In the key of C, the drone is said to mimic the sound of Om or Pranava, the highest sound vibration, promoting feelings of peace, relaxation, harmony and unity, a valuable tool for overcoming suffering and the sense of limitation or maya.
While there is no substitute for live music, this recording on YouTube is a pretty good substitute. It is a high quality recording, and long enough to use for meditation, chanting or overtone singing.
One of my students even suggested using it instead of an alarm clock in the morning. What a great way to get up on the "right side of the bed"!