Do you want to get a better understanding about audio circuits and loudspeaker designs? Then check out the free online course “Fundamentals of Audio and Music Engineering” on Coursera.
During this 6 week course you will learn the basic concepts of acoustics and electronics and how they can applied to understand musical sound and make music with electronic instruments. And you can even earn a certificate.
You don’t care about the technology and the technology, but love music? Then you might be interested in History of Rock – also brought to Coursera by the University of Rochester.