Life Without Father: The Zappa Legacy : Pop music: The late musician’s sons’ first joint album bears his quirky, complex mark--with some ‘different flavors’ added.

Frank Zappa died in December, but he’s still all over the place at Joe’s Garage, a funky rehearsal and recording complex in North Hollywood.

A framed gold record for the 1980 album that gave the building its name hangs on a wall near the entrance. The famous ‘60s poster of the scowling rock iconoclast seated on a toilet dominates a small bathroom. Pillows covered in Zappa album and tour T-shirts are scattered around the window seat in the lobby.

And from a closed room toward the rear of the building comes the sound of a band playing a hard-riffing, metal-progressive fusion. You wouldn’t mistake it for the Mothers of Invention, but its quirkiness and its rhythmic and harmonic complexity carry the clear mark of Frank Zappa.

The five-man band is called Z, and it’s led by Zappa’s two sons, Dweezil and Ahmet. They’ve just released their first joint album, “Shampoohorn” (see review on F14), and they’re getting ready for a concert tour that includes a show at the Palace next Thursday.

“We’re certainly not ashamed of Frank’s influence,” says Dweezil, sitting with his brother in a small control room packed with recording equipment. “We like to put it in wherever possible. (We recorded) 65 songs, including stuff that was a lot more heavily influenced in some way, shape or form by my dad, but we were trying to put together a record that has different flavors.”

Dweezil, 24, has three of his own albums under his belt, but the arrival of Ahmet as flamboyant singer-frontman has allowed the admittedly shy guitarist to assume a more comfortable role slightly out of the spotlight.

The brothers, along with their mother, Gail, and sisters Diva and Moon (of “Valley Girl” fame), endured Frank’s struggle with prostate cancer in upbeat and irreverent form--no surprise for one of rock’s most famously unconventional nuclear families.

“When you have a situation like that, you uncover things that you didn’t have the opportunity to do before,” says Dweezil, who, like Ahmet, has lived all his life at the Zappas’ Laurel Canyon home.

“The one good thing that an illness or whatever can bring to a family is that you end up spending more, quote, quality time, you end up talking about some stuff, you get to know each other.

“It was a very natural progression for all of us. There were no really hideous moments. You know the outcome, but you go through it in the way that is the best.

“The best thing I can say about Frank is he always had a great sense of humor about everything. I don’t know that too many people would understand it from the same level that we would. It might even scare people, the way that we joke about stuff in our house. But for us, it’s just part of our makeup. We’re brutal. We like to make jokes about anything and everything.”

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While the Zappa heritage guarantees some attention for the brothers’ enterprise, it can be a double-edged sword, they’ve discovered. Now that Dweezil has finally escaped some of the image problems that formed when he was portrayed as a Hollywood Romeo a few years ago, he finds Frank’s legacy being used to fence Z in musically.

“We always accepted who we were and who our father was. It was never a problem. . . . Our music is not nor should it be a carbon copy of his music.

“But there are people who think that it’s not right for someone who has this pedigree last name, that we would do something that could maybe be played on the radio. If we don’t go the completely bizarre route where people don’t understand what we’re doing, then we’ve sold out.”

Ahmet, 19, cuts in, sounding defiant and exasperated. “I liked Bananarama and the Thompson Twins when I was younger, OK?”

Says Dweezil, “And I was into like AC/DC, Ozzy, Van Halen, all this stuff. So I want to create music like that crossed with Bananarama and the Thompson Twins, and people won’t let us.”

“But we can’t be stopped,” says a smiling Ahmet.

For the Zappa family, Frank’s real legacy is more about personal integrity than musical direction.

Says Dweezil, “Basically we grew up being taught that we’re responsible for our own actions and that life is something that you should enjoy, and enjoy with the people that are close to you. It was a very close-knit thing, and we had a very firm grip on true reality.

“Frank was a very, very intelligent man, full of surprises, had a great sense of humor. So to us the best things in life are being able to laugh at anything and everything, don’t take yourself too seriously, and be nice to people. What else is there in life? You got good food, you got music and you got pets. That’s about it.”