Billy Bang & Kahil El'Zabar

Billy Bang was one of the truly innovative violinists of jazz.

Self-taught, his music profoundly self-imagined, he was born William Walker in Mobile, Alabama, in 1947 and grew up poor in Harlem and the Bronx. He died in April last year.

As a youth he had played some violin, but put it away before he was drafted to Vietnam at the age of 18, just before the onset of the Tet offensive.

He became a "tunnel rat" in the brutal heat of the conflict and the violence of its memory never left him. It marked his every note.

"For decades I've lived constantly with my unwillingness to deliberately conjure up the pain of these experiences," he wrote in the sleeve notes of his haunting 2001 album Vietnam: The Aftermath.

"At night, I would experience severe nightmares of death and destruction, and during the day, I lived a kind of undefined ambiguous daydream."

On his return to the US he seized the violin again, much influenced by its great swing virtuoso Suff Smith, and through the mentoring of the avant garde violin pioneer Leroy Jenkins.

Bang began recording in 1980, having co-founded the String Trio of New York in 1977 and after a stint in Sun Ra's Arkestra.

With Jenkins he became the defining artist of the free jazz violin and for the next three decades made a host of pulsating recordings, climaxing with his two sonic reflections of the epochal war Vietnam: The Aftermath and Vietnam Reflections (2004), where he sought reconciliation with the Vietnamese people by bringing together US jazzmen who were ex-combatants with Vietnamese musicians.

One of his prime recorded sessions prior to these records was the one which produced the duo album Spirits Entering in 1998 with Chicago percussionist Kahil El'Zabar, whose musical experiences stretch between his home city's blues-baked South Side and its Conservatory of Music, to Ghana.

Bang said of him: "He has such command over so many colours, whether he's playing traps or hand drums or anything else, that it almost makes me feel cheated because I've got the same old girl - I mean, my instrument - in my hands.

"He makes me try even harder to find varieties of colours and flavours on the violin."

Thus with this duo communion and emulation are forged together with simultaneous sonic beauty and discovery.

The session begins with the title track, with Bang's swirling phrases recalling Stuff Smith's humour and lithe movement and El'Zabar's snares creating a crisp, earthen rhythm - although it is his hand drums that he calls his "earth drums," soon in powerful evidence on the lyrical Sweet Irene, where Bang's folksy melody moves sinuously all around El'Zabar's thudding rhythmic centre.

Elsewhere, 2 Was Now has a stop-time formation, with Bang's bow in lightning mode and El'Zabar's rolls and flourishes keeping pace in rustling movements.

It contrasts with the mysterious opening of Love Outside of Dreams, which catches speed and upward pitch as it hurries forward.

El'Zabar's Ghanaian tutelage sparks with his playing of the mbira, or thumb piano, on The Dream Merchant with Bang's serpentine choruses creating a sonic unity which sounds much fuller than that made by just two musicians.

Song of Myself is not Walt Whitman but profoundly Billy Bang. Who knows what life memories are bursting from his solitary notes, urged on by his drum comrade's scuttling percussion.

Continents switch as El'Zabar turns to the Brazilian berimbau all through The Ituri Fantasy.

Here are two men moving through the music of three great continents as if there were no seas.

Perhaps Bang's corrosive Vietnam-ghosted notes make it four, as his bow-scraped strings wail somewhere between pain and joy.

As he asserted, playing with El'Zabarr is like "being on the same page but also getting as far from it, into creativity."

The duo achieve this by plunging deep into their own US tradition in their version of Old Time Religion, with El'Zabar's relentless hand drums and voice with the aching folk blues of Billy's violin.

The closer is the endless sublime calm of the duo's Golden Sea, a dream perhaps of peace and an end to war and misery.

It's what Billy Bang sought after the horrific jungle trauma of his late teens.

With this music of serene discovery he may have found it.