Audio filter

[ToiletDuck]

Are there any audio filters that I could apply like ffdshow does to video.

[KpeX]

DC-DSP filter (http://corecodec.org/projects/dcdspfilter/) supports a vast range of DSP effects and Winamp DSPs, if you're looking for a ffdshow for audio, this is probably it. If not, tell us what filter you're trying to apply.