A function to control audio volume directly is not available as of MATLAB R2015a.
As a workaround, you can modify the value of the signal data to control volume. Please see the code below for an example:
load handel; % 'handel' is a MAT-file which is shipped with MATLAB as an examplex = y/5; % Decrease volumeplayer = audioplayer(x, Fs);
play(player,[1 (get(player, 'SampleRate')*3)]);
x = y*5; % Increase volumeplayer = audioplayer(x, Fs);
play(player,[1 (get(player, 'SampleRate')*3)]);
As an additional workaround, you might try using the File Exchange submission called "SoundVolume", which sets or gets the computer system's speaker sound volume using Java. This submission can be found at the following link:
