An audio processing device comprising a) an input unit for converting a time domain input signal to a number N I of input frequency bands, b) a frequency band allocation unit for allocating a part of said N I input frequency bands to N P processing channels, c) a signal processing unit adapted to process said input signal in said number N P of processing channels, the number N P of processing channels being smaller than the number N I of input frequency bands, d) a frequency band redistribution unit for redistributing said N P processing channels to N O output frequency bands, e) an output unit for converting said number N O of output frequency bands to a time domain output signal, f) a control unit for dynamically controlling the allocation of input frequency bands to processing channels and the redistribution of processing channels to output frequency bands, and g) a memory storing a number of calibration constants or parameters associated with different band coupling schemes to allow an appropriate re-calibration of estimators and sensors after a change of band coupling or storing an algorithm for calculating a set of calibration constants for a given situation after a change of band coupling h) a calibration element for each particular channel PCI p, each calibration element comprising a level detector, the level detector comprising an ABS unit for determining the magnitude of the input signal of each particular channel, a combination unit connected to the output of the level detector, the combination unit configured to multiplying the calibration constant provided by the memory and adapted to the energy content of the channel in question and a level estimation unit LEST connected to the output of the combination unit for estimating the current level LCh p of the p th channel. a) an input unit for converting a time domain input signal to a number N I of input frequency bands, b) a frequency band allocation unit for allocating a part of said N I input frequency bands to N P processing channels, c) a signal processing unit adapted to process said input signal in said number N P of processing channels, the number N P of processing channels being smaller than the number N I of input frequency bands, d) a frequency band redistribution unit for redistributing said N P processing channels to N O output frequency bands, e) an output unit for converting said number N O of output frequency bands to a time domain output signal, f) a control unit for dynamically controlling the allocation of input frequency bands to processing channels and the redistribution of processing channels to output frequency bands, and g) a memory storing a number of calibration constants or parameters associated with different band coupling schemes to allow an appropriate re-calibration of estimators and sensors after a change of band coupling or storing an algorithm for calculating a set of calibration constants for a given situation after a change of band coupling h) a calibration element for each particular channel PCI p, each calibration element comprising a level detector, the level detector comprising an ABS unit for determining the magnitude of the input signal of each particular channel, a combination unit connected to the output of the level detector, the combination unit configured to multiplying the calibration constant provided by the memory and adapted to the energy content of the channel in question and a level estimation unit LEST connected to the output of the combination unit for estimating the current level LCh p of the p th channel.