Wireless multi-channel audio system

Abstract

The invention relates to a wireless multi-channel audio system (100), comprising a base station (400) which is connected to an antenna (200), a plurality of mobile devices (300) which are paired with the base station, and a control console (500) which has a user interface (501) for inputting configuration parameters for the audio system in order to define the configuration of the audio system. The audio system comprises a data memory in which the configuration parameters of the wireless multi-channel audio system are stored as a configuration parameter file. The base station (400) provides an HF channel on which the base station (400) and the mobile devices transmit and receive audio data. The configuration parameters define how the base station and the mobile devices exchange the audio data. The invention further relates to a method for configuring such a wireless multi-channel audio system.

Description

[0001] Wireless multi-channel audio system

[0002] Area

[0003] The present invention relates to a wireless multi-channel audio system in which configuration parameters are stored in a configuration parameter file.

[0004] background

[0005] Wireless multi-channel audio systems are known from the ETSI EN 300422 standard as Wireless Multichannel Audio Systems (WMAS). This type of audio system uses multiple channels for audio transmission. Multiple wireless transmitters (e.g., wireless microphones) and multiple wireless receivers (e.g., in-ear monitoring units) can communicate simultaneously with a base station. These wireless transmitters and receivers are collectively referred to as mobile devices. Before the audio system can be put into operation, it must be configured. This can be a significant amount of time depending on the number of mobile devices integrated into the system. For example, if the same audio system is to be used for different productions in a theater, the system configuration must be adapted to the new production each time a switch is made between different productions.

[0006] The German Patent and Trademark Office researched the following documents in the German patent application establishing priority: ETSI Technical Report (TR): System Reference document (SRdoc); Technical characteristics and parameters for Wireless Multichannel Audio Systems (WMAS). ETSI TR 103450 V1 .2.1 , 11 .2023, pp. 1 - 23, RTR / ERM- 559r1 ; US 2023 I 0 292 135 A1 and page "Multiplexing method". In: Wikipedia - The Free Encyclopedia. Status: February 25, 2022, 22:32 UTC. URL: https: / / de.wikipedia.orq / w / index.php?title=Multiplexyerfahren&oldid=220583214.

[0007] US Pat. No. 7,903,903 B1 discloses a video production system comprising a control console, a workstation, and a router that provides connections to input and output devices such as cameras and monitors. The connection structure of the video production system is given. The workstation comprises hardware and software for processing signals for both production and pre-production. The results of pre-production can be used in a live production. In pre-production, for example, a show is defined and the definition can be saved. At a later time, the definition can be used in conjunction with a broadcast, for example, to define the layout of a switcher.

[0008] Based on this, the object of the present invention is to create a wireless audio system with reduced configuration effort. The configuration effort should be reduced both for switching between different productions at a production site where only a single audio system is used, as well as for configuring multiple audio systems at different production sites.

[0009] To achieve this object, the invention proposes, according to a first aspect, a wireless multi-channel audio system comprising a base station connected to an antenna, a plurality of mobile devices paired with the base station, and a control console having a user interface for entering configuration parameters for the audio system in order to define its configuration. The base station and the mobile devices are configured to exchange audio data with the base station using a multiplexing method. The audio system comprises a data memory in which the configuration parameters of the wireless multi-channel audio system are stored as a configuration parameter file. The base station provides an RF channel on which the base station and the mobile devices send and receive the audio data. The configuration parameters define how the base station and the mobile devices exchange the audio data.

[0010] The data storage can be located in the base station or the control console. In principle, it is also possible for the configuration parameter file to be stored in different data storage devices, which are also located in different components of the audio system. The configuration parameter file enables the audio system to be easily configured by reading the configuration parameter file into the data storage device, then loading it into a working memory and executing it together with appropriate software. This replaces the step-by-step configuration of each individual device integrated into the audio system, thereby significantly simplifying and accelerating the configuration of the audio system. In a preferred embodiment, the configuration parameters specify the frequency and bandwidth and / or the modulation type of the RF channel.This is particularly advantageous if the audio system is installed in a theater where transmission conditions are stable and no new interference sources are normally encountered that might require moving the RF channel to a different frequency.

[0011] It is advantageous for the configuration parameters to include pairing data for the base station and the mobile devices. This eliminates the time-consuming process of pairing the mobile devices with the base station.

