Encoder for encoding an audio signal , the encoder comprising: an analyzer configured for analyzing the audio signal and for determining analysis prediction coefficients from the audio signal ; a converter configured for deriving converted prediction coefficients (122; 122') from the analysis prediction coefficients ; a memory configured for storing a multitude of correction values ; a calculator (130; 130') comprising: a processor (140; 140') configured for processing the converted prediction coefficients (122; 122') to obtain spectral weighting factors (142; 142'); a combiner (150; 150') configured for combining the spectral weighting factors (142; 142') and the multitude of correction values (162; a, b, c) to obtain corrected weighting factors (152; 152'); and a quantizer configured for quantizing the converted prediction coefficients (122; 122') using the corrected weighting factors (152; 152') to obtain a quantized representation of the converted prediction coefficients (122; 122'); and a bitstream former configured for forming an output signal based on the quantized representation of the converted prediction coefficients and based on the audio signal ; wherein the combiner is configured for combining the spectral weighting factors (142; 142'), the multitude of correction values (162; a, b, c) and a further information related to the input signal to obtain the corrected weighting factors ; wherein the further information related to the input signal comprises reflection coefficients obtained by the analyzer . an analyzer configured for analyzing the audio signal and for determining analysis prediction coefficients from the audio signal ; a converter configured for deriving converted prediction coefficients (122; 122') from the analysis prediction coefficients ; a memory configured for storing a multitude of correction values ; a calculator (130; 130') comprising: a processor (140; 140') configured for processing the converted prediction coefficients (122; 122') to obtain spectral weighting factors (142; 142'); a combiner (150; 150') configured for combining the spectral weighting factors (142; 142') and the multitude of correction values (162; a, b, c) to obtain corrected weighting factors (152; 152'); and a quantizer configured for quantizing the converted prediction coefficients (122; 122') using the corrected weighting factors (152; 152') to obtain a quantized representation of the converted prediction coefficients (122; 122'); and a processor (140; 140') configured for processing the converted prediction coefficients (122; 122') to obtain spectral weighting factors (142; 142'); a combiner (150; 150') configured for combining the spectral weighting factors (142; 142') and the multitude of correction values (162; a, b, c) to obtain corrected weighting factors (152; 152'); and a quantizer configured for quantizing the converted prediction coefficients (122; 122') using the corrected weighting factors (152; 152') to obtain a quantized representation of the converted prediction coefficients (122; 122'); and a bitstream former configured for forming an output signal based on the quantized representation of the converted prediction coefficients and based on the audio signal ; wherein the combiner is configured for combining the spectral weighting factors (142; 142'), the multitude of correction values (162; a, b, c) and a further information related to the input signal to obtain the corrected weighting factors ; wherein the further information related to the input signal comprises reflection coefficients obtained by the analyzer . <EOS>