Hello Aras:
This post is based on the assumption that a spirit might be trying to bother you. "Assumption" is the word, because I can't say for certain what's happening with you. I'm considering this possibility, because I don't know what the sound you hear has to do with a typical out of body experience. It is also possible that the presence of a spirit, might be causing the vibrational state to happen for you.
How do you feel now? Despite some fear you might have about the episodes you experienced, do you feel like your yourself? If so, this suggests that if indeed some spirit is trying to give you a hard time, it doesn't really have the power to do anything to harm you.
Except to try to scare you with those cheap Hollywood sound effects. If it really had the power to do something significant, I doubt that it would resort to such cheap tactics. Perhaps it is a low vibration earth bound spirit that gets off on scarring people.
Send it some love, and let it know that your committed to something way beyond it's meaningless games. Suggest that it stop wasting its time hanging around the physical, and that it instead seeks a way in which it can find real happiness. Ask your guides to contact this lost spirit's guides, just in case they aren't around.
If you haven't contacted your guides (guide), don't worry, because your guides can hear you. Tell the spirit to see its guide. If you get the sense that it's denying the presence of a guide, insist that its guide is there, and won't stop being there simply because it won't acknowledge its presence.
If you can't see or hear this presence long enough, this is okay. Instead just go through the above with your imagination. Since your imagination represents thought energy, the spirit that might be around can't hide from your imagination. And imagination comes from within, so trust it. Just be sincere in your purpose, and you'll be okay.
If you do this, you'll be a service to yourself, the lost spirit, and whoever else it might be annoying with its cheap scare tactics.
There is even the possibility that one of your own guides is making this noise, in order to help you get over some fears you have. Doing what I suggest could help you get over them.
P.S. The fact that you are free to read this, shows that you have nothing to worry about. The love in your heart is much stronger than anything a prankster spirit might have.
Also, sometimes sound effects do come with out of body experiences. Does the sound you hear actually sound like a voice, or does it sound like a roaring or rushing sound, that something other than a voice would make?
Here's a post with a similar experience.
http://www.afterlife-knowledge.com/cgi-afterlife-knowledge/yabb/YaBB.cgi?board=a...