EP3439328B1

EP3439328B1 - Audio playback system and audio playback method

Info

Publication number: EP3439328B1
Application number: EP17184094.5A
Authority: EP
Inventors: Alp KIRAZ
Original assignee: Vestel Elektronik Sanayi ve Ticaret AS
Current assignee: Vestel Elektronik Sanayi ve Ticaret AS
Priority date: 2017-07-31
Filing date: 2017-07-31
Publication date: 2020-05-06
Anticipated expiration: 2037-07-31
Also published as: EP3439328A1; TR201712387A2

Description

TECHNICAL FIELD

The invention relates to an audio playback system. Further, the invention relates to a respective audio playback method.

BACKGROUND

Although applicable to any audio system, the present invention will mainly be described in conjunction with a two-tier audio system, where an audio source is connected via multiple channels to an audio sink.
Modern audio equipment usually comprises a plurality of channel, e.g. two channels for stereo audio or more channels for multi-channel audio, like e.g. in a home cinema setup with 5 or more channels.
Depending on the type of audio equipment, single cables may be provided from an audio source to an audio sink for the single channels. This means that with a 5 channel system, the user needs to connect 5 cables when installing the audio equipment. With stereo setup two cables need to be connected by the user.
If the user is inexperienced or is in a hurry, he may switch some of the cables when connecting the audio source to the audio sink. Inexperienced users will probably not notice this and simply feel that the audio equipment sounds strange or has a poor quality.
Document EP 2 816 823 A1 discloses an audio system with a channel mapping method, where test signals are provided to the single sound output apparatuses. Document US 5,631,850 discloses a method for detecting an erroneous connection of a VCR and a laser disc player to a receiver. Document JP H06 52664 A discloses a method for initializing audio/video equipment by supplying stored control codes to the equipment from a control device.
There is a need for handling switched audio channels in audio equipment.

