Save stereo audio file

When using

player = audioplayer(y, fs);

This sounds stereo, as intended:

play(player) % sound stereo OK

But after saving a file to disk, stereo seems to be lost and both channels mixed:

audiowrite(filename, y, fs);

Is there anyway to overcome time?

[Walter Roberson]

audiowrite(filename, y, fs); should be okay provided that y has 2 columns.

Answer 1

[Star Strider]

Testing those functions, they both appear to be working correctly —

Fs1 = 44100;
L1 = 2;
t1 = linspace(0, L1*Fs1, L1*Fs1+1).'/Fs1;                                        % Column Vector
s = [sin(2*pi*t1*1E+3)  sin(2*pi*t1*2E+3)];                                      % Sound

audiowrite('Test.wav', s, Fs1)

[y, Fs2] = audioread('Test.wav');
t2 = linspace(0, size(y,1)-1, size(y,1)).'/Fs2;

figure
tiledlayout(2,1)
nexttile
plot(t1, s(:,1), '-', 'LineWidth',2)
hold on
plot(t2, y(:,1), '--', 'LineWidth',2)
hold off
grid
xlim([1 1.1]*1E-2)
title('Left Channel')
nexttile
plot(t1, s(:,2), '-', 'LineWidth',2)
hold on
plot(t2, y(:,2), '--', 'LineWidth',2)
hold off
grid
xlim([1 1.1]*1E-2)
title('Right Channel')

It might be appropriate to check to be certain that your audiocard drivers are up-to-date and that your audiocard is working correctly. You can use this code to check it.

.

[An]

You are right; I must have been doing something wrong. Worked fine.

Simplified your code a bit and Tested stereo sound with:

% testwav
Fs = 44100; % sample frequency (points per second)
duration = 5; %seconds
t = linspace(0, duration, duration*Fs)'; % Column Vector

f1 = 440; % frequency 1
f2 = 442; % frequency 2

s1 = sin(2*pi*t*f1);
s2 = sin(2*pi*t*f2);

nil = zeros(size(s1));

% build test: left ear, right ear, both ears
% generating a 2Hz binaural beat in the last 5s of audio
ba = [
    s1 nil;
    nil s2; 
    s1 s2;
    ];

audiowrite('Test.wav', ba, Fs)

[Star Strider]

Thank you!