Essentially, the term Chord voicings refers to the way in which notes in a chord are doubled and/or stacked. For example, looking at a standard A minor open chord the notes from low to high are, A – E – A – C – E, or root, fifth, root, third, fifth; there are two root notes and two fifths in this voicing
the notes in the following A minor shape are stacked, A – C – E – A , or root, third, fifth, root; there are two root notes in this voicing.
Note: while the chords in both examples are in root position – the A note is the lowest sounding note in each – and both contain only the notes A, C and E, the C and E notes in each chord are stacked differently: fifth, root, third, fifth in the first example, and third, fifth, root in the second; because of the doubled fifth, the first chord also contains more notes than the second. It is these combinations of notes which give each chord its voicing. Aside from voicings in root position, chords may also be inverted (see below).
Often, chord voicings will be the difference between playing a tune authentically or approximately. For example, we could attempt to play the opening riff to Nightrain, by Guns N’ Roses, using open chords instead of the song’s actual voicings (Nightrain sounds a semitone lower than written)
we would quickly hear, however, that while we are playing the same chords as the original, A5, A7, D/A etc, and that some of the inversions found in the Guns N’ Roses original are contained in the open chords, most of the voicings and inversions in each version are different.
It is the use of inversions which helps to give Nightrain’s opening riff its sound. Many of the inversions are cleverly linked by a common note, for example, the A7 and D chord is linked by the note A: the D chord is in second inversion as its fifth is in the lowest part
Also, the note G of the second inversion C chord similarly links the second inversion C chord with the root position G chord
Inversions are taken from the lowest sounding note of a chord, therefore, if another instrument such as the bass, plays a different note below the guitar’s lowest sounding note, the inversion would change. For example, if we played the following hypothetical bassline with the Nightrain opening all of the chords would be in root position.
Clearly, the use of inversions and different voicings can provide interest and character to progressions.
As stated previously, a chord is said to be in root position if the root note is the lowest sounding note of the chord
when analysing a piece of music, therefore, the sounding pitch of all notes must be taken into account when determining inversions (as seen in the Nightrain example above). It is irrelevant how many notes are doubled or the way the chord is voiced above the lowest sounding note; the lowest sounding note always determines the inversion.
If the third of the chord is the lowest sounding note, the chord is in first inversion
If the fifth of the chord is the lowest sounding note, the chord is in second inversion
Seventh chords can also be in third inversion when the seventh note is the lowest sounding note.
Chords which contain extensions above the seventh are typically written as, and referred to using slash chords