SUMMARY OF THE INVENTION

The above mentioned problem is solved with the features of the independent claims.
The present invention is based on the finding that it may be difficult for a user to notice that in the connection of an audio source to an audio sink audio channels may be switched. Therefore, the present invention provides an automatic detection and handling of switched channels in audio equipment with discrete connections for the single channels.
An audio source may be any kind of device that is capable of providing low power audio signals. "Low power" in this regard refers to the audio signals comprising signal levels that may represent the audio content but are not sufficiently high to directly drive high power speakers. Such audio sources may e.g. comprise DVD players, Bluray players, CD players, vinyl record players or the like.
The audio sink in contrast may be any type of device that receives the audio signals provided by the audio source. Such devices may typically be pre-amplifiers or amplifiers, or any type of recording device.
The audio sink may comprise e.g. two or more audio input channels, e.g. represented by dedicated connectors like RCA connectors or the like. These dedicated audio input channels may be connected by respective cables to the audio output channels of the audio source.
If the user confounds the connectors of the audio output channels or the audio input channels, the sound may be played by the audio sink over the wrong speakers.
The present invention therefore provides the audio source and the audio sink with the ability to automatically assign the output channels to the correct input channels.
To this end the audio source may output individual channel test signals on every one of the audio output channels. The individual channel test signals are uniquely assigned to every one of the audio output channels and therefore allow uniquely identifying the single audio output channels.
The audio sink in contrast may analyze for every audio input channel if one of the individual channel test signals is present on the audio input channel. The audio sink may then verify if the correct individual channel test signal is received on the respective audio input channels. The audio sink may e.g. know individual channel test signals, i.e. the individual channel test signals may be predetermined for the audio source and the audio sink. Based on this analysis the audio sink may then internally map the audio input channels to respective ones of the output channels. This means that the signal received on an audio input channel is output on the respectively mapped output channel.
In case of an audio sink that plays the audio to a user, the audio sink may e.g. suppress audio output while analyzing the individual channel test signals. If the audio input channels are correctly connected to the audio source, the signal sink may start playing the audio signals. Otherwise, the audio sink may first map the audio input channels to the output channels and then start playing the audio signal to the user.
It is understood, that the output channels may be physical channels, like e.g. high power speaker output channels. The output channels may however also be internal channels of the audio sink. If for example the audio sink is a recording device, the output channels may refer to channels on a recording medium.
The audio source may for example be a DVD player that provides a discrete 5.1 signal, with 5 directional speakers and one subwoofer. In this case six cables are required to connect the audio source to the audio sink. The audio source may therefore provide six different individual channel test signals, i.e. one on every channel. The audio sink will then analyze the signals received via the audio input channels and perform the respective mapping.
The audio sink may e.g. receive the correct or expected signals on every audio input channel. This means that the audio source and the audio sink are correctly wired. The audio sink may however for example receive the individual channel test signals of the left front speaker on the audio input channel of the right front speaker and vice versa. This means that the cables for the front speakers are switched. Via the internal mapping the audio sink may however correct this wrong cabling and output the signals received via the audio input channel for the left front speaker on the output channel of the right front speaker and vice versa.
With the present invention setting up audio equipment is therefore greatly simplified and erroneous cabling between audio sources and audio sinks may not only be detected but maybe automatically corrected without any user interaction.
Further embodiments of the present invention are subject of the further subclaims and of the following description, referring to the drawings.
In an embodiment, the audio source may comprise a connection detector configured to detect a connection of a cable to the audio output channels based on an electric resistance measurement or based on a switching signal.
The connection detector may e.g. comprise a measurement device for measuring a resistance between the single connection elements, e.g. pins, of the connectors of the single audio output channels. Such a device may e.g. be a current source combined with a voltage measurement device, e.g. an output pin of a microcontroller that provides a specific output current and an analog to digital converter of the microcontroller that measures the voltage over the single connection elements to determine the resistance. It is understood, that this microcontroller based implementation is just an example and that other implementations are possible.
A switching signal may e.g. be generated in the connector of the respective audio output channel. For example the connector may comprise a mechanical switch. It is however also possible that one connection element comprises two separate conductive sections that are electrically connected to each other when a counterpart is inserted into the connector. This arrangement may especially be used e.g. with the ground connection element. The electrical connection between the two sections may then e.g. be detected simply by connecting one section with a high signal level and evaluating the signal level of the second section. If for example the first section is provided with a 5 V signal, the second section will comprise a 0 V signal level until a counter part is inserted into the connector and the two segments are connected to each other. Then the second segment will also comprise the 5 V signal level.
In another embodiment, the audio source may comprise a test signal generator that is coupled to the audio output channels and that is configured to provide the individual channel test signals to the audio output channels after the connection of a cable is detected.
The test signal generator may comprise any type of signal generation means. The test signal generator may e.g. be integrated into the output signal chain of the audio source and may e.g. make use of amplifiers, filter and/or attenuators provided in this output signal chain. The test signal generator may e.g. be implemented in a central control device or a signal processor of the audio source. The test signal generator may e.g. be software function implemented on that processor.
The signal generator may however also be a dedicated device, like e.g. a microcontroller with a respective programming or even an analogue oscillation device.
In an embodiment, the test signal generator may comprise a configurable oscillator configured to output a number of individual channel test signals each individual channel test signal comprising a predetermined frequency, especially a frequency higher than 20 kHz, especially 25 kHz or 30 kHz.
