This classification system is widely used by investigators and others in the field who analyze paranormal audio. It is a system that was developed by the members of AA-EVP.

Class A

A distinct voice or sound that is clearly understood, universally accepted and undisputed. It can be heard without headphones by anyone with normal hearing, and without being told or prompted to what is being said or heard.

Class B

This class of voice is more common and can be heard over speakers by most people. It is usually distinct, however some may not be able to hear or understand what they are listening to until told what to listen for. Everyone may not agree as to what is heard when listening to a class B and some individuals may need the use of headphones

 Class C

A voice or sound that has paranormal characteristics, requires the use of headphones, and although it is often indecipherable and unintelligible, may contain one or two words that are clearly understood. Some investigators apply objectivity and disregard it, but may save it for reference purposes.