intervals...

[dark_chocolate]

i've read some explanation about this subject, but I still don't understand,what should I do to know the interval name between two notes...Can I find the interval based on the chord?For example, there are G and B,the interval between the two notes is major 3rd because B are the third notes of G major chord..
Please help me..

[counterpoint]

Intervals are counted from the (diatonic) scale:

C-C prime
C-D second
C-E third

and so on

[danny elfboy]

i've read some explanation about this subject, but I still don't understand,what should I do to know the interval name between two notes...Can I find the interval based on the chord?For example, there are G and B,the interval between the two notes is major 3rd because B are the third notes of G major chord..
Please help me..

The best way to determine intervals is using the C major scale as an archetype
So when you encounter an interval you first analyze it in relation to the C major scale

Therefore:

C - E = Three notes in the C major scale hence a third
C - G = Five notes in the C major scale hence a fifth
C - B = Seventh notes in the C major scale hence a seventh

Now you must remember these rules when you count the amount of notes that form an interval IN RELATION TO THE C MAJOR SCALE
In other words "you must consider the interval at its natural (without accidentals) state)

The 2nd is major when there's NO semitone and minor when there's 1 semitone
The 3rd is major when there's NO semitone and minor when there's 1 semitone
The 4th is always perfect
The 5th is always perfect
BUT (F - B = 4th augmented / B - F = 5th diminished)
The 6th is major when there's 1 semitone and minor where there are 2 semitones
The 7th is major when there's 1 semitone and minor when there are 2 semitones

The you must also remember that intervals are read from the bottom note to the top note and when there's a sharp (#) in the upper note the interval becomes larger by 1 semitone and when there's a flat (b) in the upper note the interval becomes smaller by 1 semitone. Inversely when there's a sharp in the lower note the interval becomes smaller by 1 semitone and when there's a flat in the lower note the interval becomes larger by 1 semitone.

The quality of the interval starts from either (minor/major) or (perfect) and follows the following scheme:

double augmented
augmented]
MAJOR
minor
diminished
double diminished

OR

double augmented
augmented]
major
PERFECT
minor
diminished
double diminished

So let's say you have this interval: G# - Eb

First you consider the interval in relation to the C major scale
G - A - B - C - D - E
That's 6 notes hence it is a sixth

Is it major or minor?
How many semitones are in a G - E on the major scale?
The only semitone you have in G - E is B-C hence it's 1 semitone hence it's major

Now you add the accidentals
You have a flat in the upper note hence the interval becomes smaller by 1 semitone
Hence from a 6th major it becomes a 6th minor

The you have a sharp in the lower note hence the interval becomes smaller by 1 semitone
Hence from a 6th minor it becomes a 6th diminished

Hence the interval G# - Eb is a 6th Diminished

C - Eb

C - D - E = Third
No semitone = Major
Flat in the upper note = Smaller by one semitone
Major -- > minor

C - Eb is a 3rd minor

F# - B#

F - B = 4th augmented
Sharp in the upper note = larger by 1 semitone
4th augmented -- > 4th + augmented
Flat in the lower note = Smaller by 1 semitone
4th + augmented -- > 4th augmented

Chords are composed by intervals in this way:

Major Chord = Major 3rd + Perfect 5th
Minor Chord = Minor 3rd + Perfect 5th

Diminished Chord = minor 3rd + Diminished 5th

Augmented Chord = Major 3rd + Augmented 5th

Seventh Chord = Major 3rd + Perfect 5th + minor 7th

Major Seventh Chord = Major 3rd - Perfect 5th - major 7th

Minor Seventh = minor 3rd - Perfect 5th - minor 7th

Sixth Chord = Major 3rd + Perfect 5th + Major 6th

Suspended Chord = Perfect 4th + Perfect 5th


Hope this helps

[mike_lang]

In semitones, from a non-contextual aural standpoint:

1 (i.e., C to Db) : Minor second
2: Major second
3: Minor third
4: Major third
5: Perfect fourth
6: Tritone
7: Perfect fifth
8: Minor 6th
9: Major 6th
10: Minor 7th
11(i.e., C to B) : Major 7th

[counterpoint]

It's important to say, that the position of the note heads define, which intervall it is.

Some examples:   

F - G#      that's a second (!),  the exact difference is 3 halftones, so it's an augmented second

F - Ab       that's a third, the exact difference is 3 halftones, so it's a minor third

E# - G#   that's a third, the exact difference is 3 halftones, so it's a minor third

E# - Ab   that's a fourth, the exact difference is 3 halftones, so it's a double diminished fourth

[dark_chocolate]

Thank you for your explanation,it help me a lot.. ...but I still have few question to ask you..You said that I must measure interval from the bottom note..but how if I have to measure the interval between two note in a song?How can I decide which is the bottom note and which is the top note?Did you mean that the bottom note is the lower one?
I highly appreciate your help..thank you

[danny elfboy]

Thank you for your explanation,it help me a lot.. ...but I still have few question to ask you..You said that I must measure interval from the bottom note..but how if I have to measure the interval between two note in a song?How can I decide which is the bottom note and which is the top note?Did you mean that the bottom note is the lower one?
I highly appreciate your help..thank you

Thank you for your explanation,it help me a lot.. ...but I still have few question to ask you..You said that I must measure interval from the bottom note..but how if I have to measure the interval between two note in a song?How can I decide which is the bottom note and which is the top note?Did you mean that the bottom note is the lower one?
I highly appreciate your help..thank you

Yes, the lower note
Remember that the piano keyboard itself (the grand staff) is a speculative imagine of the choir. The lower the note in the grandstaff and the lower in the keyboard the lower the note itself is and viceversa.

So let's take the soprano part of silent night for example:



You have an F at the cleff armature and are therefore in G major
The two quarter note you see are C-E
You know C-E is three notes hence a third and there's no semitone so it's a third major

The second interval is a E-B
You know E-B is five note hence a fifth and you know it's always perfect in the C major scale and since there's no accidentals it's a Perfect Fifth

Third interval is B-A
So you know it must be considered as A-B
You know it's two notes hence a second and there's no semitone hence a Major Second

The you have A-E
Again you must read E-A
E-A is four notes hence a fourth and you know that within the C major scale (hence without accidentals) except F-B all fourths are perfect. Hence Perfect Four

Then you have E-G
You know it's three notes hence a Third
How many semitones? E-F
Hence having 1 semitone it is a minor Third

Then you have G-D
You know it is five notes hence a fifth
There's no accidentals and hence in the C major scale all fifths are perfects except B-F
Hence this is a Perfect Fifth

Then you have D-A
Must be read as A-D
It's fourt notes hence a fourth
Again no accidental and therefore a Perfect Four

Now you have A-F#
Must be read as F#-A
So first you consider it in relation to the C major scale hence without accident: F-A
You know F-A is three notes hence a Third
There's no semitone hence a Major Third
You then have a sharp in the lower note hence it becomes smaller by one semitone
Hence the Major becomes a Third minor

And so on ...

[dark_chocolate]

Oh,I see!I understand..Thank you, I think I can do those question in the theory book much better now..thanks a lot