The individual channel test signals may e.g. be simple sinusoidal or continuous wave signals like e.g. square wave signals. The signals need not necessarily be sinusoidal, such as e.g. signals that are output by an oscillating pin of a microcontroller that will be square-wave-like.
Using frequencies in the frequency range above 20 kHz, like e.g. 25 kHz or 30 kHz is beneficial, since these frequencies are above the frequency range that may be heard by the human ear. This means that the individual channel test signals may be provided to an audio sink that is already driving its speakers, but the user will not hear any fragment of the individual channel test signals.
This allows using the audio source with audio sinks that are not adapted according to the present invention without causing the user any annoyance. Any audio sink that is adapted according to the present invention will however be capable of analyzing the provided individual channel test signals and mapping the output channels accordingly.
It is understood, that any other form of signals than the above describes may also be provided by the configurable oscillator.
In a further embodiment, the configurable oscillator may be configured to output for every audio output channel an individual channel test signal starting with a predetermined one of the audio output channels and increasing or decreasing the frequency for the further audio output channels by a predetermined frequency step clock-wise or counter-clockwise based on the intended position of the audio output channels.
One specific audio output channel, i.e. intended speaker, may be selected as the starting speaker. This audio output channel may be assigned the individual channel test signal with the lowest or alternatively the highest frequency. All other speakers may then automatically be identified by the increasing frequencies of the individual channel test signals. As example, the lowest frequency may e.g. be 20 kHz and the steps may increase the frequency by 2 kHz for each step.
This means that the audio source and the audio sink only need to agree on the first speaker and the order in which the individual speakers are identified by individual channel test signals with increasing frequencies. This may e.g. be preconfigured in the audio sink and the audio source. The audio sink and the audio source however need not necessarily agree on specific signals or specific frequencies with this scheme.
In for example 5.1 audio systems, i.e. with five directional speakers and 1 subwoofer, the front center speaker may be the first speaker. The sequence of the speakers may be defined clock-wise. This means that the front right speaker is the second speaker, the rear right speaker is the third speaker, the rear left speaker is the fourth speaker and the front left speaker is the fifth speaker.
The first speaker may then be identified by the individual channel test signal with the lowest frequency. The second speaker by the individual channel test signal with the second lowest frequency. The third speaker by the individual channel test signal with the third lowest frequency. The fourth speaker by the individual channel test signal with the fourth lowest frequency. Finally, the fifth speaker by the individual channel test signal with the fifth lowest or highest frequency.
It is understood that the above example may also be used with a counter-clock wise sequence and/or with descending frequencies.
In an embodiment, the audio source may be configured to output the individual channel test signals for a first predetermined amount of time after the connection of a cable to the output channels is detected, and especially for a second predetermined amount of time after a connection of the cables on the other ends to the audio sink is detected.
As explained above, the audio sink may detect via different methods, if the cables and the audio sink are connected to the audio source. For example, the switching signal may be used to detect connection of a connector only. The resistance measurement may be used to detect the connection of the audio sink on the other end. The audio source may therefore determine if only a cable or a cable and an audio sink are connected to the single audio output channels.
The audio source, e.g. the test signal generator, may provide the individual channel test signals only for a first predetermined amount of time after a connection of a cable is detected. This may reduce the interference of the individual channel test signals with any other signal or other elements of the audio source and the audio sink.
The audio source may however at least provide the individual channel test signals for a second predetermined amount of time after the audio sink is connected to the cables. If the cables are first connected to the audio sink and then to the audio source, the first predetermined amount of time and the second predetermined amount of time may be the same.
The audio source may e.g. delay outputting the audio signal until no individual channel test signals are output any more. It is however also possible for the audio source to overlay the audio signals with the individual channel test signals, especially if these are in the non-audible frequency range.
In another embodiment, the audio sink may comprise a signal analyzer that is configured to analyze signals received on the audio input channels for the presence of the individual channel test signals.
The signal analyzer may e.g. comprise a counter that counts the time intervals between zero-crossings of the received individual channel test signals. Any other method of determining the respective frequencies is also possible.
The signal analyzer may e.g. also comprise filters and attenuators that allow filtering or separating the individual channel test signals from other signals, e.g. audio signals, received on the audio input channels. Especially with individual channel test signals that comprise a frequency range that is higher than the frequency range of the audio signals, this allows clearly separating audio signals and individual channel test signals.
It is understood, that the signal analyzer may be implemented in hardware, e.g. with a counter, as explained above. As alternative, the signal analyzer may also be implemented at least in part in software. For example, a timer unit with e.g. a capture compare function of a microcontroller may also be used.
In an embodiment, the audio sink may comprise a switching matrix that is configured to controllably couple individual audio input channels to specific ones of the output channels.
The switching matrix may be a hardware based switching matrix, e.g. comprising transistors, like e.g. MOSFETs or the like, as switches. A single switch may be provided from every audio input channel to every output channel. Further, safety elements may be provided that allow driving only one switch per audio input channel at a time. This prevents one audio input channel from being coupled to a plurality of output channels at the same time.
It is understood, that the switching matrix may also be digitally implemented. The signals on the audio input channels may e.g. be converted into digital data, e.g. via analog-to-digital converters. A processor, e.g. a digital signal processor, may then perform the mapping of the digital data streams of the single audio input channels to the different output channels.
It is understood, that a processor may also perform general control of the functions of the audio sink, like e.g. analyzing the frequencies of the individual channel test signals, suppressing audio output, controlling the switching matrix and starting the audio output.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings. The invention is explained in more detail below using exemplary embodiments, which are specified in the schematic figures of the drawings, in which:

