The Sama Veda is the Yoga of Song. It consists of various hymns of the Rig Veda put to a different and more musical chant. Hence the text of the Sama Veda is a reduced version of the Rig Veda.
Its secret is in its musical annotation and rendering. The Sama Veda represents the ecstasy of spiritual knowledge and the power of devotion. The Rig Veda is the word, the Sama Veda is the song or the meaning. The Rig Veda is the knowledge, the Sama Veda its realization. Hence the two always go together like husband and wife. The Rig Veda is the wife and the Sama is the husband.
The Sama-Veda is the “Veda of chants” or “Knowledge of melodies“. The name of this Veda is from the Sanskrit word saman which means a metrical hymn or song of praise. It consists of 1549 stanzas, taken entirely (except 78) from the Rig-Veda. Some of the Rig-Veda verses are repeated more than once. Two major recensions remain today, the Kauthuma/Ranayaniya and the Jaiminiya. Its purpose was liturgical and practical, to serve as a songbook for the “singer” priests who took part in the liturgy. A priest who sings hymns from the Sama-Veda during a ritual is called an udgat, a word derived from the Sanskrit root ud-gai (“to sing” or “to chant”). A similar word in English might be “cantor”. The styles of chanting are important to the liturgical use of the verses. The hymns were to be sung according to certain fixed melodies.
Samaveda consists of a selection of poetry mainly from the Rigveda, and some original matter. It has two parts, Purva-Archika and Uttar-Archika, containing verses addressed to the three gods Agni , Indra and Soma. The verses are not to be chanted anyhow, but to be sung in specifically indicated melodies using the seven svaras or notes. Such songs are called Samagana and in this sense Samaveda is really a book of hymns.