Create a time delayed cosine function

I have a signal that I'm trying to output as sound that looks like this

ts=0.0001;   %sampling rate
n=[0:1057];  %number of samples 
t7=4.26:ts:5; %time in seconds to play
c4=261.626; %note frequencey
ynote7=cos(2*pi*c4*t7); %cosine function
sound(ynote4,1/ts,16) %plays the sound from 4.26 sec to 5 sec

but the note plays immediately with no time delay, and I have no clue what I'm doing wrong with this

Answer 1

[Kai Domhardt]

Your signal starts with the cosine wave, you will need to define the signal for 0 sec to 4.26 sec.

ts=0.0001;
freq = 261.626;
amp = 0.1; %in case somebody tries this without checking their speakers.

empty_signal = zeros(1,5/ts)
sound_signal = cos( linspace( 0, 2*pi*freq, (5-4.26)/ts ));
delayed_signal( end-length(signal)+1 : end ) = sound_signal;

sound(delayed_signal * amp, 1/ts)

[Wes Madere]

Can you tell me what's going on with

empty_signal = zeros(1,5/ts)
sound_signal = cos( linspace( 0, 2*pi*freq, (5-4.26)/ts ));
delayed_signal( end-length(signal)+1 : end ) = sound_signal;