As the summer jazz festival season gears up, a glance at its sometimes crowded bills sees singers jostling for space. Jazz is a predominantly instrumental tradition and it can be tough for vocalists to get a look in. One of the exceptions is the American singer Kurt Elling, who next month plays Rotterdam's North Sea Jazz Festival, one of the biggest in the world.
When I meet Elling at the Cheltenham Jazz Festival we talk about what makes a jazz singer, and why they don't always get the respect they deserve. "We haven't been schooling the rest of the [jazz] family," he says. "We've been adding to it . . . but what vocalist changed the music in a way that Bird [Charlie Parker] did?"
The jazz repertoire has expanded way beyond songbook classics and the blues, making the definition of what exactly a jazz singer is as unresolved as ever. For singers looking for work as well as respect it's more than just a question of category, particularly when purists can smell a "sellout" at the merest hint of a vocal. As Elling pointedly remarks, a singer has to do rather more than learn the words to "Summertime".
The evening before our meeting, Elling had performed with the BBC Concert Orchestra and Guy Barker Big Band, as part of a Frank Sinatra legacy concert. Elling, like many, sees Sinatra as part of the jazz vocal tradition and points out that John Coltrane admired Sinatra's phrasing and time.
Barker, who wrote the arrangements for the concert, wasn't quite so sure. "There are things he sang that definitely weren't jazz," he says. "And things where you feel he's landing on it." Barker believes that, like great jazz instrumentalists, vocalists must "float on top of the band". "You sense everything. You feel the harmony, the rhythm, the swing, the blues. All of that." Sinatra could do it — "look at the film clip of him and Armstrong singing 'Birth of the Blues'" — it's just that he didn't do it all the time, Barker says.
Pianist Alex Webb wrote and arranged the musical play Jazz at Café Society, which traced the history of the New York venue where Billie Holiday first performed "Strange Fruit". For Webb, jazz singers don't over-emote but let the words speak. "When you listen to Holiday singing 'Strange Fruit', 'Lover Man', the emotional impact is considerable. Yet it's interesting how little energy she's putting into it," he says.
Vimala Rowe plays Holiday in Webb's play and vividly captures the experience of performing jazz. "Each time you sing a song you can change it," she says. "You can be who you want to be, in the now, in tune with the musicians around you. What a freedom that is." But to seize that freedom, you need the tools and that means putting the work in, Elling says. "You've got to get in there and wrestle. It's not just going to give itself up."
Elling was raised in Rockford, Illinois, where his father was a Kapellmeister. It was at high school that he got into jazz. "The job of the jazz musician is to find what's new," he says. "To be bound to the past, but not bound by it. That's a razor's edge to walk."
He negotiates that edge on his recent album Passion World, which is about as far removed from the classic jazz repertoire as you can get. A Highland lament is followed by the tango "Si Te Contara" while "La Vie En Rose" is sung in French and gets new English lyrics sung to the notes of a Wynton Marsalis solo. There's even a cover of U2's "Where the Streets Have No Name". Yet it feels like a jazz album.
The jazz character of a recorded vocal performance can be shrouded, but there is no mistaking it live. The North Sea Jazz Festival this year presents a strong vocal line-up alongside a populist strand that takes in Tony Bennett, Lady Gaga and Lionel Richie. Elling's performance will be followed by Detroit-born Dianne Reeves, who has just won her fifth Best Jazz Vocal Performance Grammy Award for the album Beautiful Life.
"The greatest inspiration for me was the time that I grew up in," Reeves says. "In the 1970s the music changed, there was a fusion, and I grew up as a part of that." Her album ranges from Bob Marley to a wordless original, "Tango", and her vocals are enhanced with the rhythmic inflections of soul. But there is no missing her jazz heritage. "Jazz is my foundation," she says. "That's how everything is coloured."
Reeves sees the difference between jazz singing and other styles as one of process rather than repertoire, a sensibility that can be applied to virtually any song. "A jazz singer is not someone who has a back-up band," she says. "A jazz singer is someone who shares ideas within the band, just like any horn player. We just have the ability to sing lyrics."
Also on the North Sea bill is the young American José James, who got into jazz through hip-hop. "I was listening to a lot of 1990s bands who name-dropped people like Eric Dolphy and Miles Davis, people I'd never heard of," James says. "And that opened me up to a whole world. I was always interested in how bands like the John Coltrane Quartet could create vast worlds of tension and drama that were explosive."
James's new album is the excellent Holiday tribute, Yesterday I Had The Blues. Her sound, phrasing and deep reading of lyrics made her a big influence on James, but the biggest attraction was her honesty. "She's been quoted as saying 'I never sing a song the same way twice'. And she only sang a song she believed in." Perhaps, with regard to singing jazz, that's the heart of the matter.