For simplicity assume we're in C major. Let's say I'm playing a song, and I want to play a basic triad chord to harmonize whatever current melody note is played. In this example say the melody is a D note that I would play with my right hand. Then for my left hand, I think there's three possible chord combinations that I can play (I usually pick the one that sounds best):

  1. The note is on the left of the triad
  2. The note is in the middle of the triad
  3. The note is on the right of triad.

Does this sound about right?

Edit: In this question I (incorrectly?) assumed the triad has to include the melody note. I haven't ever seen it not including the melody note, but maybe that's just due to my inexperience.

enter image description here

  • You mean with no accidentals or alterations, right?
    – Neal
    May 10, 2018 at 16:16
  • yep no accidentals completely diatonic
    – user34288
    May 10, 2018 at 16:52
  • 1
    This is a related video that I found to be quite interesting: youtube.com/watch?v=JXfQsHT5c30&t=528s May 10, 2018 at 18:03
  • Have you considered inverting your triads?
    – Dekkadeci
    May 11, 2018 at 0:27
  • inversions don't count (for this question)
    – user34288
    May 11, 2018 at 2:54

4 Answers 4


If by “C major,” you are assuming the key of C, with, as you explained in a comment, no alterations and no accidentals, and using the note “D” as a reference point, and if you are assuming a triad to mean only the adjacent diatonic intervals of 3rds (based on your graphic), then yes, what you have built is accurate. It is pretty fundamental to music theory.

Of course, this applies to any note in the scale, not just D. In C major, start on C, and you can have C be the root (C major), the third (A minor), or the fifth (F major); go to D, and the same applies; go to E, and the same applies; etc.

Your question more particularly seems to assume the constraint that the melody be part of the triad itself or be a note that is in common with a note in the triad. This need not be the case; indeed, it often is not the case. Melodies can be tricky, fluid things when you are considering harmonization.

Take the well-known “Auld Lang Syne,” for instance:

“Auld Lang Syne” harmony

LilyBin link, with MIDI audio

In this very basic harmonization, even in the first measure, we encounter a melody note that does not “fit” into the triad of F major. In almost every measure, there is a melody note that does not “fit” into the triad that is harmonized with it.

On the other hand, if you harmonized every note in its own triad according to the rules in your question, it might arguably sound worse:

“Auld Lang Syne” too much harmony

LilyBin link, with MIDI audio

The combination of melody notes that are part of the triad and that are not part of the triad is often what provides musical interest.

This is to say nothing, of course, of extending the harmony beyond triads—suspensions, extensions, and borrowed, oh my! But, given the constraints you provided in your question, yes, notes can be harmonized with any of the three notes in a diatonic triad of which that note is a part—but when harmonizing a melody, I think it is often advisable to know how best to produce good music. To only look for triads that “fit” the melody in the way you describe seems like an inadvisable course to stay on, but it is a good starting point.

  • 5
    Note that the asker has stated elsewhere that he refuses to learn to read music (don't ask). Of course, the score in this answer will be helpful for others who are curious about the same thing. May 10, 2018 at 18:08
  • @ToddWilcox Anyway, many of others probably can't hear the second version in their heads, and don't have access to an instrument right now, so a link to a recording or a MIDI would help both OP and other readers.
    – JiK
    May 11, 2018 at 12:06
  • @ToddWilcox I said I refuse to learn a song by reading sheet music. it's different when we're talking theory and analyzing then I'm for it. and I think this answer is great. I wish lilybin would use html audio to play the thing instead of me having to download it. also I can't play the midi file with quicktime for some reason so I'm having to drag the midi files to garageband. I'm on a mac.
    – user34288
    May 11, 2018 at 15:56
  • @foreyez Sorry, I must have misunderstood when you wrote: "I'm illiterate in music by design. I don't read or write music and will never do so as I prefer everything by ear." May 11, 2018 at 16:00
  • 2
    Do I need to separate you two?
    – Neal
    May 11, 2018 at 16:08

There are actually more ways, many more ways.

One fairly straightforward way is to make the melody note the seventh of the chord. So in this case the chord would be E G B.

From there you could make the melody note an add 9 by using the chord C E G, but an octave lower, add 11 with A C E, etc.

Depending on how long you are playing the D and on what beat and whether it is emphasized or not, you could "harmonize" it with almost any chord. Each choice has a different flavor.

You could also borrow triads that contain D from related keys. And of course you could branch out beyond triads.

  • The OP asks about notes with a triad, then gives examples of those triads. Should the question read within rather than with, as your answer alludes to the latter, while mine leans to the former? Unclear question, or unclear translation thereof?
    – Tim
    May 10, 2018 at 17:01
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    @Tim I read it as asking how many ways are there to harmonize a melody note using a triad. He proposed three possible triads, a D minor triad, a B diminished triad, and a G major triad, and then asks if there are any others. I suggest that there are many other triads that can harmonize with that note, depending on the desired overall sound. May 10, 2018 at 17:03
  • The OP harmonised D with two other notes, thus making his triad. There wasn't really mention of any more than two other notes, otherwise, it's not a triad. You're right, in that D could be mixed with a myriad of other notes, diatonic or not, but I wonder whether the triad part (including D) is the crux. Not happy with the wording of the question. Seems to allow too much interpretation.
    – Tim
    May 10, 2018 at 17:16
  • 1
    @Tim The diagram doesn't exactly show what the text relates. Note the discussion of right hand playing a D and the left hand playing a triad. I think the diagram is just there to show that he assumes that the melody must always be a chord tone, not that he would only be playing three total notes in his hypothetical situation. Rather, he would be playing one note with his right hand and a triad with his left for a total of four notes. May 10, 2018 at 18:07
  • 1
    @Tim You're looking at the question title. Todd is answering the question in the text, "I want to play a basic triad chord to harmonize whatever current melody note is played." The answer being, "Don't limit yourself to the melody always being a chord tone." May 11, 2018 at 10:27

It's a very narrow question. But, within its terms, yes you're correct.

But that information isn't terribly useful. Because there are triads other than diatonic ones. And there are chords other than triads. And there are 'non-chord tones'. And all these are VERY commonly used, even in quite simple music.

But if you INSIST on "I want to play a basic triad chord" I can't argue with your logic.


That is right if you want an easy guaranteed harmony for a single note. When you consider music is a series of notes you also need to consider the sequence of chords you have and their relation to one another. It works playing several notes with the same chord, some that are in the chord and some that are not. Music that only uses "safe" harmonies tends to sound static and boring. Try holding down a chord and seeing how each note of the scale (or out of it)sounds against that chord. Some cry out to you to move them back or forward to a more harmonic note. If the next note of a melody does this it gives a feeling of tension then resolution giving a sense of dynamics in the tune. You can do this all by ear but it helps to know what the intervals between notes are so you can put a name on what you like to help remember it and duplicate it in another key.

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