Why are D-sharp and E-flat considered to be two different notes

Why do the black keys on the piano each have two different names? If the posts on r/musictheory are any indication, this is a persistent point of confusion, especially when music theory teachers get all persnickety about using the correct name. This confusion applies to all of the black keys, but in this post, I’ll be …

Why can’t you tune your guitar?

Short answer: because math. Longer answer: because prime numbers don’t divide into each other evenly. To understand what follows, you need to know some facts about the physics of vibrating strings: When you pluck a guitar string, it vibrates to and fro. You can tell how fast the string is vibrating by listening to the …