Concentration of Mantra

The mantra is like a rocket engine that propels the mind beyond the "gravitational fields" of the lower levels of consciousness, through all the turbulence of the subconscious mind, to the super-conscious - and beyond. Thus, a correct process of meditation involves the generation of immense psychic energy through intense concentration of the mantra.
Some system of meditation which involve internal repetition of certain sounds, advise the mediators not to concentrate on them. Such techniques are quite relaxing and refreshing, but for spiritual elevation, concentration is essential - the intense effort to focus the mind on the mantra. Like the farmer whose mind was concentrated on his sick son, or the chemist concentrated on his research, or the medium concentrated on her crystal ball - the fixed attention of the mind on any object of thought subtler levels. Experiments on Ananda Marga mediators whose process begins with concentration have shown that, rather than being asleep or passively relaxed, their bodies and minds are in a state of intense physiological activation; more energy, rather than less, is flowing through them.

Three qualities of Mantra: One-Pulsative
What is th especial effect of the mantra, that by focusing the mind on it, one can transcend the ignorance and illusions of the lower mind.
A mantra must have three qualities to hold the restless mind steady, to energies it and to transport it to subtler realms. It must be pulsative, incantative and ideative.
First, it must be pulsative. It must be of two syllables so that it can flow rhythmically with the breathing, for the breathing has a profound effect upon the state of one's consciousness. You may have noticed that whenever you are angry or upset, your breathing is fast and short; but when you are absorbed in any task, you naturally breathe slowly and deeply.
The functioning of breathing is closely associated with the flow of vital energy in the body, called Prana which is turn greatly affects the mind. If the breathing is fast and irregular, the Prana becomes unsteady and agitated; the mind becomes disturbed and perception and thinking are unclear. Thus control of breathing (Pranayam) is an important part of yoga training. The more the breathing is slowed and regulated, the greater the composure in the Prana, and the greater the concentration and control of the mind.
Once there was a minister who had greatly displeased his king. As punishment, the king ordered him imprisoned in the top of a very high tower, and the minister was left there to perish. That night, the minister's faithful wife came to the tower, crying to see if there was any way she could help him escape. He told her to return to the tower the following night, bringing with her a long rope, some string, some silken thread, a beetle, and a pot of honey. Wondering at this strange command, the wife obeyed, and the next night brought him the desired articles. The minister directed her to tie the silken thread firmly around the beetle's leg, then to smear its feelers with a drop of honey and place it on the tower wall, with its head pointing upward. Attracted by the scent of the honey, the beetle crawled slowly up the wall, drawing th silken thread behind it. Hours later, it reached the top, and the minister caught it and untied the silken thread. Then he told his wife to tie the other end of the thread, dangling on the ground, to the long string. The minister then pulled up the thread until he could grasp the end of the string. Next he instructed her to tie the rope to the other end of the string, and pulling up the string; he grabbed the rope and tied it to the tower window - and slide down to freedom.
The silken thread is the motion of breathing; the string is the Prana or vital energy, and the rope is the mind. By controlling the motion of breathing, we can gain control over the Prana; by controlling the Prana, we can control the mind. Then we attaing liberation from all bondages.
Thus the mantra must be of two syllables so that its slow and rhythmic internal chanting will serve to slow the breathing, steady the Prana, and calm and control the restless wandering of the mind.