“I don’t want to sound like I am anything special,” blues musician Ben Harper says rather humbly.

“I have exceeded my own expectations. I am an over-achieving slacker.”

The 44-year-old singer songwriter is chatting about the songs which mark out a singer’s career and for him, one of those tracks has been Forever.

“I wrote that when I was 21, yet people still get married to it,” he says.

Another is With My Own Two Hands, of which he says: “It’s been returned to me in a way that’s made me very proud of it.

“I have received letters from schools for having written that song. It’s been made a school anthem. I have had letters from close to 50 kids describing to me what they have done with their own two hands.”

The singer-songwriter says he is stepping out of his comfort zone by embarking on his 17-date tour of Europe, which includes a date at Symphony Hall next week.

After years of touring extensively with his bands Innocent Criminals and, more recently, Relentless 7, it will be the first time in about two decades that he has toured overseas on his own.

“I’ve loved being in the band for the camaraderie and friendship and seeing things as a band,” he says. “They are some of the most special times I have had. But playing alone you get to the heart of a song.

“I can’t wait,” he enthuses. “I’ve just loved doing it as much as anything I’ve ever done.”

It will, he says, be largely an acoustic show – just him on stage with his guitars and a piano.

“Unless someone’s in town who will sit in, which is always fun,” he adds.

“I do plug in a Stratocaster at times,” he says, “but it’s a cleaner sound. It’s the acoustic side of electric.”

It will be his first time at Birmingham’s Symphony Hall.

In fact, he can only recall playing in the city once before – at a university gig.

“When I played there the band Gomez came to the show. They were just kids,” he recalls, amused. “We hung out and talked about records we had in common that we liked. They were so bright-eyed. The next thing I was seeing them on TV.’’

Ben was raised by his maternal grandparents, who owned the Folk Music Center and Museum in Claremont, California. Its reputation was such that he recalls serving the likes of Leonard Cohen and blues musician Taj Mahal when working behind the counter.

“I am definitely a product of my grandparents’ incredible musical tastes and archives,” he says.

“It’s been there since 1958 and it’s still going. Cousins and brothers and various members of the family are keeping it open.”

But that only goes part the way towards explaining his lifelong love of the blues.

“One doesn’t have to live in a particular way to have a love of a particular art form,” he suggests. “Take Jimi Hendrix. What could he have possibly listened to that made him Hendrix?”

“Why would anyone play the hurdy-gurdy?” he adds. “Yet someone takes it and devotes their life to it, because they like the sound or they hear the call.”

For Ben, it was the slide guitar. Once he’d heard a recording of one of the old blues musicians he was hooked.

He recalls taking the bus with his fellow “outcast” friends from his first band to other music stores and rooting through the bins for old records. And at times it got quite competitive.

“There were three hands on a record numerous times,” he chuckles.

Over the course of the past 20 or so years, he has brought out some 11 studio albums, collaborated with the likes of blues harmonica player Charlie Musselwhite and gospel group The Blind Boys Of Alabama and picked up three Grammy Awards along the way.

The distinctive range and quality of his singing voice, his guitar playing and his ability to write all kinds of songs - from searing political anthems to deeply personal and light-hearted songs - have set him apart.

When I ask him if he ever sits down to write a particular type of song, the answer is an emphatic no.

“The songs have always led the charge,” he replies. “I have never sat down once and tried to write a song. The songs either come or they don’t come.

You can’t just write a Blowing In The Wind, a Slip-Sliding Away or a Bridge Over Troubled Water, he adds.

“You don’t make songs timeless,” he explains. “People do that.”

On his Wikipedia site, his occupations are listed as “musician, humanitarian”.

It’s a description, he doesn’t dispute.

“Anyone can cut a cheque. It’s almost not enough nowadays. The new model is to spend some time in the trenches and be hands on,” he says.

He has four children aged between 10 and 17 and, what with family responsibilities, his music and his charitable concerns, he admits it can get a bit much.

“You end up doing so much for your own kids, for other people’s kids and touring.

“I’ve just done the Grammys (he picked up an award for Best Blues Album) and a science fair project with one of my children. I don’t know which one was more exhausting. Or which one I am most proud of. It’s close.”

The work load is unlikely to ease up just yet. His next album is a collaboration with his mum, Ellen Chase-Verdries, which is due out in May for Mother’s Day in America.

“My mum’s a singer, a guitar player and songwriter,” he explains. “She stopped being a musician to have kids.

“I’ve been talking about doing a record with her for a long time and she’s held me to it.

“It’s really exciting to see my mum reconnecting with her music.”

He is also talking about recording a second album with Charlie Musselwhite and there’s good news for fans of the Innocent Criminals, as he is hoping to do another album with his old bandmates.

“I’ve also got another band called Fistful Of Mercy who are knocking on the door,” he adds wearily, “so I just have to reel it in a bit.”

The message, though, is catch him while you can.

“I love touring,” he says, “but I don’t plan to do it a whole lot longer. The only thing harder than getting into the music business is knowing when to get out.

“I’m a skateboarder at heart. I think I will be the only one to start a skateboarding career in his 50s.”

* Ben Harper plays Symphony Hall on April 29 at 7.30pm. For tickets, tel: 0121 345 0600 or visit www.thsh.co.uk