How will i show faults in engine using a healthy sound and faulty sound?

engine=audioread('engine.mp3');

defect=audioread('defect.mp3');
plot(engine(1:10000,1));
hold on
plot(defect(1:10000,1));

[KSSV]

Did you find any significant differences in the plot? May be a FFT of the data also helps.

[Anna Gerald]

i want to show that the audios are not same. how will i compare both the audio?