hello
there is a very simple way to implement echo effects - see demo code below
infile='DirectGuitar.wav';
outfile='out_echo.wav';
% read the sample waveform
[x,Fs] = audioread(infile);
% normalize x to +/- 1 amplitude
x = x ./ (max(abs(x)));
% parameters
N_delay=20; % delay in samples
C = 0.7; % amplitude of direct sound
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
y = zeros(length(x),1); % create empty out vector
y(1:N_delay)=x(1:N_delay); % to avoid referencing of negative samples
% for each sample > N_delay
for i = (N_delay+1):length(x)
y(i) = C*x(i) + (1-C)*(x(i-N_delay)); % add delayed sample
end
% write output
% normalize y to +/- 1 amplitude
y = y ./ (max(abs(y)));
audiowrite(outfile, y, Fs);
figure(1)
hold on
plot(x,'r');
plot(y,'b');
title('Echoed and original Signal');
sound(y,Fs);
