The absence of naad sound when sitting to meditate is not necessarily a negative. One may or may not tune into naad, it depends on the session and on the time and place and other features which are beyond control.

It is best to be on the lookout for naad and to grab it or access it, if you become cognizant of it. Otherwise simply note what happens during meditation because if naad is not happening then something else is taking place. Describe what that something else is in your journal report.

It is important to feel a sense of moving in a certain directly, as if you are progressing say up or down a river and you can tell by the changing scenery that you are moving down or up in reference to the river bank. Sometimes hearing naad is not part of the progression, just as if there is a canoe in a river, the boatman may not hear the ripping sound of the water but may see the passing vegetation or clouds over head.

Just after breath infusion, usually there is no cognizance of naad sound resonance but there should be an accounting of the energy infused into the subtle body during the breathing session, so that in the meditation you notice what that energy did in the psyche and as to the extent of its influence.

Then when that energy subsides, fades down then you should get your focus in order and continue doing whatever focus you should do at your stage of practice. If that focus is naad, then so be it. But it may be something else.

Can you stay with the focus or is that attempt hampered. If it is hampered, what hampers it? Can you remove the impediment or is it so powerful that it overpowers you and does not allow you to connect as per the objective?