%% simultaneous onset
sr = 44100;
f1 = 300;
f2 = 550;
f3 = 640;
d = 5;
t = linspace(0, d, d*sr);
tone1 = sin(2*pi*f1*t);
tone2 = sin(2*pi*f2*t);
tone3 = sin(2*pi*f3*t);
complex = tone1+tone2+tone3;
soundsc(tone1+tone2+tone3, sr)

pause(1)

%% non-simultaneous onset
offset_dur = .5;
offset = zeros(1, sr*offset_dur);
tone1 = [tone1, offset, offset];
tone2 = [offset, tone2, offset];
tone3 = [offset, offset, tone3];
soundsc(tone1+tone2+tone3, sr)