[0012] In a particularly preferred embodiment, the multiplexing method is a Time Division Multiple Access (TDMA) method with a repeating frame with a number of time slots per RF channel. In this case, the configuration parameters specify the allocation of one or more time slots to each mobile device. The allocation of time slots represents a time-consuming part of the system configuration. Simplifying this aspect of the configuration results in significant time savings in the practical operation of the audio system.

[0013] Conveniently, the configuration parameters determine whether and how the audio data is encoded. This way, once an audio encoding is defined, it can be used repeatedly without the audio system operator having to make a selection through manual input.

[0014] Advantageously, the configuration parameters include a name for each device. Assigning names to each individual mobile device facilitates practical handling of the audio system by artists and sound engineers. In particular, it makes it easier for each artist to receive their specific microphone with a predetermined transmission quality.

[0015] In a practical embodiment, a mixing console is connected to the audio system. The mixing console generates audio signals that are typically composed of multiple input signals from mobile devices, for example, for in-ear monitoring.

[0016] In this case, it is advantageous if the base station provides multiple interfaces for communication with the mixer. The configuration parameters then determine which interface on the base station is used for communication with the mixer. This arrangement allows a sound engineer or operator to enter control commands directly on the mixer, which are then transmitted to the control console and / or the base station. This simplifies operation of the audio system.

[0017] In a particularly advantageous embodiment, several configuration parameter files, each with different configuration parameters, are stored in the data memory. By loading one of the multiple configuration parameter files, the audio system can be reconfigured at the push of a button to adapt it to different productions. This feature results in considerable time savings when configuring the audio system for different productions.

[0018] According to a second aspect, the invention proposes a method for configuring a wireless multi-channel audio system according to the first aspect of the invention. According to the method, one of the plurality of configuration parameter files is read from the data memory and loaded into a working memory of the control console and / or the base station to define the configuration of the wireless multi-channel audio system. With this method, the user can reconfigure the audio system to adapt it to a different audio production by simply loading a different configuration parameter file. This method achieves significant time savings in production preparation.

[0019] The invention will be explained in more detail below using an exemplary embodiment with reference to the accompanying figures. All figures are purely schematic and not to scale. They show:

[0020] Fig. 1 is a schematic diagram of a wireless multi-channel audio system; and

[0021] Fig. 2 is a schematic representation of time slots of different wireless transmitters.

[0022] Identical and similar components are designated by identical or similar reference numerals in the figures.

[0023] Wireless multi-channel audio systems (WMAS) are known from the ETSI EN 300422 standard. These systems allow multiple mobile devices, such as multiple microphones and / or multiple in-ear monitoring units, to be used simultaneously with a base station.

[0024] If multiple audio transmitters (e.g., a handheld 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 transmit simultaneously. Instead, subscriber access is achieved using a Time Division Multiple Access (TDMA) method with a repeating frame containing a number of time slots per RF channel. For example, 128 time slots per frame can be allocated for the transmission of audio streams. Additional time slots can be allocated for control data. This allows up to 128 mobile devices to communicate with the base station.

[0025] The TDMA method ensures multiple access to a wireless audio transmission through a temporal sequence of multiple participants. The minimum latency is determined by the largest separation between two consecutive time slots.

[0026] Fig. 1 shows a schematic representation of a wireless multi-channel audio system. The wireless multi-channel audio system WMAS 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, designated collectively by the reference numeral 300, e.g., at least one first handheld microphone (mobile transmitter) 310, optionally at least one second 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 wireless multi-channel audio system 100 can vary.

[0027] In the wireless multi-channel audio system 100, the base station 400 is connected to an antenna 200 via a cable 202 and provides an RF channel. Optionally, additional antennas can be connected to the base station 400, which can provide additional RF channels. The antenna 200 can have an RF transmitter ("radiohead"), so that digital signals are transmitted via the cable 202, which are converted into analog RF signals in the radiohead.

[0028] A control console 500 connected to the base station 400 provides a user interface 501 (User Interface U1) that enables the user to enter configuration and / or control commands for the base station 400. The control console 500 is, for example, a computer running a software program for controlling the base station 400. The configuration and control commands, as well as the associated parameters, are stored in the control console 500 in a non-volatile data memory as configuration parameters in a configuration parameter file. The control console 500 has an interface for reading a configuration parameter file stored in the data memory from the control console 500 or for reading a configuration parameter file from a storage medium into the data memory.

[0029] Optionally, the base station 400 can be coupled to a mixing console 600. Using the mixing console 600, the audio signals from the respective wireless audio transmitters (e.g., microphones) can be mixed into 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 400. In one embodiment, the base station 400 and the control console 500 are configured such that the base station 400 informs the control console 500 of externally entered configuration changes, for example, configuration changes entered at the mixing console 600.

