ITS THE VOICE: subtle but overpowering, soothing as it menaces, a voice capable of lulling the innocent into the abyss, of making even mother's milk sound and sinister. It belongs to Vincent Price, and he knows how to use it.

"I'm just a touch . . . overcome," he says in a heroically resonant stage whisper after a visit to the historic corners of Ford's Theater, where he opens Tuesday as Oscar Wilde in "Diversions and Delights." "It's . . . terrifying!"

Even when he talks about his revered progenitors, the 11 generations back to the founders of Detroit on his mother's side and the 13 generations to Peregrin White, the first child born in the Massachusetts Bay Colony, on his father's. Price manages to invest his story with just the subtlest hint of unspeakable evil.

"One of my ancestors did wonderful, delicate work in silver, and do you know what was done with it?" he will say, looking at you deeply before letting his voice elegantly rise. "They . . . melted . . . it . . . down. Do you know what it's worth that way? NOTHING!"

Vincent Price can't help himself, can't stop being that way, nor does he particularly want to. After 42 years as an actor, after working with Elvis Presley as well as Orson Welles, after making 103 motion pictures that included classics like "Laura" sprinkled among ephemera on the order of "Dr. Goldfoot and the Bikini Machine," he positively revels in, not to say practically defines, the essence of theatricality.

"I love it, I really love it," he says with huge enthusiasm, delighted to be asked. "All the people in this profession I really admired, like Charles Laughton, really relished theatricality. And it is very appealing to people while underplaying, unless done by a master, is boring. You must attack a part, you can't go into it blah. I think of Dame Edith Evans, of whom it was said that while the rest of the world was turning natural, she was becoming more and more artificial."

Poet and playwright Oscar Wilde, "in the wicked flesh" in the last year of his life, is the current focus of Price's zest. "I probably feel more lost in that character than I have in any other," he says, emphasizing that he even shaved his moustache for the role. And how does Mr. Price feel without it? "Naked!" he says, immediately huddling into a fetal ball. "I feel like 'September Morn.' It's the most awful thing."

Price sees Wilde's life, which had the most brilliant of beginnings only to end in prison, exile and an early death, as "the tragedy of a person who is bored with fame. It's happened to every American playwright, to Albee, to Tennessee Williams. 'The gods had given me everything,' Wilde said, 'but I tired of the heights and looked to the depths."

All this heavy stuff aside, it was Wilde as a wit that really seduced the man of the theater in Price. "Do you know that after his prison experiences he said, 'If this is the way he majesty treats her prisoners, she doesn't deserve to have any.' He couldn't resist things like that. And the story goes that when he was dying, he looked around this terrible wallpaper in his room and said, 'One of us has go to go.' That was extraordinary."

The height of Price's theatricality, and the films for which he continues to be best known - "They're still shown every five minutes" - are the series of Roger Corman horror films adapted loosely (very loosely) from Edgar Allen Poe. Titles like "House of Usher," "Tales of Terror," "The Raven" and "The Pit and The Pendulum," wherein his acting, said the Monthly Film Bulletin, was of a "scenery-carressing style, a blend of oily solicitude and sissy sadism."

"They don't date because they were dated to begin with, they were manered and consciously so," Price explains. "And you know none of us ever considered them horror pictures, the horror pictures are things like 'Marathon Man' and 'Taxi Driver.' These are gothic tales, they have an unreality about them that is enchanting. They have the fun of a fairy tale when you're a child; you giggle, embarrassed at your own fright; you laugh at them, but you're still scared."

No matter how he sees his films, even Price is not about to argue about the enormous number and variety of villains he has played in them. "At his best, he was an egotist or a dilettante," critic David Shipman wrote. "At his worst, he was sadistic, lecherous, covetous or just plain murderous."

"I love playing villains, they're such wonderful parts," Price says quite cheerfully, recalling that he even met his current wife, actress Coral Browne, while filming something nasty at a London cemetery.

"I do a lecture on villains, and I'm writing a book called 'Man and the Monster Image; and really, the villain is the hero, he's the person who keeps you guessing. Without him you can't have conflict, you can't have drama."

An additional side benefit of being bad as well as evil is that when you exit a production, you hardly leave unnoticed. "I have been killed in more ways than anybody," Price says, practically bored with it all. "I've been drowned in a vat of wine, I've been burnt up many, many times - fire is a great immolator - and in 'Green Hell' I was shot with 40 poisoned arrows.

"I remember 'Green Hell' because it was named one of the 10 worst pictures of the year, which I thought was rather distinctive.At one point, I turn to Douglas Fairbanks Jr. and say, 'Do you think it's possible to be in love with two women at the same time, to love them with all your heart and to want to be rid of both of them?' You could have heard the laugh from coast to coast."

Speaking of his bad films, which he has no qualms at all about doing - "You name me somebody who hasn't made any" - Price especially likes to mention "Son of Sinbad," the last film Howard Hughes was involved in.

"I was sent the script, and I called back and said, 'This is the worst script I've ever read'; and all they said was, 'Isn't that the truth.' You see, Hughes had 150 girls under contract, girls who had won Howard Hughes beauty contests 15 years earlier, and his lawyers told him that by federal law he had to pay 'em off. So these poor broads had been dragged away from husbands, children and stoves, dressed in harem costumes and put into this horrible piece of drek.

"I played Omar Khayyam - that'll tell you what kind of film it was - and Dale Robertson, with a thick Oklahoma accent, played Sinbad. When I introduced him, I said, 'Here's my friend from Persia,' and I couldn't resist adding, 'the south of Persia.' Hughes really loved that one."

After having been through all that, after having frightened several generations and even after surviving 900 episodes of "Hollywood Squares," is there anything that could scare a Vincent Price?

"There is one thing that really frightens me, that makes wake up in the middle of the night screaming," he says, making his voice sound enviably sober and serious. "Being interviewed by Barbara Walters. That's a real nightmare."