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Since a major triad is comprised of a minor-third stacked on top of a major-third, and a minor triad is comprised of a major-third stacked on top of a minor-third, they should, in "theory", have the same mix, so should sound similar, at least.

Obviously they don't, but why not? Is it something to do with the overtones/harmonics which the blend of two differing intervals produce?

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The fifth is still in the same place relative to the root, regardless of the third. –  American Luke May 24 '13 at 16:43
    
Perfect, Luke ! –  Tim May 24 '13 at 17:04
    
I felt the question was semantically clear, words and phraseology fine, however, if the changes make it more intelligible and it enables more answers to be revealed, so be it. –  Tim May 24 '13 at 21:45
    
It was okay, but generally intervals do not "follow" one another when sounding simultaneously. –  jjmusicnotes May 24 '13 at 22:55

3 Answers 3

A major triad does not contain "a minor third followed by a major third" and a minor triad does not contain "a major third followed by a major third".

  • A major triad contains the root, major third, fifth.
  • A minor triad contains the root, minor third, fifth.

Or, counting in semitones:

  • Major triad: root, root + 4, root + 7
  • Minor triad: root, root + 3, root + 7

The difference in sound is accounted for by the one different note.


I see where your confusion comes from - you're looking at the interval from the first to the third, then the third to the fifth -- 4 + 3 for major, 3 + 4 for minor. But it's the interval from the root that's significant.

The fifth is an "important" interval because it echoes a frequency that is a strong harmonic in the root note. If you gently finger one third of the way up the E string of a guitar, and pluck, you will hear a B tone. That is the 2nd harmonic of E (the first is another E, one octave higher). B is E's fifth.

So, playing the fifth along with the root note is almost not a harmony, but a strengthening of the harmonics, making the sound stronger and deeper.

You can play inversions of the triad. For example a C major triad could be C-E-G, or G-C-E. But listeners will perceive that the root note is C because the G reinforces it. Neither E nor G is reinforced in the same way. The E - or Eb in a minor chord - is then heard as a modifier to that "power chord", making it sound major or minor.

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Slim, please read carefully ! But either way, they BOTH contain one maj. and one min.interval.E.g., Cmaj. C-E=maj.3rd, E-G =min.3rd. Cmin. C-Eb =min 3rd, Eb - G =maj. 3rd. –  Tim May 24 '13 at 16:35
    
!st harm.= octave, 2nd = 5th, 3rd = second octave, 4th harm. = maj.3rd. So it probably is to do with harmonics. Where does that leave min. 3rd in this scenario? Also, E -G will always be a min.3rd, as C-Eb is, so the 'echoing frequency' syndrome should still occur, given that the perfect 5th, G, is constant. –  Tim May 24 '13 at 16:49
    
I take your idea of G reinforcing C, as C has a G harm., whereas G doesn't have a C harm., at least not till number 9, when it's pretty weak. –  Tim May 24 '13 at 16:53
    
@slim - I've edited the question to be more correct with respect to word-choice. –  jjmusicnotes May 24 '13 at 18:53

This is a great question, and one that is logical. Yes, technically, major and minor triads are indeed built that way and can be thought-of as such. They can also be built and thought-of in the way slim described in his answer as well.

Interestingly enough, I would say that the majority of factors that influence how we perceive major and minor chords aren't actually theory related.

Much in the same way you use similar ingredients to make a large variety of food (take flour for example!) so too is intervallic function and pitch choice, and like many things in life, is largely dependent on context which I will expand upon in a moment.

In Set Theory you can actually prove that major and minor triads are exactly the same chord - which is always hilarious to watch a roomful of theory students as their minds explode. Mine certainly did when I first learned of it. But I digress.

When you hear a triad, I am willing to bet that you are probably not hearing it as a sum of two distinct intervals. Instead, you are probably perceiving the chord as a single, cohesive unit. Hearing distinct intervals would be pronounced in, let's say, an orchestral score where different instrument timbres can accentuate different pitches, but for sake of simplicity, let's discuss it as it occurs on a piano.

We're going to take a little shift here:

It has been proven in psychological studies that humans group together like stimuli - especially with respect to aural stimulus. Tangentially, but not completely unrelated, this is one of the reasons why you don't constantly feel your underwear throughout the day.

