% clean.m removes selected frequency components to clean up the sound
% This is nowhere near a good way to do this; it is only a first step.

[se]=wavread('e.spoken.out');      % read spoken e data
se=se-132;
se_spectrum=fft(se);
se_spectrum(1)=1;

clean_spectrum=se_spectrum;        % begin cleaning up the spectrum
for j=600:1000                     % remove high frequencies
  clean_spectrum(j)=0;
end
for j=1:50                         % remove low frequencies
  clean_spectrum(j)=0;
end
se_clean = ifft(clean_spectrum);   % inverse fast Fourier transform


subplot(2,1,1)
k=[1:1:1200];
plot(k,abs(se_spectrum(k))/5000)
title('Original spectrum')
ylabel('Strength');
xlabel('Frequency');

subplot(2,1,2)
plot(k,abs(clean_spectrum(k))/5000)
title('Cleaned spectrum')
ylabel('Strength');
xlabel('Frequency');

sound(se,41600);
sound(se_clean,41600);