What is the musical function of broken chords?

Question

I'm new to musical theory and interested in playing guitar. It seems to me that the broken chords are very often used in the music sheets arranged for guitar. I wonder if they are also usually used in piano.

And moreover, could you please explain me why broken chords are used so often in guitar?

Answer 1

Broken chords — playing each note of the chord one after the other — allows the chord to serve a more clearly melodic function in addition to its harmonic one. Broken chords are very common in piano music and across all instruments.

In Bach's Prelude in C Major, BWV 846, the entire piece is made of broken chords (recording below). This allows for several musical features:

1. A melodic feel throughout, even though each measure is essentially a single chord.
2. A rhythmic feel (constant sixteenth notes) that would be boring if accomplished simply by repeated a block chord in that same rhythm.
3. A sense of several "voices" operating simultaneously but independently. (Had Bach used block chords, each individual voice would not be as clearly articulated.)
4. A sense of tension while waiting for each chord to unfold. For example, in m. 1, the first two notes are C and E, then continuing with G, making us hear a C major chord. But in m. 5, we again here C, then E, leading us to expect C major, but this time the next note is A, causing us to hear A minor. (See score excerpts below.)
5. For non-bowed string instruments (guitar, piano, harp, ...) it allows the chord to be extended in a musically interesting was (rather than simply repeating the block chord) while avoiding the instrument's natural decay.
6. Broken chords allow for single-note instruments to give the impression of chords even while playing one note at a time. (See below.)

Bach Prelude in C Major, BWV 846, recording with score

Bach Prelude in C Major, BWV 846, measures 1 and 5

(Image Source: IMSLP, Pierre Gouin edition)

Broken chords on a single-note instrument

A classic example is the Prelude from Bach's Cello Suite No. 1, BWV 1007. Though technically a cello can play chords to a degree, this piece illustrates the ability to create both harmony and melody using broken chords.

Here, for example, is the same piece played on bass clarinet.

Answer 2

Short answer!

Broken chords work better on instruments which can sustain previously played notes.

Like piano, harp, organ, and - guitar. Playing a chord in an arpeggiated manner, and by the end all the notes are still audible, is a recognised 'trick' that works well on those instruments. Eventually, the whole chord is revealed.

Yes, broken chords can be played on any instrument, but the effect is lost, because as soon as the next note gets sounded, the last one is lost.

Answer 3

Broken chords have at least three advantages on a guitar or other plucked-string instruments:

1. There are limits to how many closely-spaced notes a guitar can play simultaneously. When using standard tuning, for example, it would not be possible to play four consecutive notes from a seventh chord simultaneously.

2. Many chords are designed to create "tension" between certain notes. Playing two dissonant notes simultaneously is not as effective at creating tension as playing some notes of a chord that fit together without any tension, and then adding a note that is (typically) a half step away from a "tension-free" note.

3. Especially on an instrument like a harpshichord which would allow many strings to be plucked simultaneously, a simultaneous attack on many notes would create a volume peak much is much louder than the sustained sound of the instrument. Plucking strings separately dilutes the volume peaks.

In many cases, when using broken chords on a guitar in a manner that cannot leave strings ringing on all the pitches, it will be desirable to use a reverb pedal or other such means to allow the sound of earlier notes to be heard simultaneous with later notes. This isn't strictly necessary, but it can do a lot to improve the audio texture. When using an alternative tuning which permits sustained chords, the sustained strings may carry the sound without need for reverb.

Answer 4

You can strum chords, playing all the notes (almost) at once. Make the strum slower, spread it over more time in a measured rhythm, it becomes a 'broken chord'. On an instrument with more sustain, the chord will, to an extent 'build up' until you hear all the notes of the chord at once. But we can also recognise the chords when the notes are heard in sequence, one after another.

Why do one or the other? Strum or arpeggiate? Well, there's no magic rule. Maybe (on guitar) you want more notes than can be played in one chord shape or (on keyboard) in one hand-stretch. Maybe you want the notes to be played in a different order than just bottom-to-top (or top-to-bottom). But, basically, they're just different ways of laying down the harmony. Artistic choice.

Answer 5

The harmonic function of a broken chord is EXACTLY the same harmonic function as a block chord. There is zero difference.

The melodic function of a broken chord is to provide melodic interest. Block chords have almost zero melodic interest.

The rhythmic function of a broken chord is to provide rhythmic interest. Block chords have almost zero rhythmic interest.

There really is no rhyme or reason in music. It's done because it "feels good". It's like wondering why people have sex. Because they do. If they did not want to they wouldn't. People play broken chords because they can.

Much of music is that way. There are no universal laws saying that you have to do X Y or Z in music. You do things because you can and want to.

Obviously on monophonic instruments you only have the choice of broken chords and hence it is obvious they would show up.

Broken chords are also called arpeggio's. Again, they do more than just block chords(which only provide harmonic interest/color). All music uses them because it's just sounds and all music uses sounds.

In music, the primary goal is to express harmonic clarity. Chords are precisely what do this. Arpeggios do this but sort of stretch it out in time. Generally speaking a piece that is only of block chords is quite boring. 99.99% of all music consists of combinations of elements to make it interesting.

Also music is independent of instrument. The guitar is not special.