Thanks for sharing! I’ve often speculated that absorption in naad sound resonance would yield similar results as mindfulness of breathing (anapanasati). It might be that one-pointed concentration, on any object, leads to absorption, in which one is disconnected from the 6 gates, namely the 5 senses and the mind. It’s a great accomplishment.  A weight or burden is removed when one is isolated from the sense gates and the mind.  It’s a relief to be freed from sensuality. Whenever you enter this state, just observe it and see where it leads. And keep us posted!