Wireless multi-channel audio system with increased reliability

Abstract

A wireless multi-channel audio system is proposed, comprising a production base station connected to an antenna and a plurality of mobile devices. The production base station and the mobile devices are configured to exchange audio data with each other using a multiplexing method. The production base station provides an RF channel on which the production base station and the mobile devices send and receive audio data. The production base station and the mobile devices connected to each other in the audio system mutually exchange unique device identifiers, so that data exchange is only possible between devices whose device identifiers are mutually known. All settings and data of the audio system are stored in the production base station as production data. A backup base station is communicatively connected to the production base station during the transmission of the production data.All production data from the production base station is also stored in the replacement base station.

Description

Field of InterestThe present invention relates to a multi-channel wireless audio system with increased fail-safe.BackgroundWireless multi-channel audio systems are known from the ETSI EN 300422 standard as wireless multi-channel audio systems (WMAS). Such an audio system is a wireless audio system in which a plurality of channels are used for audio transmission. In this case, a plurality of wireless transmitters (for example wireless microphones) and a plurality of wireless receivers (for example in ear monitoring units) can communicate simultaneously with a base station. If the base station fails, then the entire audio system is no longer operational.On the basis of this, it is the object of the present invention to provide an audio system with increased reliability, in which the failure of an individual component, in particular of the base station, does not result in the entire audio system no longer being functional.DESCRIPTION OF THE INVENTIONTo achieve this object, the invention proposes, according to a first aspect, a multi-channel wireless audio system having a production base station connected to an antenna and a plurality of mobile devices. The production base station and the mobile devices are configured to exchange audio data with each other in a multiplex method. The production base station provides an RF channel on which the production base station and the mobile devices transmit and receive audio data. The production base station stores unique device identifiers of the mobile devices that are connected to the production base station in the audio system. In the mobile devices connected to the production base station in the audio system, a unique device identifier of the production base station is stored, so that data exchange is possible only between devices whose device identifier is mutually known. The data exchange between known devices takes place in encrypted form. In the production base station, all settings and data of the audio system are stored as production data. All production data of the production base station are stored in the replacement base station.The proposed multi-channel audio system ensures that even in the event of a failure of the production base station, production which is currently being produced is not completely discontinued, but is interrupted, at most, for a short time and can be continued by means of the replacement base station. For large and important events, this is a considerable advantage and is much less expensive to provide than two complete and redundant audio systems, which would not be feasible in many cases for practical and / or economic reasons.A replacement base station is communicatively connected to the production base station at least during transmission of the production data. After the production data are stored in the replacement base station, communication between the production and replacement base stations is no longer necessary.In an advantageous embodiment, the production base station and the mobile devices are configured to exchange data with one another in a TDMA method. The TDMA method is a reliable and well-established method for transmitting multiple audio channels over a single RF channel.In a preferred embodiment, an audio link is provided between the production base station and each connected mobile device, after which audio transmission is performed on the basis of repeating superframes divided into a number of time slots, and each connected mobile device transmits or receives audio data in at least one fixed time slot of the superframe. The defined time slot or slots are stored as production data in the production base station. The production data includes all the settings required to set up the replacement base station so that the replacement base station can take over the function of a failed production base station at button pressure. Time-consuming settings are therefore not necessary in the event of a malfunction.Advantageously, the carrier frequency, the modulation method, synchronization data and / or the bandwidth of the RF channel is or are stored as production data in the production base station. Advantageously, this data is also stored in the replacement base station.In the event of a failure of the production base station, the replacement base station advantageously assumes the function of the production base station. The increased reliability of the audio system is of great importance to a user, in particular in the case of expensive productions or productions which are important for other reasons.Since the audio transmission is encrypted, the key exchanged during the connection setup is decisive for the communication. A replacement base station can accordingly be activated only if it also has the key. A simple copy of the configuration