The Blues Orphans perform at the Penn Brewery in early February. From left to right: Drummer Dave Yoho, harmonica player Charlie Barath filling in for Andy Gabig, trombone player Nelson Harrison, upright bass player Dave Erny, trumpet player Mark Custer and frontman Bob Gabig. (Photo/Kelly Thomas)

At the Penn Brewery on a Friday night, with tables packed and chatter thick in the air, six gentlemen with graying hair ferry heavy-looking instruments, amps and speakers into a corner opposite the bar.

No one pays attention as they set up. Those who aren’t engaged in conversation keep their eyes on the restaurant’s sole television where the Penguins battle the Buffalo Sabres.

The Blues Orphans step up to their microphones, instruments in hand, and launch into their patented style: blues blended with rock, hip hop, punk and everything else.

The guitar, drums, brass instruments, harmonica and upright bass keep each other in check as they plow through the ambient noise.

By the time the Orphans get to “Yinzer Polka,” the chatter has died out and more than a few patrons are dancing around tables and twirling each other jubilantly.

If you ask any member of the band for a definition of “conventional music,” he will look at you as if something particularly odd is growing out of your head and inform you that he has no idea what you’re talking about.

Over the band’s thirty years, 70 original songs and four albums that span every genre imaginable have had Pittsburghers up and dancing, or at least tapping or swaying along to the beat in bars, restaurants and venues across the city.

Blues Orphans founder and chief lyricist Bob Gabig might take his musical influences from everywhere, but the most important part of any song, he says, is the lyrics.

 “Hooks are easy to come by, but a good story really makes a song.”

When composing lyrics, Gabig starts with a “crazy idea for a topic,” or something about Pittsburgh or an issue that affects the world, and writes from that.

His songs often touch upon serious topics, such as pollution in the ocean in “Plastic Soup,” but he laces humor throughout.

After the lyrics, Gabig, who also plays guitar and sings, writes the chord progressions, but allows each band member to play his own part however he wants.

“We could play it 10 different ways before it starts to settle,” Gabig says.

The rest of the band consists of Andy Gabig on harmonica, Dave Yoho on drums, Mark Custer on trumpet, Nelson Harrison on trombone and Dave Erny on upright bass.

They never rehearse, and they don’t need to. Those who have been with the band less than three decades are still life-long music lovers, and all are incredibly talented.

“It’s probably every musician’s dream to not have to rehearse,” Yoho says. “[Our performance is] very non-structured but it’s tight, and it’s tight because because of the longevity of the band.”

Sometimes, Gabig will start playing and no one will know exactly which song he’s playing until he starts singing. They just roll with it.

“None of us know what Bob’s going to pull out of his pocket,” Yoho says.

Over three decades, the Orphans have defied everything that music has ever thought about defying, and some things it hasn’t. Trombone player Nelson Harrison even invented his own instrument: the trombetto.

Harrison bought a pocket clarinet at a pawn shop, but when he took it home he was disappointed with its sound. So, he put a trombone mouthpiece on it, and after playing it that way for awhile he asked a friend of his to add some extra tubing and another valve.

“I’m the best player in the world,” Harrison says, “because I’m the only one!”

A samba line forms as complete strangers give in to the Orphans’ siren call to dance.

“There’s a party going on on the Northside all the way to Sunday,” Gabig shouts into the audience.

They cheer and keep dancing.

You can find the Orphans online at www.myspace.com/bluesorphans.