Chances are good that when John Valby plays the Musicians Exchange Saturday night, the audience will hear a little ditty about Broward’s most notorious couple, Jeff and Kathy Willets. An equal-opportunity parodist, Valby also will probably poke fun at South Florida’s favorite rich guy, H. Wayne Huizenga.

And he’ll do it all in a way that would make a biker blush.

Valby, a resident of Buffalo, N.Y., is known throughout the northeast as his alter ego, Dr. Dirt.

Dirt, as he is called on second reference, is a man in a white tux who has made a comfortable living singing songs with lyrics that describe every human function (and some bovine ones) in the rudest way possible. He considers himself a pornographic Mark Russell.

Put it this way: If we were to try to print the lyrics to a Dr. Dirt song in this family newspaper, it would look like Morse code.

Many of the tunes are created from items Valby reads about and hears on the news before going to a job. A performance generally contains several tunes he’s playing for the first time.

“I’m very much in tune with current events,” he said. “Burt and Loni, Clinton’s hair cut, Letterman’s last show, Cheers’ last show, Saddam and the Bush thing.”

When he’s not on stage swearing like a drill sergeant to tunes ranging from Beatles to blues to Yankee Doodle (don’t ask), Valby is a serious musician who owns a record label and is building a high-tech children’s theme park. Most people are amazed when they meet him, he said, and discover he’s nothing like his foul-mouthed stage persona.

“It’s a very definite Jekyll and Hyde, but it’s very controlled,” Valby said. “I only swear when I’m on stage and when I play hockey. I completely shut it out the rest of the time.”

The parent of four girls and a boy ages 9 to 1 1/2, he’s reconciled himself to the fact that what he does for a living may not be great music, but it pays the bills. His younger children know that Dad plays the piano and sings, but that’s about it. The oldest heard one of the cassettes at a cousin’s house, but there’s certainly no family sing-alongs.

He’s made 18 recordings of Dr. Dirt material, and another dozen or so of clean material.

“What I do best is beautiful music,” he said, “but that’s not what people go to clubs for. America is comedy crazy and sex crazy. I’ve become a mirror of what the audience reflects, and people are a lot dirtier than I am.”

Pat Curry is a free-lance writer based in Plantation.

— John Valby, aka Dr. Dirt, is scheduled to perform adult-oriented comedy music at 8:30 and 11 tonight at the Musicians Exchange, 739 W. Sunrise Blvd., Fort Lauderdale. Tickets are $11 general admission, $16 reserved. Call 764-1912.