Why don’t some songs fit in any key?
Why don’t some songs fit in any key? Are other scales used to make guitar chord progressions and songwriting? How do songs change key and how should a guitarist play over key changes? Do complex songs still emerge from common guitar music theory or are there different types of theory for different types of music styles and songs?
Anything goes in the world of musical composition. Many artists play solely by ear, putting together ideas through trial and error. But there are fundamental concepts that underlie all music such as scales, chords, progressions, modes, etc.
If a song doesn’t fit in one key, then it’s a combination of different keys. This is sometimes thought to be borrowing elements from other keys. In this case, you need to split the song and separate it into parts that fit in one key.
Another possibility in this type of situation is the use of scales beyond the common pentatonic and major scale patterns. For example, the harmonic minor and melodic minor scales. But first you need to understand pentatonic and major scale theory, as advanced concepts are derived from them.
Going through this problem to understand song construction is usually not necessary in styles that don’t require much melody or harmony. For example, some heavy metal riffs are simply based on chromatic movement or rhythmic noise. It can be a bit pointless trying to connect these things to some kind of structured music theory for guitar.
