Why do Guitar chords work the way they do compared to a Piano?

Question

I'm a Tabla (North Indian percussion instrument) player and I know just the basics of western music because I'm learning it bit by bit. I borrowed a Piano to learn music theory and it's going pretty good. My friend plays Guitar and we were jamming one day when I noticed how chords are played on a Guitar and it is confusing me to why they work.

So let's say I want to play the C major chord. On the piano I play the notes C, E and G together. But when my friend plays the same chord on his Guitar, he places his fingers on some frets and strums the Guitar. Now what bugs me is how he strums all 6 strings. And it doesn't matter which chord he plays, he will strum all 6 strings. What I don't understand is how can playing all 6 strings give the same result as playing just 3 notes on the Piano. Because to me, that's like playing some extra notes on the Piano.

Can anyone explain me why playing the open strings with the fretted ones on the Guitar gives the same result as just playing the notes on the Piano?

Answer 1

Yes, you're right, it is like playing some extra notes on the piano. Note that when your friend plays a C major chord, he probably plays 5 strings (but for other chords, e.g. the G major, it might be 6). The guitar strings will be playing the following notes: a middle C, a middle E, a middle G (the same notes as you are playing on the piano) plus a high C and a high E. You can play those last two notes on the piano as well with your other hand to hear the difference.

Due the nature of musical tones, whenever you play, say, a middle C, you hear not only the fundamental frequency of the middle C, but also higher harmonics, one of them being the high C. Therefore, higher tones will (usually) not change the 'essence' of the chord (but they can add to the 'richness').

Answer 2

I think that you haven't understood yet that to play a chord one has to play the notes of the chord but one is free to choose the order of the notes, if they are played high or low (one or several octaves up or down) and if some notes are doubled higher up or lower down.

All these changes define the 'voicing' of a chord. The chord is essentially still the same but it has a different character of 'colour'.

In a three note chord a guitarist plays the same note on different strings, but one or two octaves higher or lower. An experienced guitarist knows several different voicings of a chord. A pianist has an almost endless way to combine notes together in a chord-voicing.

Answer 3

Adding to the existing answers, but making it more personal to you. When your guitar playing friend plays his chords, try to find those particular notes, in their respective octaves, on your piano. You should be able to 'strum' them, and it'll sound remarkably like the chord he's playing, due to having the same voicing. Then you'll understand simply what is happening. Yes, sometimes he plays open notes in his strumming. Those notes will be part of the chord he's on, so will need no fingers pressing those strings down on certain frets.

Answer 4

To answer your question frankly, it does not work like that at all. (or maybe sometimes).

So you need to be more explicit with your description of "all strings" and "fingers on some frets".

A major chord is the same on all instruments, it is the combination of 1, 3, 5 notes of the major scale. If your friend fingered three and only three notes for a Gb major chord in standard tuning and played all strings it may sound really cool, but it would not sound like a Gb major chord.

The compatibility of the other strings with a given three note chord depends on a few factors.

1) we usually double notes, like the 1 and the 5. Even in 4 voice harmony theory we are taught to double notes. So if your friend is playing a bar chord in standard tuning then no harm no foul, all the notes are part of the chord. For example, a Major chord in bar chord form is voiced (1, 5, 1, 3, 5, 1), spanning 2 octaves. You have three occurrences of the 1 and 2 of the 5. You can do this on the piano by the way. Voicing refers to the ordering of notes.

2) if your friend and you are playing songs in a key that is referred to in guitar speak as "an open string key" (i.e. a key that is compatible with open string notes) then he/she can freely play open strings along with the notes of a chord and they will either be part of the chord or a compatible extension of the chord, so it will sound pleasing.

3) your friend may have tuned the guitar differently compared to standard tuning, allowing them to strum open strings as they play chords.

It is actually not typical for a guitarist to strum ALL strings even when playing in open string keys with open string chord forms. A typical example is a dominant 7th chord. The bar chord form is voiced (1, 5, 7, 3, 5, 1) using all 6 strings. A more typical voicing in jazz is (1, x, 7, 3, 5, x) where x means don't play. Now the guitarist can play the chord finger style with the right hand or "mute" the unwanted notes by gently draping the left hand fingers over the strings that should not be heard. In this way they can appear to "strum" all strings but are really playing only the 4 they want.

So, in general one does not play all the strings all the time, but you can see that in some cases it's okay. Those cases are limited and it is no surprise that much of classical guitar music (or guitar music in general) is written in what I call open string keys (hence, my comment maybe sometimes). Jazz guitarists get used to playing in Bb and Eb which do not lend themselves to open string voicing (at least not easily and not over a large number of chords in the key).

Answer 5

imagine he plays piano with 3 notes on one hand, and those same three notes an octave higher with the other hand, then it's similar to what's happening on guitar - as guitar strings span 2 octaves. It's the same 3 notes (e.g. C, E, G) just in different pitches.

Answer 6

Because the guitar is being tuned in 'open tuning':

(low) EADGBE (high)

When he does a Cmaj, 'open' position, fretting the A,D, and B string the notes become:

(low) ECEGCE (high)

He could optionally also add third fret on the low E string (G note) to have:

(low) GCEGCE (high)

... both of which are Cmaj, C-E-G.

If by chance you're actually asking how do six strings sound 'at once' it's because the time between the start of each up or down strum motion is quite quick. 120 beats per minute, one down-up strum per beat, means 240 swipes a minute, a quarter-second each.

And one can certainly play more than three keys at once on the piano.

Answer 7

Can't comment directly, but here are some points:

"Folk" guitarists will often just strum across all strings and thus play "extra" notes, but this is not universal. Sometimes a guitarist will mute strings by pressing lightly on strings that may be strummed but should not sound, and/or simply not strum those strings.

For jazz guitarists this is pretty much the default -- they tend to mute and/or not strum strings that they don't want to sound -- and with "jazz" chords (maj7b5) it's especially important, because the player is trying to create a very specific sound with specific harmonies.

All of the above of course assumes use of a pick (plectrum).

Fingerstyle guitarists have it much easier in this regard, since they can pluck (not strum) only the strings they want. (Of course, this means they can pluck at most five strings - if they want all six then it's back to strumming).