Spirit Stone Radio

The Spirit Stone Radio was invented by Dr. Kunihiko Asou, who was hoping to prove the existence of the spirit world. It allows the user to hear voices from the past and voices of any spirits contained within "Spirit Stones". Once a Spirit Stone is inserted into the circuitry of the radio, the radio replays any voices contained within the stone. Asou used a modified Echo Stone Earring with the crystal receiver to enable hearing of the voices. The radio is able to receive supernatural sounds and voices from the spirit world that could normally not be detected.

Fatal Frame II / Deep Crimson Butterfly

One radio was given to Seijiro Makabe, a folklorist visiting Minakami Village to research its rituals. It was found by Mio Amakura during her exploration of the village.

Fatal Frame III

Another radio ended up in the hands of Yuu Asou. It was stored in the attic above his room, where his fiancée Rei Kurosawa found it after Yuu's death. This radio seems to have been more sensitive than the one given to Makabe; it does not require the spirit stone to be placed inside it, but instead responds to the voice of stones in the vicinity. After Rei finds the radio, she starts to be able to hear the voices of spirits in her dreams, guiding her through the Manor of Sleep.

The radio eventually became known as an item of "Mystical Science", along with the Camera Obscura and Projector.

Fatal Frame IV

In Fatal Frame IV, there are various Spirit Stone Radios scattered throughout the hall. In this game, however, spirit stones are no longer present; the radios pick up thoughts from the past on a special frequency. There are radios in both Room 206 and Room 310, and in the basement Switchboard Room. There also appears to be a radio in Ruka's mother's room in the Yomotsuki Residence, although it is never used and appears to be broken.