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Help with sound function

Asked by David Daminelli on 1 Jun 2019
Latest activity Commented on by Walter Roberson
on 2 Jun 2019
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;
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!

  1 Comment

Walter Roberson
on 2 Jun 2019
http://www.earlevel.com/main/1996/10/21/a-question-of-phase/

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