is therefore not sufficient. On the other hand, the key must be secured with the necessary care to avoid unauthorized listening.In a further development of the invention, the production data in the replacement base station cannot be changed. In this way, it is achieved that a user does not generate a plurality of replacement base stations and use them in different productions. This procedure would be followed by the efforts for data security in the audio transmission between the mobile devices and the respective base station, because all spare base stations would use the same key for encrypting the data transmission.In this exemplary embodiment, it is expediently provided that the replacement base station can be reset to a factory state by a command and then all configuration and command parameters can be set again. After the replacement base station has been returned to the factory state, it can be used again as a full-scope production base station like any other base station, because there are no differences between a production and replacement base station at the hardware level.In an advantageous embodiment, the production and replacement base stations are connected to a network router or switch that selectively connects wired connections to either the production base station or the replacement base station. This embodiment has the advantage that an operator does not have to make any manual interventions in order to change from a failed production base station to a replacement base station during production.In a further development of the invention, the wired connections are network connections.In a preferred embodiment of the invention, the production base station is connected to a control console which receives input commands from an operator to change production data. The control console provides an ergonomic user interface for operating the audio system. The control console is, for example, a control computer connected to the production base station.In a non-inventive method of operating an audio system according to the first aspect of the invention, when the production base station is normally operating, the backup base station receives data of mobile devices and production data from the production base station, but does not transmit data. In the event of a malfunction, if the production base station no longer functions properly, the replacement base station is activated by a changeover command and takes over all functions of the production base station. The method realizes the advantages already described in connection with the audio system according to the first aspect of the invention.According to a second aspect, the invention proposes a method for operating an audio system according to the first aspect of the invention, the replacement base station is switched off in normal operation when the production base station is functioning normally. In the event of a malfunction, if the production base station no longer functions properly, the production base station is switched off and the replacement base station is switched on and performs all functions of the production base station.When multiple base stations are used in a production, the settings of all base stations can be loaded into the spare base station. If a fault then occurs in one of the active base stations, its configuration can be selected at the replacement base station,In a further development of the method, in the event of a malfunction, a user interface of the control console is completely or partially blocked in order to prevent changes in the production data. In this way, it is ensured that a plurality of productions are not made parallel with identical production data, in particular not with identical keys for coding the audio data.Alternatively, it can also be provided that in the event of a malfunction, the replacement base station does not allow any changes to the already stored production data. This also achieves the situation where a plurality of identical replacement base stations are not used for different productions.Brief Description of the FiguresThe invention is explained in greater detail below by way of example on the basis of an embodiment with reference to the accompanying figures. All figures are purely schematic and not to scale. The following are shown: FIG. 1 is a schematic illustration of a multi-channel wireless audio system; FIG. 2 shows a schematic illustration of time slots of different wireless transmitters; FIG. 3 is a schematic illustration of a frame in the transmission of the audio data; FIG. 4 shows a first exemplary embodiment of an audio system according to the invention without mobile devices; FIG. 5 shows a second exemplary embodiment of an audio system according to the invention without mobile devices; and FIG. 6 shows a third exemplary embodiment with two base stations of an audio system according to the invention without mobile devices.Identical or similar elements are provided with identical or similar reference numerals in the figures.DESCRIPTION OF AN EMBODIMENTMulti-channel wireless audio systems WMEAS are known from the ETSI EN 300422 standard. In this case, a plurality of mobile devices, such as a plurality of microphones, a plurality of in-ear monitoring units, can be used simultaneously with a base station.When multiple audio transmitters (e.g., a hand-held microphone or other microphones) simultaneously transmit audio signals to a base station and the base station transmits a second audio signal composed of these audio signals to an in-ear monitoring unit or a beltpack, the microphones do not simultaneously transmit, but instead subscriber access is performed by a time division multiple access (TDMA) method with a repeating superframe having a number of time slots per RF channel. For example, 128 time slots per superframe may be provided for the transmission