I know this feeling .
The voice is in your head but there is no one close by is, Non Proximity hearing. The Brain being every bit as good receiver as it is a transmitter.
My question was...How does that work then ? I had to do some investigating.
My conclusions currently are :
Non Proximal hearing is very common during the Theta state of brain frequency. A number of theory's surround this phenomena.
Theta is a low brain frequency in which REM dream takes place... You will note that dreams seem very real. It is as though ones awareness consciousness is far removed from the head resting on the pillow.
To get to sleep properly..The timeless black void of sleep...Delta frequency it is usual to to pass through Theta in departing Alpha Frequency(restful wakefulness... So in a sense you do traverse these frequencies from deep sleep to total awake and alert Beta.
Interestingly (To me anyway) Mediums..Meditators and Astral Projectee's occupy the Theta state during those activities that they practice.
Other examples of Non proximal hearing that have happened to me while dropping off to sleep.
My name being called, Loud knocking,Music, Crashing noises.
I conclude all of this to be normal, further and more excitingly for me are the accompanying visuals (seeing behind closed eyes) that will start to occur. Now this is the part that a lot of people find difficult.
Once you focus it's gone... caput...disappeared.. Because you bring your attention Alpha, even Beta to bear upon Theta ..You are switching brain frequency and moving away from the subject matter of Theta where you are required to nothing more than passively observe...
Anyway...It's a really interesting subject and I could go on and on about this area of interest but I'd bore off most of you.. So here's a small illustrative read me.
Beta Brain Waves (13-30 cycles per second). The fastest, representing the most intense state of alertness. The result of heightened mental activity. Maximum mind power. All five external senses, logical mind, memory from the five senses & logical thinking.
Alpha Brain Waves (8 to 12 cycles per second) This brain wave indicates a relaxed state of mind.. State of relaxed alertness, good for inspiration and learning facts fast. A meditative mind. In this state tap into internal “antenna” like qualities. Visions, powerful ideas, mindless creation of the incredible. Internal feeling & sensations.
Theta Brain Waves (4 to 8 cycles per second) Deep meditation. Deep inward thought. This is associated with life-like imagination. High state of mental concentration. A magical mind. Internal pictures / visualization. Intuition, inner guidance. Access to unconscious material. Dreaming.
Delta Brain Waves (0.5 to 4 cycles per second) Deep dreamless sleep. Deep relaxation. State of oneness, whole body feeling. Pure being & will.
Note that the lowest range of delta is 0.5 hz and that No Brain activity is 0. This provides a very comforting view of what life is like after physical death may actually be like.. A very deep perpetual sleep. Which should provide some solace to those who have no faith that an afterlife exists...
My next Question was...
What if it's just my imagination?
Gibran says ....."Imagination finds a road to the realm of the gods, and there man can glimpse that which is to be after the souls' liberation from the world of substance."
So my inner skeptic was duly given a proper telling off in so far as I asked/told/admonished myself "Do imaginary experiences lack any authenticity when compared to what is "real"?
Surely your cognitive bias has already hindered you in that respect.
What you believe to be true is only true because you believe it to be so...
Give your guides a chance because what you think is only your imagination might in fact be inspiration.
"
I hope all of that was helpful to you or someone reading it.