3 - 1 = 1

You remember that quirky duo with the cute boombox, don’t you?

With “The Future’s So Bright, I Gotta Wear Shades” in 1986, Timbuk 3 scored a Top 20 hit that led to an appearance on “Saturday Night Live” and a Grammy nomination.

The techno-roots twosome known as Timbuk 3--the husband-wife team of Pat MacDonald and Barbara K.--was no one-hit wonder. The pair crafted an impressive, mostly satirical body of work over the course of seven albums and toured frequently with that boombox subbing for a backing band before eventually coalescing into a funky quartet for its 1995 album, “A Hundred Lovers.”

Those good times must seem like a distant memory. Pat and Barbara’s 18-year marriage--and partnership as Timbuk 3--dissolved nearly two years ago, and now each is focusing on solo projects.

MacDonald’s solo debut, the introspective “Pat MacDonald Sleeps With His Guitar,” was released in July; Barbara K.’s album is due later this year.

Reached by phone last week before a gig in San Diego, a soft-spoken MacDonald--who appears Thursday at Club Mesa in Costa Mesa and Friday at McCabe’s in Santa Monica--spoke openly about the emotional turmoil that invaded the partnership.

He said that as his marriage unraveled, his feelings of pain and confusion forced him to look inward; at times he was surprised and dismayed by what he saw.

“For a while, I felt like I was dead,” offered MacDonald, 45. “Or at least the person I used to be was dead. It was like a new being was waiting to form inside of me--and break out.

“In the past, a lot of things had been suppressed . . . and I realize now that I had this bad side that I wasn’t dealing with . . . that part of you that you normally don’t care to show. It’s a scarier side of yourself, one that has the ability to hurt others as well as yourself. But sometimes the truth does hurt--and it has to come out.”

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When it did surface, it wasn’t one big explosion.

“For us, it was more of a long, slow heartbreak . . . so when we broke up, it was actually a mature decision that we both made,” said the Wisconsin-born, Texas-based musician.

“We have a 14-year-old son, so the hardest part was figuring out the parenting thing. But we’ve become very cooperative with that aspect of it. In fact, we both consider the other to be kind of a best friend.

“We did go through some tough, heavy [stuff] before the split, no doubt about that. Still, we laugh and cry together now over the telephone. The only time we sing together, though, is when we sing ‘Happy Birthday’ to Devin.”

Out of MacDonald’s divorce came “Sleeps With His Guitar.” The mostly autobiographical 16-song cycle shifts away from the wry social commentary that marked his Timbuk 3-era themes. Sonically spare, the songs are volatile and edgy.

Many are powered solely by MacDonald’s low-tuned, beat-up 1959 Martin acoustic guitar. The album’s most memorable--and lump-in-your-throat inducing--number may be the bittersweet “Daddy’s Down in the Mine,” which finds MacDonald extending a hopeful hand to his son:

There are countless worldly wonders

Not even Daddy understands

But if you should have a question

Drop me a line

Daddy’s just down in the mine

(Having visited his son in Wisconsin over the holidays, MacDonald said, “Devin is doing just great. He’s learning to play some percussion and has a cool, colorful group of friends.”)

Financially, MacDonald’s present could have been brighter--or richer at least--had he joined the parade of artists who have sold songs for corporate consumption.

Even today, with limited prospects for mass success of his recordings, he turns down substantial offers (from both Ray-Ban and McDonald’s) for commercial rights to “The Future’s So Bright. . .”

“To hear and see a song--one that’s touched your life and maybe others’ in some sort of meaningful way--being used to sell something . . . it just gives me this queasy feeling inside. It diminishes the work and forever tarnishes your memory of it. I feel like I’m--how’s that [R.E.M.] song go?--’Losing My Religion.’ I’m not willing to do that.”

“There was a period of time when I thought Miles [Copeland] was the devil,” MacDonald said with a laugh, referring to the ex-I.R.S. Records and current Ark 21 label head who co-owns the publishing rights to that MacDonald-penned song. “He was tempted, and everyone wanted to talk us into taking the money and run. But now these people seem to finally be getting the message.”

Yet for artistic reasons, MacDonald enjoys collaborating. He has written and sung with Aerosmith (“The History of Man”), pop singer-songwriter Jill Sobule (“The Secretive Life,” for the “Harriet the Spy” movie soundtrack), Italian superstar Zucchero and Japanese composer Ryuichi Sakamoto.

“Writing with people, . . . you learn all of their little tricks,” he said. “It’s a real education. And a few have poetic souls, and in the process of writing a song together, it’s great to go there with a person. Collaborating adds another dimension. . . . It’s really quite unique and just a heck of a lot of fun.”

* Pat MacDonald plays Thursday at Club Mesa, 843 W. 19th St., Costa Mesa. 8 p.m. $6. (714) 642-6634. Also Friday, with opening act Maia Sharp, at McCabe’s, 3101 Pico Blvd., Santa Monica. 8 p.m. $12.50. (310) 828-4403 (recorded information) or (310) 828-4497 (box office).