Finding the key of songs
Question by Ankit Raj
Question: Can you please share some ways to find out the key of the songs and how to find out the chord progressions by using melody lines in scales.
In most rock and pop music, you can find the key of the song by identifying the first (and often final) chord in the verse (although the key may change for the chorus). However, key isn't always dependent on these chords, because you can start a song on a chord that later resolves to the tonic (home) chord of the key.
The key is defined by the chord that brings your chord journey home. For example...
G major - A minor - D major - G major
G major is clearly the key of that progression because it marks the beginning and end AND it sounds resolved, like we've returned home.
So a lot of this is about training your ear to hear these resolutions because resolution is an integral part of what gives songs a key centre (whether major or minor).
There are a few sections on this site that look at the theory behind key, the main one being the chord progressions section. In that section you can learn the theory behind "chord scales" and how the tonic (root) chord of this scale defines the key.
Building Chord Progressions from Scales
This is something I've just started adding to the site for each scale in the scales section.
E.g. Natural minor scale chord progressions - looks at how to build and identify chord progressions suitable for using the natural minor scale.
At first it'll seem complicated, but all we're really doing is using the intervals of a given scale and building chords on each one. The intervals then become root notes for the chords we build.
However, you need to know which chord to build on which degree (major, minor, diminished etc.) so my lessons should help break that down for you.
Once you've spent time learning these chord scales, you'll be able to hear them being applied in songs. For example, take this common chord sequence...
G D Em C (I V vi IV)
That sequence was taken straight from the major scale. The G major tonic was built on the root, D major on the 5th degree, E minor on the 6th and C major on the 4th.
And this sequence can work in any key, just like the major scale can, which is why we use Roman numerals to represent chords built on these scale degrees.
Anyway, as you can see, this stuff is slightly more advanced theory, but spend time going through the scales section on this site and the bigger picture will gradually become clearer.