what is the highest level of education in terms of sound engineering?

Hi Johnsy, a career in Sound Engineering probably doesn't require an advanced degree if you want to work in a studio. The more you know about computer science and programming, the better off you'll be. Look for certified programs that give you a lot of hands on experience.  If you are musically included, you'll have an advantage. Understanding music will be an asset. However, if you want to have a technical career in sound engineering i.e. designing audio equipment etc, then you would want to aim for a Masters degree in Electrical Engineering.  All that being said, I received a BS degree in Audio Recording. the degree consists of 1/2 music classes and 1/2 Electrical Engineering classes. The Engineering classes open you up to a much wider choice of jobs.

It really depends on the type of engineering but in my experience a Masters is all you will need and maybe not right away. Getting anything higher is nice but is really for someone who wants to go into the theoretical field and research.  That being said I recommend getting some life experience before going for the Masters.