I want to get FFT of a live sound stream on guide, i have used following code to initialize a sound devise in MATLAB

d = daq.getDevices ;

dev = d(2);

handles.s = daq.createSession('directsound');

addAudioInputChannel(s,dev.ID,1:2);

handles.s.isContinuous = true;

handles.s.Rate =8000;

handles.NotifyWhenDataAvailbleExceeds = 4000;