Apparatus for generating a plurality of audio channels (12; 12-1; 12-2) for a first speaker setup (14; 14-1), comprising: an imaginary speaker determiner (18; 18-1) configured for determining a position of an imaginary speaker (22; 22a-d) not contained in the first speaker setup (14; 14-1) to obtain a second speaker setup (24; 24-1; 24-2; 24-3) containing the imaginary speaker (22; 22a-d), such that the imaginary speaker (22; 22a-d) is arranged at a location in the second speaker setup, the second speaker setup being implemented according to a predefined setup and comprising some or all of the speakers (16a-c) of the first speaker setup (14; 14-1); an energy distribution calculator (26; 26-1) configured for calculating an energy distribution from the imaginary speaker (22; 22a-d) to other speakers in the second speaker setup (24; 24-1; 24-2; 24-3), wherein the energy distribution represents an amount or a share of an energy of the imaginary speaker (22; 22a-d) being distributed to the other speakers in the second speaker setup (24; 24-1; 24-2; 24-3); a processor (28; 28-1) configured for obtaining an energy distribution matrix based on the energy distribution and for computing a power (D n) of the energy distribution matrix with an exponent (n) greater than 1 to obtain a downmix information for a downmix from the second speaker setup (24; 24-1; 24-2; 24-3) to the first speaker setup (14; 14-1), wherein the energy distribution matrix comprises energy distribution coefficients (d xy) that represent an allocation or re-allocation of energy of each of the speakers in the second speaker setup to other speakers in the second speaker setup; wherein the energy distribution coefficients of the energy distribution matrix that represent a distribution of a real speaker comprised both in the first speaker setup and in the second speaker setup to another speaker of the second speaker setup comprise a value of zero; wherein the energy distribution coefficients of the energy distribution matrix that represent a distribution of the imaginary speaker (22; 22a-d) to another speaker of the second speaker setup comprise a value of 1 or less than 1; wherein the power of the energy distribution matrix leads the energy distribution coefficients that represent the imaginary speaker (22; 22a-d) to decrease and the energy distribution coefficients that represent the real speaker to increase in order to allocate or re-allocate energy from the imaginary speaker (22; 22a-d) to the real speaker; wherein the processor is configured to ignore or to round down to zero the energy distribution coefficients that have decreased below a defined threshold value; and a renderer (38; 38-1) configured for generating the plurality of audio channels (12; 12-1; 12-2) by applying the downmix information to an input signal. an imaginary speaker determiner (18; 18-1) configured for determining a position of an imaginary speaker (22; 22a-d) not contained in the first speaker setup (14; 14-1) to obtain a second speaker setup (24; 24-1; 24-2; 24-3) containing the imaginary speaker (22; 22a-d), such that the imaginary speaker (22; 22a-d) is arranged at a location in the second speaker setup, the second speaker setup being implemented according to a predefined setup and comprising some or all of the speakers (16a-c) of the first speaker setup (14; 14-1); an energy distribution calculator (26; 26-1) configured for calculating an energy distribution from the imaginary speaker (22; 22a-d) to other speakers in the second speaker setup (24; 24-1; 24-2; 24-3), wherein the energy distribution represents an amount or a share of an energy of the imaginary speaker (22; 22a-d) being distributed to the other speakers in the second speaker setup (24; 24-1; 24-2; 24-3); a processor (28; 28-1) configured for obtaining an energy distribution matrix based on the energy distribution and for computing a power (D n) of the energy distribution matrix with an exponent (n) greater than 1 to obtain a downmix information for a downmix from the second speaker setup (24; 24-1; 24-2; 24-3) to the first speaker setup (14; 14-1), wherein the energy distribution matrix comprises energy distribution coefficients (d xy) that represent an allocation or re-allocation of energy of each of the speakers in the second speaker setup to other speakers in the second speaker setup; wherein the energy distribution coefficients of the energy distribution matrix that represent a distribution of a real speaker comprised both in the first speaker setup and in the second speaker setup to another speaker of the second speaker setup comprise a value of zero; wherein the energy distribution coefficients of the energy distribution matrix that represent a distribution of the imaginary speaker (22; 22a-d) to another speaker of the second speaker setup comprise a value of 1 or less than 1; wherein the power of the energy distribution matrix leads the energy distribution coefficients that represent the imaginary speaker (22; 22a-d) to decrease and the energy distribution coefficients that represent the real speaker to increase in order to allocate or re-allocate energy from the imaginary speaker (22; 22a-d) to the real speaker; wherein the processor is configured to ignore or to round down to zero the energy distribution coefficients that have decreased below a defined threshold value; and a renderer (38; 38-1) configured for generating the plurality of audio channels (12; 12-1; 12-2) by applying the downmix information to an input signal.