Beginner Guitar Lesson OnLine
Music Theory 102
Lets Roll up Our Sleeves and Get Down on Some Theory!
Now let's take a look at the 1/2 tones or steps and whole tones or steps in this key based on Figure "A" Below...
We have all 12 notes in naturals and sharps to illustrate this... Notice on the top, between each 1/2 tone is labeled 1/2 step. Below is labeled the distance between each natural, which is what the key of "C" is based on. The steps between naturals are 1..1..1/2..1..1..1..1/2. That is 2 half steps and 5 whole steps. Also look at the order first (2) wholes, next (1) 1/2, then (3) wholes and last (1) 1/2 step.
In Figure "A", we striped away the sharp notes and just left the naturals, which is what the key of "C" is comprised of: See the pattern? 1..1..1/2..1..1..1..1/2 This is 6 total 1/2 steps or tones and 12 1/2 steps or tones.
This pattern is very important. Why? Because EVERY scale has the exact same amount of 1/2 and whole steps and in that exact order - Memorize it!
Now lets apply this rule to a different Key - say the Key of "D". We would write the scale the same. Start with a "D" and End with a "D":
Right? No, not at all. Because the scale has to conform to the 1..1..1/2..1..1..1.2 pattern, we cannot use all naturals. We have to alter or augment certain notes to "force" them into the pattern. Why? Because it is a rule and this one can't be broken.
Remember that there is 1/2 step between E and F and between B and C naturally? In order to "force" the pattern we have to make the F sharp and the C sharp. The "D" scale would then look like this:
Does that meet our "set in stone" pattern? Lets take a look...Refer To Figure "C" Below
In this illustration again, we list ALL the notes so we can set all the 1/2 steps on the top and our 1..1..1/2..1..1..1..1/2 rule below the notes. Notice how we have to make the F and C notes sharp to make the rule work?
Let's strip away the notes that don't meet the rule and it will even be clearer.. Refer To Figure "D" Below.
How about one more? We will make it really difficult this time, but by living by this rule you can simplify it very much. Lets select a key from our list... Lets go with say Ab? Ok remember the scale begins and ends with the note Ab. Hmmm this isn't looking good already!
Alright let's write down all 12 notes: Refer To Figure "E" Below.
Again we will refer to the illustration...
This time, since this is a "Flat Key" we will list the notes as flats rather than sharps so as not to confuse you....
Apply our rule to the scale.. Refer To Figure "F" Below.
And strip away the notes that don't meet the rule. There you have it, the Key of "Ab" or A-Flat. It has for flatted notes the Ab, Bb, Db and Eb, and the key bears the name of the first note in the scape Ab.
Alright, so that is the rule and you can apply it to all 12 scales, and to meet the rule, we learned that certain notes have to be augmented to meet the rule.
Here is the complete list of keys and how many sharps or flats each has to have to meet the rule.