Music theory is not logical

[mediumaevum]

I'm trying to learn music theory, and I am a logical thinking person.

I have a lot of difficulties figuring out the logic in music theory, simply because... it defies all logic.

Let's take a Third Interval as example.

A Third Interval is defined as:

Three halfnotes to and from the root note (we are always counting the root note & interval too).

From A to C there are 2 whole steps + ½ step, which makes 4 half steps.
But Third Interval is described by halfnotes only. Yet when counting the Third Interval (or any other interval) it varies wether or not we count in halfsteps or not, as if one have to remember a whoe bunch of rules of what a Third Interval is, there is no underlying logic behind it. You cannot count mathematically.

If a Third Interval is defined as three (3) half steps/half notes from the root, ie. C, then the Third Interval should be D. But it's not.
One has to remember "as is". It "just is this way", you can't count.

[sjm]

That's because you've got it backwards. Here are your notes in C major:
C D E F G A B C

Give each of them a number:
C D E F G A B C
1 2 3 4 5 6 7 8

The E is the third.

Now in C minor:
C D Eb F G Ab Bb C
1 2 3 4 5 6 7 8

Eb is your third.

One of those thirds is 3 semitones (the minor third) and one is 4 (the major third). Btw, you don't count the root. 3 half steps from C is not D, that's 2 half steps (or 1 whole tone). C-> C# is one semitone. C#->D is another semitone. That's two semitones. Otherwise by your reckoning, C->C is 1 semitone. That obviously can't be true, C cannot be a different note from C. Similarly, A to C is 3 semitones (it's a minor third). So your numbers are all off. I'm not sure how you figured out that A to C is 5 semitones; just look at a keyboard layout or in the piano roll and count the notes: A (0) A# (1) B (2) C (3).

So there is both a major third and a minor third, and they are not the same thing. But a major third is always an interval of 4 and a minor third is always an interval of 3. I'm not sure where you got your definition of a third from, but it's not correct (or you have incorrectly interpreted the information and taken it out of context).

[mediumaevum]

That's because you've got it backwards. Here are your notes in C major:
C D E F G A B C

Give each of them a number:
C D E F G A B C
1 2 3 4 5 6 7 8

The E is the third.

Now in C minor:
C D Eb F G Ab Bb C
1 2 3 4 5 6 7 8

Eb is your third.

One of those thirds is 3 semitones (the minor third) and one is 4 (the major third). Btw, you don't count the root. 3 half steps from C is not D, that's 2 half steps (or 1 whole tone). C-> C# is one semitone. C#->D is another semitone. That's two semitones. Otherwise by your reckoning, C->C is 1 semitone. That obviously can't be true, C cannot be a different note from C. Similarly, A to C is 3 semitones (it's a minor third). So your numbers are all off. I'm not sure how you figured out that A to C is 5 semitones; just look at a keyboard layout or in the piano roll and count the notes: A (0) A# (1) B (2) C (3).

So there is both a major third and a minor third, and they are not the same thing. But a major third is always an interval of 4 and a minor third is always an interval of 3. I'm not sure where you got your definition of a third from, but it's not correct (or you have incorrectly interpreted the information and taken it out of context).

If you're not counting C, then Third Interval D#. Counting first C#, D, D#.

[tehlord]

You're just confusing notes in a scale to notes on a keyboard. The third note in a scale can change depending on the scale, but three half tones (or semitones) will always be three half tones.

[mediumaevum]

You're just confusing notes in a scale to notes on a keyboard. The third note in a scale can change depending on the scale, but three half tones (or semitones) will always be three half tones.

So this is depended on scale, not a keyboard... interesting, I'd wish this was made clear to me from the very beginning that there is a VAST DIFFERENCE between the two.

All too often music teachers (or just about any other teacher in this world) takes crucial information too obvious, when it is not.

[Niklashe]

You always have to refer to the scale (major or minor). In a scale you don't count a single note twice, that is if you move from d, you move to e. The way you describe is only for counting semitones. So in your previous post you move from d to Eb and not to D#, counting as a minor third. Look at sjms post where he describes the C minor scale.

From which book, or page, are you trying to learn music theory?

[cturner]

I'm trying to learn music theory, and I am a logical thinking person.

It’s probably better to think of what you’re learning as “common practice harmony” as opposed to “theory”. It’s the codification of a few hundred years of the development of the European music system, and not without its quirks.

[AsPeeXXXVIII]

From A to C there are 2 whole steps + ½ step, which makes 4 half steps.

I don't understand what you're trying to say here.

A to C is 3 semitones (not 4, stupid me), but that doesn't equal 2 tones plus a semitone. If it did, that'd be 5 semitones. A tone is always 2 semitones.

Music theory is more logical than you think it is.

[mediumaevum]

You're just confusing notes in a scale to notes on a keyboard. The third note in a scale can change depending on the scale, but three half tones (or semitones) will always be three half tones.

Well, now I'm a bit more confused. As I understand your comment, any given interval is depending on the scale. I've been told this is wrong.

So please explain to me what you mean by this.

[mediumaevum]

A tone is always 2 semitones.

So the halfnotes, like the black keys on a piano are 2 semitones too?

[Delta Sign]

The color of the keys doesn't matter. It's always one semitone from one key to the next.

[mediumaevum]

The color of the keys doesn't matter. It's always one semitone from one key to the next.

I'm trying to count to a third (tertian, Latin, Terts, Danish, Third Interval).

It should be a simple task, but I guess not...

1. I have a C. Now, where's the third? According to music theory lessons I've taken and wikipedia and WHAT NOT! - a "Third" is composed of THREE SEMITONES (halfnotes).

2. Question: Do I count C too when counting to a third? Or do I count C#, D, D# (or Eb) - three semitones?

3. Question: Which direction? If I have a C, and I go DOWN, my "third" is not a D# (or Eb) - it's instead A.

Summed up my simple questions I have yet to have answered are:

Do you count the root tone (don't know the proper name, I begin with C, so let's call C root tone) when counting to a Third Interval?

Do you go up or down/right or left on the keyboard when counting an interval?

[tehlord]

You're just confusing notes in a scale to notes on a keyboard. The third note in a scale can change depending on the scale, but three half tones (or semitones) will always be three half tones.

Well, now I'm a bit more confused. As I understand your comment, any given interval is depending on the scale. I've been told this is wrong.

So please explain to me what you mean by this.

You can have a major third, which is four semitones apart, and a minor third which is three semitones apart. Both are thirds (in terms of intervals in a scale....notes one and three in scale) but both can be a different amount of semitones apart.

Another example is a perfect 5th (the fifth note in a scale, which is actually seven semitones from the root note.

[Delta Sign]

You don't count the C and it doesn't matter in which direction you count. Three semitones are a minor third and four semitones are a major third. You can count those up or down, it doesn't matter. The "third" is only the name of the distance, or interval. The "minor" and "major" is the "quality" of the interval.

If you want to build chords, you have to count up, of course. The root note + a major third + a perfect fifth is a major chord, for example.

Edit: Yeah, what tehlord said.

[topaz]

If your music teacher hasn’t taught you the difference between minor and major intervals you should find a new one.