Help with sound function

Hello!

I'm working on a project, and my ideia is shows that human ear cannot differentiate phase. I've alreay seen someone making this using matlab, and I'm tryng to replicate it, But somehow it's not working as I expected.

Here is my code:

load train;
X = y;          % X is now the traun sound


Fs = 8192;      %Sampling frequency, same as the loaded sound
T = 1/Fs;       %Sampling period
L = length(X);  %Lenght of signal
t = (0:L-1)*T;  %Time vector        
Y = fft(X);     %

randY = rand_angle(Y); %Here i use a function that i have created to randomly change the angle, but not change the absolute

Y1 = ifft(Y);
Y2 = ifft(randY);

Here is the rand_angle function:

function y = rand_angle(x)

vetor = x;
n = length(vetor);
vetor1 = zeros([n,1]);

for j = 1:(n/2)
    
    if j == 1
        
        vetor1(j) = vetor(j);                
        vetor1(n/2 + 1) = vetor(n/2 + 1);
        
    else
        
        k = rand * 2 * pi;
        
        vetor1(j) = abs( vetor(j) )* exp( 1i * k );
        vetor1(n + 2 - j) = abs( vetor(j) ) * exp(-1i * k );
    end
    
    
end

y = vetor1;

That funcion is based on this post: https://www.mathworks.com/matlabcentral/answers/451578-fft-and-ifft-random-phases

Ok, now when I try

sound(Y)
sound(Y1)
sound(Y2)

I expected that the 3 functions results on the same sound, but its not what is happening. I dont know if my premise that "human ear cant differenciate phase" is wrong, or if there is something wrong on my code. Hope someone can help. Thanks!

[Walter Roberson]

http://www.earlevel.com/main/1996/10/21/a-question-of-phase/