in the closed system. Depending on the signal, a processor in the headphones can change software and / or hardware parameters to activate the higher or lower volume limit.

[0028] Fig. 4 shows a block diagram of a headset 100. The headset 100 includes a wireless interface or wireless receiver 410, an audio processing unit 420, which may also be suitable for, e.g., noise cancellation (ANC), an amplifier 4204, and a sound transducer 430. Certain parts, e.g., transducer 430 and amplifier 4204, may be duplicated, namely one for the left and one for the right side of the headset, as is usual. The audio processing unit 420 includes a volume control 4201, which the user can operate with a user interface 4202, e.g., a control on the headset and / or with a virtual control on the audio source, to select a volume between 0% and 100% along a characteristic curve, as shown in Fig. 2.When the wireless connection is established or changed, the audio data processing unit 420 can receive one or more parameters from the radio interface 410 that define the type of audio source and thus the type of audio playback, in particular whether it is an open or a closed system. The absence of such a parameter is interpreted as an open system. This parameter or a corresponding characteristic value (e.g., a bit) is stored in a memory 4203 and specifies the maximum adjustable volume that the user can set via the user interface 4202, as described above. The user interface 4202 itself and the settings of the handset can remain unchanged from the user's perspective, i.e., a switchover does not have to be immediately noticeable to the user.

[0029] In one embodiment, conventional headphones do not use the signaling or parameter, but ignore it. The audio source device can—but does not have to—be informed whether the headphones are using the signaling. In another variant, signaling is used that is implicit or actually has a different purpose. For example, the device's MAC address can be set to a specific range of values, e.g., addresses beginning with 80:AAhex. The parameter received by the radio receiver 410 contains information about the transmitting device from which the parameter was wirelessly received, which information identifies this transmitting device as one with which the headphones can form a closed system.

[0030] In one embodiment, the maximum value of 250 can also be below 100 dB, e.g., at 70 dB, to allow only lower maximum volumes (e.g., for children or general hearing protection). The playback device can then inform the headphones whether the user has set a volume limit there or enabled it. The headphones can then only play a lower maximum volume when connected to certain devices (e.g., those used by children), but in other cases, the "normal" maximum volume can be reached, which could then be, for example, 100 dB.

[0031] As an alternative to Bluetooth, the headphones according to the invention can also use other types of connection, e.g., wired or wireless via Wi-Fi. In these cases, the signaling can be adapted accordingly, which is easy for those skilled in the art based on the present description. Audio sources generally refer to devices that function as audio signal sources, such as smartphones, computers, televisions, radios, etc.

[0032] As an alternative to the maximum volume, other parameters can in principle also be transmitted to the headphones in order to control or enable functions in the headphones depending on the current operating mode, and in particular to set or change limits.

[0033] The invention can be implemented with a configurable computer or processor. The configuration is carried out by a computer-readable data carrier with instructions stored thereon that are suitable for programming the computer or processor to execute the steps of the method described above.

Claims

Patent claims 1 . Wireless headphones (100) with - a radio receiver (410); - an audio data processing unit (420); and - at least one sound transducer (430) for reproducing audio data received by the radio receiver (410) and processed by the audio data processing unit (420); - wherein the audio data processing unit (420) contains a volume control (4201) which follows a characteristic curve (210, 220) depending on a user interface (4202), characterized in that - the volume control (4201) can switch between at least two characteristics (210, 220) which allow different maximum volumes, and - the volume control (4201) receives at least one wirelessly received parameter from the radio receiver (410) and selects one of the at least two characteristics (210, 220) depending on the value of the parameter.

2. Headphones according to claim 1, wherein the parameter contains information about a transmitting device from which the radio receiver (410) has wirelessly received the parameter.

3. Headphones according to claim 1 or 2, wherein the second characteristic curve (220) enables a greater maximum volume than the first characteristic curve (210) and is selected in cases where the parameter satisfies a certain condition, and wherein the first characteristic curve (210) is selected in all other cases.

4. Headphones according to claim 3, wherein the first characteristic curve (210) enables a maximum user-adjustable volume of 100 dB.

5. Headphones according to one of claims 1-4, wherein the parameter is transmitted as a Bluetooth attribute or as a UUID.

6. Headphones according to one of claims 1-4, wherein the parameter is transmitted by a MAC address of the transmitting device, wherein the second characteristic curve (220) is selected when the MAC address of the transmitting device lies in a certain value range, and otherwise the first characteristic curve (210) is selected.

7. Headphones according to one of claims 1 -6, wherein the parameter is transmitted at the beginning of the wireless connection and is stored as a characteristic value in a memory (4203) of the headphones.

8. Headphones according to one of claims 1-7, wherein the value of the wirelessly received parameter can change during operation, and wherein when the volume control (4201) changes from the first characteristic curve (210) to the second characteristic curve (220) upon a change in the parameter, the sound pressure level remains substantially constant (230).

9. Headphones according to claim 8, wherein when the volume control (4201) changes from the second characteristic curve (220) to the first characteristic curve (210) upon a change in the wirelessly received parameter, the sound pressure level is either reduced to the maximum value of the first characteristic curve or remains substantially constant.

10. Headphones according to claim 8 or 9, wherein the value of the wirelessly received parameter changes by wirelessly connecting the headphones to another transmitting device.

11. Headphones according to claim 8 or 9, wherein the value of the wirelessly received parameter changes when the transmitting device switches to a different operating mode.

12. A method (300) for automatically limiting the volume of a wireless headset (100), the method comprising the following steps: - connecting (310) the headphones to an audio source and requesting audio playback (320); - checking (330) the type of audio source, wherein at least one parameter is received wirelessly from the audio source; - automatically selecting (340) an operating mode of the headphones depending on the wirelessly received parameter, wherein a choice can be made between a first operating mode (350) and a second operating mode (360), wherein the first operating mode (350) corresponds to a first volume characteristic curve (210) with a first maximum volume (250) and wherein the second operating mode (360) corresponds to a second volume characteristic curve (220) with a second maximum volume that is higher than the first maximum volume; and - playback (370) of wirelessly received audio data through the headphones, wherein a user can set a volume based on the selected volume characteristic curve by means of a user interface (4202).

13. The method according to claim 12, wherein the second volume characteristic curve (220) is selected in cases where the parameter satisfies a certain condition, and wherein the first volume characteristic curve (210) is selected in all other cases.

14. The method according to claim 12 or 13, wherein the parameter is transmitted as a Bluetooth attribute, as a UUID, or via a MAC address.

15. The method according to claim 12 or 13, wherein the parameter is transmitted as a Bluetooth attribute and leads to the selection of the first or second operating mode, and wherein at a later time, a modified parameter is transmitted from the same audio source as a Bluetooth attribute, which leads to the selection of the respective other operating mode.

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