function [y,fs]=tune(notes)
tones=[261.6,277.2,293.6,311.1,329.6,349.2,370,392,415.3,440,466.2,493.9];
tones=[tones,2*tones];
y=[];fs=4000;
[M,K]=size(notes);
s=[zeros(1,40),2*ones(1,100),ones(1,560),zeros(1,300)];
b=1.0e-004 *[0.2915 0.8744 0.8744 0.2915];
a=[1.0000 -2.8744 2.7565 -0.8819];
envelope=filter(b,a,s);
for k=1:min(K,16)
if M>1
s=zeros(size(envelope));
for m=1:M
s=s+modulate(envelope,fs,tones(notes(m,k)));
end
y=[y,s];
else
y=[y,modulate(envelope,fs,tones(notes(k)))];
end
end
sound(y,fs)