[0030] Alternatively or additionally, in another embodiment, the mixing console 600 is connected to the control console 500 to display the parameters set or changed on the mixing console on the user interface of the control console 500. The configuration and control commands from the mixing console 600 and the associated parameters are also stored in the configuration parameter file.

[0031] The multi-channel audio system 100 described so far functions as follows:

[0032] The first 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.

[0033] The base unit 400 transmits control data 201 via the antenna 200 to the respective mobile devices, e.g., transmitter / receivers 310, 320, 330, 340, 350. The control data 201 is used by the mobile devices 310-350 to set wireless transmission parameters. Using the control data 201, the base station 400 can specify parameters for the mobile devices 300, such as a transmission frequency, transmission power, etc., which define the RF channel. The base station 400 can use the configuration parameters to control the transmission of audio data from the mobile devices to the base station 400 and from the base station 400 to the mobile devices 300.

[0034] The control data 201 includes control and / or status information that is exchanged between the mobile devices and the base station. In addition to the control information or control data, further data can be exchanged as part of the control data 201.

[0035] For example, in a case with 128 TDMA time slots per frame, one time slot can be reserved after every 16 time slots. This time slot can be used for control data such as synchronization information and control and status signals.

[0036] Optionally, a frame can have 128 TDMA time slots for audio transmission and 8 time slots for control signals, so that a frame has, for example, 136 time slots.

[0037] Alternatively, the control data can also be transmitted in those time slots that are not reserved and therefore free. In this case, no separate time slots are reserved for the transmission of the control data; instead, the control data is transmitted depending on the availability of time slots not used for audio transmission.

[0038] Communication from base station 400 to mobile devices 330, 340, 350 occurs, for example, in a multicast, and communication from mobile devices 310, 320 to base station 10 occurs in a unicast. The handheld microphone 310 transmits audio data as the first audio data 311 in the form of an audio stream, wirelessly transmitted as a unidirectional radio transmission to base station 400. This transmission 311 occurs, for example, in a unicast. The audio transmission can be in the form of mono microphone data.

[0039] 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 beltpacks 330, 340 (mobile receiving units) receive audio data 331, 341, all in a unidirectional radio transmission, from the base station 400. This radio transmission can, for example, contain in-ear monitoring data. 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, additional audio data. This data can be transmitted as a 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 that the beltpack has received via the microphone input is transmitted, for example, as unicast to the base station 400.In-ear monitoring data is transmitted from the base station 400 as unicast or multicast.

[0040] In one embodiment, the audio data from the respective audio data transmitters (microphones 310, 320) is transmitted using a TDMA method. The TDMA method ensures multiple access to a wireless audio transmission through a temporal sequence of multiple participants. For low-latency transmission, for example, a deterministic and equidistant grid of time slots per audio channel can be used.

[0041] Before operating the multi-channel audio system 100, the system must be configured. a) System configuration of the multi-channel audio system WMAS a.1) RF setup

[0042] In order for the mobile devices 300-350 to communicate with the base station via the RF channel, they must be "paired" with the base station. Pairing can occur in several steps. First, the operator decides which frequency the base station will use to provide the RF channel. In practical applications, transmission occurs, for example, in the frequency ranges 470-698 MHz (UHF) and 1350-1525 MHz (1 G4), with a channel bandwidth of 6 MHz, 8 MHz, or 10 MHz. Optionally, the base station can be configured to identify other transmitters in the permitted frequency band, allowing the operator to select the frequency for the RF channel so that interference from other transmitters is minimal or negligible. The time required for RF setup is approximately 10% of the total system configuration effort. a.2) Pairing

[0043] The base station transmits a control slot within a frame on the RF channel. The control slot contains a unique ID for the base station. After the pairing process has been initiated on 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 the control slot sent by the base station. In another control slot, the mobile device then sends its own unique ID to the base station 400, where it is displayed as a device ready for pairing. The operator of the base station 400 confirms the found mobile device, and the base station saves the mobile device's unique ID. The mobile device receives a confirmation from the base station in the next control slot and, in turn, saves the base station's unique ID.

[0044] Optionally, the base station operator can complete the pairing by having the user verify a PIN code of the mobile device. Only after pairing is complete are the mobile devices ready to send a signal to the base station 400. Typically, the pairing of the mobile devices with the base station is performed by a sound engineer before a production in such a way that all mobile devices are physically available to him, making it impossible for third parties to "smuggle" a mobile device into the audio system and, for example, to eavesdrop without authorization. Furthermore, it is not possible for the base station to process signals from unpaired devices. This functionality is important, for example, for confidential conferences or the performance of copyrighted works.

