I understand that the human ear works as a band-pass filter and I have doubt regarding the number of such bandpass filters in the filter bank.
I came across these two possible explanations of how it happens:
There are no fixed bands and the critical bandwidth of a sound depends on which audio frequency the ear is exposed to. In such a case, the audio frequency could be treated as the center frequency of a bandpass filter and another frequency occurring in the same band gets masked out.
There are 24 fixed bandpass filters with their corresponding fixed bandwidths independent of the audio frequency the ear is exposed to. In such a case too, frequencies occurring in the same band sound like a single frequency and the difference goes undetected.
Which one of them is correct? Do the critical bands exist only between the 24 fixed values or are they continuous values?