function y=expdist(x, gain, mix)
% function y=expdist(x, gain, mix)
% y=expdist(x, gain, mix)
% Distortion based on an exponential function
% x - input
% gain - amount of distortion, >0
% mix - mix of original and distorted sound, when 1=only distorted
q=x*gain/max(abs(x));
z=sign(-q).*(1-exp(sign(-q).*q));
y=mix*z*max(abs(x))/max(abs(z))+(1-mix)*x;
y=y*max(abs(x))/max(abs(y));