[0045] In any case, the pairing information from the base station and mobile devices, as well as the parameters of the used RF channel, are stored in a configuration parameter file. The time required for pairing is approximately 20% of the total system configuration time. a.3) Audio configuration

[0046] After the base station 400 is paired with the mobile devices 300, the user can assign a name to each mobile device using the control console 500 to avoid microphone confusion. Assigning names to the mobile devices is part of the audio configuration. In this case, the assignment of names to individual mobile devices is also included in the configuration parameter file.

[0047] With the Time Division Multiple Access (TDMA) method used for mobile devices 310-350 to access the transmission channels, the number of participants can be up to 128 independent audio channels per broadband channel or RF channel. For example, to provide a lead singer with higher audio quality for other artists in a production, multiple time slots are assigned to the lead singer's microphone within a frame.

[0048] For each of the TDMA resources (i.e., for each audio stream) in the audio transmission system, the RF modulation used for wireless transmission can be specified. Examples of RF modulation are Q-PSK or QAM 64. While Q-PSK modulation allows for greater robustness against interference and greater directivity, QAM 64 modulation enables higher data rates. The total available data rate for a stream is then determined by the RF modulation used and the number of time slots provided in a frame. The modulation method can be Orthogonal Frequency Division Multiplexing OFDM in combination with various subcarrier modulation or coding methods. Audio coding can be performed using various methods and sampling rates, as well as in mixed mode. For example, the sampling rates can be 48 kHz or 96 kHz.

[0049] To meet data protection requirements, the communication between the mobile devices and the base station can 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. The base station 400 provides a synchronization signal, manages connected or paired devices, and allocates the corresponding communication resources. The base station 400 or the mixer 600 can generate audio signals from the received audio signals from the wireless transmitters, which can represent a mix of the audio signals from the wireless transmitters. These audio signals can then represent an in-ear monitoring audio signal.

[0050] The audio data transmitted in a stream can be transmitted uncompressed or compressed. The required data rate for uncompressed transmission of an audio channel is the product of the sample rate (e.g., 48 kHz, 96 kHz) and the resolution (e.g., 16 bit). Audio codecs can be used to reduce the data rate. An audio codec can be configured using parameters to increase audio quality at the expense of data rate, or conversely, to decrease the data rate at the expense of audio quality.

[0051] The parameters for the RF modulation used, the modulation method, the number of time slots assigned to a mobile device, the audio coding or audio decoding and the keys for the public / private key method are also stored as configuration parameters in the configuration parameter file in the base station 400.

[0052] The allocation of time slots to individual audio streams is illustrated in Fig. 2. Fig. 2 shows a representation of time slots from various wireless transmitters, which are received by the wireless receiver. In the TDMA method, one or more time slots in a frame F are allocated to the respective audio transmitters. In Fig. 2, eight time slots SL1 - SL8 are provided per frame F as an example. However, this is only an example for illustrative purposes. Thus, eight time slots SL1 - SL8 can be transmitted per frame. The time slots SL1 - SL8 are repeated in each frame F.

[0053] In this example, there are three streams S1, S2, S3. Each stream is assigned a wireless audio transmitter. Furthermore, the frame F may contain unused time slots (stream S0). In the example in Fig. 2, the first stream S1 requires 2 / 8 of the resources, stream S2 4 / 8, and stream S3 1 / 8 of the resources. Stream S0 is only a placeholder for unused time slots. This is not an actual audio stream that transmits audio data. The first stream S1 occupies time slots SL4 and SL8. The first, third, fifth, and seventh time slots SL1, SL3, SL5, and SL7 are occupied by the second stream S2. The third stream S3 occupies time slot SL2. The sixth time slot SL6 is not used.

[0054] The assignment of the time slots SL1-SL8 to the audio streams is also stored in the configuration parameter file.

[0055] If a mixer 600 is present and connected to the base station 400, the interface on the base station to which the mixer is connected is also specified and saved in the configuration parameter file.

[0056] The time required for audio configuration is approximately 70% of the total time required for system configuration.

[0057] Thus, all the information required to configure an audio system is stored in the configuration parameter file. According to the invention, multiple configuration parameter files can be stored in the base station 400 or the control console 500, so that an operator can set an associated configuration of the audio system by calling up a specific configuration parameter file with an input command on the user interface 501.

