This plugin was inspired by the incredible foo_musical_spectrum plugin for the foobar2000 audio player. It offers variable FFT size (up to 32768), Blackmann-Harris and Hanning window functions, and lots of other options..
See ebuilds here
First install DeaDBeeF (>=0.6) and fftw3 and their development files.
(e.g. on Ubuntu: sudo apt-get update && sudo apt-get install build-essential git libgtk2.0-dev libgtk-3-dev libfftw3-dev
)
make
./userinstall.sh