clc; clear; clf;

file = 'Windows XP Startup.wav';
[I_all, fs, nbits] = wavread(file);  % int16 format...Matlab 7.0 syntax
nbits
wavwrite(I_all,fs,8,'filename.wav');

[I_a, fs, nbits1] = wavread('filename.wav');
nbits 
wavplay(I_all, fs);
size(I_all)
figure(1)
plot(I_all(:,1));

pause;
wavplay(I_a, fs);
figure(2)
plot(I_a(:,1));
figure(3)
plot(I_all(:,1));hold on;plot(I_a(:,1),'r');