A melody is most simply described as a series of pitches sounded in succession, but this definition does not explain how melodies are built and how they function in music. In this section we will explore the concept of melody in greater detail and discuss the relationships between melodies and accompaniments, the sounds meant to support and enhance melodies.
Contour describes the linear motion of a melody up and down. Does it generally ascend or descend? Does it come back to the same pitch on which it began? Does the melody use large intervals or small ones?
When melodies move by whole or half steps (like a scale), this is conjunct motion. Movement in larger intervals is called disjunct motion. Most melodies combine the two, as in this example from "Twinkle, Twinkle". In this melody the contour begins with a leap upwards (disjunct motion), then a gradual descent using smaller intervals (conjunct motion) that finishes on the original pitch.
Melodic contour is also important in the history of music notation. Before our current system of notation was developed, musicians sometimes wrote down the contour of a melody in order to remember it. Over time, composers and performers started adding horizontal lines to make sure that when the same pitch returned it would be written at the same height, which made their contour drawings more specific, more accurate, and easier to read. They started with only one line, but they soon began adding more. Sometimes the lines were even color-coded, using red for C and yellow for G, for example. Color-coding fell out of practice, but musicians kept adding lines until there were five staff lines, as in our modern notation system.
Range refers to the total range of pitches encompassed in the melody: how high and low the melody goes. If the score does not indicate which voice or instrument should be used to perform the music, the range can be used to help determine which voices and instruments are appropriate for use. For example, if the range includes pitches that are too high or too low for a voice then it must be played on an instrument. For more on instrument ranges, see Timbre.
A motive or motif is the shortest possible melodic unit and may consist of as few as two different pitches, as in Beethoven's 5th Symphony.
Beethoven's 5th Symphony
Motives are the musical equivalent of a catch phrase or slogan and are often used in that capacity in commercials. Notice the motive on "by Mennen" and "Hot Pockets" in these commercials:
Hot Pockets Commercial
Motives may also be incorporated into a larger melodic unit: a phrase. Phrases are the musical equivalent of sentences, clauses, or lines of poetry. They can be divided by commas in lyrics (for vocal music), breaths (for voices and wind instruments), rests (silences), or simply by the shape of the melody. Phrases tend to be lyrical (singable, song-like) even if they are performed by instruments, and they usually occur in regular lengths.
In musical analysis, phrases are identified by lower case letters: "a" for the first, "b" for the second, etc. If the phrase repeats, the letter is used again. Also, phrases tend to end with cadences, which are melodic and harmonic formulas that bring a sense of closure to the phrase.
Antecedent and Consequent Phrases
Two important and interrelated types of phrases are antecedent and consequent phrases. Antecedent and consequent phrases occur when one phrase seems to ask a question (the antecedent) and the other seems to answer it (the consequent). The antecedent phrase sounds unfinished or unresolved when it ends because its final pitch is not the tonic pitch. The consequent phrase then responds to the antecedent and finishes with a stronger sense of resolution, often by landing on the tonic pitch.
When melodies are written specifically for a particular instrument or voice, the composer will capitalize on the strengths and avoid the weaknesses of that instrument or voice. This is called composing idiomatically. For example, some melodies are more suited to instruments than voices: those that use large leaps (intervals) between pitches, those that are too high or too low for voices, or those with very fast passages, for example. Voices, on the other hand, are often considered more expressive than instruments, particularly because they are uniquely capable of performing lyrics. So, when composers are writing melodies, they consider these strengths and weaknesses and adjust their compositions accordingly.