ishitaisha6840 asked . 2021-02-18

Why Cross Correlation (xcorr) of Two simultaneously Recorded Audio Signals Always return randomly different lags?

   if true
  fs = 48000 ; %sampling frequency in Hz
  recObj1 = audiorecorder(fs, 16, 1, 1);
  recObj2 = audiorecorder(fs, 16, 1, 2);

record(recObj1);
record(recObj2);

pause(5);         % record for 5 seconds simultaneously 

stop(recObj1);
stop(recObj2);

out1 = getaudiodata(recObj1, 'int16');
out2 = getaudiodata(recObj2, 'int16');

    L = out1 ;
    R = out2 ;

t1 = (0:length(L)-1)/fs;
t2 = (0:length(R)-1)/fs;

figure;

plot(t1,L);
figure;
plot(t2,R);
 threshold = 100;

k=1;
win =200 ;
[k max(L) max(R)]
if max(L)>th && max(R)>th     %set power threshold

[c, lags] = xcorr(L, R);
[a1,b1] = max(L);
[a2, b2] = max(R);
[a3, b3] = max(c);
s = lags(b3);   
time_delay = s/fs ; 
disp(time_delay);
 s = abs(s);            % taking absolute of s

disp('Estimated angle');
 c = 342;       % avg speed of sound at room temperature
dis = 1 ;       % mean distance between the two microphones                 
cal = ((time_delay*c)/dis) ;
if cal<-1
cal=-1;
elseif cal>1
cal=1;
end
ang =((acosd(cal))

disp(ang);     %displays the angle of sound source due to these microphones

    end

matlab , signal , signal processing , simulation