Claims

1 . A rendering system (100), comprising:

plurality of loudspeakers (102);

at least one microphone (104);

a signal processing unit (106);

wherein the signal processing unit (106) is configured to determine at least some components of a loudspeaker-enclosure-microphone transfer function matrix estimate (H) describing acoustic paths (1 10) between the plurality of loudspeakers (102) and the at least one microphone (104) using a rendering filters transfer function matrix (H_{D}) using which a number of virtual sources (108) is reproduced with the plurality of loudspeakers (102).

2. The rendering system (100) according to the preceding claim, wherein the signal processing unit (106) is configured to estimate at least some components of a source-specific transfer function matrix (H_{s}) describing acoustic paths (1 12) between the number of virtual sources (108) and the at least one microphone (104); and

wherein the processing unit (106) is configured to determine the loudspeaker- enclosure-microphone transfer function matrix estimate (H) using the estimated source-specific signal transfer function matrix (H_{s}).

3. The rendering system (100) according to claim 2, wherein the signal processing unit (106) is configured to adaptively estimate the source-specific transfer function matrix (H_{s}) by minimizing a cost function derived from a difference between a recorded signal of the at least one microphone and an estimated signal of the at least one microphone obtained using the estimated source-specific transfer function matrix (H_{s}).

4. The rendering system (100) according to one of the preceding claims, wherein the signal processing unit (106) is configured to determine the components of the

loudspeaker-enclosure-microphone transfer function matrix estimate (H) which are sensitive to a column space of the rendering filters transfer function matrix (H_{D}).

The rendering system (100) according to one of the preceding claims 2 to 4, wherein the signal processing unit (106) is configured to determine at least some components of the loudspeaker-enclosure-microphone transfer function matrix estimate ( ?) based on the equation

H = fl_{s}H+

wherein H represents the loudspeaker-enclosure-microphone transfer function matrix estimate, wherein H_{s} represents the estimated source-specific transfer function matrix, wherein H_{D} represents the rendering filters transfer function matrix, and wherein Hp represents an approximate inverse of the rendering filters' transfer function matrix H_{D} .

The rendering system (100) according to one of the preceding claims, wherein in response to a change of at least one out of a number of virtual sources (108) and a position of at least one of the virtual sources (108), the signal processing unit (100) is configured to update at least some components of the loudspeaker-enclosure-microphone transfer function matrix estimate using a rendering filters transfer function matrix corresponding to the changed virtual sources.

The rendering system (100) according to the preceding claim, wherein the signal processing unit (106) is configured to update at least some components of the loudspeaker-enclosure-microphone transfer function matrix estimate based on the equation

K)H£ K)

wherein κ - 1 denotes a previous time interval, wherein κ denotes a current time interval, wherein between the previous time interval and the current time interval at least one out of a number of virtual sources (108) and a position of at least one of the virtual sources (108) is changed, wherein β(κ\κ) represents a loudspeaker-enclosure-microphone transfer function matrix estimate, Η-'-Ο - 1) represents

components of the loudspeaker-enclosure-microphone transfer function matrix estimate which are not sensitive to the column space of the rendering filters transfer function matrix, H_{s}(K \ K) represents an estimated source-specific transfer function matrix, and wherein Hp Qc) represents an inverse rendering filters transfer function matrix.

8. The rendering system (100) according to one of the claims 6 or 7, wherein the signal processing unit is configured to update at least some components of the loudspeaker-enclosure-microphone transfer function matrix estimate based on the equation

in order to reduce an average load of the signal processing unit;

wherein κ - 1 denotes a previous time interval, wherein κ denotes a current time interval, wherein between the current time interval and the previous time interval at least one out of a number of virtual sources (108) and a position of at least one of the virtual sources (108) is changed, wherein (κ\κ) represents a loudspeaker- enclosure-microphone transfer function matrix estimate, wherein Η(κ\κ - 1) represents a loudspeaker-enclosure-microphone transfer function matrix estimate,

represents an estimated source-specific transfer function matrix, wherein Η{κ\κ - 1) represents a loudspeaker-enclosure-microphone transfer function matrix estimate, and wherein Η (κ) represents an inverse rendering filters transfer function matrix.

9. The rendering system (100) according to one of the claims 6 or 7, wherein the signal processing unit (106) is configured to update at least some components of the loudspeaker-enclosure-microphone transfer function matrix estimate based on the distributedly evaluated equation

H(K \ K - 1) = #(K - - 2) + Η (κ - 1)/¾(K - 1)

as part of an initialization of a following interval's estimated source-specific transfer function matrix by

H_{S} (K + 1 \ K) = (H (K - 1 \ K - 2) + H (K ~ 1)H+ (K - 1))H_{D} (K + 1) + ¾^{Δ}(κ)/ ^{κ}'^{κ+1)}

in order to reduce a peak load of the signal processing unit;

wherein κ - 2 denotes a second previous time interval, wherein κ - 1 denotes a previous time interval, wherein κ denotes a current time interval, wherein κ + 1 denotes a following time interval, wherein between the time intervals at least one out of a number of virtual sources (108) and a position of at least one of the virtual sources (108) is changed, wherein R(K \ K - 1) represents a loudspeaker- enclosure-microphone transfer function matrix estimate, H_{s}(K +

represents an estimated source-specific transfer function matrix, wherein Η(κ - 1\κ - 2) represents a loudspeaker-enclosure-microphone transfer function matrix estimate, wherein ? (κ - 1) represents an update of an estimated source-specific transfer function matrix, H£ K - 1) represents an inverse rendering filters transfer function matrix, H_{d}(K + 1) represents a rendering filters transfer function matrix, HS (K) represents an update of an estimated source-specific transfer function matrix, and wherein //^'^{K+1)} represents a transition transform matrix which describes an update of an estimated source-specific transfer function matrix of the current time interval to the following time interval, such that only a contribution of Ης (κ)Η_{γ}^{Κ,κ+1}^ is computed between two time intervals.

10. The rendering system (100) according to one of the preceding claims, wherein a number (N_{s}) of virtual sources (108) is smaller than a number (N_{L}) of loudspeakers (102).

1 1 . The rendering system (100) according to one of the preceding claims, wherein the signals of the virtual sources (108) are statically independent.

12. A rendering system (100), comprising:

plurality of loudspeakers (102);

at least one microphone ( 04);

a signal processing unit (106);

wherein the signal processing unit (106) is configured to estimate at least some components of a source-specific transfer function matrix (H_{s}) describing acoustic paths (1 12) between a number of virtual sources (108), which are reproduced with the plurality of loudspeakers (102), and the at least one microphone (104); and

wherein the processing unit (106) is configured to determine at least some components of a loudspeaker-enclosure-microphone transfer function matrix estimate (H) describing acoustic paths (1 0) between the plurality of loudspeakers (102) and the at least one microphone (104) using the source-specific transfer function matrix (H_{s}).

Method (200), comprising:

determining (202) a loudspeaker-enclosure-microphone transfer function matrix (H) describing acoustic paths between a plurality of loudspeakers and at least one microphone of a using a rendering filters transfer function matrix (H_{D}) using which a number of source signals is reproduced with the plurality of loudspeakers.

Method (210), comprising:

estimating (212) at least some components of a source-specific transfer function matrix (Hs) describing acoustic paths between a number of virtual sources, which are reproduced with a plurality of loudspeakers, and at least one microphone; and

determining (214) at least some components of a loudspeaker-enclosure-microphone transfer function matrix estimate (H) describing acoustic paths between the plurality of loudspeakers and the at least one microphone using the source-specific transfer function matrix (H_{s}).

Computer program for performing a method according to one of the claims 13 and 14.