Are there many alternatives of chord sequence given a progression?

Question

I just started my journey of music, and I am wondering if the possible choices for chord sequence can be many given a progression, according to music theory.

I am worried about using the wrong or misleading terms here. To be more specific, given the popular progression 1-4-5, can we find many different chord sequences (also consider inversion and not necessary triad) which are correct and reasonable in key of C? E.g. C-F-G, C-Fm-Gm and C/E-Fm-Gm all sound good IMO, so I am curious if there are something related to music theory.

EDIT:

I am considering a particular scenario where one figures out chord sequences without any melody provided, which means there is no constraint for chord sequences imposed by melody. The only limitation is the given 1-4-5 (or any other like 1-2-5, 1-2-7, 6-4-5, etc.) in one key.

note: I avoid using I-IV-V because it refers to the specific Cmaj-Fmaj-Gmaj in key of C. On the other hand, 1-4-5, though informal, makes generality because it only fixes the roots but not chord types (triad, seventh, major, or minor, etc.). Sorry I am just a beginner, lots of misleading terms here.

Answer 1

Pretty well any chords can and are used in chord sequences. But - if you are referring to chord sequences over a particular melody, then the choices become limited. It's fairly apparent that underlying chords have some relationship to that melody - chord tones feature very often. So, given a set of notes, and their relationship to each other, chords are somewhat predetermined.

A simple example cropped up the other day, someone said about 'Do, a Deer' that although it uses mainly do, ray, mi etc., you can't play a do (C) chord over do, then a ray(D) chord over ray, and a mi(E) chord over mi.

Given extra info., adding extensions happens quite often. Instead of playing bog-standard C-F-G, it gets added to with something like Cmaj7-Fmaj9-Gm7, which would then lead to F in some cases. Some extended chords in a sequence will tend to dictate what follows - here, the Gm7 has elements of C9, which pushes the harmony through the dominant of F, to F.

Answer 2

Basically, if one uses only I, IV, and V, then there's no way to put those into a pattern that won't make much sense. There's just too few combinations to really get anything to sound objectively unusual. If you consider, say, all the diatonic triads, you can really mke some weird progressions, ie. ii-vi-V-IV or something rather unusual. The more chords you consider, the more possibilities. For example, considering the two chords I and V. If one uses I-V, then it seems to ask a question, setting up what the cool kids call a half cadence. However, switching the order and moving from V-I yields a different feeling, as if one has arrived at a destination. In general, The more chords you use, the more ways to use them, and the order really changes their effects.

Answer 3

1, 4, 5 (more usually notated with Roman numerals, I, IV, V) in C are C major, F major and G major. Anything else wouldn't be I, IV, V. You can certainly extend or substitute those chords to make something that does the same job as I IV, V - a tonic, a pre-dominant and a dominant. But then you'll have to name them as what they are, which won't be I, IV, V any more!

ii or ii7 (thats Dm or Dm7) are common substitutes for IV. Db7 is a common substitute for G7. So I, IV, V could become I, ii7, bII7 (C, Dm7, Db7). But it won't be I, IV, V any more.

A 'progression' IS a 'chord sequence'.

Answer 4

There are lots of options. The purpose of chord sequences is to harmonize melodies (in the classical sense) but modern music typically goes the other way. You will learn more as you go, but theory is secondary to sound. If a sequence of chords "sounds good" then compose using that sequence.

Staying in a particular key, a basic rule or guideline from classical harmony theory is that melodies based on the major scale can be harmonized using only the I IV and V chords. These chords cover the notes of the scale. This is why the I-->IV-->V sequence is so useful (though sometime you don't follow this exactly as you may have I-->IV-->I-->V, etc).

There are relationships between the chords that naturally occur in a scale. First, in any key you naturally have the following triads on each degree from Do to Ti (I to vii), I maj, ii min, iii min, IV maj, V maj, vi min, vii dim (maj = major, min = minor, dim = diminished). These are related in pairs by (I, vi), (IV, ii), and (V, iii) just for starters. The 6th degree defines the relative minor key to the major key on the 1st degree. In fact the vi can be used as a substitute for the I, and likewise for the other pairs. There are other chord parings that lead to substitutions and whether or not a substitution works depends in part on the motion of the individual intervals from one chord to the next, as well as the melody. So the short answer to your title is yes, there are many alternatives to a given chord sequence.