In nada sanchalana you will be required to move your awareness through the arohan and awarohan psychic passages. Arohan is the ascending frontal passage and awarohan the descending passage.
As you rotate your awareness through these psychic pathways try to feel that each chakra and kshetram is being pierced in turn by a powerful flow of prana. If you wish you can imagine that each of the centres is like a bead and that together they form a chakra-kshetram mala. Imagine that each bead is being pierced and threaded by a sharp needle of prana. This penetration should be more of a feeling than a thought. Try not to bring in intellectual speculation.
When your awareness reaches bindu at the top of the arohan you should mentally say the word ‘bindu’ three times.
On reaching mooladhara at the bottom of the awarohan passage you should mentally repeat ‘mooladhara’ three times.
As your awareness passes through each of the other centres mentally say its name once.
Chanting of Aum
You should chant the mantra Aum as your awareness descends through the awarohan passage. The sound must be loud and explosive as it starts from bindu. Then as your awareness moves through the chakras in the spine the sound should become a humming sound. Try to feel the sound piercing the chakras in turn. In fact, you should identify the sound with the flow of prana. The sound should end when your awareness reaches the mooladhara chakra.
We can summarize the process as follows: bindu to ajna – explosive sound; ajna to mooladhara – a humming sound concentrated in the spine.
The sound of Aum should be loud and penetrating; in this way it has the greatest power to sensitize the chakras. However, it is not always possible to make a lot of noise, especially if it is early in the morning, as you may disturb other people living in your house. Under these circumstances you can chant Aum as a loud whisper.
Preferably sit in padmasana or siddhasana (siddha yoni asana for women). These are the two sitting poses that have been taught by tradition. However, if you cannot sit in any of these asanas choose any other comfortable sitting position such as vajrasana, ardha padmasana, etc. You should remain in the same sitting position that you used for kriya number 2.