Fig. 1 shows a block diagram of an embodiment of an audio playback system according to the present invention;
Fig. 2 shows a block diagram of another embodiment of an audio playback system according to the present invention; and
Fig. 3 shows a flow diagram of an embodiment of an audio playback method according to the present invention.

In the figures like reference signs denote like elements unless stated otherwise.

DETAILED DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a block diagram of an audio playback system 100. The audio playback system 100 comprises an audio source 103 and an audio sink 106. The audio source 103 comprises a number of audio output channels 104, 105, wherein only two are explicitly shown and more are hinted at by three dots. It is understood, that the audio source 103 may comprise any number of audio output channels 104, 105, but will at least comprise two audio output channels 104, 105. In Fig. 1 audio content 101, 102 is shown for the two audio output channels 104, 105.
The audio sink 106 comprises a number of audio input channels 107, 108, wherein only two are explicitly shown and more are hinted at by three dots. It is understood, that the audio sink 106 may comprise any number of audio input channels 107, 108, but will at least comprise two audio input channels 107, 108. It is further understood, that the number of audio output channels 104, 105 need no necessarily be the same as the number of audio input channels 107, 108. The audio input channels 107, 108 may be coupled to output channels 109, 110 that serve to output the audio content 101, 102.
The audio output channels 104, 105 may be coupled to the audio input channels 107, 108 via cables 113, 114 that each comprise a connector 115, 116 on their first end and a connector 117, 118 on their second end.
The connectors 115, 116 may be connected to the audio output channels 104, 105. When the connectors 115, 116 are inserted into the respective receptacles of the audio output channels 104, 105, this may be detected in the audio source 103. The audio source 103 may then start providing individual channel test signals 111, 112 to the audio output channels 104, 105.
If the connectors 117, 118 are connected to the audio input channels 107, 108, the individual channel test signals 111, 112 will be transmitted to the audio input channels 107, 108 and the audio sink 106 may analyze the signals received on the audio input channels 107, 108 to detect the individual channel test signals 111, 112.
Since the individual channel test signals 111, 112 uniquely identify the respective audio output channels 104, 105, the audio sink 106 may determine, if the cables 113, 114, i.e. the connectors 117, 118, are correctly connected, e.g. by comparing the received individual channel test signals 111, 112 with signals stored in the audio sink or at least with parameters, like e.g. a frequency. If they are e.g. interchanged or swapped, the audio sink 106 may map the audio input channels 107, 108 to the correct output channels 109, 110. The audio content 101, 102 will therefore still be played through the correct output channels 109, 110.
It is understood, that the audio source 103 may e.g. suppress playback or output of the audio content 101, 102. The audio source 103 may e.g. output the individual channel test signals 111, 112 for a first predetermined amount of time, e.g. 1 s - 10s, after the connection of a cable 113, 114 to the output channels 109, 110 is detected. The audio source 103 may further output the individual channel test signals 111, 112 for a second predetermined amount of time, e.g. 1 s, 2 s, 3 s, 5 s or more after a connection of the cables 113, 114 on the other ends to the audio sink 106 is detected.
Fig. 2 shows a block diagram of another audio playback system 200. The audio playback system 200 is based on the audio playback system 100 and therefore also comprises the audio source 203 with a plurality of audio output channels 204, 205, and the audio sink 206 with a plurality of audio input channels 207, 208 and output channels 209, 210.
In addition, the audio source 203 comprises a connection detector 220 that evaluates a switching signal 221 to detect if the connectors 215, 216 are inserted into the receptacles of the audio output channels 204, 205. Although only shown for the audio output channel 204, it is understood, that the connection detector 220 may evaluate switching signals 221 for all audio output channels 204, 205. The switching signal 221 may be generated by two conductive segments or sections in the receptacle of the audio output channel 204 that are electrically isolated from each other. When the connector 115 is inserted into the receptacle, the two sections are bridged and current may flow. This current flow may be detected as the switching signal 221.