[0058] Two typical use cases are described below. b) Theater case

[0059] With a base station storing configuration parameter files, switching between different productions is possible with negligible effort, as described, provided that essentially the same hardware is used for the different productions, i.e., a base station 400 and mobile devices 300-350. This is possible, for example, in a theater where different musicals are performed one after the other, such as an afternoon children's program and an evening program. A configuration parameter file is stored for each program in the base station or control console. To switch between the two programs, it is therefore sufficient to load the corresponding configuration parameter file to execute the system configuration. c) Production template

[0060] The situation is different, but still comparable, if the same production (for example, "The Lion King") is to be performed at different production sites, each with its own hardware. Even if a configuration parameter file has already been created for this production and loaded into the respective control consoles at the different production sites, it is still necessary to repeat the RF setup and pairing at each production site because the RF channel must be adapted to the local conditions of each production site. Since different hardware is used at each production site, it is also necessary to repeat the pairing at each production site.

[0061] In contrast, the audio configuration is the same for each production site, so that even in this situation, the method according to the invention can save approximately 70% of the work required for system configuration.

[0062] In the description, a single unit or device can perform the functions of several elements recited in the claims. The fact that individual functions and elements are recited in different dependent claims does not mean that a combination of these functions and elements could not be used advantageously.

[0063] List of reference symbols

[0064] 100 audio system

[0065] 200 antenna

[0066] 201 Control data 202 Cable

[0067] 300 Total mobile devices

[0068] 310 First Microphone

[0069] 311 First audio data

[0070] 320 Second microphone 321 Second audio data

[0071] 330 First Beltpack

[0072] 340 First Beltpack

[0073] 331 Received audio data

[0074] 341 Received audio data 350 Second beltpack

[0075] 351 Bidirectional radio transmission

[0076] 400 base station

[0077] 500 Control console 600 Mixing console

[0078] F-Frame

[0079] SL1 - SL8 time slots

[0080] SO - S3 Stream

Claims

Claims 1. A wireless multi-channel audio system (100) comprising a base station (400) connected to an antenna (200), a plurality of mobile devices (300) paired with the base station (400), and a control console (500) having a user interface (501) for entering configuration parameters for the audio system to determine its configuration, wherein the base station (400) and the mobile devices (300) are configured to exchange audio data with the base station (400) in a multiplexing process, wherein the audio system comprises a data memory in which the configuration parameters of the wireless multi-channel audio system are stored as a configuration parameter file, characterized in that the base station (400) provides an RF channel on which the base station (400) and the mobile devices (300) transmit and receive the audio data, and that the configuration parameters define,how the base station (400) and the mobile devices (300) exchange the audio data.

2. Wireless multi-channel audio system (100-102) according to claim 1, characterized in that the configuration parameters determine the frequency and the bandwidth and / or the modulation type of the RF channel.

3. Wireless multi-channel audio system (100-102) according to claim 1 or 2, characterized in that the configuration parameters comprise pairing data for the base station (400) and the mobile devices (300).

4. Wireless multi-channel audio system (100-102) according to one of the preceding claims, characterized in that the multiplexing method is a Time Division Multiple Access (TDMA) method with a repeating frame (F) with a number of time slots (SL) per RF channel, and that the assignment of one or more time slots (SL) to a respective mobile device (310-350) is defined in the configuration parameters.

5. Wireless multi-channel audio system (100-102) according to one of the preceding claims, characterized in that the configuration parameters determine whether and in what manner the audio data is encoded.

6. Wireless multi-channel audio system (100) according to one of the preceding claims, characterized in that the configuration parameters contain a name for each mobile device (310-350).

7. Wireless multi-channel audio system (100) according to one of the preceding claims, characterized in that a mixing console (600) is connected to the audio system (100).

8. Wireless multi-channel audio system (100-102) according to claim 7, characterized in that the base station (400) provides a plurality of interfaces for communication with the mixer (600) and that the configuration parameters determine which interface of the base station (400) is used for communication with the mixer (600).

9. A wireless multi-channel audio system (100-102) according to any one of the preceding claims, characterized in that a plurality of configuration parameter files, each with different configuration parameters, are stored in the data memory.

10. A method for configuring a wireless multi-channel audio system (100) according to Claim 9, characterized in that one of the plurality of configuration parameter files is read from the data memory and loaded into a working memory of the control console (500) and / or the base station (400) in order to define the configuration of the wireless multi-channel audio system (100).

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