Updated: May 3
Electronic Voice Phenomena (EVP) are voices found on electronic recordings that were not heard during the recording. Parapsychologist Konstantins Raudive popularized EVP’s in the 1970s. Most consider EVP to be spirits communicating with the living.
So how do we capture the EVP? Honestly, no one knows for sure. Let's first understand how a microphone works (fundamentally). Sound is air molecules bouncing into one another creating a force. This is why you can feel bass. This force pushes against the diaphragm in the microphone and as this diaphragm moves, it creates voltage. This voltage is recorded and when played back that same voltage is applied to a speaker which works in reverse of a microphone. In theory, you can turn a speaker into a microphone. So, do the spirits or ghosts speak, like us, and move air molecules that play against the diaphragm, or does the spirit use some form of electrical energy and imprint through the voltage recorded from the diaphragm?
This is why I like to use condenser microphones. They require external power and are extremely sensitive. They, in theory, should pick up on voltages much easier than a standard dynamic microphone. The polar pattern is insignificant in catching an EVP. The standard cardioid microphone will do just fine.
When playing back a recording it is sometimes helpful to clean up the audio. I like to use Audacity. It is free and powerful. I also use Adobe Audition but find myself using Audacity because it is simple to remove noise.
In Audacity, to remove noise, import your audio file. Select a region that has no talking but has “room” noise. Go to Effect then Noise Reduction. Click on Get Noise Profile in Step 1. This will teach Audacity what the noise profile looks like. Next, select the entire audio clip and, again, select Effect and Noise Reduction. This time select OK in step 2. Next, let's Normalize the audio. This will raise the volume without clipping. With the audio clip selected, click on Effect and select Normalize. Defaults are fine, select OK.
This should have cleaned up the audio file making the EVP stand out. Or maybe help you locate an EVP you missed otherwise.