Why A-Sharp is Not B-Flat

I've talked before about note naming but because I was recently IMing with a friend about why A♯ != B♭ I've been thinking about a simpler way to explain it. It also explains why you can have double flats and double sharps (leading to 35 possible note names for 12 different pitches). Here goes...

So, imagine you're in the key of Gm. The diatonic notes are: G A B♭ C D E♭ F. What does A♯ mean? It means you've taken the second note of the scale and raised it. What does B♭ mean? It means the third note of the scale.

In 12-tone equal temperament, they may sound the same; you may play them the same on the piano or the guitar. But if the function of the note at a particular point in the piece is as the third note in the Gm scale, you can only write it B♭ and not A♯. A♯ means something completely different.

It's the musical equivalent of "hear" versus "here". Just because they are homophonic doesn't mean they are the same word. Similarly, in western tonal music B♭ doesn't mean the same as A♯.

The original post was in the category: music_theory but I'm still in the process of migrating categories over.

The original post had 23 comments I'm in the process of migrating over.