Guides
What a spirit box is and does, from the hardware manuals and schematics, the community's protocols and the published teardowns of apps. Each guide answers its question in the first paragraph and cites its sources at the end.
How a spirit box works
The P-SB7, the SB11-ANC and the original Frank's Box, with the numbers from their manuals and schematics.
The Estes method, step by step
The protocol that became the standard: who does what, the settings, what it controls for, and a session plan.
Why spirit box apps with word banks aren't spirit boxes
How sound-bank apps work, how to spot one in thirty seconds, and which ones have said so themselves.
Spirit box, ghost box, EVP: a glossary
The vocabulary, from ITC and EVP to dwell, bleed and squelch, in one table.
Sweep speed, explained
Why 50 ms sounds like noise and 350 like radio, what the devices offer, and which speed to use when.
The best spirit box apps, by where the audio comes from
The two kinds of app, how to tell them apart in a minute, and which ones use a live source.