I have recorded a speech where the speaker was too close to the microphone, causing distorted “s” effects. I tried the low pass filter, which helped a bit, also click removal. Maybe I need to try something else? Would appreciate advice. I am not an Audacity expert!!!
Sounds like a job for De-Esser , (Audacity specific De-Esser plugin here).
http://manual.audacityteam.org/man/effect_menu.html#nyquist_effects
If you’re using Audacity on Windows there are free VST De-esser plugins, e.g. SpitFish , TDR Nova.
NB: Only download 32-bit versions VST plugins for Audacity, even if your computer OS is 64-bit.