An MPEG spatial audio object coding, MPEG-SAOC, audio signal decoder (100; 420) for providing an upmix signal representation (130; 484a to 484M) on the basis of a downmix signal representation (110; 430) and an object-related parametric information (112; 432) of an MPEG-SAOC and depending on a rendering information (120; 482), the apparatus comprising: an object parameter determinator (140; 464, 468, 474) configured to obtain inter-object-correlation values for a plurality of pairs of audio objects, wherein the object parameter determinator is configured to evaluate a bitstream signaling parameter in order to decide whether to evaluate individual inter-object-correlation bitstream parameter values, to obtain inter-object-correlation values for a plurality of pairs of related audio objects, or to obtain inter-object-correlation values for a plurality of pairs of related audio objects using a time/frequency dependent common inter-object-correlation bitstream parameter value; and a signal processor (150; 480) configured to obtain the upmix signal representation on the basis of the downmix signal representation and using the inter-object-correlation values for a plurality of pairs of related audio objects and the rendering information; wherein the object-related parametric information (112;432) comprises object level difference data, the bitstream signaling parameter and further comprises the individual inter-object-correlation bitstream parameter values or the time/frequency dependent common inter-object-correlation bitstream parameter value; wherein the object parameter determinator (140; 464, 468, 474) is configured to evaluate an object-relationship-information, describing whether two audio objects are related to each other; and wherein the object parameter determinator is configured to selectively obtain inter-object-correlation values for pairs of audio objects, for which the object-relationship-information indicates a relationship, using the time/frequency dependent common inter-object-correlation bitstream parameter value and to set inter-object-correlation values for pairs of audio objects, for which the object-relationship information indicates no relationship, to a predefined value; wherein diagonal elements ||s 1 || 2, ||s 2 || 2,..., ||s N || 2 of a time/frequency variant covariance matrix are directly reconstructed with the object level difference data, and wherein non-diagonal elements of the covariance matrix are given by the inter-object-correlation values IOC mn according to ρ mn =∥ s m ∥·∥ s n ∥·IOC mn, wherein signals s 1, s 2,..., s N represent the audio objects. an object parameter determinator (140; 464, 468, 474) configured to obtain inter-object-correlation values for a plurality of pairs of audio objects, wherein the object parameter determinator is configured to evaluate a bitstream signaling parameter in order to decide whether to evaluate individual inter-object-correlation bitstream parameter values, to obtain inter-object-correlation values for a plurality of pairs of related audio objects, or to obtain inter-object-correlation values for a plurality of pairs of related audio objects using a time/frequency dependent common inter-object-correlation bitstream parameter value; and a signal processor (150; 480) configured to obtain the upmix signal representation on the basis of the downmix signal representation and using the inter-object-correlation values for a plurality of pairs of related audio objects and the rendering information; wherein the object-related parametric information (112;432) comprises object level difference data, the bitstream signaling parameter and further comprises the individual inter-object-correlation bitstream parameter values or the time/frequency dependent common inter-object-correlation bitstream parameter value; wherein the object parameter determinator (140; 464, 468, 474) is configured to evaluate an object-relationship-information, describing whether two audio objects are related to each other; and wherein the object parameter determinator is configured to selectively obtain inter-object-correlation values for pairs of audio objects, for which the object-relationship-information indicates a relationship, using the time/frequency dependent common inter-object-correlation bitstream parameter value and to set inter-object-correlation values for pairs of audio objects, for which the object-relationship information indicates no relationship, to a predefined value; wherein diagonal elements ||s 1 || 2, ||s 2 || 2,..., ||s N || 2 of a time/frequency variant covariance matrix are directly reconstructed with the object level difference data, and wherein non-diagonal elements of the covariance matrix are given by the inter-object-correlation values IOC mn according to ρ mn =∥ s m ∥·∥ s n ∥·IOC mn, wherein signals s 1, s 2,..., s N represent the audio objects.