An apparatus for spatial audio signal encoding comprising means configured to: receive a plurality of audio objects each comprising an audio direction parameter, wherein each audio direction parameter comprises an elevation value and an azimuth value and wherein each audio direction parameter has an indexed position giving a plurality of indexed audio direction parameters, wherein the apparatus is characterized in that the apparatus comprises means configured to: derive for each of the plurality of indexed audio direction parameters a corresponding derived indexed audio direction parameter comprising an elevation and an azimuth value, corresponding derived indexed audio direction parameters being arranged in a manner determined by a spatial utilization parameter defined by the elevation values and the azimuth values of the plurality of indexed audio direction parameters; rotate each derived indexed audio direction parameter by the azimuth value of a first indexed audio direction parameter of the plurality of indexed audio direction parameters to determine for each derived indexed audio direction parameter a corresponding rotated derived indexed audio direction parameter; for each further indexed audio direction parameter, determine an azimuth value of a rotated derived indexed audio direction parameter which is closest to the azimuth value of the further indexed audio direction parameter, and change the index of the further indexed audio direction parameter to a further index which coincides with the index of the rotated derived indexed audio direction parameter whose azimuth value is closest to the azimuth value of the further indexed audio direction parameter; quantize the rotation, by quantizing the azimuth angle of the first indexed audio direction parameter, to determine for each derived indexed audio direction parameter a corresponding quantized rotated derived indexed audio direction parameter; determine a difference between the first indexed audio direction parameter and a first quantized rotated indexed derived audio direction parameter and quantize the difference with a quantization resolution based on a spatial extent of the first indexed audio direction parameter; for each further indexed audio direction parameter, determine a difference between the further indexed audio direction parameter and a quantized rotated derived indexed audio direction parameter whose azimuth value is closest to the azimuth value of the further indexed audio direction parameter and quantize the difference with a quantization resolution based on the spatial extent of the further indexed audio direction parameter; and encode a permutation of indices representing the order of the indices of the further indexed audio direction parameters, encode the spatial extents of the indexed audio direction parameters and encode the space utilization parameter. derive for each of the plurality of indexed audio direction parameters a corresponding derived indexed audio direction parameter comprising an elevation and an azimuth value, corresponding derived indexed audio direction parameters being arranged in a manner determined by a spatial utilization parameter defined by the elevation values and the azimuth values of the plurality of indexed audio direction parameters; rotate each derived indexed audio direction parameter by the azimuth value of a first indexed audio direction parameter of the plurality of indexed audio direction parameters to determine for each derived indexed audio direction parameter a corresponding rotated derived indexed audio direction parameter; for each further indexed audio direction parameter, determine an azimuth value of a rotated derived indexed audio direction parameter which is closest to the azimuth value of the further indexed audio direction parameter, and change the index of the further indexed audio direction parameter to a further index which coincides with the index of the rotated derived indexed audio direction parameter whose azimuth value is closest to the azimuth value of the further indexed audio direction parameter; quantize the rotation, by quantizing the azimuth angle of the first indexed audio direction parameter, to determine for each derived indexed audio direction parameter a corresponding quantized rotated derived indexed audio direction parameter; determine a difference between the first indexed audio direction parameter and a first quantized rotated indexed derived audio direction parameter and quantize the difference with a quantization resolution based on a spatial extent of the first indexed audio direction parameter; for each further indexed audio direction parameter, determine a difference between the further indexed audio direction parameter and a quantized rotated derived indexed audio direction parameter whose azimuth value is closest to the azimuth value of the further indexed audio direction parameter and quantize the difference with a quantization resolution based on the spatial extent of the further indexed audio direction parameter; and encode a permutation of indices representing the order of the indices of the further indexed audio direction parameters, encode the spatial extents of the indexed audio direction parameters and encode the space utilization parameter.