"Chord melody" is a style of guitar playing in which the melody of a tune and the chordal accompaniment (harmony) are played simultaneously on the same instrument. Guitar occupies an interesting place in the spectrum of instrument polyphony - it is possible to play melody and accompaniment (and full of rich harmonic possibilities at that) but due to the idiosyncrasies of the instrument it is more challenging than many other primarily polyphonic instruments.
Consider, for example, strictly melodic instruments (such as brass or woodwinds), for which playing a melody and accompaniment simultaneously is simply not possible because the instrument can't produce more than one note at the same time. On the same side of the spectrum we might also put "primarily melodic" instruments (such as bowed strings, or bass) where some polyphony is possible, but full melody and accompaniment playing is not part of typical performance technique due to either the difficulty, or the limited possibilities that the number of strings or the tuning allow.
On the other side of the spectrum, consider a primarily polyphonic instrument like the piano (or others like the harp or accordion). The ability to play a melody and chords simultaneously is a fundamental expectation of pianists in all styles. The most simple version of this might be playing a melody with the right hand, while the left hand accompanies with chordal harmony. The relative ease of this kind of playing on piano is due to both the construction and layout of the instrument (essentially uniform buttons in a row), as well as the available manipulations of the performer: both hands are free to independently control pitch and rhythm, and all 10 fingers are available to play up to 10 (or more) notes simultaneously.
Finally, consider the guitar, which presents unique challenges and opportunities for chord melody playing. The guitar can sound up to 6 notes simultaneously, which, while not as many as a keyed instrument, is enough to produce many varied full chord voicings. For this reason guitar is a shoo-in for a chordal accompaniment instrument, and was original mostly performed as such. Of course, a huge swath of contemporary music has also demonstrated the power of the guitar as a melodic lead instrument.
However, with traditional playing technique the guitarist is limited to note selection using only one hand (usually the left) and producing rhythm only with the other (usually the right). Furthermore, the thumb of the left hand is used to support the neck of the guitar, meaning that the guitarist is essentially limited to using only 4 fingers to select the up-to-6 notes to be played at any time. Altogether this means that to play chord melody style, a guitarist needs to figure out how to play the melody and chords simultaneously with one hand (not two independent hands) and with only 4 fingers of that hand.
In addition to the physical challenges, the standard tuning of the guitar comes with its own mental challenges. A given chord voicing on one set of strings can easily be moved up and down in pitch by moving the 2d "shape" (hand position) up or down the fretboard, but due to the asymmetry of the intervals between strings (a major third between the G and B, versus a fourth between all others) that same chord voicing will usually require a different hand position ("shape") when played on a different set of strings. For even one chord voicing a guitarist may have to learn 4 or more different shapes in order to play that voicing in different places on the guitar.
Finally, even to play a melody by itself without simultaneous accompaniment requires a non-trivial decision process for a guitarist. For a single given note as notated in sheet music, for example, on a piano there is exactly one place to play that note, but on a guitar there are often 4 or more equally valid places to play the exact same note (for a 24 fret guitar, the highest open E note can be played in fully 6 different places on the fretboard). To play a written melody exactly as written on piano is an entirely prescriptive process: there is a one-to-one mapping between the written notes and the piano keys. To play a written melody exactly as written on guitar is already an interpretive process: the guitarist has to decide in which position to play each note: maybe positions that make it easier to play physically, maybe ones that make it sound the best, maybe ones to fit some other consideration such as positions that allow particular options for simultaneous chord accompaniment, etc.
Thus, the challenge for a guitarist to learn chord melody style playing is multifold. For a simple melody with accompanying chord symbols (as in the case of a jazz leadsheet) the guitarist needs to:
Given this, a naive or brute-force process for learning how produce chord melody arrangements might look something like:
While those basics would form a great foundation for a general ability to produce chord melody arrangements, trying to learn by brute-force memorization of chord voicing and melody note combinations is imposing, the process is likely to be tiring, and often may feel unmusical. Ideally, one might develop this ability instead (or additionally) by learning existing chord melody arrangements, and eventually generalizing the chord voicing and melody combinations to new pieces.
There is no question that learning existing pieces is an effective way of learning any musical language, but the breadth and variety of concepts found in professional chord melody arrangements may be overwhelming for beginners, and limiting oneself to learning existing arrangements may not be as immediately and effectively generalizable as a more focused and systematic approach. Perhaps there could be a learning approach that strikes a balance between brute force permutations of melody and chords (generalizable but overwhelming and not musical), and the complexity of full arrangements (musical but not generalizable, maybe still overwhelming).
chordmelody.io exists to support the learning and pedagogy of guitar chord melody style playing by generating chord melody études using real jazz tunes (or any existing tunes), using a limited subset of fundamental genre-specific chord voicings, and a systematic approach to matching melody and chord positions. The intent is ensure that the playability of these arrangements is mostly uniform, and that across different tunes the student begins to see the same ideas, the same chord voicings, repeated in different contexts. The student will simultaneously be learning full and (hopefully) nice-sounding arrangements of real tunes, and also be learning fundamental building blocks that they may eventually apply to their own arrangements.
For now, the chord voicings in the app are limited to "drop" voicings. For an explanation of drop 2 voicings (for example) and how they apply to guitar, as well as visual fretboard diagrams showing these voicing all across the guitar neck for the most common chord types, please visit the following link: