The Yoga of Sound (usually called Nada Yoga, one of the three principal forms) is an excellent spiritual technique that is not taught or talked about that much in the West. Here is a link:
http://www.yogamag.net/archives/2004/6dec04/nada.shtmlAnother article (part 1):
http://www.spiritsound.com/nadayoga.html(part 2):
http://www.spiritsound.com/toning.htmlThis technique is usually called the tone meditation in the West. It is a very powerful technique to connect to a part of your consciousness that is usually hidden. Western techniques are usually taught to students who have been meditating to music for a while. It is taught as a whole new meditation technique and the two should not normally be combined (at the beginning).
The key difference is in the music meditation, the eyes are closed. In the tone meditation, the eyes are open. This keys the body and brain into the fact that this is a different technique. Also at the begining, ear plugs are normally used to block external sound ("struck sounds") and allow greater focus on internal sounds ("unstruck sounds").
Eventually one reaches a level where they find "the tone" ("para nada" or transcendental sound). Then start looking for the second sound (just like the first article says).
Coyote