''The audience started out with the print-handicapped, but now we've expanded to people who just don't have time to read. I mean, in this day and age who does?'' That's Sandy Spencer talking about the growth of Recorded Books, a mail order firm in Charlotte Hall, Md. (800-638-1304). The firm has been in business since 1979 recording books, unabridged, on cassettes for sale or rent.

Spencer, a well-spoken Englishman, is an actor. He lived in Paris from 1972 until 1979 making his living dubbing French films into English and doing technical postproduction work. He came to this country and auditioned for Recorded Books. Now he pretty much runs the show, although he declines to give himself a title.

Recorded Books' catalogue of close to 100 titles ranges from classics like Sherlock Holmes mysteries and Lewis Carroll to Cynthia Helms' memoir of her life as an ambassador's wife in Iran and "The Art of Loving" by Erich Fromm.

Not all books record well. "What doesn't seem to work are books that are too explicit. They don't leave the reader enough for his imagination," he says. An example he gives of an unrecordable book is "Robinson Crusoe." He says DeFoe never lacked for words and left little room for the reader's imagination.

One has to find the right actor for the book. Spencer says that's "essential" because most books are recorded by one actor reading all the characters. The average book takes about 75 hours to record. Each individual session is about three hours long, which is "the maximum any actor can handle," according to Spencer.

Spencer himself has recorded several books. "The first book I read was part of our Sherlock Holmes series. I figured this was a chance to do my funny voices," he said. "But it doesn't work." Spencer is emphatic when he says, "The actor has to be aware that if he does too much, if he goes too far, he makes it impossible for the listener to bring anything to the book."