What Key Is This Tune In? Which key harmonica to use?
You’re listening to a tune or you get up to sit in with a band – what key is the tune in?
Most pieces of music have a centre, home or key-note. It’s the note that the piece gravitates to. We hear “Blues in F”, “Key of A minor”, “Scale of C”, “Chords in Bb” etc. All these phrases come from the fact that tunes are built from scales and chords are built from those scales i.e. the scale and chords relate to each other.
The most popular tunes in Western music are built on three different scales – major, minor and blues. This is a simplification but harmonica players are most likely to meet these scale-types in tunes.
Whichever scale a tune is based on there will be a home or key note. Many start on this note and most finish on this note. A major tune like ‘Twinkle, Twinkle’ in G major could use G, C and D chords but the centre is G or the I chord built on 1st, 3rd and 5th notes of the G major scale. (Roman numerals are used to describe chords and their place in the scale.)
‘Summertime’ in A minor starts on an E note but the A minor chords and it’s relationship to the other chords especially E7 creates the key centre.
A blues song like ‘Sitting On Top of the World’ if played in G would use a G minor blues scale and work over G7, C7 and D7 as basic blues chords. Here the I chord is G7 with it’s characteristic blues sound.
Very often these differing tunes will end on the key or home note. There is also a very strong ‘signpost’ chord that points to the home note. This chord is built on the 5th note of the scale (V) and is called the Dominant. With the added 7th it becomes an even stronger draw to the centre of the scale. The Dominant 7th chord works the same way in Major, Minor or Blues tunes and invariably precedes and points to the I chord.
So, listen for the centre of a tune and try to hear where it’s going. Having some understanding of the common ‘maps’ that form songs will also help you hear where things are going.
To summarize: you need to find the home or key note. Listen for the last note of the tune or the dominant(V) chord resolving to the I chord. Try to sing this note and then play it on your harmonica – it will be hole 1 blow in 1st position. For cross harp blues (2nd position) the keynote will be hole 2 draw or hole 3 blow.
Good luck and keep your ears open!
Paul Lennon 9.7.2013