I have released: https://hackage.haskell.org/package/fftw-ffi https://hackage.haskell.org/package/comfort-fftw This is an alternative to the 'fft' package (based on 'carray' and 'ix-shapable'). The package comfort-fftw is based on comfort-array and uses Cyclic and Half Spectrum shapes. The Cyclic shape allows you to access the (n-1)-th element also by index (-1). This reflects the cyclic interpretation of data implied by the discrete Fourier transform. The Half Spectrum shape greatly simplifies working with the spectrum of real data, both of even and odd length, and reduces the danger of mistakes. The bindings use distinct array shapes for the four kinds of both cosine and sine transformation and thus ensure, that you use the right one for back transformation. Two examples may demonstrate its usage: https://hackage.haskell.org/package/align-audio Find relative displacement of two recordings of the same music. https://hackage.haskell.org/package/sound-collage Assemble a mosaic of sound snippets according to a target music recording.