# How do you know what chords to use for a song/melodies you don't know?

I was given this exercise but unlike the other questions, this didn't have the title of the song in it. I thought it was just something I had to analyze and try to put chords that fit with the melody. Apparently I was correct, except for the 75th measure. I'm not sure what chords to put there. I tried V-I (E - A) but it preempts the ending. Unless there are slash chords here? How would you know what chords would work?

• This exercise seems to be about phrase and period analysis. You should have had material presented about how to analyze melodic phrases and periods and what the traditional cadences are for each phrase ending based on period type. It would not normally be just whatever chords you think go with it. There is a right answer based on common practice. Commented Nov 21, 2021 at 7:10
• Most obvious way would probably V7-VI (deceptive cadence). A slightly more uncommon way would be V-I6, which works somewhat similarly to a deceptive cadence. And if you want to do something interesting you can do V-IV6, which is very similar to a desceptive cadence.
– Lazy
Commented Nov 21, 2021 at 8:22
• From the header, it sounds as though you feel the 'right' chords are those which get played when the original song is heard. They aren't the right chords - they're simply the chords the composer decided to use.
– Tim
Commented Nov 21, 2021 at 12:20
• One more daring possibility for (the assumed) Bar 75: a Rossini-like V -> vii°7/V (or V -> vii half-diminished 7/V). I have to admit I like it more than V -> vi. Following it up with an extended and decorated I6/4 into V -> I makes sense. Commented Nov 21, 2021 at 15:09

The "how would you know" part comes with more study and especially with practical experience. In this case, use V and VI — a deceptive cadence.

You're correct to observe that the melody suggests a cadential quality and also that V - I undermines the actual ending. That is something of the "purpose" of a deceptive cadence — a "fake out" ending before the "real" one.

• There are other ways to know. Studying motif, phrases, sentences, and periods would suggest that a half or plagal cadence would traditionally end the first phrase, especially since the period ends on a PAC. It’s an a a’ a’’ b melodic structure, so it has a form and that form has conventions which can be studied and learned outside of or in addition to experience. Commented Nov 21, 2021 at 7:03
• @ToddWilcox Studying doesn't count as experience? And what exactly are the conventions of an a a' a'' b structure? Commented Nov 21, 2021 at 7:09
• The most common cadences would be IAC - HC - IAC - PAC, which fits in the asker’s exercises except for the third cadence which can’t be an IAC because of the A in the melody. So it could be a three phrase period with a deceptive cadence to extend it for one more phrase, but that also doesn’t conform well to style. So it’s strange. Commented Nov 21, 2021 at 7:33
• I think of experience as distinct from study. As in something that you learn by doing as opposed to learning by reading. Perhaps that’s not what you meant. But one decent answer to the question “how do you know what chords to put” is “by doing a web search on ‘phrase and period structure’”. Commented Nov 21, 2021 at 7:39
• @ToddWilcox I can see the misunderstanding about "experience." I've updated to clarify. But given that it's a phrase that "doesn't conform ... to style. So it's strange", I'm skeptical that a web search for a general phrase is going to turn up an answer. I would be happily surprised to see the solution you find that way. Commented Nov 21, 2021 at 7:57

For starters, there's rarely one way in which to harmonise a melody. That's been proved thousands of times. Right now, I'm playing Summertime with four different bands, all with very different chords underneath !

Without getting into PACs etc., it makes sense that the chord tones and the melody lines match up. Obviously not totally, that would maybe mean a chord change every note, but by and large. Let's face it - if the melody doesn't match the chords, or the chords don't match the melody, the piece just won't sound right.

Since in 4/4 time, usually the 1st and 3rd beats are the predominant ones, that's a good place to start considerations. As an example, the 1st and 3rd beats of bar 70 are C♯ and A - both important components of the A major triad. So A would fit happily there. However, the B and G♯ in that bar (beat 2) fit better to an E chord - quite o.k., as that's the V of A. So either A or E will fit on the 2nd beat.

You ask what might fit in bar 75. I'm not certain whether that is an allowable question here! But, bearing in mind what I've already said, perhaps you can come up with a solution. There's one obvious, one not so, at the level of this question on the sheet, and some others that work nicely in a jazz situation, perhaps inappropriate here.

For the how-do-you-know part -- I was never good at this stuff so I used the brute force method. Here's what you do. You look at the notes that are sounding on that beat and check if they are part of some triad. There might be two or three choices. At that point you can narrow things down by playing it and checking if one or the other sounds better in the context. If it's a very pedagogical exercise, as yours seems to be, then you can pick something that seems similar to the examples and exercises you've been doing for your class.

But you might have to watch out for appoggiaturas, passing tones, etc.

There's often no 'right answer to this sort of question'. V - I would be fine. There's nothing wrong with 'pre-empting the ending'. (Call it 'emphasizing the ending' if it makes you feel better!) V - VI would be another option - and I suspect that's the one your teacher is looking for. It would complete the exercise with one of each of the four main cadence types.

• "Pre-empting" and "emphasizing" are polar opposites in this context. Commented Nov 21, 2021 at 8:15
• Yup. And they can both be applied to this bit of melody. Repetition is good. Variation is good. I can give you three different answers to a question, I can give the same answer three times. Both are OK. Commented Nov 21, 2021 at 8:24