An audio processor for processing an audio signal to obtain a subband representation of the audio signal, the audio processor comprising: a cascaded lapped critically sampled transform stage configured to perform a cascaded lapped critically sampled transform on at least two partially overlapping blocks (108_1;108_2) of samples of the audio signal, to obtain a set (110_1,1) of subband samples on the basis of a first block (108_1) of samples of the audio signal, and to obtain a corresponding set (110_2,1) of subband samples on the basis of a second block (108_2) of samples of the audio signal; and a time domain aliasing reduction stage configured to perform a weighted combination of two corresponding sets (110_1,1;110_1,2) of subband samples, one obtained on the basis of the first block (108_1) of samples of the audio signal and one obtained on the basis on the second block (108_2) of samples of the audio signal, to obtain an aliasing reduced subband representation (112_1) of the audio signal; wherein the cascaded lapped critically sampled transform stage is configured to segment a set (124_1) of bins obtained on the basis of the first block (108_1) of samples using at least two window functions, and to obtain at least two sets (128_1,1;128_1,2) of bins based on the segmented set of bins corresponding to the first block (108_1) of samples; wherein the cascaded lapped critically sampled transform stage is configured to segment a set (124_2) of bins obtained on the basis of the second block (108_2) of samples using the at least two window functions, and to obtain at least two sets (128_2,1;128_2,2) of bins based on the segmented set of bins corresponding to the second block (108_2) of samples; and wherein the sets (128_1,1;128_1,2;128_2,1;128_2,2) of bins are processed using a second lapped critically sampled transform stage of the cascaded lapped critically sampled transform stage, wherein the second lapped critically sampled transform stage is configured to perform lapped critically sampled transforms having the same framelength for at least one set of bins; characterised in that the audio processor is configured to activate or maintain activated the time domain aliasing reduction stage, if the same framelengths are used for two subsequent blocks (108_1, 108_2), and/or the audio processor is configured to deactivate or maintair deactivated the time domain aliasing reduction stage, if different framelengths are used for two subsequent blocks (108_1, 108_2). a cascaded lapped critically sampled transform stage configured to perform a cascaded lapped critically sampled transform on at least two partially overlapping blocks (108_1;108_2) of samples of the audio signal, to obtain a set (110_1,1) of subband samples on the basis of a first block (108_1) of samples of the audio signal, and to obtain a corresponding set (110_2,1) of subband samples on the basis of a second block (108_2) of samples of the audio signal; and a time domain aliasing reduction stage configured to perform a weighted combination of two corresponding sets (110_1,1;110_1,2) of subband samples, one obtained on the basis of the first block (108_1) of samples of the audio signal and one obtained on the basis on the second block (108_2) of samples of the audio signal, to obtain an aliasing reduced subband representation (112_1) of the audio signal; wherein the cascaded lapped critically sampled transform stage is configured to segment a set (124_1) of bins obtained on the basis of the first block (108_1) of samples using at least two window functions, and to obtain at least two sets (128_1,1;128_1,2) of bins based on the segmented set of bins corresponding to the first block (108_1) of samples; wherein the cascaded lapped critically sampled transform stage is configured to segment a set (124_2) of bins obtained on the basis of the second block (108_2) of samples using the at least two window functions, and to obtain at least two sets (128_2,1;128_2,2) of bins based on the segmented set of bins corresponding to the second block (108_2) of samples; and wherein the sets (128_1,1;128_1,2;128_2,1;128_2,2) of bins are processed using a second lapped critically sampled transform stage of the cascaded lapped critically sampled transform stage, wherein the second lapped critically sampled transform stage is configured to perform lapped critically sampled transforms having the same framelength for at least one set of bins; characterised in that the audio processor is configured to activate or maintain activated the time domain aliasing reduction stage, if the same framelengths are used for two subsequent blocks (108_1, 108_2), and/or the audio processor is configured to deactivate or maintair deactivated the time domain aliasing reduction stage, if different framelengths are used for two subsequent blocks (108_1, 108_2).