Konstantīns Raudive (1909 in Asūne, Vitebsk Governorate – 1974) was a Latvian writer and intellectual, and husband of Zenta Mauriņa. Raudive was born in Latgale in eastern Latvia (then part of Vitebsk Governorate) but studied extensively abroad, later becoming a student of Carl Jung. In exile following the Soviet re-conquest of Latvia in World War II, he taught at the University of Uppsala in Sweden.
Raudive studied parapsychology all his life, and was especially interested in the possibility of the afterlife. He and German parapsychologist Hans Bender investigated electronic voice phenomena (EVP). He published a book on EVP, Breakthrough in 1971. Raudive was a scientist as well as a practising Roman Catholic.
In 1964, Raudive read Friedrich Jürgenson's book, Voices from Space, and was so impressed by it that he arranged to meet Jürgenson in 1965. He then worked with Jürgenson to make some EVP recordings, but their first efforts bore little fruit, although they believed that they could hear very weak, muddled voices. According to Raudive, however, one night, as he listened to one recording, he clearly heard a number of voices. When he played the tape over and over, he came to believe he understood all of them. He thought some of which were in German, some in Latvian, some in French. The last voice on the tape, according to Raudive, a woman's voice, said "Va dormir, Margarete" ("Go to sleep, Margaret").
Raudive later wrote (in his book Breakthrough):
These words made a deep impression on me, as Margarete Petrautzki had died recently, and her illness and death had greatly affected me.
Raudive started researching such alleged voices on his own and spent much of the last ten years of his life exploring EVP. With the help of various electronics experts he recorded over 100,000 audiotapes, most of which were made under what he described as "strict laboratory conditions." He collaborated at times with Bender. Over 400 people were involved in his research, and all apparently heard the voices. This culminated in the 1968 publication of Unhörbares wird hörbar (“What is inaudible becomes audible”) (published in English in 1971 as Breakthrough).
Raudive developed several different approaches to recording EVP:
Raudive delineated a number of characteristics of the voices, (as laid out in Breakthrough):