EMF meters are scientific instruments used to detect and measure fluctuations in both the AC and DC electromagnetic fields. The theory of using EMF meters is that when a disturbance exists in an area where there is no normal electrical explanation, paranormal activity may be occurring. It is believed that when a spirit is manifesting, it draws energy from the surrounding area causing a shift in the electromagnetic field.
The various audio equipment is used to capture and record electronic voice phenomena – or EVPs. EVPs are typically voices that are recorded on digital audio. These voices are not heard at the time of recording, they are only heard after the recording is played back.