Whats next after FFT? signal comparison

Hi i want to compare two signals one is record the other will be played then recorded.

recObj = audiorecorder;
    disp('Start speaking.')
    recordblocking(recObj, 4);
    disp('End of Recording.');
    myRecording = getaudiodata(recObj);
    wavwrite(myRecording,'chordread.wav');
    [x, Fs] = wavread('chordread.wav');
    [x1, Fs1] = wavread('chordA.wav');
    Y = fft(x);
    Z = fft(x1);

now I have the data Y and Z how can i compare them? i wanna know if the input signal is chord A of a guitar...