Singing is particularly powerful if practised in a group. Each person’s length of breath will be different, so new notes will be starting all the time. Sometimes the effect will be harmonious and sometimes discordant. Lack of harmony does not matter and is part of the experience of the exercise. When the sound is discordant, allow this to be interesting rather than experiencing it as unpleasant.
Relaxing into Meditation, Ngakma Nor’dzin, Aro Books worldwide, 2010, ISBN: 978-1-898185-17-8, p22