of audio streams. Additionally, time slots for control data may be provided. Up to 128 mobile devices can thus communicate with the base station.The TDMA method ensures multiple access to a wireless audio transmission by a chronological sequence of a plurality of subscribers. The minimum latency is determined by the maximum distance between two successive time slots.FIG. 1 is a schematic illustration of a multi-channel wireless audio system. The wireless multi-channel audio system WMEAS 100 is based on the ETSI EN 300422 standard and comprises a base station 400, at least one antenna 200 and a plurality of mobile devices 300, e.g. at least one hand-held microphone (mobile transmitter) 310, optionally at least one multi-channel microphone (mobile transmitter) 320, optionally a first Beltpack (mobile receiver) 330, 340 with an output for in-ear monitoring, optionally a combined second Beltpack (mobile receiver) 350 with an input for microphone signals and an output for in-ear monitoring. Thus, the number of mobile transmitters 310, 320 or mobile receivers 330, 340, 350 in the multi-channel wireless audio system 100 may vary.In the multi-channel wireless audio system 100, the base station 400 is connected to an antenna 200 by a cable 202 and provides an RF channel. Optionally, further antennas can be connected to the base station 400, which antennas can provide further RF channels. The antenna 200 may include an RF transmitter ("radio header") such that digital signals are transmitted via the cable 202, which are converted into analog RF signals in the radio header.A control console 500 connected to the base station 400 may provide a user interface by which an operator may input configuration and control commands for the base station 400. The control panel 500 is, for example, a computer on which a software program for controlling the base station 400 is executed. The configuration and control commands and the parameters associated therewith are stored in the base station 400 in a nonvolatile memory as production data. Optionally, the base station 400 may be coupled to a mixing console 600. By means of the mixing desk 600, the audio signals from the respective wireless audio transmitters (e.g. microphones) can be mixed to form an overall audio signal. In one embodiment of the invention, configuration and control commands are transmitted directly from the mixing console 600 to the base station 400The multi-channel wireless audio system 100 may include, for example, a number of microphones, namely a hand-held microphone 310, a multi-channel or stereo microphone 320, and mobile receiving devices 330, 340, 350. The mobile receiving devices 330- 350 may have an output for what is known as in-ear monitoring, which allows a carrier to receive an audio channel. The mobile receiving device 350 is additionally equipped with a microphone input for a plug-in microphone or Lavaler microphone. The user of mobile receiver 350 is thereby able to simultaneously receive one audio channel and transmit another audio channel. The microphones 310, 320 and mobile receiving devices 330- 350 are collectively referred to below as mobile devices. In other applications, more or fewer mobile devices may be incorporated into the multi-channel wireless audio system 100 than shown in FIG. 1.The microphone 310 sends first audio data 311 in the form of an audio stream to the base station 400. The second microphone 320 sends second audio data 321 in the form of an audio stream to the base station 400. Finally, the mobile device 350 (beltpack) sends third audio data 351 in the form of an audio stream via the antenna 200 to the base station 400. The mobile devices 330 and 340 receive audio data 331, 341, 351 in the form of an audio stream from the base station 400.The base unit 400 transmits control data 201 to the respective mobile devices, e.g. transmitter / receiver 310, 320, 330, 340, 350, via the antenna 200. The control data 201 is used by the mobile devices 310- 350 to set parameters of the wireless transmission. The base station 400 can use the control data 201 to specify transmission parameters to the mobile devices 300 such as, for example, a transmission frequency, a time slot in the transmission frame, a transmission power, etc. These transmission parameters belong to the already mentioned production data. The base station 400 can control the transmission from the mobile devices to the base station 400 and from the base station 400 to the mobile devices 300 by means of the production parameters.The control data 201 comprises control and / or status information which is exchanged between the mobile devices and the base station. In addition to the control information or control data, other data may be exchanged as part of the control data 201.For example, in a case with 128 TDMA time slots per superframe, one time slot after 16 time slots may be reserved. This time slot can be used for control data such as synchronization information and control and status signals.Optionally, a superframe can thus have 128 TDMA time slots for the audio transmission and 8 time slots for control signals, so that a superframe has, for example, 136 time slots.Alternatively, the control data can also be transmitted in those time slots which are not reserved and are thus free. In this case, no separate time slots are then provided for the transmission of the control data, but rather the control data is then transmitted depending on the presence of time slots not used for the audio transmission.The communication from the base station 400 to the mobile devices 330, 340, 350 takes place, for example, in a multicast and the communication from the mobile devices 310, 320 to the base station 10 takes place in a unicast.The control console 500 is connected to the base station 400 and has a user interface (UI) which enables the user to input