Auditory perception is based on critical band analysis in the inner ear where a frequency to place transformation occurs along the basilar membrane [3]. The power spectra are not represented on a linear frequency scale but on a limited frequency bands called critical bands. The auditory system can be described as a bandpass filterbank, consisting of strongly overlapping bandpass filters with bandwidths in the order of 100 Hz for signals below 500 Hz and up to 5000 Hz for signals at high frequencies. Up to 24000 Hz 26 critical bands have to be taken in to account.