ONE SHOT- Royal High senior Matt Garren hopes his 15-minute guitar performance in Los Angeles will be worthy of acceptance and a scholarship to Boston's Berklee College of Music. Matt Garren admits he's a little nervous.

Tomorrow is a big day for the Royal High School senior: He'll be playing his guitar in hopes of winning a music scholarship to the prestigious Berklee College of Music, the alma mater of such music greats as Quincy Jones, Melissa Etheridge and Branford Marsalis.

The scholarship audition in Los Angeles will test his "musicianship," the 17-year-old said.

"(They look at) how well I read (music), how well I can improvise and my originality. Then they say, 'Here's what we think about you and here's your scholarship,' if you're good enough," Matt said.

If good genes count for anything, Matt has all the makings of success.

His oldest brother, Kevin, now 28, won an $8,000 scholarship to Berklee 10 years ago and his brother, James, now 24, also earned a scholarship to continue his musical education.

The Garren brothers and their sister, Julie, 31, grew up surrounded by music.

Their father, Bobby, 66, sang and played guitar for fun. Although the siblings all tried to get their father to record or book a show, it just wasn't his thing.

"As long as I can remember he was always playing some type of song," James said. "We'd kid him and say it's out of tune and he'd say 'No, that's the way it sounds.'"

The boys said their dad's deep voice drew comparisons to Johnny Cash.

"I played in many western and country bands around the area and on the sets at lunchtime," Bobby Garren said. "They called me Johnny Trash."

Matt's mother, Debbie Cardosa, 51, who lives in Michigan, played the piano.

Kevin is a professional saxophone, flute and clarinet player. He's the band director on Princess Cruise Lines and plays with wellknown L.A. jazz bands when he's ashore.

James, a drummer, has played in several bands and jammed at such venues as the House of Blues on Sunset Boulevard.

Julie's worked at Universal Studios for the past five years in the audio mixing department.

As a 10th-grader, she won a spot playing the snare drums in an honorary marching band for the 1991 Los Angeles Festival in Dodger Stadium.

"I had to audition for the event. It was exciting to make it," Julie said. "We practiced all summer and I was the only girl in the drum line."

Like the rest of her family, Julie is proud of her little brother Matt and his dedication to music.

"Whenever I go into his room, he always has his guitar strapped on playing something," Julie said. "He's really dedicated."

Matt has been practicing for the audition and even ordered a new guitar- this despite the fact that his family already keeps 16 six-strings in their home.

"I ordered a custommade guitar and then I realized it wouldn't arrive in time," Matt said. "I've been actually working with my old guitar. It's broken in like old shoes."

Last year the three brothers performed together in Royal High's talent show. It was the first time on stage together for the brothers, who creatively met the challenge that arose when James broke his hand not long before the show.

"We got everybody together and we had no idea what we were going to do. We did an instrumental we all knew," James said. "Two weeks before the show I broke my hand. I played left-handed with one arm. Kevin played the guitar and so did Matt."

The crowd responded enthusiastically, James said, and the brothers are looking forward to participating in the school's talent show in February.

Although Matt, who also plays in the Royal's marching and jazz bands, enjoys playing drums, the guitar is his passion.

"He jumped on the guitar. It's amazing from where he started to where he's at now," said James, who works at Music World in Simi Valley. "We've had about 20 different teachers in this facility and he could go up with any of (them) and I'm sure he could match them and top them."

Whether Matt wins his Berklee scholarship or not, there's no question that music will always be a part of his life, he said.

"Even if I don't make it, I want to see how I did so I can improve from there."