A FAMILY conference on TV. Should they sell the pizza business? A teen-age son starts to talk. "I don't see the pride in your face anymore, Dad . . . " and his voice falters and his chin quivers and he starts to cry. It is a touching moment, an intimate moment, a supremely private family moment.

And we are there.

"You become like sentient wallpaper," said Peter Davis, whose six-part Middletown series opens Wednesday at 9 p.m. on PBS and runs for the following five Wednesdays. The first episode, "The Campaign," 90 minutes long, covers a mayoral election in Muncie, Ind., a town made famous as "Middletown" by Robert and Helen Lynd's landmark books about America in miniature.

"I went out there looking for change," Davis said. "So much has been happening to this country--the counterculture, the women's revolution and all the other revolutions--that I thought there must be a lot of radical change in the small towns. What I found was continuity."

What he found was that he could have gone into Muncie 50 years ago, 100 years ago, and watched the same kinds of people facing the same kinds of crises and making the same kinds of decisions. If television makes things different today, then radio did the same for another generation, and telephones for still an earlier one.

The trick was to get all this to happen in front of the cameras.

"We were shooting the episode about two divorced people getting married to each other, and they were sitting at the table and they started to have a really heavy confrontation right there in front of us. Did they really want to do this? It was more than a fight. They paid no attention to us shooting."

Davis, who won an Oscar for his Vietnam documentary "Hearts and Minds" and whose "Selling of the Pentagon" was a TV sensation in 1971, picked a mostly young group to work on this project, along with famed filmmaker Richard Leacock. The core team of eight logged many months in Muncie during the three years they were filming. Some rented rooms and lived in town for as long as two years.

"People literally didn't know we were there," the producer said. "In three years the local paper only ran one item, and that was when we had four camera crews covering the basketball game."

Davis did a dry run for the Middletown project in the six years he spent at Hamilton, Ohio, for his new book "Hometown," a more personal record of a microcosmic American town than the Lynds' books. There, he learned how to be invisible and yet to be trusted when the people he was observing came to a crisis.

Picking the stories that would bring Muncie to life for a nationwide audience wasn't too hard. "I knew I wanted to have a basketball game and a wedding, and we discovered the election thing when we got there and met Jim Carey (a classic pol right out of "The Last Hurrah" running against a stiff-lipped engineer). I looked for stories with built-in endings. We tried to find drama in people's lives."

Sometimes it was hard to come by, as in the episode about a family involved in evangelical religion. Sometimes the drama appeared of its own account, as in the story of the family pizza business. The final show, "Seventeen," which will air April 28, is something Davis has been wanting to do for years: senior year in high school. It's not at all like Frederic Wiseman's astonishing documentary "High School."

"It's much more personal and interior than that. Wiseman was studying an institution. This is a portrait of individuals. I try to give the audience a sense of the experience the characters are going through, in hopes that it will reflect back on their own lives, their attitudes. I would like to think this piece aspires to a place in the literature of youth. Like 'Catcher in the Rye.' Though I'm not comparing it, of course."

Most of all, Davis hopes his Muncie dramas won't look planned. "A documentary is all accident," he said. "As my favorite philosopher Branch Rickey put it, 'Luck is the residue of design.' "