configuration and / or control commands for the base station 400.The handheld microphone 310 wirelessly transmits audio data as first audio data 311 in the form of an audio stream to the base station 400 as unidirectional radio transmission. This transmission 311 takes place, for example, in a unicast. In this case, the audio transmission can take place in the form of mono-microphone data.The microphone 320 transmits audio signals 321 as an audio stream in the form of a unidirectional radio transmission. Stereo or multi-channel microphone data can be transmitted in a unicast. The first and / or second belt packs 330, 340 (mobile receiving units) receive audio data 331, 341 all unidirectional radio transmission from the base station 400. This radio transmission can have in-ear monitoring data, for example. In a practical application, the audio data 331, 341 are composed of the audio data 321, 311 from the two microphones 310, 320 and optionally further audio data. This data may be transmitted as unicast or multicast from the base station 400. The beltpack 350 (receiving unit) can communicate with the base unit 400 in the form of a bidirectional radio transmission 351. The microphone data which the beltpack has received via the microphone input is transmitted to the base station 400, for example, as a unicast. In-ear monitoring data is transmitted from the base station 400 as unicast or multicast.In one embodiment, the audio data of the respective audio data transmitters (microphones 310, 320) are transmitted in a TDMA method. The TDMA method ensures multiple access to a wireless audio transmission by a chronological sequence of a plurality of subscribers. For low latency transmission, for example, a deterministic and equidistant grid of time slots per audio channel may be used. The minimum latency is determined by the maximum distance between two successive time slots.If a multi-channel audio system is to be provided, wherein more than two audio channels are to be transmitted from the base station to the mobile receivers, then the transmittable audio samples must be divided in one frame into the existing audio channels. If three audio channels are to be transmitted, then, for example, the possible number of samples transmittable in a frame can be divided by the three audio channels, i.e., audio samples of the existing audio channels are transmitted in each frame.Thus, each of the audio channels contributes only a portion of the audio samples in a frame or time slot. Thus, although the transmission of audio samples per channel per frame is reduced, this is offset by the reduced frame latency between successively transmitted frames.The multi-channel wireless audio system 100 may have a channel bandwidth of 6 MHz, 8 MHz, or 10 MHz. The transmission takes place, for example, in the frequency ranges 470-698 MHz (UHF) and 1350-1525 MHz (1G4).Subscribers are accessed on the transmission channels using the time division multiple access (TDMA) method. Optionally, the subscriber count may be up to, for example, 128 independent audio channels per wideband channel. The modulation method may represent orthogonal frequency division multiplexing OFDM in combination with different subcarrier modulation or coding methods. Audio coding can be effected in various methods and sampling rates and in mixed operation. For example, the sampling rates can be 48 kHz or 96 kHz. Audio coding may be performed in the OPUS method, in the ADPCM method, in the PCM method or in another suitable coding method. Synchronization of the TDMA raster and the carrier offset estimate CFO estimation can be ensured via synchronization patterns. A base TDMA raster is ≤ 10 ms and can be divided into 1 / 2, 1 / 4, 1 / 8 or 1 / 16 sub rasters.The audio transmission is preferably effected in encrypted form. Base station 400 provides a synchronization signal, manages paired devices (discussed below), and allocates the appropriate communication resources. The base station 400 may generate audio signals from the received audio signals from the wireless transmitters, which may represent a mixture of the audio signals of the wireless transmitters. These audio signals can then represent an in-ear monitoring audio signal.Mobile devices 300, 310-350 may log in to base station 400 to enable communication with base station 400. The mobile devices 310-350 may optionally initiate transmission of audio data if they have previously detected a base station 400 with which they are to communicate.For this purpose, it is necessary for the mobile devices to be "paired" with the base station. Pairing can proceed in several steps. First, the operator decides at which frequency the base station provides the RF channel. Optionally, the base station is configured to identify other transmitters in the allowed frequency band so that the operator can select the frequency for the RF channel so that interference from other transmitters may not occur. The base station transmits a control slot within a superframe on the RF channel. The control slot contains a unique ID (unique identifier) of the base station. After the pairing process at the respective mobile device has been triggered at the mobile devices, for example by pressing a button, the mobile device searches for an RF signal, finds the RF channel of the base station and reads out the control slot. In another control slot, the mobile device then sends its own unique ID to the base station and is indicated there as a device ready for pairing. The operator of the base station confirms the found mobile device, and the base station stores the unique ID of the mobile device. The mobile device receives an acknowledgement of the base station with the next control slot and in turn stores the Unique ID of the base station.Optionally, pairing may be completed by the base station operator by the user verifying a pin code