There are 12 keys in music. And you can shift (transpose) a song to play any to them, as I explain in this video:
https://youtube.com/live/kKJG4_3hego
On the guitar, key changes are relatively easy using a capo. You just clamp the device onto the instrument’s neck and then play chord shapes to alter the pitch ... where the higher you rise up the fretboard, the higher the pitch.
Or at least this is how most guitarists transpose a song — mindlessly using the capo like a crutch, and never really understanding the underlying theory behind each key change.
If this hits a little close to home, don’t feel too bad. According to legend, famed composer, Irving Berlin, did this too. Only he played the piano. So the process was more involved. It’s said he had a special keyboard made that allowed him to play everything in the key of F# … mechanically moving the piano’s hammers to shift into any key by operating a crank.
But you don’t need to live this way — ignorant to the real theory at play behind key changes.
It turns out, it all pretty easy to understand transposition (a.k.a., the art of changing keys) using the circle of fifths. To illustrate, here are the diagrams that accompany the video. It’s the song, “Can’t Help Falling in Love," in three different keys….
The result is a visually complex system of blotches and squiggles that’s confusing and even counterintuitive.
