GENERALIZED CROSS CORRELATION xcorr of TWO SIMULTANEOUSLY RECORDED AUDIO SIGNALS!

Question

Ali Soban 2018-1-15

0
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https://ww2.mathworks.cn/matlabcentral/answers/377270-generalized-cross-correlation-xcorr-of-two-simultaneously-recorded-audio-signals

Hi everyone! I'm trying to record two audio signals simultaneously and estimating the angle of sound source using the following code:

if true
fs = 48000 ; 
recObj1 = audiorecorder(fs, 16, 1, 1);
recObj2 = audiorecorder(fs, 16, 1, 2);
record(recObj1);      % recording starts
record(recObj2);       % recording starts
pause(5);                % recording for 5 seconds
stop(recObj1);           % recording stops
stop(recObj2);            % recording stops
out1 = getaudiodata(recObj1, 'int16');
out2 = getaudiodata(recObj2, 'int16');
[c, lags] = xcorr(out1, out2);
[a1, b1] = max(out1);
[a2, b2] = max(out2);
[a3, b3] = max(c);
s = lags(b3);
time_delay = s/fs ;
dis = 1 ; % distance between two microphones in meters
c = 342 ; % avg speed of sound at room temperature
   angle = acosd((time_delay*c)/dis);         % calculation of estimated angle
end

But the lags or time_delay is always different whenever I run the program again. IS it the right way of angle estimation using Cross Correlation function in MATLAB ? Please help if there is an efficient way of estimating the angles through slight changing or modification The sounds are being recorded by using 02 external USB microphones . Thank you!