Two weeks ago, musician Russ Gershon was in his rehearsal space in Boston.

He was explaining to his ensemble the Either Orchestra the finer points of a new and rather complex Ethiopian song they were about to perform.

The composition, Derashe, is by the innovator of Ethiopian Jazz, Mulatu Astatqe.

The Either Orchestra has played Mulatu's music before. Probably more than any other western jazz ensemble. But the rehearsal this night was different. Mulatu Astatqe was in the room, listening.

Russ Gershon lives in Boston. Mulatu Astatqe used to live here.

He was the first African student admitted to Boston's prestigious Berklee College of Music in the late fifties.

This academic year, Astatqe is back in Boston as a resident scholar at Radcliff College.

Before all this though, Russ Gershon simply loved the slinky sound of Ethiopian jazz from the sixties.

And since Mulatu Astatqe is the man who actually came up with the name Ethio-Jazz, Gershon sought him out some years ago, and started a long-distance correspondence with him.

Then in 2004, Gershon and the Either Orchestra went to perform at the Ethiopian Music Festival in Addis Abeba.

And Gershon finally met Mulatu Astatqe.

Gershon: Mulatu came by the hotel and said, "Hi, I'm Mulatu, what do you want to do, what do you want to see, let's hang out." And it was great. He was a great host for our band, and came to rehearsals, and then wound up playing in the concert. And then I'm reading my history books and I discover he did the same for Duke Ellington's band 31 years earlier. So I felt honored that we were the next band to get the Mulatu treatment.

That's a taste of that Either Orchestra concert in Addis, featuring Mulatu Astatqe.

Gershon: I have to say, we lose some of the original flavour that comes from Mulatu's tunes being played by Ethiopian musicians who aren't western and aren't trained in the conservatory. They have a concept of pitch and phrasing that comes out of Ethiopian singing. On the other hand, we add a lot of vocabulary that comes from our background and training, the modern jazz and latin vocabulary, and of course we have a larger group than Mulatu originally recorded this music with, so it's more orchestrated and with a bigger, more expansive sound.

Mulatu Astatqe says that the orchestration within the ten man Either Orchestra was precisely what he has been looking for.

Astatqe: I was actually thinking for a long time to hear Ethiopian music with this kind of orchestration, with this kind of great musicians. So it was really a great opportunity to meet Russ and work with this great band now.

Werman You've been back and forth to Boston over the years, a number of times, but now you're here for a year, so it feels kinda like, does it feel like a homecoming to you?

Astatqe: Oh yeah, because all this music, like Ethio-Jazz music, starts off in New York and Berklee. I mean that's where I started experimenting with all this music. So for me it's very historical to be back again, and probably try to do something different and in different directions. It's just so great to be back.

The different directions Mulatu Astatqe wants to go in include working with Ethiopian church singing, one.

And two, composing jazz with an Ethiopian tribal version of the diminished scale.

Tonight in Boston, Mulatu Astatqe and the Either Orchestra will perform together.

They'll play what they were rehearsing two weeks ago.

And they will dust off some of Mulatu's funkiness from the 60s.

Filmmaker Jim Jarmusch used a few of these Mulatu songs in the movie Broken Flowers.

A track like "Yekermo Sew" hasn't vaulted Mulatu Astatqe into stardom here in the US.

But at least it now has the status of "crowd pleaser."