Term 2 Theory Lessons & Quiz
4 Major and Minor Intervals
In Grade 7, we learned how to name an interval based on its distance. When counting an interval, you need to start with the note you are on and count up.
This is a fourth. If you start on the bottom one as 1 and then count up each line and space until you reach the top note, you will have 4 counts.
Major and Minor Intervals
We can also name an interval by its quality. You may have heard of major and minor scales before. Intervals can also be major or minor. They can have other qualities too, but we will not be studying that this year.
You can determine the quality of an interval two ways: using semitones and using key signatures. The method using semitones is technically easier, but there is a lot of memorization involved. If you are confident with your key signatures, you may want to use that method because it's a bit faster. If you are still unfamiliar with key signatures, then you may want to stick to the semitone method. The choice will be up to you. Both methods will be explained here.
Once you have determined the distance (2nd, 3rd, 4th, etc.) of an interval, you can count the number of semitones between the two notes to determine whether it is major or minor.
A major second is made up of 2 semitones. You can see them on the keyboard to the right. Every major second, regardless of what note it begins on, will be 2 semitones apart.
A minor second is made up of 1 semitone. You can see that on this keyboard. The minor second is 1 less semitone than the major.
A major third is made up of 4 semitones. They are numbered on the keyboard. E to G# is a Major 3rd. C to E is also a Major 3rd.
A minor third is made of 3 semitones. That is one less than a major 3rd. You will see this same pattern throughout - a minor interval will always be one less semitone than its major.
Here is a chart which shows the intervals and number of semitones that you will be required to know for your theory quiz. The cells that are greyed out, you do not need to know.
You can see on this chart that some intervals are called "major" and some are called "perfect." Unison, fourth, fifth, and octave intervals are called perfect instead of major. This is because way, way back in the olden times of music, those intervals were thought to have the perfect consonant sound for harmony. For centuries, harmonies using unison, 4th, 5th, and octave intervals were the only ones allowed in sophisticated church music. Other intervals like seconds, thirds, and sixths were thought to have a rough and displeasing sound and were inappropriate for important sacred music. We don't really believe that today, but we still hang onto the old names for tradition's sake. You will never see a "major fourth" written as an interval - it's always called a "perfect fourth." Likewise, a "major seventh" would never be called a "perfect seventh." Even though major and perfect mean the same thing in this case, that's just the way it's done.
Key Signature Method
If you are very familiar with your key signatures, then you may use this method for determining the quality of an interval.
Step One - Look at the bottom note of the interval. What key is that? What is the key signature Which notes are flat and sharp?
"The bottom note is C. The key signature of C major contains no sharps or flats."
Step Two - Look at the top note of the interval. Does this note follow the key signature?
- Yes! This interval is major (or perfect).
- No! If the note is a semitone lower than it should normally be in that key signature, then it is a minor interval.
"In the key of C major, the note A should be a natural. The top note is an A natural, so this is a major sixth."
You can see that knowing your key signatures makes this process quite simple. No counting involved. Let's try a couple more.
The first interval starts on a C. We already know that the key signature of C major has no sharps or flats. The top note, B, fits in perfectly with the key signature of C major. That means the first interval is a major seventh.
The second interval starts on a D. They key signature of D major has 2 sharps: F# and C#. The top note of this interval is a C natural. According to the key signature of D major, there should be a C#. The top note of this interval is only C natural though and that's a semitone lower than C#. That means this interval is a minor seventh.
In Grade 8, you will only be required to identify intervals that start on C, G, and F. Even if you are not very confident with key signatures, you should be able to remember the key signatures of those 3 keys.
Here is an exercise to help you practice naming major and minor intervals in those keys:
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