The audio source 203 further comprises a test signal generator 222 that is coupled to the audio output channels 204, 205. The test signal generator 222 generates and provides the individual channel test signals 211, 212 to the audio output channels 204, 205 after the connection of a cable 213, 214 is detected. The test signal generator 222 comprises a configurable oscillator 223 for generating the individual channel test signals 211, 212. The configurable oscillator 223 then outputs the individual channel test signals 211, 212 to the audio output channels 204, 205.
The configurable oscillator 223 may generate the individual channel test signals 211, 212 comprising a predetermined frequency, especially a frequency higher than 20 kHz, especially 25 kHz or 30 kHz. The configurable oscillator 223 may e.g. output for every audio output channel 204, 205 an individual channel test signal 211, 212 starting with a predetermined frequency for a predetermined one of the audio output channels 204, 205 and increasing or decreasing the frequency for the further audio output channels 204, 205 by a predetermined frequency step clock-wise or counter-clockwise based on the intended position of the audio output channels 204, 205.
The audio sink 206 comprises a signal analyzer 225 that analyzes the signals received on the audio input channels 207, 208 for the presence of the individual channel test signals 211, 212. The signal analyzer 225 is coupled to a switching matrix 226 that controllably couples individual audio input channels 207, 208 to specific ones of the output channels 209, 210. Based on the analysis results of the signals received on the audio input channels 207, 208, the signal analyzer 225 may control the switching matrix 226 to individually couple in each case one of the audio input channels 207, 208 to the respective output channel 209, 210.
For sake of clarity in the following description of the method based Fig. 3 the reference signs used above in the description of apparatus based Figs. 1 and 2 will be maintained.
Fig. 3 shows a flow diagram of an audio playback method for playing back audio content 101, 102 with an audio source 103, 203 comprising a number of audio output channels 104, 105, 204, 205, and an audio sink 106, 206 comprising a number of audio input channels 107, 108, 207, 208 and a corresponding number of output channels 109, 110, 209, 210.
The audio playback method comprises outputting S1 individual channel test signals 111, 112, 211, 212 on every audio output channel 104, 105, 204, 205 upon connection of a cable 113, 114, 213, 214 to the audio output channels 104, 105, 204, 205, analyzing S2 signals received on the audio input channels 107, 108, 207, 208 for the presence of the individual channel test signals 111, 112, 211, 212, and mapping S3 the audio input channels 107, 108, 207, 208 to respective ones of the output channels 109, 110, 209, 210 based on the analysis of the individual channel test signals 111, 112, 211, 212.
The audio playback method may comprise detecting a connection of a cable 113, 114, 213, 214 to the audio output channels 104, 105, 204, 205 based on an electric resistance measurement or based on a switching signal 221. The method may further comprise providing the individual channel test signals 111, 112, 211, 212 to the audio output channels 104, 105, 204, 205 after the connection of a cable 113, 114, 213, 214 is detected.
Providing the individual channel test signals 111, 112, 211, 212 may comprise outputting a number of individual channel test signals 111, 112, 211, 212, each individual channel test signal 111, 112, 211, 212 comprising a predetermined frequency, especially a frequency higher than 20 kHz, especially 25 kHz or 30 kHz. The individual channel test signal 111, 112, 211, 212 of a starting audio output channel 104, 105, 204, 205 may comprise a predetermined frequency and the frequency of the individual channel test signals 111, 112, 211, 212 for the further audio output channels 104, 105, 204, 205 may increase or decrease by a predetermined frequency step clock-wise or counter-clockwise based on the intended position of the audio output channels 104, 105, 204, 205.
The audio playback method may comprise outputting the individual channel test signals 111, 112, 211, 212 for a first predetermined amount of time after the connection of a cable 113, 114, 213, 214 to the output channels 109, 110, 209, 210 is detected, and especially for a second predetermined amount of time after a connection of the cables 113, 114, 213, 214 on the other ends to the audio sink 106, 206 is detected.
On the receiver or audio sink 106, 206 side, the method may comprise analyzing signals received on the audio input channels 107, 108, 207, 208 for the presence of the individual channel test signals 111, 112, 211, 212, and controllably coupling, i.e. mapping, individual audio input channels 107, 108, 207, 208 to specific ones of the output channels 109, 110, 209, 210 based on the analysis result.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/ or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims. Further, the present invention provides a respective audio playback method.

