I have learned an enormous amount from the best EVP specialist I know, a man on the team, API, that I recently joined. I have admired his work in the field for years and he has taught me much about the best methods. You can hear many of his amazing EVPs on the site (API link above).
Recorders: Digital recorders and analog (cassette) are the two most popular devices for EVP sessions.
The pro's of digital recording devices are that they are easy to handle and have little in the way of mechanical noise and are easy to plug into your computer and listen to on programs like Audacity.
With cassette, some people believe that the magnetic tape can be better affected by ghostly imprints, but they need an external plugged in dynamic mic to record away from the noisy motor and cassette. They also need to have their tapes often changed, do not have a time stamp, and are much more difficult to transfer into an audio version for online.
1. You should use about 4 or more recorders around the periphery of the room. The reason for this is that typical EVPs will show up on one recorder and not the others. If an EVP comes out on all recorders, it was something in the room that sounded, not an EVP. You have a better chance to record an EVP if you have more devices and you cover more of the room in case this phenomena is actually location-dependent.
2. You need to tag. When you do recordings, give 15-20 seconds between questions. And, tummy rumbling, cars going by, someone coughing, all need to be called out so the person listening to the recording later on can determine what was phenomena and what was explainable. Stomach growls can really sound like voices. Be careful about that.
3. Do not whisper. It sounds like an EVP. If you are speaking at a clear speaking level, then whispers can be determined more easily as EVPs.
4. Do not hold the device in your hand and walk around, your hand, your clothing, the air movement all cause unexplained noises.
Classes of EVPs
A: Sounds like language and people need no prompting to figure out what it is saying.
B: Sounds like language, but everyone hears something slightly different.
C: Sounds, but not necessarily language.
I was lucky enough to help out on teaching an EVP class with my mentor and it was fascinating to listen to him explain the methods and let people know that they should just toss out what they see on TV ghost hunting shows--it's entertainment and not method.
You should ideally bring all your members out of the building or have them together around the table while you do EVP so everyone is accounted for. As well, place a recorder or a camera at each entrance and exit to the building so shenanigans can be ruled out.
When we set up at Birdcage in Tombstone, we set a recorder outside of the manager's door. She was supposed to be in there all evening working on stuff, but we needed to know if she did leave to use the restroom or go somewhere so that sounds could be attributed to someone loose in the building or not.
Also, a great deal of times, a question is asked in one room and answered in another, so just because you're doing an EVP session in the living room, doesn't mean you won't get an answer in a bedroom.
I hope to bring you a lot more amazing findings and experiments the team will be doing in the future. Y'all know me. I'm all about the theories and experiments!