In another example, if you were listening to three different conversations simultaneously, it would be difficult to describe each conversation. However, if you heard a conversation, a jet going by, and a police siren, such disparate sounds would be easy to remember and describe.

Such is the case with major and minor chords. Because each chord contains a perfect-fifth where the fifth is harmonically supported by the root's overtone series, the fifth essentially becomes non-existent, as you would likely hear the overtone without the fifth's presence. This is why in four-part writing the fifth is usually the first note to be dropped from a chord voicing, and the same applies to Jazz as well.

The root establishes a "tonality" as it were, and the third merely denotes the "quality" or "color" of the chord, and the fifth is nothing more than overtone support. This is why chords that contain the same intervals sound differently from one another.

Earlier I referenced context, and context is important to note here as it can affect how a chord is perceived as well. For example, a major chord in the lowest register will sound very different from a major chord in the highest register (even using the same pitches!) Further, that same chord will sound differently played by a saxophone choir or tuned bass drums.

Apart from timbral context, major and minor chords can sound different depending on their harmonic function as well in a given key, tonal center, or pitch collection.

Hope that helps.

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Playing TWO notes from a chord, earlier, made me think that some of what you state is right. In context is the key, excuse the pun. When one's ear is tuned to, say Cmaj, the C+E is obviously a major blend. But - follow on with E+G, and it's still (in my ears) major. In a different context, say E minor, E+G sounds minor, only because it is. All this we maybe know - but the original question still stands - WHY ? (or WHY NOT? ) –  Tim May 24 '13 at 21:57
    
I fail to see how my answer does not fully answer your question. The reason why E+G still sound "major-y" in C major is not only the context I mentioned, but also aural memory. Aural memory helps define how the listener experiences context. Even though you're not playing "C", it is still in your aural memory, which provides a context for the E+G. If you were to play, say, an "F#", giving your aural memory a different context, you would find that the E+G would take on a different role. –  jjmusicnotes May 24 '13 at 23:00
    
If you have perfect pitch, they all sound the same, regardless of whether the C major sounds in the higher register or lower or is played by whatever group of instruments. –  Chris Olszewski May 25 '13 at 6:46
    
Mozart certainly did not hear them as any different just as a mathematician would not distinguish between two different group of numbers that relate in the same way –  Chris Olszewski May 25 '13 at 6:47
    
Thanks, jjmusicnotes, I re-read your answer when I had more time, and appreciate it. Chris, the question was more about how (and why) certain notes blend as they do, not what a particular note sounds like. –  Tim May 25 '13 at 11:36

Function, function, function.

To use colors for a moment: let's say that a major third in this case is red, and that a minor third is blue. Bear with me.

Say we have two squares, where for one, the bottom half is red, and the top half is blue, while on the other, vice versa.

Now, turn off the logic in your brain for a moment that says, "Well, just flip one over and they're the same."

In this case, these two things are different. They look different. The frequencies that these colors give off in that order are different. One has red on the bottom, one has blue on the bottom. The function of color in each case is different.

In the same sense, having a major third on the "bottom" of a chord sounds and IS different than having a minor third. Yes, both contain similar elements, both have a major and minor third, but the way these tones function in the chord as a whole is what makes them different.

In a major chord, the bottom interval, in equal temperament, is 400 cents; a minor chord has 300 cents in the bottom interval. This is the relationship between the root and the third of the chord, its quality "center" if you will. The difference between having 400 vs. 300 on the bottom is a matter of function, and not makeup. Just because something has two of the same things in it, does not make it the same.

Function, function, function.

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JPDoherty, thanks for an interesting answer.I got thinking again, and your last para. made me play a minor triad, root position. This (obviously) sounded to me like a minor chord, yet when I played 1st inversion, to me it sounded like a major 6th.2nd inversion - jury's out right now.So it could well be the relationship between 'bottom' note and other two, as human ears apparently hear the lowest note as the base - yes base - or root of the chord. –  Tim May 31 '13 at 6:47
    
Well, the inverse of a minor third is a major sixth, so the outer tones would give that impression. Doubling the b3 up an octave strengthens the "minor-ness" of that inversion. So, Eb, G, C, Eb (up an octave) –  JP Doherty Jun 4 '13 at 10:37

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