of the mobile device. Only after pairing are the mobile devices ready to send a signal. Typically, pairing of the mobile devices with the base station is performed prior to production by a sound engineer in such a way that it is physically available to all mobile devices and it is thereby impossible for third parties to "snub" a mobile device into the audio system in order, for example, to be able to listen to it in an unauthorized manner. Furthermore, it is not possible for the base station to process signals from non-paired devices.For each of the TDMA resources (i.e. for each stream) in the audio transmission system, it is possible to define by means of which RF modulation the wireless transmission takes place. Examples of RF modulation are Q-PSK or QAM 64. While Q-PSK modulation allows higher robustness against interference and higher directional range, QAM 64 modulation enables higher data rates. The total available data rate for a stream is then obtained from the RF modulation used and from the number of time slots provided in a superframe.The audio data transmitted in a stream may be transmitted uncompressed or compressed. The necessary data rate for an uncompressed transmission of an audio channel results from the product of the sample rate (e.g., 48 kHz, 96 kHz) and the resolution (e.g., 16 bits) To reduce the data rate, audio codecs can be used. An audio codec may be adjusted by means of parameters such that the audio quality is increased at the expense of the data rate or conversely the data rate is decreased at the expense of the audio quality. The parameters for audio coding or audio decoding are likewise stored as production parameters in the base station 400.To meet data protection requirements, the communication between the mobile devices and the base station may be encrypted with a symmetric key. The key exchange between the base station and the mobile devices takes place using a public / private key method.FIG. 2 shows an illustration of time slots of different wireless transmitters which are received by the wireless receiver. In the TDMA method, a time slot in a frame (superframe) is allocated to the respective audio transmitters. In FIG. 2, eight time slots (time slots) SL1-SL8 are provided per superframe SF, for example. However, this is merely an example for illustration. Thus, eight time slots SL1-SL8 can be transmitted per frame. The time slots SL1-SL8 are repeated in each superframe SF.In this example, there are three streams S1, S2, S3. Each stream is associated with a wireless audio transmitter. Furthermore, time slots S0 may be present in the superframe SF, which are not used. In the example of FIG. 2, the first stream S 1 requires 2 / 8 of the resources, the stream S 2 requires 4 / 8, and the stream S 3 requires 1 / 8 of the resources.The first stream S1 occupies the time slots SL4 and SL8. The first, third, fifth and seventh time slots SL 1, SL 3, SL 5, SL 7 are occupied by the second stream S 2. The third stream S 3 occupies the time slot SL 2. The sixth time slot SL 6 is not used.When transmitting the audio data of the respective wireless audio transmitters, it is important that the latency of the respective audio transmission is as low as possible.FIG. 3 is a schematic diagram of a frame in the transmission of the audio data. In FIG. 3, a superframe SF having eight time slots SL1-SL8 is shown in particular. In this case, two time slots SL7, SL8 are not required for the transmission of the audio data. Thus, these time slots are idle time slots S0. In this example, a first stream S1 uses stream 2 / 8 of the resources and four further streams S2-S5 each use 1 / 8 of the resources. Since two time slots S0 are not used, another stream requiring 2 / 8 resources could be included in the superframe SF. However, if this stream is inserted at the location where the two unused time slots SL7, SL8 are provided, then this may result in a degradation of the latency of the new stream.From the perspective of the users of the audio system 100, in productions of high importance, there is a need to ensure high reliability. A total loss of production as a worst-case scenario is to be avoided from the point of view of the users in any case. In order to avoid a single point of failure (single point of failure), an obvious and always possible solution is to build the system twice-with different frequencies, power supplies, building parts etc. However, this is not economical in practical applications.The conceivable disturbances include radio disturbances, power failure, cable break, defective control console or defective control computer, defective microphone and defective base station. Hereinafter, a base station with which audio production is made is referred to as a production base station. The present invention addresses in particular the problem that the production base station unexpectedly fails during ongoing production. For this case, a replacement base station is available in which all production data of the production base station are already stored.FIG. 4 schematically illustrates an audio system 101 according to the invention, omitting the mobile devices. In contrast to the audio system 100 illustrated in FIG. 1, in the audio system 101 a replacement base station 401 is connected to the production base station 400 via a communication connection 402. The communication connection 402 is preferably a wired connection in the interest of the greatest possible data security. In principle, it is also possible in other exemplary embodiments to provide a correspondingly secured wireless connection 402 between the production base station 400 and the replacement base station 401. All production data and their changes are transmitted from the production base station to the replacement base station 401 via the connection 402, so that all production data that were set at the