Spirit box, ghost box, EVP: a glossary
"Spirit box" and "ghost box" name the same device: a radio receiver whose scan never locks on a station. EVP is the practice of reviewing recordings for voices not heard at the time, and ITC is the umbrella term that covers both.
| ITC | Instrumental transcommunication: the umbrella term for using any device — radios, recorders, cameras — in attempts at communication. Everything below is a kind of ITC. |
|---|---|
| EVP | Electronic voice phenomenon: words perceived on a recording that were not heard when it was made. An "EVP recorder" is any recorder used that way; the Panasonic DR60 is the famous one, for technical reasons unrelated to ghosts. |
| Spirit box / ghost box | The same device under two names: a radio whose scan never stops on a station, so it plays fragments of broadcasts separated by noise. "Ghost box" is the older term, from Frank Sumption's device; "spirit box" spread with the P-SB7. Hardware boxes sweep AM/FM; apps sweep internet radio streams. |
| Sweep | The tuner's movement across the band. Stepped on the P-SB7 (channel to channel), continuous on Frank's Box (a slide). Forward or reverse. |
| Dwell | The time the tuner spends on each channel before stepping: 50 to 350 ms on a P-SB7. Also called sweep rate or sweep speed. 200 ms is the Estes standard. |
| Bleed | A station heard faint and detuned from a neighbouring channel. On a real tuner it happens one channel either side of a strong station; the app reproduces it one or two dial steps away. |
| White noise | The hiss between stations. The P-SB7 generates it synthetically rather than letting the tuner's own noise through, so the background stays constant. |
| Squelch | The circuit that mutes a radio when no station is present. A spirit box is a radio with no squelch — or, on the SB11-ANC and in the app, with an adjustable one called ANC. |
| Frank's Box | Frank Sumption's original ghost box (2002): a voltage-tuned AM/FM module swept continuously, with a physical echo chamber. Documented in his 2007 schematics. |
| Shack Hack | A late-1990s Radio Shack scanner with the seek-mute wire cut so it plays everything it passes. The bridge between Frank's Box and the mass-market P-SB7. |
| P-SB7 · SB11 · SB7 Pro | The commercial line: stepped sweep with seven speeds; two independent tuners (ANC variant); configurable steps and 17 speeds. |
| Estes method | A session protocol: one person on isolating headphones and a blindfold says aloud what they hear while the others ask questions they cannot hear. FM, 200 ms, never below 100. The guide. |
| Word bank | Recorded words or phonemes inside an app, played at random. An app built on one is not a spirit box, whatever it is called. The guide. |
| Reverse audio | A recording played backwards. Used to rule out broadcast bleed: a clear forward phrase inside reversed audio cannot be a presenter. |
| Auditory pareidolia | The brain's habit of hearing speech in speech-like noise. It is why fragments of three stations can sound like a sentence, and it is the mechanism every spirit box relies on. |
| Source log | SpiritBox's record of a session: for every change, which station became audible (TUNE), half-heard (BLEED) or absent (AIR), and when MARK was pressed. |
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Questions
Is a spirit box the same as an EVP recorder?
No. A spirit box produces sound live from radio; an EVP recorder captures ambient sound for later review. Many sessions use both: the box for the sweep, a recorder for the room.
Is a ghost box a different device from a spirit box?
Not in current usage. The terms are interchangeable; "ghost box" was the original name and "spirit box" became common with the P-SB7.
What does ANC stand for?
Adaptive noise cancellation, the name on the SB11-ANC. In practice it is an adjustable squelch: it lowers the hiss between stations.