Harmonica Theory
Hopefully by now you've got a reasonable idea of what Scales are... However, they are much more than just pretty ways of putting notes into an order that sounds nice: Scales form the basis of all music. The type of Scale can help give music it's character; hence, a tune in a Minor Scale will be sad and down, while a tune in a Major Scale is likely to be upbeat and bouncy...
Now, you are probably wondering what I mean when I say 'in a Minor Scale'? Basically it means that the tune in question is written/played using only (or mainly) the notes present in a particular Minor Scale... So if I was to say that a tune is 'in A Minor', it means that it only consists of the notes in the Minor Scale of A (and maybe a few different ones here and there for musical colour), i.e. A, B, C, D, E, F, G. The Scale is like the 'musical alphabet' of a tune. Because the Scale is like the 'foundation' of a tune, it is the main source of character and style for the music...
Chords
You may have noticed that the notes in the A Minor Scale are the same as the notes in the C Major Scale... So you are probably asking 'How can two tunes, that are made up of the same notes, sound different?' That is a very good question... it is all to do with 'CHORDS' (yes, another term I'm afraid...). Now, you don't need to understand Chords completely to play the harmonica, but just for the record here's a very brief explanation of what they do:
Chords usually form the background harmony of tunes; in piano-playing, Chords (and derivatives thereof) are usually played with the left hand, and the melody is usually played with the right hand. The result is that the melody is blended in with the Chords that correspond to the Scale that the tune is written in. So a tune written in C Major will usually include a Chord taken from the C Major Scale (i.e. THE CHORD IS MADE UP OF NOTES FROM THE SCALE), and this will emphasize the character of the tune (using the C Major Scale as the basis). The simplest C Major Chord is C, E, and G all played at the same time... If you play this Chord you will see that it is typical of the Major Scale (i.e. it sounds 'agreeable'); with Chords like this being played along with a melody it will easily sound 'upbeat' and is unlikely to accidently end up sounding like a tune written in A Minor.
This is all general detail, but it must be understood that Scales and Chords are ribs and spine of harmonica playing, so much so that they form the basis of where the notes are on a harmonica...
Harmonica History
In 1821, a very young man (of age 16!) called Christian Friedrich Buschmann registered the first European patents for his new invention. His so-called 'Aura' was a free-reed instrument consisting of a series of steel reeds arranged together horizontally in small channels. Early designs by Buschmann were widely imitated, leading to many modifications and advancements: Around 1826, a Bohemian instrument maker named Richter created an instrument remarkably similar to modern diatonic harmonicas. He developed a variation that consisted of ten holes and twenty reeds, with separate blow and draw reed plates mounted on either side of a cedar comb. Most importantly, the way that the notes were arranged was exactly the same as it is today. Richter's tuning became the standard configuration of what Europeans referred to as the 'Mundharmonika' or mouth organ...
Richter (being German) was a very logical and organized musician. He arranged the notes the way he did for a very specific purpose: He planned to make it easy to play European folk and classical music on the harmonica. The Major and Minor Scales are the 'musical alphabets' of most European folk and classical music; so Herr Richter arranged the notes of the harmonica so that is would be easy to play Major and Minor Scales. For example, the C Major and A Minor Scales can be played easily on ten-hole harmonica in the key of C.
However, in order to achieve his intended layout, he was forced to leave certain notes out of the harmonica; so many notes, in fact, that players must learn to 'BEND' existing notes to supply the missing ones (more on that later).
| BLOW | C | E | G | C | E | G | C | E | G | C |
| HOLE | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| DRAW | D | G | B | D | F | A | B | D | F | A |
You can probably tell from the diagram above that almost all the notes needed, to play three complete octaves of the C Major Scale and several octaves of the A Minor Scale, are present on the C harmonica. Plus the layout is such that if you blow into any three holes in a row you end up playing the C Major Chord. Not only that, by drawing on holes 1,2, and 3 you produce the G Major Chord (the 2nd Inversion - this detail isn't important, but you can see the next section for an explanation if you want), and by drawing on holes 4,5, and 6 you produce the D Minor Chord. By doing this it was Richter's intention to create as much versatility as possible in his small, metallic instrument...
The harmonica came to America during the American Civil War. And after the war many of the former slaves searched for an inexpensive and portable instrument to let out their rich musical heritage. But the kind of music that African-Americans played was very different to the European folk and classical music that the harmonica had been designed for: Their music was a very rhythmic and vocal sort with strong emotion and runs of improvization. Plus the notes they prefered to sing were in between the Major and Minor Scales; notes that could be easily sung but were impossible to play on the piano without special tuning (you could almost say that they were in the cracks between the keys!). The notes sung also tended to be warbled and slurred, which was definitely impossible on the piano - what was needed was an instrument that could be controlled by the same muscles that controlled the voice.
After many years of trial and error, a new Scale evolved. It had only seven notes and was a fusion of both the Major and Minor Scales. It was lovingly called the 'BLUES SCALE'. This new Scale, and a new Chord structure called the 'TWELVE BAR BLUES STRUCTURE' (more on that later), merged to form a brand new musical style that combined the emotion of traditional European music, the rustic tones and rhythms of African music, and the creativity of American music - 'THE BLUES'.