Delay Unit for a Conference Audio System, Method for Delaying Audio Input Signals, Computer Program and Conference Audio System

1. A delay unit ( 16 ) allocated to a single delegate unit of a conference audio system ( 1 ) having a first audio input signal and a second audio input signal, the delay unit ( 16 ) adapted to delay the first and second audio input signals for an adjustable time delay, thereby generating an audio output signal, the delay unit ( 16 ) comprising a circular buffer ( 17 ); a write pointer (W) to write a sample (S 1 ) of the first audio input signal to the circular buffer ( 17 ) at a first write position; a read pointer (R) to read a sample from the circular buffer ( 17 ) at a first read position as a sample of a first output signal, whereby the distance between the first write position and the first read position determines a first time delay (d old ); a buffer control module adapted to move the write pointer (W) to a next position after writing and to move the read pointer (R) to a next position after reading; whereby the buffer control module is adapted to adjust a second time delay (d new ) by moving the write pointer (W) to a second write position to write a sample (S 2 ) of the second audio input signal to the circular buffer ( 17 ) at the second write position, whereby the distance between the first read position and the second write position determines the second time delay (d new ); wherein the buffer control module is adapted to adjust the time delay during a change from the first audio input signal with the first time delay to a second audio input signal with the second time delay.

3. The delay unit ( 16 ) according to claim 1 , characterized in that the buffer control unit is adapted to zero a location of the circular buffer after reading the sample from the location.

4. The delay unit ( 16 ) according to claim 1 , characterized in that the buffer control unit is adapted to partly overlap samples of the first signal (S 1 ) and samples of a second signal (S 2 ) in case the second delay (d new ) is smaller than the first time delay (d old ).

5. The delay unit ( 16 ) according to claim 1 , characterized by a processing unit, which is adapted to fade out the first audio signal.

6. A conference audio system ( 1 ) comprising a plurality of delegate units ( 2 ), a control means ( 15 ) for distributing at least one audio signal from at least one sound source to a plurality of the delegate loudspeakers ( 5 ), the plurality of delegate loudspeakers ( 5 ) generating a common audio atmosphere, delay means ( 16 ) operable to add a time delay on the audio signal, whereby the delay means comprise the delay unit according to claim 1 .

7. The conference audio system ( 1 ) according to claim 6 , characterized in that the time delay is determined based on a distance between the position of the sound source generating the audio signal and the individual delegate loudspeaker ( 5 ) position.

8. The conference audio system ( 1 ) according to claim 6 , wherein each delegate unit ( 2 ) has a delegate loudspeaker ( 5 ) and a delegate microphone ( 4 ).

9. The conference audio system ( 1 ) according to claim 6 , wherein each delegate unit ( 2 ) has a delegate loudspeaker ( 5 ).

10. The conference audio system ( 1 ) according to claim 6 , wherein each delegate unit ( 2 ) has a delegate microphone ( 4 ).

11. The conference audio system ( 1 ) according to claim 6 , wherein the sound source is one or more delegate microphones ( 4 ).

12. The delay unit ( 16 ) according to claim 1 , characterized by a processing unit, which is adapted to fade out the first audio signal and to fade in the second audio signal.

13. The delay unit ( 16 ) according to claim 1 , characterized by a processing unit, which is adapted to fade in the second audio signal.

14. A method for delaying audio input signals for an adjustable time delay, carried out by a delay unit ( 16 ) having a first audio input signal and a second audio input signal and a circular buffer ( 17 ), the delay unit ( 16 ) adapted to delay the first and second audio input signals for an adjustable time delay, thereby generating an audio output signal, the method comprising: writing a sample (S 1 ) of the first audio input signal by a write pointer (W) to the circular buffer ( 17 ) at a first write position; reading a sample of the first audio input signal by a read pointer (R) from the circular buffer ( 17 ) at a first read position, whereby the distance between the first write position and the first read position determines a first time delay (d old ); moving the write pointer (W) to a next position after writing and the read pointer (R) to a next position after reading; setting, by the delay unit, the write pointer to a second write position during a change from the first audio input signal with the first time delay (d old ) to the second audio input signal with a second time delay (d new ), whereby the distance between the first read position and the second write position determines the second time delay.

15. A non-transitory computer readable medium containing a computer program comprising program-code for carrying out the method according to claim 14 , when the computer program is carried out on a computer.

16. A non-transitory computer readable medium containing a computer program comprising program-code for carrying out the method according to claim 14 , when the computer program is carried out on a computer and a delay unit.

17. A non-transitory computer readable medium containing a computer program comprising program-code for carrying out the method according to claim 14 , when the computer program is carried out on a delay unit.