Once I had tried to practice concentration through various methods, they were all effective in achieving it more or less.
One of them was following the Nada which is inside you. The technique is quite simple, insert your forefingers into both the ears and block all sounds from outside, close your eyes. And listen, at first you would only be able to hear the chirrup of the crickets, some practitioners say that it is coming from within, but I have my doubts on it. It could also come from outside, their noise being penetrating and persistent.
So seal your ears more closely, if possible think of the chakra called the Mooladhara. You need not visualize it or think about its properties. Think of the base of the spine and continue listening. Soon the noise of the crickets would be replaced by a humming sound as if you were near the sea. This of course is the effect of the blood coursing through your veins in that area.
Continue your effort. Very soon there would be a faint strain of music, just like the music made by the mosquitoes; if you can hear it then you have achieved some progress in your effort at concentration. There would soon be other sounds as well; I used to hear the beating of drums and other instruments inside. If you do it for some time everyday when you are quite and alone you will soon start to hear this inner music clear enough so that you can distinguish it easily from others.
If you continue with the practice you would be able to hear the music going on within you even without closing your ears and at all times by thinking about it. It is said that the AUM resides at the root chakra and is audible to the inner ears of the Yogis, so practicing this technique also may be a way to reach the state of yoga.
I have suggested this as an easy exercise to achieve concentration. Everyone is curious to know what really goes on inside us and would normally be more enthusiastic to check it out.
Listening to the Anahata Sound
There is a variation to this practice. It is aimed at hearing the Anahata Dwani or the pulse coming from the Anahata Chakra or the Heart Chakra. This practice doesn’t involve closing of the ears. Instead it tries to tune in to the Anahata Dwani by doing Nadi Sudhi Pranayanma or making the nerves clean.
I have explained the practice of Nadi Sudhi Pranayama elsewhere I think. If not here is it. Close the right nostril and inhale through the left for say 12 seconds. Then close the left nostril and exhale through the right for twelve seconds. Now inhale through the right as before and exhale through the left. This completes one round of Nadi Sudhi Pranayama. You can keep count by counting one two three if you want.
Some say five rounds like this in morning noon evening and night for three months would enable you to hear a particular sound in the right ear. This is not taken as the Anahata sound but a forerunner of it. If you concentrate on it the sound would appear like that of cricket and then change into that of a humming bee.
With the deepening of the concentration it would change to the sound of a bell or a conch. Also this sound is likely to shift to the back of the head from the right ear and might feel coming from the back bone later. The real source of this sound is said to be the heart or the navel.
If you want to follow this practice you need to close the eyes and sit erect while following the Nada.