Download Cooledit Pro, a mighty sample editor with *lots* of functions to manipulate
samples.....also there's a very good "Scientific Filter" section with butterfilters etc all
with controls and and visual response curves ! It helped me a lot to get the intuitive feel
for using filters etc in Csound without having the visual response.

CoolPro is great to do a last optimise of sounds made by Csound like
removing unaudible rumble (0-40Hz) to free up amplitude space for normalization.

I prefer the non-creative stuff (like optimising, calibrating and balancing) doing in
a very visual environment like CoolEdit Pro or SoundForge.
 
 

David.