MATLAB: Distortion when hiding a signal inside another signal

Question

Im trying to hide a signal (hidden signal) inside another signal (main signal), both are sounds. first I applied a low pass filter to each signal, pi/8 for the hidden and pi/4 for the main, and i multiplied the hidden signal with 0.01*cos(2*pi*n/4), after that I add the two signals and i play the sound of the combined signals, the problem is that the total signal has alot of distortion and the main signal is played twice, but it did succeed to hide the other signal, how to I improve my code ?

this is my code:

%%% Data Hiding

[y0,Fs0]= audioread('Main Signal.wav');

y0=y0(:,1);

[y1,Fs1]= audioread('Hidden Signal.wav');

y1=y1(:,1);

T0=length(y0)/Fs0;

T1=length(y1)/Fs1;

t0=-T0/2:(T0/length(y0)):(T0/2-(T0/length(y0)));

t1=-T1/2:(T1/length(y1)):(T1/2-(T1/length(y1)));

w1=pi/8;

h1=(w1/pi)*sinc(w1/pi*t1);

y2=conv(y1,h1);

Y1=fftshift(fft(y2));

wy=(-length(Y1)/2:length(Y1)/2-1)*48000/length(Y1);

y1=ifft(Y1);

t1=-T1/2:(T1/length(y1)):(T1/2-(T1/length(y1)));

y1=y1*0.01.*cos(2*pi*t1/4);

Y1=fftshift(fft(y1));

w0=pi/4;

h0=(w0/pi)*sinc(w0/pi*t0);

y0=conv(y0,h0);

t0=-T0/2:(T0/length(y0)):(T0/2-(T0/length(y0)));

Signal_Total=[y0 zeros(1,length(y1)-length(y0))]+y1;

Answer 1

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