function y=play_scale(start_note,ss)
% Plays any major scale.
% Notes C D E F G A B C B A G F E D C for start_note = 40.
% Key #40 is middle C.
% SS: enter string 'sound' to play scale by SOUND command.
%
keys = [40 42 44 45 47 49 51 52 51 49 47 45 44 42 40 0];
keys = keys + (start_note-40);% adjusting the the starting
   %  for the major scale.
dur = 0.125* ones(1,length(keys));% 1/8 sec. duration
fs = 11025; % Sample rate
y  = zeros(1,sum(dur)*fs + 1);
n1 = 1;
for kk = 1:length(keys);%creates long vector of tones
   keynum = keys(kk);
   tone = note(keynum, dur(kk));
   n2 = n1 + length(tone) - 1;
   y(n1:n2) = y(n1:n2) + tone;
   n1 = n2;
end
y=y/max(abs(y));

if ss=='sound',
   sound(y,fs);
end
% --------- End play_scale.m ----------