What Is EVP?
EVP stands for Electronic Voice Phenomena. These are sounds found on electronic recordings that are interpreted as spirit voices. The defining characteristic of EVP is that the voices are not heard at the time of recording. They only show up during playback.
If you have ever been on a ghost tour in San Diego and watched an investigator hold up a digital recorder and say “Is anyone here with us?” – that is an EVP session. The investigator is not expecting to hear a response in real time. They are hoping the recorder picks up something the human ear missed.
EVP recordings are typically short. A single word, a name, a brief phrase. Researchers have noted that the rhythm and cadence often differ from normal conversational speech.
The History of EVP
Friedrich Jurgenson – The Accidental Discovery (1959)
The story of EVP starts with a Swedish filmmaker named Friedrich Jurgenson. In 1959, he was recording bird songs in the countryside outside Stockholm. When he played the recording back, he heard what he believed was the voice of his late mother calling his name.
Jurgenson spent years making additional recordings and capturing hundreds of unexplained voices. He published his findings in 1964 in a book called Voices from the Universe. That book put EVP on the map as a serious area of paranormal research.
Konstantin Raudive – 100,000 Voices (1960s-1970s)
Latvian psychologist Konstantin Raudive met Jurgenson in 1965 and became obsessed with the phenomenon. Over the following years, Raudive recorded more than 100,000 voices using various methods, including a custom diode circuit designed to enhance the recordings.
His 1971 English-language book Breakthrough: An Amazing Experiment in Electronic Communication with the Dead brought EVP to the English-speaking world. For a time, EVP recordings were actually called “Raudive voices” before the term EVP became standard.
Sarah Estep and the Classification System (1982)
American researcher Sarah Estep founded the American Association of Electronic Voice Phenomena (AA-EVP) in 1982. Her most lasting contribution was creating the EVP classification system that investigators still use today – Class A, B, and C. She recorded EVP for decades and was considered one of the world’s leading authorities on the subject until her death in 2008.
The organization, now called the Association TransCommunication (ATransC), continues her work.
The Spiricom Controversy (1980-1982)
Not all EVP history is straightforward. Retired industrialist George Meek and psychic William O’Neil claimed their device, the Spiricom, could produce real-time conversations with the dead. They recorded over 20 hours of supposed dialogue with a deceased scientist.
Nobody was able to replicate the results. Forensic audio analysis later revealed strong evidence of fraud – the two voices never overlapped the way natural conversation does, and vocal characteristics suggested O’Neil was producing both voices, likely with an electrolarynx.
The Spiricom episode is worth knowing about because it illustrates why serious investigators are careful about verification and why the classification system matters.
Frank’s Box and the Spirit Box Era (2002)
In 2002, Colorado-based Frank Sumption built a modified AM radio that constantly scans through stations. He called it Frank’s Box and claimed it allowed real-time two-way communication with spirits. Sumption built just over three dozen of these devices before his death.
His invention spawned the entire spirit box category of ghost hunting equipment, including the popular P-SB7 and P-SB11 models you will see on nearly every paranormal TV show today. We cover spirit boxes in a separate article.
EVP Classification: Class A, B, and C
Sarah Estep’s classification system is the standard used by paranormal investigation teams worldwide, including those of us working in San Diego.
Class A
Clear and distinct. Anyone with normal hearing can understand what is being said without headphones or enhancement. You do not need to be told what the voice is saying – you hear it clearly on your own. Class A recordings are rare. Most investigators go years between legitimate Class A captures.
Class B
Partially intelligible. Most people can hear something, but interpretation varies. Headphones help. Some amplification or enhancement may be needed. This is the most common classification for recordings that are genuinely interesting but not definitive.
Class C
Indistinct. Often sounds like background noise or static. May require significant amplification to detect at all. Different listeners frequently hear completely different things. Skeptics and many investigators consider Class C recordings unreliable because of how easily the human brain finds patterns in noise (more on that below).
How to Conduct an EVP Session
This is the basic methodology we teach people interested in paranormal investigation in San Diego.
Equipment
- A digital voice recorder set to the highest quality settings. WAV format is preferred over MP3 because it preserves more audio detail. Popular models include the Zoom H1n, Tascam DR-05, and various Olympus recorders.
- An external microphone positioned away from the recorder to reduce handling noise.
- Headphones for playback analysis.
- A notepad or phone to log timestamps and ambient sounds.
