[x]=gdist(a,x)

function [x]=gdist(a,x)
%[Y] = GDIST(A, X) Guitar Distortion
%
%   GDIST creates a distortion effect like that of
%   an overdriven guitar amplifier. This is a Matlab 
%   implementation of an algorithm that was found on 
%   www.musicdsp.org.
%
%   A = The amount of distortion.  A
%       should be chosen so that -1<A<1.
%   X = Input.  Should be a column vector 
%       between -1 and 1.
%
%coded by: Steve McGovern, date: 09.29.04
%URL: http://www.steve-m.us

k = 2*a/(1-a);
x = (1+k)*(x)./(1+k*abs(x));