List of reference signs

100, 200: audio playback system
101, 102: audio content
103, 203: audio source
104, 105, 204, 205: audio output channel
106, 206: audio sink
107, 108, 207, 208: audio input channel
109, 110, 209, 210: output channel
111, 112, 211, 212: individual channel test signal
113, 114, 213, 214: cable
115, 116, 117, 118, 215, 216, 217, 218: connector

220: connection detector
221: switching signal
222: test signal generator
223: oscillator

225: signal analyzer
226: switching matrix

S1 - S3: method steps

Claims

Audio playback system (100, 200) for audio content (101, 102), the audio playback system (100, 200) comprising:
an audio source (103, 203) comprising a number of audio output channels (104, 105, 204, 205), and

an audio sink (106, 206) comprising a number of audio input channels (107, 108, 207, 208) and a corresponding number of output channels (109, 110, 209, 210),

a cable (113, 114) that comprises a first connector (115, 116, 215, 216) on a first end and a second connector (117, 118, 217, 218) on a second end for each one of the audio output channels (104, 105, 204, 205) and that couples the respective one of the audio output channels (104, 105, 204, 205) with one of the audio input channels (107, 108, 207, 208),

wherein that audio source (103, 203) is configured to output individual channel test signals (111, 112, 211, 212) on every audio output channel (104, 105, 204, 205) upon connection of a cable (113, 114, 213, 214) to the audio output channels (104, 105, 204, 205), and

wherein the audio sink (106, 206) is configured to analyze signals received on the audio input channels (107, 108, 207, 208) for the presence of the individual channel test signals (111, 112, 211, 212) and map the audio input channels (107, 108, 207, 208) to respective ones of the output channels (109, 110, 209, 210) based on the analysis of the individual channel test signals (111, 112, 211, 212).
Audio playback system (100, 200) according to claim 1, wherein the audio source (103, 203) comprises a connection detector (220) configured to detect a connection of a cable (113, 114, 213, 214) to the audio output channels (104, 105, 204, 205) based on an electric resistance measurement or based on a switching signal (221).
Audio playback system (100, 200) according to any one of the preceding claims, wherein the audio source (103, 203) comprises a test signal generator (222) that is coupled to the audio output channels (104, 105, 204, 205) and that is configured to provide the individual channel test signals (111, 112, 211, 212) to the audio output channels (104, 105, 204, 205) after the connection of a cable (113, 114, 213, 214) is detected.
Audio playback system (100, 200) according to claim 3, wherein the test signal generator (222) comprises a configurable oscillator (223) configured to output a number of individual channel test signals (111, 112, 211, 212) each individual channel test signal (111, 112, 211, 212) comprising a predetermined frequency, especially a frequency higher than 20 kHz, especially 25 kHz or 30 kHz.
Audio playback system (100, 200) according to claim 4, wherein the configurable oscillator (223) is configured to sequentially output for every audio output channel (104, 105, 204, 205) an individual channel test signal (111, 112, 211, 212) starting with a predetermined one of the audio output channels (104, 105, 204, 205) clock-wise or counter-clockwise based on the intended position of the audio output channels (104, 105, 204, 205), wherein the configurable oscillator (223) is configured to increase or decrease the frequency by a predetermined frequency step for each one of the audio output channels (104, 105, 204, 205) in the sequence.
Audio playback system (100, 200) according to any one of the preceding claims, wherein the audio source (103, 203) is configured to output the individual channel test signals (111, 112, 211, 212) for a first predetermined amount of time after the connection of a cable (113, 114, 213, 214) to the output channels (109, 110, 209, 210) is detected, and especially for a second predetermined amount of time after a connection of the cables (113, 114, 213, 214) on the other ends to the audio sink (106, 206) is detected.
Audio playback system (100, 200) according to any one of the preceding claims, wherein the audio sink (106, 206) comprises a signal analyzer (225) that is configured to analyze signals received on the audio input channels (107, 108, 207, 208) for the presence of the individual channel test signals (111, 112, 211, 212).
Audio playback system (100, 200) according to any one of the preceding claims, wherein the audio sink (106, 206) comprises a switching matrix (226) that is configured to controllably couple individual audio input channels (107, 108, 207, 208) to specific ones of the output channels (109, 110, 209, 210).
Audio playback method for audio content (101, 102) with an audio source (103, 203) comprising a number of audio output channels (104, 105, 204, 205), and an audio sink (106, 206) comprising a number of audio input channels (107, 108, 207, 208) and a corresponding number of output channels (109, 110, 209, 210), the audio playback method comprising:
coupling each one of the audio output channels (104, 105, 204, 205) with one of the audio input channels (107, 108, 207, 208) via a cable (113, 114) that comprises a first connector (115, 116, 215, 216) on a first end and a second connector (117, 118, 217, 218) on a second end for each one of the audio output channels (104, 105, 204, 205),

