An apparatus (100; 250; 350; 440; 450) for providing one or more adjusted parameters (120; 252; 352; R̃; T̃) for a provision of an upmix signal representation (220; 430a-430M) on the basis of a downmix signal representation (210; 420) and a parametric side information (212; 422) associated with the downmix signal representation, the apparatus comprising: a parameter adjuster configured to receive one or more parameters (110; 214; 337) and to provide, on the basis thereof, one or more adjusted parameters (120; 252; 352), wherein the parameter adjuster is configured to provide the one or more adjusted parameters in dependence on an average value (132; ( R; T) of a plurality of parameter values (110; 214; 337; R; T), such that a distortion of the upmix signal representation caused by the use of non-optimal parameters for the provision of the upmix signal representation is reduced at least for one or more parameters deviating from optimal parameters by more than a predetermined deviation; wherein the apparatus is configured to receive one or more transcoding coefficients (337; T) describing a mapping of one or more channels of the downmix signal representation (210; 420) onto one or more channels of the upmix signal representation (220; 430a-430M), and wherein the apparatus is configured to provide one or more adjusted transcoding coefficients (352; T̃) as the adjusted parameters; wherein the parameter adjuster is configured to receive, as the input parameters, a temporal sequence of transcoding coefficients (337; T); characterised in that the parameter adjuster is configured to compute, as the average value, a temporal mean in dependence on a plurality of transcoding coefficients; and wherein the parameter adjuster is configured to provide the adjusted transcoding coefficients (352; T̃) such that a deviation of the adjusted transcoding coefficients from the temporal mean is restricted; wherein the parameter adjuster is configured to calculate the temporal mean using a recursive low pass filtering of the sequence of transcoding coefficients (337; T). a parameter adjuster configured to receive one or more parameters (110; 214; 337) and to provide, on the basis thereof, one or more adjusted parameters (120; 252; 352), wherein the parameter adjuster is configured to provide the one or more adjusted parameters in dependence on an average value (132; ( R; T) of a plurality of parameter values (110; 214; 337; R; T), such that a distortion of the upmix signal representation caused by the use of non-optimal parameters for the provision of the upmix signal representation is reduced at least for one or more parameters deviating from optimal parameters by more than a predetermined deviation; wherein the apparatus is configured to receive one or more transcoding coefficients (337; T) describing a mapping of one or more channels of the downmix signal representation (210; 420) onto one or more channels of the upmix signal representation (220; 430a-430M), and wherein the apparatus is configured to provide one or more adjusted transcoding coefficients (352; T̃) as the adjusted parameters; wherein the parameter adjuster is configured to receive, as the input parameters, a temporal sequence of transcoding coefficients (337; T); characterised in that the parameter adjuster is configured to compute, as the average value, a temporal mean in dependence on a plurality of transcoding coefficients; and wherein the parameter adjuster is configured to provide the adjusted transcoding coefficients (352; T̃) such that a deviation of the adjusted transcoding coefficients from the temporal mean is restricted; wherein the parameter adjuster is configured to calculate the temporal mean using a recursive low pass filtering of the sequence of transcoding coefficients (337; T).