production base station before production are also stored in the replacement base station. The replacement base station 401 is synchronized with the production base station 400 and with the mobile devices 310-350. The replacement base station 400 accepts the unique identifier (unique ID) of the production base station 400, but remains "mute" during normal operation and does not transmit any signals as long as the production base station 400 is functioning properly. Specifically, the replacement base station 401 does not transmit any signals to the mobile devices and also does not emit any signals at its wired outputs. Only when a problem occurs at the production base station 400 and the operator decides to change to the replacement base station does a single command of the operator in one exemplary embodiment suffice so that the replacement base station 401 can take over the role of the production base station 400. In this case, the production base station 400 is switched off, in particular the production base station 400 no longer sends and receives signals, and the replacement base station 401 takes over all tasks which were previously fulfilled by the production base station 400.According to another embodiment, the replacement base station is switched off during normal operation of the audio system 101. If the production base station 400 fails, then the operator shuts down the production base station 400 and ideally disconnects it from the power grid. Then, all the connecting cables are inserted into the replacement base station 401 in the same way as was the case with the failed production base station 400. Then, the operator starts the replacement base station 401 to continue production with the replacement base station 401.Due to the complete acceptance of the production data from the production base station 400, the base station 401 is already configured at the moment of switching over or switching on in such a way that it can accept all connections of the production base station 400. That is, the operator must have copied the entire configuration of the production base station 400 to a replacement base station 401 before the event. The production data can be stored and copied, for example, as a production file. In this case, copying takes place as a file which is ideally encrypted with a public / private key pair. In an alternative embodiment, the transmission of the production data is performed by the control software of the control console 500 in the background. The replacement base station 401 also receives the keys for encryption and all pairing information with the production data. For a complete restoration of the functionality of the audio system 101, it is then only necessary for the operator to change wired connections from the production base station 400 to the replacement base station 401.FIG. 5 shows a further exemplary embodiment of an audio system 102 according to the invention. In the audio system 102, the production base station 400, the spare base station 401, the control panel 500, and the mixer 600, and the antenna 200 are connected to a switch RX. In normal operation, when the production base station 400 is functioning properly, the switch 700 establishes the data connections between the production base station 400, the control console 500, the mixer 600 and the antenna 200. In the case of failure, when the production base station 400 fails wholly or partly and the operator decides to change to the replacement base station 401 to continue production, then by a corresponding command from the operator, not only the replacement base station 401 is activated but also the switch 700 is switched so that the replacement base station 401 is connected to the control panel 500, the mixer 600 and the antenna 200 in place of the production base station 400. In the audio system 102, no manual interventions by the operator are necessary for the change from the production base station 400 to the replacement base station 401, for example, in order to change wired connections.In FIG. 6, an extension of the audio system 101 from FIG. 4 is illustrated. To the replacement base station 401, there is connected another audio system 101' via a connection 402' comprising a production base station 400', a control console 500', a mixing desk 600', and an antenna 200'. Audio systems 101 and 101' are used, for example, for different productions on two different stages in a theater or other event site. In the replacement base station 401, the production data from both the production base station 400 and the production base station 400' are stored. Thereby, the replacement base station 401 is able to replace the production base station 400 as well as the production base station 400' as required by making an appropriate selection by the operator. The specific further procedure of the operator in order to replace one of the two production base stations is identical to the procedure described in connection with FIG. 4. The concept described with reference to FIG. 6 can be applied to applications in which more than two production base stations are connected to a replacement base station.In a further embodiment, after the switch to the clone base station, its configuration can no longer be changed in order to make further use after the damage case unattractive. In this way, it is to be prevented that a plurality of cloned base stations are generated "on stock" to some extent, which are used in different productions, because all base stations have the same coding key therewith. Data security would thus be endangered. A base station once cloned can be used again in full-scale production when a reset has taken place and configuration parameters are retransmitted by a control computer. In this case, a newly generated individual key of the relevant base station would be used for encrypting the data.

