% ECE301 HW1 % YeeChin, Chiam
% Playing Music % Part a
% Tempo bpm=112;
% Pitch fA=2*pi*440; fBb=(2^(1/12))*fA; fC=(2^(3/12))*fA; fG=(2^(-2/12))*fA; fDb=(2^(4/12))*fA;
% Length crotchet=0:0.00005:(60/bpm); d_crotchet=0:0.00005:(4*60/(3*bpm)); quaver=0:0.00005:(60/(2*bpm)); minim=0:0.00005:(2*60/bpm);
music=[sin(fG*crotchet),sin(fBb*crotchet),sin(fC*d_crotchet),sin(fG*crotchet),sin(fBb*crotchet),sin(fDb*quaver),sin(fC*minim),sin(fG*crotchet),sin(fBb*crotchet),sin(fC*d_crotchet),sin(fBb*crotchet),sin(fG*crotchet),sin(0:0.00005:(2.5*60/bpm))]; sound(music,1/0.00005) wavwrite(music,1/0.00005,'a.wav')
% Part b
% Tempo bpm=2*112;
% Length crotchet=0:0.00005:(60/bpm); d_crotchet=0:0.00005:(4*60/(3*bpm)); quaver=0:0.00005:(60/(2*bpm)); minim=0:0.00005:(2*60/bpm);
music=[sin(fG*crotchet),sin(fBb*crotchet),sin(fC*d_crotchet),sin(fG*crotchet),sin(fBb*crotchet),sin(fDb*quaver),sin(fC*minim),sin(fG*crotchet),sin(fBb*crotchet),sin(fC*d_crotchet),sin(fBb*crotchet),sin(fG*crotchet),sin(0:0.00005:(2.5*60/bpm))]; sound(music,1/0.00005) wavwrite(music,1/0.00005,'b.wav')
% Part c
% Tempo bpm=112;
% Length crotchet=0:0.00005:(60/bpm); d_crotchet=0:0.00005:(4*60/(3*bpm)); quaver=0:0.00005:(60/(2*bpm)); minim=0:0.00005:(2*60/bpm);
music=[sin(2*fG*crotchet),sin(2*fBb*crotchet),sin(2*fC*d_crotchet),sin(2*fG*crotchet),sin(2*fBb*crotchet),sin(2*fDb*quaver),sin(2*fC*minim),sin(2*fG*crotchet),sin(2*fBb*crotchet),sin(2*fC*d_crotchet),sin(2*fBb*crotchet),sin(2*fG*crotchet),sin(2*0:0.00005:(2.5*60/bpm))]; sound(music,1/0.00005) wavwrite(music,1/0.00005,'c.wav')
% Hidden Backward Message beatles=wavread('Beatles.wav'); rbeatles=flipud(beatles); sound(rbeatles,44100); wavwrite(rbeatles,44100,'reverse_beatles');
Forward: speech sounds like "number nine", background music is flipped on 00:16
Backward: speech sounds like "let me on the man",
Conclusion: Different background musics are put together, with one in forward and one in backward form, while there are no really clear messages from the speaker.
