I am trying to implement a Chebyshev waveshaper according to the description on the bottom post here:
Add odd/even harmonics to signal?
It looks similar to the algorithm here: http://www.juce.com/forum/topic/voice-changer-plugin
The results for any odd order setting sound good. But all even order results just end up in massive distortion. I also tried x * abs(x) instead of x², but the result is similar. How should I handle the even order terms? Or do I have to use a completely different method for producing even harmonics?