Why do IV and V chords in a scale not start on their root?

Question

When discussing chord construction, my piano instructor couldn't offer much other than "that's the way it is", so I want to see if anyone can offer insight. Why are the IV and V chords of a scale (major- not sure if this matters) played in an inversion?

For instance, in the C Maj scale, C is played C4 E4 G4. The IV (F) chord is played A3 C4 F4. The V chord is played similarly. Why wouldn't you play the IV chord as F4 A4 C5 instead? Is there a historical reason for this, or is there some other reason that I'm missing?

Answer 1

This process is called "voice leading".

To understand it pretend that each note in the chord is being played by a different instrument. So for 3 note triads you'd have 3 different "parts". If you look at each part in isolation it forms not a progression of chords, but a single line—a melody.

The idea is to make each of those parts move to the closest note in the next chord. So if the chords share a note, it's as if that part repeats a note without changing. Or maybe it moves up or down a step or so.

If you were to avoid the voice leading concept then you'd have each voice jumping roughly the same interval in the same direction. That interval is frequently large (say a 4th or 5th) and larger melodic intervals tend to stick out and sound interesting. But when all the voices are moving by the same amount in the same direction, none of them really stick out or sound individually interesting. Those large parallel intervals tend to not sound as nice as voice-led ones.

On the other hand, if say one part stays the same, one moves a small step, and another moves a larger step, 1) there's some melodic variety and 2) the notes that define that chord as different from the previous one tend to get the larger melodic interval which makes them stick out more.

This is all to say: it usually sounds better. It's also frequently easier because the finger movements (the parts) are smaller.

But you don't always have to voice-lead the chords or do so in the same way. The voicings that you decide to play are part of the art.

Answer 2

first off, get rid of that piano instructor. and fast.

to answer your question - probably because it sounds better that way.

a chord is not required to start anywhere. you could play every F, A, and C on the piano (with friends helping you) and it would still be an F chord.

You could toss out any of the notes except for 2 and it would probably still be recognized as an F chord in the song.

Feel free to move any of the notes to any octave you like - still an F chord.

There's not just root position, 1st inversion, 2nd inversion. There's "arrangement" where you move notes to any octave that "sounds good" - double up the bass note (F) in the bass octaves. It's still an F chord.

Usually the F will be pronounced in the bass octaves and A and C can show up anywhere that sounds good.

So there's no one right way. You try out all the kajillions of possibilities and find the way that sounds best. (Well, and the one that's physically possible to play. But there are others in the band who could play the extra notes, too.)

So experiment. See what sounds good to you. Usually the root note in the bass and the rest of the chord notes hovering near middle C so melody can use above middle C freely works pretty good. But ya never can tell till you try.

Answer 3

You are not being told anywhere near the whole story. I, IV and V in standard triad form (basic 1st 3rd and 5th notes) can be played in any order, with doubling or more of some or all of those notes, and also in closed (three closest notes) position, or open, where there's a bigger gap between.

Truth is, whether a triad is a I, IV or V - or any other - it has what are known as inversions. C E G is root position, E G C is first inversion, and G C E is second inversion. The lowest note is the deciding factor, so, actually, C G E in open form could still be called root.

On piano, which is where the question emanated from, if one plays in C - C E G for the root (I) chord, C F A would be an easy change for the IV. Despite what teacher said. But voicings which is what all this is about, can be used in many ways with other instruments, to obtain different sound mixes.

Oh, and one other thing. Consider a different teacher...

Answer 4

I think your instructor may be showing you simple left-hand close-position voicings, designed to move smoothly from one to another. That's OK as far as it goes. But it's FAR from the whole story.

Have a chat with the instructor before assuming he's an idiot. He probably isn't. You've just latched on to one thing and inflated it into a general rule. It's easy to do, no-one's fault and is easily corrected.

Answer 5

I think that user37496 has the right answer. I wound up expanding far more than I intended:

Based on a theory/history class I took decades ago, the basic "voice-leading" idea stems from the way Bach revolutionized Western music when he invented 4-part harmony. (That's obviously an over-simplification of the history).

I think this is probably a piano-centric view of "the way things work." Normally, a piano keyboard is amazing way to visualize/experience/summarize the way Western music "works." It's almost like each finger follows the path charted for every instrument in the orchestra.

I kind-of suspect that, in this particular instance, you're getting the overly simplified beginner version of the full experience.

In many cases, the tuba is just playing the root of whichever chord is currently "active." A lot of times, you'll have horns playing the higher notes on off-beats, shifting around which part of the chord is being played (check out marches by Sousa to hear what I'm talking about...I hated playing the oom-pah parts of those in marching band).

When I play this particular progression on a guitar, I'll almost always have the chord's tonic as the lowest note. Unless I want to add a little extra volume/oomph by another string to the mix: adding the bottom E is a cheap way to make the C chord boom a little more.

That doesn't work as well in most other keys, when my soft finger would be taking the place of the rigid nut at the top of the fret board. I have never done more than dabble at the piano, but I don't think those sorts of considerations apply. (But they're relevant: these sorts of things are why it's good to understand the characteristics of the instrument you're playing).

When you get into more complicated arrangements, you do wind up with coordination issues with the rest of your band. Especially in jazz.

But, honestly, it seems like the real answer to your question is probably either "This makes it easier for you to play" or "The composer chose this voicing to provoke a specific response from the audience."