It's a challenge to keep even a small band going for any length of time in the current jazz climate, and maintaining a big band that splits its time and membership between two cities is even harder.

But pianist Orrin Evans has done just that, helming his Captain Black Big Band for more than four years since its beginnings at Chris' Jazz Cafe in late 2009. So why does he regularly corral 14 musicians from New York and Philly to tackle the ensemble's boisterous arrangements?

"When I figure that out, I'll probably stop doing it," Evans said with a shrug last week over lunch at McMenamin's Tavern near his home in Mount Airy. "It's overwhelming - I've got to make sure everybody's there, we're not making tons of money, there's a lot of people to pay. Musically, I love the sound of all these different colors and different sounds coming together. But I still haven't quite figured out why I like doing it, and that's what makes me get on that highway every week to see what happens."

These days, Captain Black calls New York City home, with a residency on Monday nights at the Upper West Side club Smoke. The band returns to Philadelphia Wednesday night to celebrate release of its second CD, Mother's Touch, at World Cafe Live with a pair of guests, both Philly natives: vocalist Joanna Pascale and guitarist Kurt Rosenwinkel.

Rosenwinkel, who will also perform Tuesday at Underground Arts with his new psych-rock-improv trio Bandit 65, writes by e-mail that he's a big fan of Evans: "Orrin is a brilliant pianist and dynamic composer and bandleader - a very soulful artist. It's going to be a lot of fun."

Wednesday's show will mark their first chance to play together. "I wanted the opportunity to play with him and to get myself out of the comfort zone," Evans said. "I don't normally use guitarists that much, but with Rosenwinkel, I get a chance to play with a guitarist, someone from Philly, and someone I've wanted to play with for a while."

Pascale is an old friend. Their first encounter was a near-disaster. She was 14 years old when her mother brought her to the now-defunct Blue Moon Jazz Club, where Evans was leading a regular jam session. When he called her to the stage, she brought up sheet music for Billie Holiday's "Good Morning Heartache." He waved it away.

"This was honestly the first time I'd ever sung when I wasn't singing along to a record," Pascale recalls. "Orrin starts playing, and something wasn't right. I start singing, and he's in a different key, and I'm horrified. So I turn around, and the bassist and drummer are laughing hysterically to the point where tears were rolling down their faces and their shoulders were shaking trying to hold it in."

Nevertheless, Pascale and Evans established a musical relationship that has lasted nearly two decades. Most recently, he produced Wildflower, her coming CD, which also features an appearance by Rosenwinkel. "Joanna's like a little sister to me," Evans said. "I think we really see time and space and rhythm in the same way. So whatever we do, there's going to be space for us to grow and make something happen."

What's cool about Captain Black, Pascale says, "is how loose it is. But the level of musicianship of every single person in that band is so high that no matter what you put in front of them, it elevates the music to a whole other level."

Mother's Touch reveals a far more refined ensemble than the raw, combustible band captured live on its self-titled debut. Still, Evans is never one to plan much in advance and enjoys the thrill of the unexpected - even if it means occasionally playing a gig where not a single trombonist manages to show up.

"A part of me thinks it would be great to walk in and have a full band every week," he said. "But I prefer to not know what's going to happen. As much as it seems like it would be easier for it to all be the same every week, that would get real boring for me. I never really get nervous - but I get nervous about the big band."

CONCERT

Orrin Evans'

Captain Black Big Band

8 p.m. Wednesday, World Cafe Live, 3025 Walnut St.

Tickets: $20.

Information: 215-222-1400, www.philly.worldcafelive.com.EndText