Shaman as: singer, "one who knows", rainbow-bridge

Spirits

Also the beliefs related to spirits can explain many different phenomena too, [Hoppál 2007c: 18] for example, the importance of storytelling, or acting as a singer, can be understood better if we examine the whole belief system: a person who is able to memorize long texts or songs (and play an instrument) may be regarded as having achieved this ability through contact with the spirits (for example among Khanty people).Hoppál 2005: 99]

Knowledge

Cognitive, semiotic, hermeneutic approaches

As mentioned, a (debated) approach explains the etymology of word “shaman” as meaning “one who knows”. [Hoppál 2005:14] [Diószegi 1962:13] Really, the shaman is a person who is an expert in keeping together the multiple codes through which this complex belief system appears, and has a comprehensive view on it in their mind with certainty of knowledge. [Hoppál 2005:15] The shaman uses (and the audience understands) multiple codes. Shaman express meanings in many ways: verbally, musically, artistically, and in dance. Meanings may be manifested in objects, such as amulets. [Hoppál 2005:14]

The shaman knows the culture of their community well, [Pentikäinen 1995: 270] [Boglár 2001:24] Hoppál 2005:25–26,43] and acts accordingly. Thus, their audience knows the used symbols and meanings — that's why shamanism can be efficient: people in the audience trust it. Such belief system can appear to its members with certainty of "knowledge" — this explains the above described etymology for the word “shaman”.Hoppál 2004:14]

Drum as the rainbow bridge

Drum is used by shamans of several peoples in Siberia; same holds for many Eskimo groups, [Barüske 1969: 24, 50–51] although its usage for shamanistic seances may be lacking among the Inuit of Canada. [Kleivan & Sonne 1985: 25]

The beating of the drum allows the shaman to achieve an altered state of consciousness or to travel on a journey. The drum is for example referred to as, “‘horse’ or ‘rainbow-bridge’ between the physical and spiritual worlds”. [Maxfield, Melinda. "The journey of the drum." ReVision 16.4 (1994): 157.] The journey mentioned is one in which the shaman establishes a connection with one or two of the spirit worlds. With the beating of the drum come neurophysiological effects. Much fascination surround the role that the acoustics of the drum play to the shaman. [http://texts.00.gs/Siberian_Shamanism,_2-D&C.htm Siberian shamans' drums] are generally constructed of an animal-skin stretched over a bent wooden hoop, with a handle across the hoop.

There are two different worlds, the upper and the lower. In the upper world, images such as “climbing a mountain, tree, cliff, rainbow, or ladder; ascending into the sky on smoke; flying on an animal, carpet, or broom and meeting a teacher or guide”, [Maxfield, Melinda. "The journey of the drum." ReVision 16.4 (1994): 157.] are typically seen. The lower world consists of images including, “entering into the earth through a cave, hollow tree stump, a water hole, a tunnel, or a tube”. [Maxfield, Melinda. "The journey of the drum." ReVision 16.4 (1994): 157.] By being able to interact with a different world at an altered and aware state, the Shaman can then exchange information between the world in which he lives and that in which he has traveled to.

For more information see:
http://dic.academic.ru/dic.nsf/enwiki/16431