Major and Minor Third

[RonDen]

Let's see if I get this right.
Thirds are the base of all chords.
Major third is 4 semi tone
Minor third is 3 semi tone
Ron

[Nate Miller]

base of all chords in tertian harmony. Quartal harmony is based on 4ths but I'm only mentioning that to be pedantic

but yes, you have the number of chromatic steps in both 3rds right

[RonDen]

Thanks,
It seems from looking at this
the major triad 1,3,5 is the basis of everything else?? maybe
Ron

[goldenwave77]

Let's see if I get this right.
Thirds are the base of all chords.
Major third is 4 semi tone
Minor third is 3 semi tone
Ron

One thing that can be confusing in music theory in the beginning is the distinction between distances and the number of steps involved if one is counting the end points. Musicians do the former, not the latter, in labeling intervals.

For example, C to E is a major 3rd, but it contains 5 musical points, i.e. C; C #; D; D #, and E. But on the guitar C is on the third fret, 5th string, and E is on the 7th fret. So really....3 separate things going on here...(1) the name assigned to the interval: Major 3rd, (2) the distance from C to E is 4 semi-tones, and (3) the notes contained in the interval...of which there are 5, as noted above.

[JonR]

Let's see if I get this right.
Thirds are the base of all chords.
Major third is 4 semi tone
Minor third is 3 semi tone
Ron

Correct - for the two common triads anyway. The "major" 3rd is the bigger one. "Minor" just means smaller.
And that's where those two triads (at least) get their name from.
Both chords have a perfect 5th, so the 3rd is what differentiates them. No need to consider the interval between 3rd and 5th; it doesn't help, and may actually confuse the issue.

When it comes to other chord types, then other intervals enter the picture....

[Joe Dalton]

Hey Ron Den it's funny I worked it out almost the same way before going to my teacher with it. Though was still unaware of thirds at the time, just counted the steps between the notes of chords and saw a pattern.

My teacher was unsurprisingly confused by my explanation of it though.
So a chord in tonal steps would indeed be first note the root. From that 3 semi tones creates a minor third interval and 4 semi tones make a major third interval. Then the inverse is going to be true for the semi tones till you get to the fifth. So 4 on a minor 3 on a major.

The term third however comes from scales which is the better way to look at building chords. The regular major scale on C is an easy teaching tool for it so here goes.
The C major scale goes like this.

C 2 semitones D 2 semitones E 1 semitone F 2 semitones G 2 semitones A 2 semitones B 1 semitone C.
C Root/first I D second I E third I F fourth I G fifth I A sixth I B seventh

So the term third comes from it's place in the scale. Now we build a traditional chord as root > third > fifth
The variation of minor and major comes from the third.

That would be how we would explain it from a musical theory perspective. This is in my opinion one of the most fun steps in learning music because it's the first step in understanding how we build music. It's always tempting to go deep into right away but I think this should help you put your new information in the right context. From there I believe whats most important is your own curiousity and interest to explore the topic more. For fun you can see if you can add some notes from the same scale to a chord you are playing!

[JonR]

Hey Ron Den it's funny I worked it out almost the same way before going to my teacher with it. Though was still unaware of thirds at the time, just counted the steps between the notes of chords and saw a pattern.

My teacher was unsurprisingly confused by my explanation of it though.
So a chord in tonal steps would indeed be first note the root. From that 3 semi tones creates a minor third interval and 4 semi tones make a major third interval. Then the inverse is going to be true for the semi tones till you get to the fifth. So 4 on a minor 3 on a major.

Yes, but that interval is irrelevant. The 5th is called the "5th" for a reason. It's that interval from the root that matters, not the interval between 3rd and 5th.
Some people like to talk about "stacking 3rds" - which is kind of what it looks like - but the measure (and the chord structure terminology) is always from the root. The only 3rd we care about is that from root-3rd!

The term third however comes from scales

Right: it's just about counting letters, ignoring tones or semitones, sharps or flats. The semitone count then comes in to define the quality of the specific interval (major, minor, perfect, augmented, diminished).

The terms "major" and "minor", meanwhile, just mean "bigger" and "smaller", when there are only two choices (as there are with 2nds, 3rds, 6ths and 7ths).
Like chords, scales are defined (in the first instance) by their 3rd intervals, because that's the one with the most distinctive character (assuming the 5th is perfect).
A "major" scale (like a major chord) is one that has a major 3rd. (It just happens to also have major 2nd, 6th and 7th)
A "minor" scale (like a minor chord) is one that has a minor 3rd. (All minor scales - except phrygian - have a mix of major and minor among the other intervals. In melodic minor, the 3rd is the only minor interval.)

[Joe Dalton]

Hey those are great points. But when I answer questions I try to put it in a context that is relatable to the person who asked it and feeds their curiosity.

[bako]

Yes, but that interval is irrelevant. The 5th is called the "5th" for a reason. It's that interval from the root that matters, not the interval between 3rd and 5th.

Irrelevant perhaps when building a chord from a formula measured against the major scale.

From a musical standpoint, I find all relationships between the 3 notes as highly relevant.
Each interval contributes to the overall chordal sound.

[JonR]

Irrelevant perhaps when building a chord from a formula measured against the major scale.