outputting (S1) individual channel test signals (111, 112, 211, 212) on every audio output channel (104, 105, 204, 205) upon connection of a cable (113, 114, 213, 214) to the audio output channels (104, 105, 204, 205),

analyzing (S2) signals received on the audio input channels (107, 108, 207, 208) for the presence of the individual channel test signals (111, 112, 211, 212), and

mapping (S3) the audio input channels (107, 108, 207, 208) to respective ones of the output channels (109, 110, 209, 210) based on the analysis of the individual channel test signals (111, 112, 211, 212).
Audio playback method according to claim 9, comprising detecting a connection of a cable (113, 114, 213, 214) to the audio output channels (104, 105, 204, 205) based on an electric resistance measurement or based on a switching signal (221).
Audio playback method according to any one of the preceding claims 9 and 10, comprising providing the individual channel test signals (111, 112, 211, 212) to the audio output channels (104, 105, 204, 205) after the connection of a cable (113, 114, 213, 214) is detected.
Audio playback method according to claim 11, wherein providing the individual channel test signals (111, 112, 211, 212) comprises outputting a number of individual channel test signals (111, 112, 211, 212) each individual channel test signal (111, 112, 211, 212) comprising a predetermined frequency, especially a frequency higher than 20 kHz, especially 25 kHz or 30 kHz.
Audio playback method according to claim 12, wherein providing the individual channel test signals (111, 112, 211, 212) comprises sequentially outputting for every audio output channel (104, 105, 204, 205) an individual channel test signal (111, 112, 211, 212) starting with a predetermined one of the audio output channels (104, 105, 204, 205) clock-wise or counter-clockwise based on the intended position of the audio output channels (104, 105, 204, 205), wherein the frequency is increased or decreased by a predetermined frequency step for each one of the audio output channels (104, 105, 204, 205) in the sequence.
Audio playback method according to any one of the preceding claims 9 to 13, comprising outputting the individual channel test signals (111, 112, 211, 212) for a first predetermined amount of time after the connection of a cable (113, 114, 213, 214) to the output channels (109, 110, 209, 210) is detected, and especially for a second predetermined amount of time after a connection of the cables (113, 114, 213, 214) on the other ends to the audio sink (106, 206) is detected.
Audio playback method according to any one of the preceding claims 9 to 14, comprising analyzing signals received on the audio input channels (107, 108, 207, 208) for the presence of the individual channel test signals (111, 112, 211, 212), and controllably coupling individual audio input channels (107, 108, 207, 208) to specific ones of the output channels (109, 110, 209, 210) based on the analysis result.