Types of Sleep

[HisServant]

I've really been confused about this topic for the past few weeks so I thought I would ask about it. I tried looking through other topics but because my knowledge/terminology is limited I kept getting even more confused. Could someone help me understand what the types of sleep are?

 

I commonly drift into a sleep where there is complete stillness and peace but many gurmukhs have said to try and stay awake/focus on jaap. I recently came across this video and it gives a decent explanation of what happens: 

 

 

But my question is - is any spiritual progress being made in this sleep? Why don't I hear anything in this sleep? What has to occur on a sukham level for sound to arise? I think the main confusion has to do with the fact that the mind is "still" (while in that sleep) but there is no sound - But I thought sound would be heard when the mind is still. Many other sounds are heard outside of sleep but none of them are true shabad. 

 

Just as an FYI - these are just questions that I keep having and want to clear them up. I'm not trying to stay in sleep for long periods of time. It happens frequently but I go back to gurmantar as soon as I'm awake. 

[Sat1176]

You can make effort on this side, but once the surti crosses over into deep sleep you are no longer in control. You will have to patiently wait for His grace, and it will happen when you least expect it.

[sarabatam]

I think its combination of perfect stillness from deep sleep state and pure awakefulness from wake state, perfect equilibrium- achal morat.