FFT Filter Banks

This section, based on [265], describes how to make practical audio filter banks using the Short Time Fourier Transform (STFT). This material bridges the filter-bank interpretation of the STFT in Chapter 9 and the discussion of multirate filter banks in Chapter 11. The filter banks of this section are based entirely on the STFT, with consideration of the basic Fourier theorems introduced in Chapter 2. In Chapter 11, filter banks such as used in audio compression are addressed. However, when not doing compression, i.e., when each channel of the filter bank does not have to be critically sampled, the methods of this section may suffice in many applications.