An audio decoder (100) comprising: effect means, decoding means, and rendering means. The effect means (500) generate modified down-mix audio signals from received down-mix audio signals. Said received down-mix audio signals comprise a down- mix of a plurality of audio objects. Said modified down-mix audio signals are obtained by 5 applying effects to estimated audio signals corresponding to audioobjects comprised in said received down-mix audio signals. Said estimated audio signals are derived from the received down-mix audio signals based on received parametric data. Said received parametric data comprise a plurality o f object parameters for each of the plurality of audio objects. Said modified down-mix audio signals based on a type of the applied effect are decoded by 10 decoding means or rendered by rendering means or combined with the output of rendering means. The decoding means (300) are arranged for decoding the audio objects from the down-mix audio signals or the modified down-mix audio signals based on the parametric data. The rendering means (400) are arranged for generating at least one output audio signal from the decoded audio objects.