Do not adjust your TV set -- it might be tuned in to another dimension.
That's the premise of the thriller "White Noise," opening today, about an architect (Michael Keaton) who is contacted by his murdered wife through a process called electronic voice phenomenon (EVP).
It's a spooky plot device familiar from old "Twilight Zone" episodes and movies like "Poltergeist" (1982) and "The Ring" (2002).
But EVP -- "hearing" otherworldly voices in the crackling white noise between radio and television signals, or on tape recorders, answering machines and cell phones -- is not a Hollywood invention.
Those who study such things say that since the late 19th century, people have claimed they've recorded the sounds of the dead.
"This phenomenon has been seen on all types of recorders, and as technology has evolved, we've seen an increase," says Tom Butler, who, with his wife, Lisa, is director of the American Association of Electronic Voice Phenomena, based in Nevada.
"In addition to EVP, there's also ITC -- instrumental transcommunication -- which includes images on TV and photographs. Most basic equipment can pick things up, but one has to discern what's real or not. Radio towers, for instance, create signals that make people think they've recorded things."
"In Europe, EVP is used mostly as grief management for those who have lost loved ones," Lisa Butler says. "People want to believe. But it is a bit of a hard sell to the public."
Not to all the public, though.
"The best time to record things is from 9 p.m. to 3 a.m., which are the 'psychic hours' of the night," says Lorraine Warren, a psychic researcher who, with her husband, Ed -- a "religious demonologist" -- founded the New England Society for Psychic Research, based in Connecticut.
"In photos from over a hundred years ago, there were some occurrences, but there weren't nearly the number of psychic photos we have today," Warren says. "I don't have the answer why. Kodak doesn't have the answer. But for those who believe, the reason may be that spirits are utilizing this new technology."
And in audible media such as cell phones, Warren claims, "Spirits can do the same type of thing."
But she warns, "This is not something amateurs should do, because they can ... open doors." As in "White Noise," she says, "It could open a door for an 'outward manifestation' -- a demon, or a force that never walked the earth in human form."
But even in the paranormal world, it seems not everyone is on the same EVP wavelength.
"There's no way you can get a true 'white noise' because of all the man-made signals around us. It just isn't reliable," says Bobbie Atristain, director of the Center for Paranormal Research and Investigation in Richmond, Va.
"Usually, what's recorded is so garbled everyone hears something different. It could be from CB radios, satellites, a nearby military base. There are many frequencies running through the air that get caught on magnetic tape easily."