The Session
- Establish a baseline. Before asking any questions, record 2-3 minutes of silence. This captures the ambient sound environment so you can distinguish genuine anomalies from normal background noise later.
- Place the recorder on a stable surface. Never hold it in your hand. Every finger shift, every sleeve rustle becomes a potential false positive during playback.
- Note every sound source. HVAC, traffic, distant conversations, animals, your own stomach. If you hear it during the session, say it out loud so the recorder captures your acknowledgment. “That was a car outside.” “Someone coughed.” This saves hours of false-positive chasing during review.
- Ask questions with pauses. Ask a question, then leave 10-15 seconds of silence for a potential response. Keep questions simple and direct. “What is your name?” “Were you here before this building was built?” “Do you want us to leave?”
- Use multiple recorders when possible. If something shows up on two recorders in different positions, it is harder to dismiss as an artifact.
- Do not whisper. Speak at normal volume. Whispers sound eerily similar to alleged EVP during playback and create confusion.
- Review carefully. Use headphones. Listen at normal speed first, then slow it down. Compare across recorders. Be honest with yourself about what you are hearing versus what you want to hear.
The Skeptical Perspective
Any honest discussion of EVP has to include what mainstream science says, and it is not favorable.
Auditory Pareidolia
The human brain is wired to find patterns, especially voice patterns, in random noise. This is called auditory pareidolia. It is the audio version of seeing faces in clouds. Studies have shown that when people are told what an EVP recording supposedly says before they listen, they are far more likely to “hear” those words. Without the suggestion, many listeners hear nothing meaningful at all.
Audio Artifacts
Electronic equipment generates noise. Digital recorders compress and process audio in ways that can create artifacts – brief sounds that resemble speech but are byproducts of the recording process. Radio frequency interference from cell phones, Wi-Fi routers, and broadcast signals can also introduce voice-like sounds into recordings.
The Ideomotor Effect
Some researchers suggest that EVP captured during sessions where investigators speak aloud may include unintentional subvocalizations – sounds too quiet for the investigator to notice but loud enough for a sensitive microphone to capture.
Where We Stand
We do not claim that EVP recordings are proof of ghosts. What we can say is that the phenomenon is real in the sense that unexplained voices do appear on recordings under controlled conditions, and the cause is genuinely debated. Some of those recordings are compelling enough that dismissing all EVP as noise and wishful thinking feels like an incomplete answer.
The responsible approach, and the one we teach, is to document everything, control for known explanations, classify honestly, and let the evidence speak for itself.
EVP and San Diego’s Haunted Locations
San Diego has several locations with long histories of reported EVP captures.
El Campo Santo Cemetery in Old Town is one of the most active recording sites in the city. The cemetery dates to 1849, and modern development actually paved over portions of the original burial ground. Investigators working the cemetery after dark have reported capturing voices in both English and Spanish, which tracks with the site’s history as a burial ground for San Diego’s early Mexican and American settlers.
The Davis-Horton House, San Diego’s oldest surviving structure in the downtown area, has produced EVP recordings during private investigations. The building’s age and layered history – from frontier home to boarding house to historic landmark – make it a frequent target for serious investigators.
Heritage Park Victorian Village in Old Town, where several relocated Victorian-era homes sit together, has generated reports of period-appropriate voices and sounds during EVP sessions. Investigators have noted captures that seem to reference names and events consistent with the homes’ original occupants.
Villa Montezuma in Sherman Heights, the ornate 1887 mansion built for musician Jesse Shepard, has its own reputation among San Diego paranormal investigators. Shepard was known for holding seances in the home during his lifetime, which adds an unusual historical layer to any investigation conducted there.
If you have conducted EVP sessions at locations in San Diego and captured something you cannot explain, we want to hear about it. Tell Us Your Story / Location.
Start Your Own Investigation
EVP recording is one of the most accessible entry points into paranormal investigation. You do not need expensive equipment to start. A decent digital recorder and a quiet location are enough to begin.
If you want to learn investigation techniques firsthand and practice at some of San Diego’s most historically haunted sites, book a paranormal event with us. We bring the equipment, the locations, and the experience. You bring the curiosity.
San Diego Paranormal Investigation Tours and Ghost Hunting is the investigation and education arm of Haunted San Diego Ghost Tours – San Diego’s highest-rated ghost tour company operating for over 18 years.