The basic idea behind a Spirit Box is that spirits can manipulate radio    waves.  At least many people in the paranormal community believe      that to be the case.

  There are numerous spirit box type devices available, as well as quite    afew phone apps that perform similar functions, but the GBPA                primarily uses the SB7 Spirit Box and I think it's probably the one            most often used by investigators.

  We also use the ExchoVox phone application.

  If you ask 100 investigators I believe you'll get 75 explanations about    the hows and whys of a Spirit Box.

  My personal belief is that entities need all the help they can get to          manifest, and the Spirit Box, by scanning AM and FM radio                        frequencies, provides an entity with the white noise and speech              fragments it needs as a spring board to audio manifestation.

  Sometimes the voices are altered in terms of pitch or tone and other    times they're crystal clear.

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