Cantes libres is a Spanish expression that literally means "free songs""". It is applied on any flamenco palos (musical forms) in which there is no recognisable metre (music) or rhythmic pattern. The melody thus flows freely, unconstructed by metre, so singers can shorten or lengthen musical phrases at will, as long as they respect the basic melodic line of the style they are singing.
The meaning of this expression should not be confused with concepts like rubato or ad libitum which usually refer to a relative freedom of the musician in following the time signature. In this type of singing there is no time signature at all, so freedom is absolute, and the only restrictions are those imposed by the traditional basic melody.
Roles of guitar and dance.
When these palos are played in the guitar, either as accompaniment or as solo, they are known as "toques libres", meaning "free guitar playing". The guitar accompaniment used for most of this "palos" (when they are accompanied) consists in short musical phrases leading to a chord that the singer has previously reached at the end of a line of verse. So the function of the guitar, more than really "accompanying" the melody throughout, consists in responding to the singer and underlying the harmonic progression of the song, plus adding a chord occasionally to support the singer. Guitar written scores for "toques libres" do not include any time signature for the totally free sections. However, falsetas (guitar solo interludes between stanzas) can include sections with a definite time signature.
Owing to their lack or regular rhythm, these "palos" are not normally danced. However, from the 1960s there was a tendency to create choreographies for them, as they provide an opportunity for the dancer to show other aspects of flamenco dance, like "braceo" (movement of the arms).
Palos classified as cantes libres.
The "palos" traditionally classified as "cantes libres" are all derived from earlier rhythmic fandangos.
Other palos with more or less free rhythm.
Apart from the styles usually called "cantes libres", there are other "palos" to which this term could be applied, even if traditionally it is not. Such is the case of the group of "palos" known as Cantes a palo seco (that is, "Songs a cappella"), also known as the toná group. It comprises tonás, martinetes and carceleras, saetas, debla and trilla. Although percussion can be added to them, its function is not to constrain the melody to a rhythm: it is rather added to create ambience. When these styles are sung as a basis for the dance, they are known as "martinetes", even when they include other styles of this group.
There is, therefore, a reversible tendency in flamenco: many styles that originally started as rhythmical and dance-oriented were later slowed-down and eventually lost their link to dance and their metre subjection, while other styles, originated as free songs, were later adapted to a rhythm to make them apt for dancing.
Discography.
BLAS VEGA, José (compiler) "Magna antología del cante flamenco", CD edition, 1982, Vols. I, VII, VIII, IX,