How can i record with a microphone?

I'm working on a program that have to make a noise reduction. The audio in input arrives, in theory, from an external microphone. The record will be convert in a Wav file and then I can work on it. The problem is when I record, because I don't know where the audio come from. I have always the same wave form.

    fprintf('-> Step 1/5 Registrazione file: \n\n');
    recOg=dsp.AudioRecorder ('OutputNumOverrunSamples', true);
    rec=dsp.AudioFileWriter('prova.wav', 'FileFormat', 'WAV')
    disp('Stai registrando');
    fprintf('\n');
    tic;
    while tic<5
      [audioIn,nOverrun] = step(recOg);
      step(rec,audioIn);
      if nOverrun > 0
        fprintf('La registrazione ha sforato di %d samples\n'... 
            ,nOverrun);
      end
    end
    release(recOg);
    release(rec);
    disp('Fine della registrazione');

This is the part of the code where I acquire the audio file

[Walter Roberson]

These days you would use https://www.mathworks.com/help/audio/ref/audiodevicereader-system-object.html instead of dsp.AudioRecorder.

Answer 1

[Piyumal]

fprintf('-> Step 1/5 Registrazione file: \n\n');
recOg=dsp.AudioRecorder ('OutputNumOverrunSamples', true);
rec=dsp.AudioFileWriter('prova.wav', 'FileFormat', 'WAV')
disp('Stai registrando');
fprintf('\n');
tic;
while tic<5
    [audioIn,nOverrun] = step(recOg);
    step(rec,audioIn);
    if nOverrun > 0
        fprintf('La registrazione ha sforato di %d samples\n'... 
            ,nOverrun);
    end
end
release(recOg);
release(rec);
disp('Fine della registrazione');

[Walter Roberson]

This appears to be the same code that was posted by @Matteo Nava without any changes.