Sure. Except "the major scale" bit is not necessary . For chord symbol shorthand, we're counting notes from a root, according to a process unrelated to the major scale of the root. The principle is just based on the most common kind of interval at each stage: major 3rd, perfect 5th, minor 7th, major 9th, perfect 11th, major 13th.
That's admittedly a little different from the classical principle, whereby a "I7" chord symbol means what we would call a "Imaj7" .

From a musical standpoint, I find all relationships between the 3 notes as highly relevant.
Each interval contributes to the overall chordal sound.

Absolutely . We're only talking chord structure principles and terminology.
In practice, a triad (with just one of each note) consists of three intervals, and the voicing and inversion will govern what those intervals are.
Meanwhile, when it comes to 7th chords, they have six intervals! (In close-voiced root position, three 3rds, two 5ths and a 7th). They all play a part in the harmony we hear.

[JonR]

Hey those are great points. But when I answer questions I try to put it in a context that is relatable to the person who asked it and feeds their curiosity.

Well I try too; but OK I do tend to lapse into Too Much Info... (see above ) Apologies for any confusion caused.

[bako]

Jon,

I say measured against the major scale because that is the starting reference for interval names within a tonal mentality. (the post tonalists use key neutral numbers/letters 0 1 2 3 4 5 6 7 8 9 T E)

Perfect Unison
Major 2nd
Major 3rd
Perfect 4th
Perfect 5th
Major 6th
Major 7th
Perfect Octave

Major 9th
Major 10th
........ 11th
Perfect 5th
Major 13th
Major 7th

Chord formulas either concur with these intervals or modify them as per details indicated within the formula.
Of course, once intervals are 2nd nature, there is no longer any need to reference a major scale.
Anyway, this is how I conceive of it.

[JonR]

Jon,

I say measured against the major scale because that is the starting reference for interval names within a tonal mentality.

Sure. My only point was that chord symbol terminology treats a minor 7th as standard rather than the major 7th in the major scale.
We take it for granted that we're using the 7 note letters of tonal music to start from. But the idea we use the major scale of the root as the basis of chord names can lead to confusion when it comes to 7ths. "C7" doesn't mean a C chord with the 7th note of the C major scale added. And "Cmaj7" is a different chord: the "maj" refers to the raising of the standard 7th, not to the triad. (I know you know all this - but I have seen confusion over it, quite often.)

[ColMc]

Just as a point of interest, I always refer to the third as part of a toggle switch.
The 3rd interval has 2 properties. It can be major or minor.
If we look at the 5th interval, there is a major 3rd and a minor 3rd.

So depending on the order of those 3rds, we are able to name the chord.

If the lower interval is a major 3rd, the interval above will be a minor 3rd.and together they make a perfect 5th.

G
min3rd.
E
maj3rd.
C

And that is a C major triad.

Now if the lower interval is a minor 3rd, then the upper interval is a major 3rd and together they add to a perfect 5th.

G
maj3rd
E
Minor 3rd.
C.
And this is a C min triad.

All the chords in the harmonised scale conform to this formula except for the last chord which is a diminished and
and has 2 minor 3rds.

So now you can see how they toggle between major and minor. Cheers.

[JonR]

Just as a point of interest, I always refer to the third as part of a toggle switch.
The 3rd interval has 2 properties. It can be major or minor.
If we look at the 5th interval, there is a major 3rd and a minor 3rd.

So depending on the order of those 3rds, we are able to name the chord.

If the lower interval is a major 3rd, the interval above will be a minor 3rd.and together they make a perfect 5th.

G
min3rd.
E
maj3rd.
C

And that is a C major triad.

Now if the lower interval is a minor 3rd, then the upper interval is a major 3rd and together they add to a perfect 5th.

G
maj3rd
E
Minor 3rd.
C.
And this is a C min triad.

All the chords in the harmonised scale conform to this formula except for the last chord which is a diminished and
and has 2 minor 3rds.

So now you can see how they toggle between major and minor. Cheers.

Yes, but - as explained earlier - this is an overcomplicated view. There's no need to invoke the 3rd between 3rd and 5th.
Both chords contain a perfect 5th (7 semitones root-5th).
So the chords are distinguished by their 3rds:
root-3rd = 4 semitones = major 3rd = major chord
root-3rd = 3 semitones = minor 3rd = minor chord
That's it. (You can make it more complicated if you like, but there's no need )

A diminished chord, meanwhile, is named after its 5th, because the lowered 5th is the more distinctive interval. It happens to also have a minor 3rd (because no tonal scale contains a major 3rd and diminished 5th), and the m3 between 3rd and 5th is (again) nothing to do with the name of the chord. Similar with an augmented chord: named after its 5th, and assumed to have a major 3rd because no scale contains a minor 3rd and augmented 5th.

Similar considerations apply with 7ths and extended chords. In naming the chord, we always measure from the root, and disregard any intervals between other chord tones. So we don't need to look at those intervals to understand the naming principles.
Obviously the other intervals play a part in the chord's overall sound, and are important when considering arrangements, choosing inversions and voicings, or (aagh!) writing counterpoint, or anything like that. But the names alone are completely understandable with reference to the intervals with the root only (and in close voiced root position).

[ColMc]

Like I said, just as a point of interest.
Not trying to usurp your post.
Cheers.

Edit: On second thoughts, reread the OP.
The question was very simple. I gave a simple answer.

[emanresu]

The OP was already answered so lets derail it more. Why one sounds happy and the other sad?

[ColMc]

It's a bipolar 5th.