Udgitha (उद्गीथः)

The Sama Veda has special links to Pranavam and Nadhopasana. The Sama Veda Mantras are sung by Udgatri Preists at Vedic rituals. Their singing is known as Udgita. The Pranavam is also referred to as the imperishable Udgita by Chandogya Upanishad, a major Upanishad belonging to the Sama Veda. The Links  between Nadhopasana  and  Udgita of Samans  is hinted by Lord Krishna , when he says that He is the Sama Veda  among all the Vedas. He points out the efficacy of attaining Him thru Nadhopasana  with its roots in Pranavam (Udgitam).

In his Saramati Raga Kriti, Thygaraja expatiates on the origin of Nada from Om. He recognizes the birth of Nada from the interaction of Pranaa and Agni. He points out further that the seven Svaras and Nada originated from the Omkara described by the Udgita of the  Upanishads.

References

1. http://www.ramanuja.org/sv/bhakti/archives/oct95/0085.html Posted by V. Sadagopan | Oct 16, 1995.