Intervals Part one Lesson by flyinglibra51

Two types of intervals exist

A Harmonic Interval is when you play two notes at the same time.
A Melodic Interval is when those two notes are played one after the other.

The identity of an interval is determined by two things.
1. Quantity
2. Quality

The Quantity (or number size) of an interval is based on the number of
lines and spaces contained by the interval on the music staff.
Unison (Prime)
Second
Third
Fourth
Fifth
Sixth
Seventh
Octave 

Determine quantity by adding up the lines and spaces, including those
taken by the notes. Accidentals don't count.

---------

---------
    
----x----5
         4  EXAMPLE
---------3
         2
----x----1

Melodic Intervals

-----------------------------------|
                                x  |
-----------------------------x-----|
                         x         |
---------------------x-------------|
                 x                 |
-------------x---------------------|
        x                         |
-x--x---x----x---x---x---x---x---x-|
unison  2nd  3rd 4th 5th 6th 7th Octave

If the Interval spans more than one Octave, it is called a 
COMPOUND INTERVAL (example)

------------------
          X       10
------------------9
                  8
------------------7
                  6
------------------5
                  4
------------------3
                  2
        --x--     1
         10th

Quality, considers the half steps.
Interval quality is based on the number of half steps from one note to 
another. Unlike the interval quantity, accidentals ( sharps and flats)
which raise and lower a pitch by a half step, do matter in quality.
Quality is what gives the interval it's distinct sound.

Each of the intervals below have the exact same quantity but they sound
different because each has a different quality.

--o---#o---#0---bo---bo--
--o----o---b0---#o----o--

The terms used to describe quality and their abbreviations are below.

MAJOR (M) contains two half steps between notes
minor (m) contains a half step between notes
PERFECT (P) refers to harmonic quality of unison, octave, 4ths and 5ths
Diminished (dim) has a half step less than a minor or perfect interval
AUGMENTED (aug) has a half step more than a major or perfect interval

Naming Intervals

Every interval gets it's name from the combination of both the quality
and the quantity of the interval. For example, you may encounter a 
MAJOR 3rd or a PERFECT 5th. Here are the possible combinations that you use to describe intervals.
PERFECT (P) can only be used with Unisons,4ths, 5ths and octaves.
MAJOR (M) and minor (m) can only be used with 2nds,3rds,6ths, and 7ths.
Diminished (dim) can be used with any interval except unisons.
Augmented (aug) can be used with any interval.

next time more about Unisons, Octaves, 4ths and 5ths

flyinglibra51
God Bless Glen Travis Campbell