It has been unanimously acknowledged that the origin of our classical music is Sama Veda or more simply Saman singing.
Authentic texts like Bharatha’s Natyasastra and Matanga’s Brihaddeshi attribute the art and science of music to the third Veda (Sama) which is the source of the seven notes/Saptaswara that form the basic scale of musical notation. The raga (tonal framework) developed from a series of rhythmic syllables set to a pattern which again can be traced to the tradition of Saman chanting,
Like all ancient treatises of India, the Saman chanting was handed down to generations by the teacher-pupil oral tradition. Interpolations are bound to occur in oral repetition but then, the Vedic chants (Mantras where sound had spiritual connotations) were such that there was hardly any room to meddle. Improvisation in mode of chanting may have occurred decades later but there was never any distortion, so to say, according to Saman music scholars like Dr. A. C. Burnell (1876).
Authorities on the subject state that the modern musical notation by numerals is far more simple than that followed in the Sama Veda chants.
Despite the origin, our musicologists have noted that the Sama swaras/notes do not sound at the same swarasthanas (note position) of our present day classical music notes. The values of sruti are also slightly different, since Samans were chanted with sacred mantras unlike our musical notation to lyrical compositions.
Despite the absence of instruments in very early times of the Sama-music, there was a relativity of pitch from the beginning.
The ancients worked close to Nature in formulating musical syllables by paying close attention to the cries of birds and beasts over a period of time. The fine distinctions may have been noted and made use of to form a scale. The accent all along was a mark of musical pitch. The upper, middle and lower (uttama or tara, madhyama, mandra) were connected with three spots (sthanaas) corresponding to the voice registers. The count and mode of emphasis was by means of finger and hand movements (present day tala).
Since the basis of Sama chant was for rituals to extol and appease the element forces of Nature, the morning chant to Agni (Fire), was generally sung in the bass; the noon chant to Indra was in the middle octave, the afternoon chant to Vishwadevas was in the third octave and on all other occasions it was the middle octave that was usually adopted as it was steady and believed to secure good fortune.
Indian musicologists like Dr. V. Raghavan (The Music of Hebrews-Resemblance to Samaveda chant) were able to trace amazing similarities and strong links to Sama recital and the Jewish liturgical and folk music. The Emenite song and the Sabbath song at synagogues resembled the Sama singing so close as to emphasise the Ga (gandhara), Ri, Sa and that too in the same descending order! What more do we need to aver that music has always been a universal truth.