The block chord, also known as “chord melody”, is a musical technique used by jazz musicians since the end of the 1950s. It consists in building an agreement under each note of the melody. This technique can be used by any polyphonic instrument such as piano, guitar or vibraphone.
As opposed to arpeggio chords, the “chord style block” is the way to play the chord, tacked in one go, without detaching the notes from the chord one by one.
At the piano
At the piano, both hands operate in parallel, simultaneously and only flatten chords, to the rhythm of the melody. The phrasing of the left hand is thus modelled on that of the right hand from where the other name of this technique: “locked hands”. Each hand plays several notes simultaneously (hence chords of 4 to 10 notes, mostly in “closed positions” in the medium register of the instrument). Harmony usually proceeds by parallel movements but less agreed solutions can be used. Thus Shearing voicings (or broken chord) were made popular by George Shearing, although initiated by Phil Moore.
The block chord is used frequently to reinforce the melody, bring it out, when it is rather of a style swing, for example to evoke the “riffs” of a section of brass or to make the tension grow during a solo. The technique was mostly used by jazz orchestras such as those of Duke Ellington or Count Basie.
Red Garland was one of the first jazz pianists noted for his use of the chord block. He played a 7- or 8-note accompaniment behind the melody, often on fixed chords in the left hand and an octave in the right hand, with one or two notes on the inside. Excellent examples are recorded on his recordings with the Davis Davis quintet. Bill Evans also made an impression for his block-chords with Miles Davis’ orchestra in 1958. We can also mention Erroll Garner, Jimmy Jones, Bobby Timmons, Wynton Kelly, André Persiani …
On the guitar
On the guitar, the technique is developed on the central strings and more often referred to as “chord melody” (i.e. “chord melody”) or “comping”.
Guitarists such as Johnny Smith, Jim Hall or Joe Pass have helped popularize this technique on guitar, a technique that John McLaughlin and Ron Eschete are two of the leading specialists.
One of the ways to harmonize a piece for jazz pianists is to use the block chords: the hands move in parallel and play a chord on each melody note. It is actually a derivative of a technique used by jazz arrangers for winds in orchestral formations.
There are a variety of methods to get the block chords that will accompany the melody.
- The block chord that we could call generic, which simply describe the rules stated above.
- Shearing voicing (in reference to George Shearing) with an additional fifth that emphasizes the melody, an octave lower.
- The so-called drop 2 (actually not really block chord, but considered as such), the second voice from the top is transposed an octave lower.
If the melody note is part of the chord, then the chord notes are also chosen to form the chord block. If it is not part of it you can use a diminished chord for example (stacking of minor thirds). If the melody note in question is considered a passing note, you can choose a diminished chord or a chord increased or decreased by one semitone. The chord can also be converted with a 6th, but that’s not a rule.