Claims

A multi-channel wireless audio system (100-102) comprising a production base station (400) connected to an antenna (200), and a plurality of mobile devices (310-350), the production base station (400) and the mobile devices being configured to multiplex audio data with each other, wherein the production base station provides an RF channel on which the production base station and the mobile devices (310-350) transmit and receive audio data, characterized in that unique device identifiers of the mobile devices (310-350) connected to the production base station in the audio system are stored in the production base station (400), and a unique device identifier of the production base station is stored in the mobile devices (310-350) connected to the production base station in the audio system, so that data exchange is possible only between devices whose device identifier is mutually known, that all settings and data of the audio system (100-102) are stored as production data in the production base station (400), and that all production data of the production base station (400) are stored in the replacement base station (401).Audio system according to claim 1, characterized in that a replacement base station (401) is communicatively connected to the production base station at least during the transmission of the production data.Audio system according to claim 1 or 2, characterized in that the production base station (400) and the mobile devices (310-350) are configured to exchange data with each other in a TDMA method.Audio system according to any of the preceding claims, characterized in that an audio link is provided between the production base station (400) and each connected mobile device (310-350), after which an audio transmission is performed on the basis of repeating superframes (SF) divided into a number of time slots (SL), and each connected mobile device (310-350) sends or receives audio data in at least one fixed time slot of the superframe (SF), and that the fixed time slot or slots are stored as production data in the production base station.Audio system according to one of the preceding claims, characterized in that the carrier frequency, the modulation method, synchronization data and / or the bandwidth of the RF channel is or are stored as production data in the production base station (400).Audio system according to one of the preceding claims, characterized in that in the event of a failure of the production base station (400), the replacement base station (401) assumes the function of the production base station.Audio system according to one of the preceding claims, characterized in that the production data in the replacement base station (401) cannot be changed.Audio system according to claim 7, characterised in that the replacement base station (401) can be reset to a factory state by a command and then all configuration and command parameters can be set again.Audio system according to any of the preceding claims, characterized in that the production and replacement base station are connected to a switch (700) which establishes wired connections optionally either to the production base station (400) or to the replacement base station (401).Audio system according to claim 9, characterized in that the wired connections are network connections.The audio system of any preceding claim, wherein the production base station is connected to a control console (500) that receives input commands from an operator to change production data.Audio system according to one of the preceding claims, characterized in that the data exchange between the production base station and the mobile devices or between the replacement base station and the mobile devices is encrypted.Method for operating an audio system according to one of Claims 1 to 12, wherein, in normal operation, when the production base station (400) is functioning normally, the replacement base station (401) is switched off, wherein the method is characterized in that, in the event of a fault, when the production base station (400) is no longer functioning properly, the production base station (400) is switched off and the replacement base station (401) is switched on and performs all functions of the production base station (400).Method according to claim 13, characterised in that in the event of a malfunction, a user interface of the control console (500) is completely or partially blocked in order to prevent changes in the production data.Method according to claim 13 or 14, characterised in that in the event of a fault the replacement base station (401) does not allow any changes to the already stored production data.

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