Get ideas from other libraries

[jeroendoggen]

How to structure the filters (OOP design)
(partial) Filter implementations?
http://spuc.sourceforge.net/

http://stackoverflow.com/questions/1761212/any-good-c-c-dsp-library

Lots of filters: (BlkDSP.cpp)
http://www.icst.net/research/projects/dsp-library/