Device and Method for Producing a Surround Sound

1 . A surround sound audio processing system, comprising:

a source that supplies a first signal for producing a first sound impression and a second signal for producing a second sound impression;

a processing unit for modifying the first signal and the second signal to produce a third sound impression of a virtual source, and provides first and second modified signals indicative thereof; and

wherein the processing unit modifies the first signal and the second signal relative to each other such that the first and second modified signals have a phase shift of between 170° to 190°.

2 . The system of claim 1 , wherein the processing unit includes a phase shifter that phase shifts the second modified signal with a phase shift of 180° with respect to the first modified signal.

3 . The system of claim 1 , wherein the processing unit comprises a first phase shifter that applies a first phase shift to the first modified signal and a second phase shifter that applies a second phase shift to the second modified signal, such that the first and second modified signals have a phase difference of between about 170 to 190 degrees.

4 . The system of claim 3 , where the first phase shifter applies a phase shift of about 70 to 100 degrees while the second phase shifter applies a phase shift of about −100 to −70 degrees.

5 . The system of claim 4 , wherein

a first delay element and/or a first decorrelator delay(s) the first signal supplied by the signal source and apply(ies) it with a delay to a third adder for additive combination with the phase-shifted first signal and

a second delay element and/or a second decorrelator delay(s) the second signal supplied by the signal source and apply(ies) it with a delay to a fourth adder for additive combination with the phase-shifted second signal.

6 . The system of claim 1 , wherein

an adaptation module forms an adaptation value (Hd*) from the first and second signals supplied by the signal source and applies it to a third adder with a delay for additive combination with a phase-shifted first signal and to a fourth adder for additive combination with the phase-shifted second signal.

7 . The system of claim 1 , wherein a rotation module is laid out and/or controlled for the cyclic rotation by 90°, in each case, of the phases of the first signal or of the first modified signal, of the second signal or of the second modified signal, and of a middle signal formed from the first and second signals or of one of the modified middle signals formed from the first and second modified signals.

8 . The system of claim 1 , wherein

the source supplies additional signals (L, R, C) for producing additional sound impressions, and

means for producing the third sound impression of the virtual source comprises means for changing the phases of the first or the second signal, and means for changing the phases of additional signals (L, R, C), so as to change at least the phase of a first of the additional signals (L) with respect to the phase of the first modified signal (SL′) by +90° and the phase of the first of the additional signals (L) with respect to the phase of the second modified signal (SL′) by −90°.

9 . A method for producing a surround sound, wherein

at least one first signal (SL) for producing a first sound impression and one second signal (SR) for producing a second sound impression are supplied and the first signal (SL) and the second signal (SR) are modified for producing a third sound impression of a virtual source (SC) and output as a first signal modified in this way (SL′) and as a second signal modified in this way (SR′),

wherein during the modification, the first signal (SL) and the second signal (SR) are phase-shifted relative to each other with a phase shift (φ) of 170° to 190°.

10 . The method of claim 9 , wherein the phase shift (φ) is carried out with 180° relative to each other.

11 . The method of claim 9 , wherein

the first signal (SL) supplied or modified by the signal source and the second signal (SR) supplied or modified by the signal source is delayed and

the first signal (SL) is modified with a positive phase shift (φ) with respect to the first signal (SL) supplied by the signal source and

the second signal (SR) is modified in relation to the former with a negative phase shift (φ) with respect to the second signal (SR) supplied by the signal source.

12 . The method of claim 11 , wherein the first signal (SL) is shifted with a phase shift (φ) of +70° to +100°, particularly of +90°, and the second signal (SR) is shifted with a phase shift (φ) of −100° to −70°, particularly of −90°.

13 . The method of claim 9 , wherein

the first signal (SL) supplied by the signal source is decorrelated and/or delayed and added with a delay to the phase-shifted first signal and

the second signal (SR) supplied by the signal source is decorrelated and/or delayed and added with a delay to the phase-shifted second signal.

14 . The method of claim 9 , wherein an adaptation value (Hd*) is formed from the first and second signals (SL, SR) supplied by the signal source and the adaptation value is added with a delay both to the phase-shifted first signal and to the phase-shifted second signal.

15 . The method of claim 9 , wherein phases of the first signal (SL) or of the first modified signal, of the second signal (SR) or of the second modified signal, and of a middle signal (R) formed from the first and second signal (SL, SR) or a modified middle signal formed from the first and second modified signal are rotated by 90° in each case.