<p>I have to say that ear training was the hardest part of my musical education. At the school where I attended we took 3 credit classes in Music Theory (1-4) and 1 credit classes in Sight Singing and Ear Training (which we called Sight Screaming and Ear Straining). Some schools offer Music Theory as a series of 4 credit classes which includes theory, sight singing and ear training. </p>
<p>I got straight As in theory, but struggled with the ear training where I got mostly Bs (one C+). I am a very good musician but I really struggled with the ear training part of my degree. I would say that if the OPs son wants to be a music major/minor he will have to take these classes. All music related majors/minors will require these classes as part of the core curriculum.</p>